INQUA 2007 Abstracts

Quaternary International 167–168 (2007) 3–486

Abstracts

INQUA 2007 Abstracts

1299 Environmental Responses to Holocene Climate and Cultural Changes in South-central Chile

0503 The Potential Application of Trace Element Analysis to Distal Tephrochronology

Ana M Abarzúa1, Mario Pino2, Tom Dillehay3 1

Peter M Abbott1, Siwan M Davies2, Nicholas J G Pearce3, Jørgen Peder Steffensen4, Stefan Wastegård5

2

1

Instituto de Geociencias, Universidad Austral de Chile, Chile Instituto de Geociencias, FORECOS, Universidad Austral de Chile, Chile 3 Department of Anthropology, Vanderbilt University, United States

The Araucanian Chilean Region represents an interesting area to evaluate the human impact in the landscape, relationships with the climate changes during the Holocene. The present work describes the environmental changes in Purén-Lumaco valley (38ºS) in answer to the climate change and the intensive occupation by indigenous people (pre-Mapuche and Mapuche populations) during the Holocene. Sedimentological, palynological, and charcoal results from sediments cores of Purén peat-bog site, shows the vegetation and land use changes in the landscape previous to human occupation. The valley floor constituted an extent lake surrounded by closed Lauraceae forests, associated to plans of pollen of Nothofagus obliqua type until ~10,500 14C years BP. The most evident environmental change in the Purén record is the expansion of a Myrtle forest, drained abruptly the lake into a swamp/ bog, reflecting the dry/warm climate condition of early Holocene in south-central Chile. Later, the sediments indicate lacustrine levels with high variability, the increase of charcoal particles, and the presence of aquatic species, associated to species of Valdivian forests, with climatic conditions similar to present ones. This pollen spectrum contrasts with a strongly disturbed landscape of the area. Actually, the valley floor constitutes a complex peat-bog system dominated by grasses species and exotic forest species (Pinus radiata and Eucalyptus spp.). Some archaeological antecedents in the area document the human development as of 7000 14C years BP. The greater archaeological characteristic present in the valley is the “kuel” (a Mapuche concept that means ceremonial human earth accumulation). The presence and extension of almost 300 “kuel” in the valley reflect a certain level of social and economic development that, partly, explains why the region was a center of resistance to Spanish colonization in the XVI-XVII centuries. The influence of climate and other natural processes, and human impact on Holocene environments provide a better basis for understanding and managing the present landscape in the area, and prediction and modeling of future changes in the climate. Almost the absence of native forests in the area makes urgent strategies for the recovery and rehabilitation of a relict ecosystem that today represents their regional analog only in the tops of the Chilean Coastal Range, locally called Cordillera de Nahuelbuta. 1040-6182/$ - see front matter © 2007 Published by Elsevier Ltd. doi:10.1016/j.quaint.2007.03.000

Swansea University, United Kingdom Department of Geography, Swansea University, United Kingdom 3 Institute of Geography and Earth Science, University of Wales, Aberystwyth, United Kingdom 4 Department of Geophysics, University of Copenhagen, Denmark 5 Department of Physical Geography and Quaternary Geology, Stockholm University, Sweden 2

The majority of distal tephrochronological studies rely upon the characterisation of the major element composition of glass shards, using electron microprobe analysis, to correlate tephra horizons between sequences. However in some situations this information cannot be used adequately to discriminate between tephra horizons. This issue is becoming more pertinent due to the increased use of tephrochronology as a tool to link diverse climatic records and the continual recognition of new tephra horizons. One of the potential solutions to this problem is improving the geochemical characterisation of tephra horizons using trace element analysis. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is ideal for this purpose and can provide concentration data for up 30 trace elements. This technique has a high potential, but has rarely been applied to the analysis of single glass shards from distal tephra horizons. Here we report on preliminary experiments using a newly installed Coherent GeoLas 193nm Excimer laser ablation system at the University of Wales, Aberystwyth. To date, LA-ICP-MS has produced reliable trace element data from shards as small as 40µm in diameter. Current instrumentation has the potential to produce trace element compositions for shards ~20µm in diameter and concentrations for some trace elements from shards ~10µm in diameter. Successful application of trace element analysis to distal tephrochronology relies on two major factors, the ability to gain reliable trace element characterisations from small glass shards and a lack of spatial variation of trace element composition within individual tephra horizons deposited over a wide geographical extent. We present the results of experimental work to assess the capabilities of the Excimer system, which involved analysing basaltic and rhyolitic tephra shards between 60–10µm in diameter from Greenland ice core and North Atlantic marine sequences. The trace element compositions of these samples, previously correlated using major element geochemistry, are also explored to ascertain if consistency in trace element composition occurs within these widely dispersed tephra horizons.

Abstracts / Quaternary International 167–168 (2007) 3–486

This approach will be employed within the creation of a tephrochronological framework for the Greenland ice cores. These records potentially preserve a large number of tephra horizons that have similar major element compositions and are composed of small glass shards. However the methodological advances achieved within this study could be applied to any distal tephrochronological studies.

0686 Proxy Calibration to Instrumental Dataset: Implications for Paleoceanographic Reconstructions Fatima F Abrantes1, Teresa Rodrigues1, Cristina Lopes1, Isabelle Gil1, Helga Jonsdottir1, Ian Harris2, Lynn Witt3, Joan Grimalt4 1

0677 Sedimentation and Climatic Processes on the Tagus River System (Portuguese Margin) Fatima F Abrantes1, Teresa Rodrigues2, Geert-Jan Vis3, Ulrich Alt-Epping4, Antje Voelker5, Isabelle Gil6, Susana Lebreiro7, Ralph Schneider8 1

Departamento de Geologia Marinha, INETInovação, Portugal Departamento de Geologia Marinha, INETInovação, Portugal, Portugal 3 Institute of Earth Sciences, Free University of Amsterdam, The Netherlands, The Netherlands 4 Universitaet Bremen (GeoB), Germany 5 Departamento de Geologia Marinha, INETInovação, Portugal, Portugal 6 Departamento de Geologia Marinha, INETInovação, Portugal, Portugal 7 Departamento de Geologia Marinha, INETInovação, Portugal, Portugal 8 Marine Palaeoklimaforschung, Institut fuer Geowissenschaften, ChristianAlbrechts-Universitaet zu Kiel, Germany 2

To investigate the linkage of marine and terrestrial processes and the past climatic oscillations, that have occurred in the North Atlantic, on the Tagus River system, river discharge, sedimentation processes, Sea Surface Temperature (SST) and biological productivity were reconstructed through a multi-proxy study, in decadal-to-centennial scale resolution, from sediment cores collected on the Lower-Tagus floodplain, the shelf mud complex and the Tagus Canyon levee. Land crosssections show a transgression in the Early-to Middle-Holocene with maximum flooding until ~5700 Cal yr BP. After ~5700 Cal yr BP, the fluvial system is marked by a prevailing progradation and after 2000 Cal yr BP a strong increase in sedimentation is noticed. Synchronous with the rapid infilling of the upper estuary, the shelf sedimentation rate increases by four times, while the Tagus canyon, marked by high terrigenous input and increased turbiditic activity during the glacial becomes starved during the Holocene. On the shelf mud complex, the record covers the last 14,000 Cal yr BP and the SST profile reveals the well known major climatic events, the Allerod/Bølling interstadial at the bottom of the sequence, the Younger Dryas SST minimum, a maximum SST Holocene Optimum (HO) and a 4ºC-cooling trend from the HO to the Present. On a century scale, the 2ºC SST variability during the last 2000 Cal yr BP allows the identification of the Medieval Warm Period (MWP) and the Little Ice Age (LIA). The MWP mild centuries reflect the occurrence of coastal upwelling conditions, while the LIA appears associated with an increased influx of terrigenous material. Based on the excellent match found during the last century between negative phases of the North Atlantic Oscillation (NAO) index and intensified Tagus River discharge, we hypothesize a period of negative NAO-like state or the occurrence of frequent extreme NAO minima during the LIA, while positive NAO-like state or the frequent occurrence of extreme NAO maxima should have marked the MWP. Furthermore, a major peak in magnetic susceptibility, 90 cm below the surface of the mud complex, is interpreted as a record of the 1755 AD Lisbon earthquake and accompanying tsunami. Such events are estimated to have eroded 39 cm of sediment (355 years) and instantaneously deposited a 19-cm sediment bed towards the SE, while a loss of 461 years and an instantaneous deposition of a 150-cm sediment bed are found to the W of the river mouth.

Marine Geology Department, INETInovaçao, Portugal Climatic Research Unit, University of East Anglia, UK, United Kingdom 3 Pacific Fisheries Environmental Lab, United States 4 Department of Environmental Chemistry, Institute of Chemical and Environmental Research (CSIC), Spain 2

Forecasts of future climatic trends depend on widespread accurate and quantitative records of past climate. More and independent reconstructions, based on improved proxy records, are needed to understand the last centuries climatic variability, and estimate whether 21st-century warming is likely to be nearer the top or the bottom of the latest IPCC range of 1.4 oC – 5.8 oC. A multiproxy analysis of two high-sedimentation shallow water sedimentary sequences recovered off Lisbon (Portugal) provide a view of continental climate, oceanic conditions and biological response over the last 100 years. Sea Surface Temperature (SST) is derived from alkenones, upwelling strength indicated by diatom abundance, river input and indirectly precipitation, are indicated by Fe concentration and Sea Surface Salinity (SSS) derived from planktonic foraminifera isotopes. The comparison of these generated proxy records to long-term instrumental time series of marine and atmospheric parameters (SST, Sea Level Pressure, Precipitation, River Flow and Upwelling Intensity) provide important information relative to the validity of those proxies. Besides, the statistical relation between the different proxy records and the River Flow and Upwelling Intensity is investigated through multiple regression, with the aim of making available a function to quantitatively reconstruct those processes back in time. 0268 The Impact of Human Activities in Africa, The North and South Pole Regions on Global Climate Change Babagana Abubakar Independent Researcher, Nigeria

As a result of the rapid increase in the petroleum exploration, Industrial, deforestation and other human activities going on within or around the Arctic and Antarctica ice caps near or in the temperate region countries like Canada, Greenland, Russia, U.S.A (Alaska), Iceland, Finland, Argentina, Tasmania and New Zealand among many others plus the increase in deforestation activities in Tropical world countries like the Amazon of Brazil, The Tropical Rain forest of Nigeria, Zaire (Democratic Republic of Congo), Côte d’Ivoire, Indonesia etc. in addition to the Sahara and the Kalahari deserts encouragement as a result of human factors plus the uncontrolled disposals of broken Refrigerators, Air conditioners and propellants containing chlorofluorocarbon substances capable of destroying the Ozone layer in African refuse dumps (B.Abubkar, 2006) are collectively becoming a threat to the world climate. This explains why the volume of the Ocean keeps on rising, global temperature keeps ascending and the global climate is becoming abnormal since the beginning of the above mentioned activities in the above mentioned locations. It was in view of the above that this research was conducted and came up with the under listed suggestions/recommendations:


1. The temperate region countries like Canada, Russia, U.S.A, Argentina etc. should come up with polices restricting certain industries with the possibilities of causing environmental hazards from operating near the Ice Caps of the Arctic or Antarctica even in areas which the Ice was frozen thousands of years ago as the case with Greenland. 2. The research and exploration activities going on around or on the Arctic and the Antarctica regions should be carried out with utmost care and concern to the global climate. 3. The International Maritime Organization (IMO) should check and control the Ocean Pollutions caused as a result of the degreasing activities of the “QUAY APRONS” currently going on at the various African Sea Ports in order to protect the Ocean pollution with chemicals that can make the World’s ice to be melting. 4. Organizing seminars, Conferences and Workshops on a regular basis by the United Nations and other related organizations can help in the areas of public enlightenment and the education of the rural populace who are also great contributors to the situation. 1438 Calcic and Petrocalcic Horizons from Coimbatore Area, Tamil Nadu: Micromorphology and Geochemistry Hema Achyuthan, Navin Shankar Department of Geology, Anna University, India

Calcic and petrocalcic horizons form important litho units in the colluvial soils and over the bed rock around Coimbatore, Tamil Nadu. In this paper, we present geochemistry and micromorphology (petrography and SEM data) study of these lithounits. Petrocalcic horizons are formed over dolomite limestone, amphibolite gneisses and charnockites of Precambrian age. Understanding the formation of calcic and petrocalcic horizons is important to paleoclimate studies because this area falls in the rain shadow region due to the Western Ghats and the Palghat gap acting as a prominent barrier. The area receives both the southwest as well as northeast monsoon rains. In the study area the calcic horizons represent the Bk horizon that occur as thick complex profiles (~300 cm thick) in the foothill regions while the laminar petrocalcic horizon (80 – 100 cm thick) formed on bedrock occur in the topographic low lying area. Calcic horizons are powdery, nodular and rhizoliths with 95.2 % to 64.5% of CaCO3. The 13C values vary from −5 to −5.6‰, 18O values vary from −5.3 to −5.1‰. Petrocalcic horizons are compact with well rounded coalesced nodules and contain 56 – 64% CaCO3. The 13C values vary from −0.1 to −1.2‰, 18O values vary from −5.8 to −6.4‰ indicating the near surface formation with a thin veneer of soil cover. The trace metal data indicate higher concentration of Zn and Ni in calcic and petrocalcic horizons. Micromorphology study and scanning electron microscopy of the calcic horizons show features such as alveolar septal structures, calcified filaments, coated grains, spherulites, calcified root cells and calcispheres that indicate the biogenic origin mainly induced by plant root related microbial activity. They consist of quartzose sand grains cemented by fine crystalline, glaebular, grain-coating and pore-filling micrite. This development took place in phases of soil formation, erosion and reworking. The inter-relationships between these processes caused the formation of different cumulative soil profiles with calcic nodules in the foothill region. Microfabrics of laminar petrocalcic horizon with detritus hosts show evidence of replacement, displacement and shrinkage indicating that the laminar petrocalcic horizon formed under relatively semi arid

conditions. These characteristics reflect that the laminar petrocalcic formed in a relatively near-surface environment with relatively high rates of evaporation and ground water action. 0925 High-resolution paleoceanographic records from the Gulf of Alaska, Northeast Pacific Ocean: Inferring Holocene changes in the Aleutian Low Pressure system Jason A Addison, Bruce P Finney University of Alaska - Fairbanks, United States

The Gulf of Alaska (GoA) is the northeastern-most sector of the Pacific Ocean, and serves as an important region linking climatic change between the Arctic and Western North America. The GoA is in turn influenced by climate regimes in both the Equatorial Pacific and the Northwest Pacific. However, the Quaternary history of the Gulf of Alaska remains poorly constrained, and what data exist are derived primarily from short-term terrestrial and ice-core archives. This study seeks to use one of the most comprehensive sets of marine sedimentary cores recovered from this area to describe the paleoceanographic evolution of the GoA over the Late Quaternary using an extensive suite of isotopic and biogeochemical datasets. Furthermore, because the proximal St. Elias Range serves as an effective orographic barrier to precipitation derived from the Gulf, and due to high biological productivity, this region is marked with one of the highest sedimentation rates in the world permitting rare high-resolution geochemical analysis. Using a combination of bulk sedimentary organic carbon, opal, 13C, 15N, and C/N ratios of organic matter as indicators of biogenic and terrigenous influx, we have reconstructed changes in productivity and terrestrial runoff. During the period of instrumental records, periods with a stronger Aleutian Low pressure system are related to both enhanced productivity and higher precipitation and runoff. Marine biological proxies indicate periods of increased diatom-dominated primary productivity associated with both the Little Ice Age (LIA) and the Neoglacial periods of the Holocene, while reduced productivity is observed during the Medieval Warm Period and the Hypsithermal. Periods of increased runoff are also inferred during the LIA and Neoglacial. Using these biogeochemical records, a marine-based Holocene record of the Aleutian Low has been developed that indicates oscillating variability during the Little Ice Age and the Neoglacial on 70- to 80-yr frequencies, agreeing with previous terrestrial-based studies. A weakened Aleutian Low system is also inferred during the Medieval Warm Period, further in agreement with prior studies. Correlations between transition metals (e.g. V, Cr, Co, Ni, Cu, & Zn) and biological proxies also indicate changes in biogeochemical cycling at frequencies similar to those of the Aleutian Low variability, suggesting a coupling exists between the redox conditions at the sediment-water interface and regional climate cycles. 0147 Sedimentology and Geomorphology of a Pleistocene Wetland, Dakhleh Oasis, Western Desert, Egypt Katherine A Adelsberger, Jennifer R Smith Washington University in St. Louis, United States

Lacustrine, spring, and fluvial sediments preserved in the currently hyperarid Western Desert of Egypt document pluvial, or humid, climatic phases that have recurred throughout the Quaternary. In Dakhleh Oasis iron-rich spring sediments record enhanced outflow from the Nubian


Aquifer, whereas carbonate sediments overlying these iron-rich deposits formed during a later lacustrine phase of surface runoff and more localized pluvial input. Previous investigators recovered both Acheulian and Middle Paleolithic artifacts from spring mound sediments, indicating that this groundwater-dominated environment was utilized by hominin groups during the Pleistocene; the wetlands of Dakhleh may have been an important resource for early human groups moving north through what is now the Western Desert. Spring mounds occur as isolated hills of Cretaceous age shales capped by iron-rich silts and sands and iron precipitates, often preserving vegetation casts. Microstratigraphic investigations reveal that basal units are goethite- and jarosite-stained silts, which variably underlie goethite-cemented sands and ferricrete. Sedimentary units are laterally discontinuous, indicating isolated deposition of similar units at spring vents and localized ponds supporting vegetation. Mound formation was likely controlled by the regional potentiometric surface and variably vegetated landscape; silt deposition would have been limited to areas of direct groundwater discharge, whereas vegetation would have served as a trap for aeolian sands. The combination of these depositional systems led to sand-rich mounds in vegetated areas while lower, silt-rich mounds formed near spring vents. The height of sandy mounds would be limited only by the depth of local root systems and their ability to reach subsurface water sources, allowing these sand catchments to build above the local potentiometric surface. In contrast, silt deposition would be limited to areas of direct discharge and ponding of surface water, leading to a paleoenvironment with significant topographic variability. The most likely modern analog for this Pleistocene wetland environment is the modern mound-forming springs of Queensland, Australia, where recent studies indicate groundwater discharge leads to the formation of mounded wetland complexes that build within the limits of local hydrostatic head gradients. A comparison of these environments suggests that topographic irregularities may have been an inherent characteristic of the original Dakhleh wetland, and not necessarily a product of erosional hiatuses in mound formation as previously suggested. Reconstruction of these features provides a more accurate paleohydrologic model of Dakhleh Oasis while furthering our understanding of the habitability of the Sahara during the Pleistocene. 0426 Holocene environmental change physical and Human perspective on sabkhat Al Jazirah Al Hamrah, northern UAE Asma M Al-Farraj1, Andrew Goudie2 1

UAE University, United Arab Emirates United Kingdom

2

Coastal areas one of the most affected zones by human activities, as a fact of two thirds of the world’s population lives on the coastal zone. Al Jazirah Al Hamrah on the north coast of the UAE serves as a typical example for sabkha (supratidal) environmental changes in response to physical and human impact. There are at least two environmental problems in the study area; invasion by exotic species, and loss of habitat. Both are resulted from transformation of coastlines by standardised construction of tourist accommodation. Three lines of data have been used in this study to determine environmental changes on sabkha; sedimentlogical analysis, aerial photos analysis archaeological data analysis. Sediment analysis and archaeological data used to investigate physical perspective. The aerial photos analysis used to trace human impact. The results show that the Man used to follow the Nature rules until the 1980 of the 20th century. But, during the 1980s and 1990s the nature followed the man roles. During the beginning of the 21st century the Nature rules have vanished. However, from comparing this

situation elsewhere indicates that the nature rule may takeover again, by silent slow drown of the area. As a result of being built on geologically immature landscape (sabkha). 0910 An Automated Pollen Recognition and Counting System Gary P Allen, Robert M Hodgson, John R Flenley, Stephen R Marsland, Rory C Flemmer, Greg Arnold, David W Fountain Massey University, New Zealand

STUDY PURPOSE: An automated pollen classifier and counter has been developed and tested. Automation of Pollen classification and counting removes the drudgery involved in manually identifying and counting pollen on microscope slides. It allows the researcher to gather more data using the time saved and minimises human error providing a less variable result. Amongst many other important uses of pollen identification, is the estimation of past climates. A system that is affordable by most modest laboratories is an aim of the project. RESULTS: AutoStage, including controlling software and image processing algorithms has been tested as a working unit by preparing four slides in a manner similar to present practice for manual counting, and comparing counts of classified pollen on the slides by five expert palynologists with four counts of classified pollen of each slide by AutoStage. These initial results are very good indicating a system that would already have some uses in a laboratory. The AutoStage count result is on average slightly lower than humans but with clear methods of improving this, however variation in counts is significantly improved. METHODS: AutoStage uses a digital imaging microscope on a computer controlled XY stage with auto-focus. Pollen are segmented in a series of images of the slide and high resolution images of each pollen obtained for mathematical feature extraction. An artificial neural network is trained using features extracted from pollen identified by expert palynologists. The trained neural network uses the features from pollen images from a slide, to classify the those pollen grains. A count of each pollen type is presented to the user with matrices of sorted images for verification by the user. CONCLUSIONS: The prototype automatic pollen classifier and counter developed is useful and inexpensive, giving comparable results to expert palynologists counting a known variety of pollen on microscope slides. It is highly configurable with a variety of uses within palynology and for small and microscopic object automated analyses. 0813 The terrestrial Eemian in Southern Italy Judy R M Allen1, Brian Huntley2, Achim Brauer2, Jens Mingram2 1

Durham University, United Kingdom GeoForschungsZentrum Potsdam, Germany

2

The palaeoenvironmental record from Lago Grande di Monticchio, Basilicata, southern Italy was extended by the recovery of a new set of mid-lake piston cores in summer 2000. Analyses of the 30m of new material, matched to the previous records by microstratigraphy and tephra layers, have extended the previous detailed record back into the Saalian glacial. Most of the Late Saalian and Eemian material is varved giving a detailed chronology of this interval which extends the previously published sedimentation rate chronology to ca. 132 ka BP. Pollen is well preserved throughout this sequence and pollen analyses at an average temporal resolution of ca. 130 years allow detailed exami-


nation of the vegetation changes during the terrestrial Eemian, as well as during the transitions into and out of the last interglacial, in this region. Using the pollen data and the chronology we are able to provide independent dates and hence durations for the Eemian interglacial and its transitions. This independence allows us to compare critically this site with other records of this interval and to make inferences about the climate system. 0814 Investigating the potential role of available food resources in Late Quaternary megafaunal extinctions across northern Eurasia: a new approach Judy R M Allen1, Brian Huntley1, Tony J Stuart2, Adrian M Lister3

It has also been tried to overcome the difficulties scaling the scan maps and fitting their coordinates in the said software and also Surfer software to do the relevant manipulations in order to eventually obtain a method and a working pattern for a sustainable development. In comparative studies of this research for the first time the evidence for the existence of ice-caps in sunny valleys of SHIR-KUH mountain with a large ice cap in the fourth period using the Write’s (1963) method has been established. The beginning of civilization from the lowest zero line in six cold months of the year is very similar to Zefrah region in Isfahan. 0896 Precipitation patterns during MIS2-3 glacial advances in South Island New Zealand

1

Durham University, United Kingdom Durham University/University College London, United Kingdom 3 University College London, United Kingdom 2

Peter C Almond1, Philip Burge2, Fiona L Shanhun1, Carol MS Smith1, James Shulmeister2, Kevin Faure3 1

During the late Weichselian and the transition to the Holocene a number of megafaunal species, such as Megaloceros giganteus (giant deer), Mammuthus primigenius (woolly mammoth), Ursus spelaeus (cave bear) and Crocuta crocuta (spotted hyaena), became extinct across northern Eurasia and in some cases globally. These extinctions have been variously attributed to human activity and/or to habitat changes. In this project we are investigating these events by developing a novel approach to estimating, from pollen data, available food resources. Using the LPJ-GUESS dynamic global vegetation model, that simulates the responses of vegetation and ecosystems to climatic and environmental variation, and pollen data from a suite of surface samples and Late Quaternary stratigraphic profiles, we are developing calibration models relating important ecosystem properties, such as biomass, biomass fractions and net ecosystem productivity, to the composition of the pollen spectra. These models will then be applied to estimate the properties of late Weichselian and Holocene ecosytems in Northern Eurasia. 0099 Quaternary change – Ice Caps in Central Mountains of Iran— Sakhvid Basin SA Alhoseini Almodaresi1, MH Ramesht2, MH Mobin3 1

Geography Department of Isfahan University, Iran Geography Department of Isfahan University, Iran 3 Faculty of Natural Resources Yazd University, Iran 2

The nature of different forms and outside functions of the Earth basically depend on the environmental conditions ruling the particular region in a given period. Therefore the effects and the evidence for environmental changes from the fourth period the most important of which the remains of that period, have created considerable and very special verity in geomorphological studies and with taking these into consideration, one can reconstruct the environmental evidence. Although ice-cap studies has been attributed to BOBEK’s studies in but some great Iranian researchers especially, in the past decade have worked on stronger empirical researches and reached greater achievements concerning the fourth period environmental conditions of Iran. In the present study which considers the water basin sakhvid located KM south west of Yazd it has tried to carefully study the obtained data, climate, geology, hydrology, geomorphology, environment, economic, cultural and sociological characteristics and specifically the local knowledge of Sahhavid region the mutual impacts and functional characteristics utilizing the most up-to-date software namely Arcview GIS.

Division of Agriculture and Life Sciences, Lincoln University, New Zealand Department of Geological Sciences, University of Canterbury, New Zealand 3 Rafter Isotope Laboratory, GNS Science, Gracefield, New Zealand 2

Two hypotheses are presented to explain the timing and nature of glaciation in New Zealand (NZ). One emphasises the importance of temperature depression reducing ablation, whereas the other invokes precipitation increases that fuel ice production. To explore the role of precipitation in NZ glaciation we present two quantitative paleoprecipitation records covering ca 35–22 ka, one from the west and the other from the east of the Southern Alps. The eastern record (present MAR 700 mm) derives from stable isotope analysis (13C) of pedogenic carbonate in loess, while the western record (present MAR 2190 mm) is based on fossil beetles from a peat. As demonstrated by the instrumental record, distinct circulation patterns across the NZ region produce contrasting precipitation behaviour either side of the Southern Alps. We interpret our paleoprecipitation records in light of these patterns and infer the circulation modes prevailing during glacial advances. The paleoprecipitation records indicate an antiphase relationship between precipitation east and west of the Southern Alps. Around 35 k cal. yr BP rainfall is ca 20% less than present on the east coast and similar to present day on the west coast. Between 33 and 26 k cal. yr BP rainfall increases to at least present day levels on the east coast and is around 50% less on the west coast. Between 26 and 22 k cal. yr BP the east coast is 30% drier than present and the west coast shows a trend of increasing wetness. NZ glaciers advanced between 30 and 27 k cal. yr BP (1 major advance) and between 25 and 19 k cal. yr BP (2 major advances). The 33–26 k cal. yr BP dry west coast/moist east coast phase indicates a reduction in zonal westerlies and increasing importance of a meridional (southerly) circulation component. Precipitation over the Southern Alps may well have been less than present day under these conditions, suggesting a significant role for temperature depression during the earlier advance. The wet west coast/dry east coast phase between 26 and 22 k cal. yr BP indicates an enhanced zonal (westerly) flow when compared to today during the later advances. The increased precipitation over the Southern Alps that would have resulted could have supported glacial advance with less temperature depression than during the 30–27 ka advance. The data suggest a complex and temporally variable relationship between precipitation and temperature determines NZ glaciation.


0032 Environmental impact of the 73 ka Toba eruption reflected by paleosol carbonate carbon isotope ratios in central India Stanley H Ambrose1, Martin A Williams2, Umesh Chattopadhyaya3, Jaganath N Pal4, Parth Chauhan1 1

United States University of Adelaide, Australia 3 India 4 India 2

The explosive volcanic eruption of Toba, northwest Sumatra, 73 ka, coincides with the sudden onset of the coldest 1500-year-long stadial of the Upper Pleistocene (Stadial 19/20) in Greenland ice cores, and with harsh boreal environments in the Grande Pile pollen record in France. Toba ash occurs in Indian Ocean cores as far west as the Arabian Sea, and beds up to two meters thick occur in terrestrial sediments in central India. In order to evaluate the impact of this eruption on tropical terrestrial environments we analyzed the stable carbon isotopic composition (13C/12C) of 97 paleosol carbonate nodules and root casts in three localities with Toba ash in the Son and Narmada river valleys of central India. Trees, shrubs, most dicotyledous herbs and shade-tolerant grasses use the C3 photosynthetic pathway and have low d13Cpdb values, averaging –26‰. Tropical grasses that are adapted to strong sunlight, high temperatures, aridity and low atmospheric CO2 concentrations use C4 photosynthesis and have higher d13C values, averaging –12‰. The carbon isotope ratio of pedogenic carbonate reflects that of the floral biomass with an enrichment of 14 –17‰. Pedogenic carbonates formed under forests thus have d13C values of –12‰ to –9‰, while those formed under C4 grasslands range from – 1‰ to +2‰. In the Khunteli section the d13C values of samples beneath the ash average –11.9 ± 0.7‰, –5.8 ± 3.2‰ in the first 1.7 m above the base of the ash, and decrease to –11 ± 3.5‰ above 1.8 m. At Rehi they average –9.3 ± 2.6‰ below the ash and –5.9 ± 3.2‰ from 1.7 to 4.8 m above the ash. At Hirapur they average –9.7 ± 0.2‰ below the ash, –6.3 ± 0.2‰ at 42-45 cm, and 10 ± 0.2‰ 90–110 cm above the ash. In all localities, d13C values of nodules beneath the Toba ash show that it fell on nearly pure C3 habitats that were probably forested. High values for nodules within and immediately above the ash show that the post-eruption floras were dominated by tropical C4 grassland to wooded grassland habitats. The subsequent decrease in d13C values in two sections indicates C3 forest habitats were eventually reestablished, probably with the onset of the warm climate of Interstadial 19. We conclude that Toba caused widespread deforestation in central India. The environmental impact of this super-eruption may have initiated the population bottleneck evident in the genetic structure of modern human populations. 0765 Fine-resolution palaeoclimatic reconstruction of abrupt events within the past 1000 years from ombrotrophic peat bogs in northwest Europe

‘signal’. Here we present research that aims to determine whether fineresolution, multi-proxy analyses from ombrotrophic bogs with high rates of accumulation can accurately reflect sub-decadal palaeoclimatic change. There is currently a significant gap between the established decadal resolution used in peat-based research and annually resolved sources of palaeoclimatic evidence used to corroborate the record. By focusing on time-slices within the past 1000 years, this research offers the chance to investigate both an interesting period of climate change and a pressing methodological question. We present two sets of results. Firstly, three fine-resolution, multi-proxy (testate amoebae, peat humification and plant macrofossil analyses) palaeoclimatic records from sites in England, Germany and Sweden have been produced that span abrupt climatic deteriorations coinciding with the period of the Little Ice Age. Secondly, a further fine-resolution, multi-proxy record from Sweden spanning the period c.1865 – 1950 has been compared with a local instrumental climate record in order to validate the fine-resolution methodologies used and to investigate the climate parameters forcing the bog surface wetness record. Initial results show significant correlations with the instrumental record which suggest that it may be possible to push forward the ‘ultimate resolution’ of the peat-based proxy-climate record. 0059 Modeling artificial recharge of groundwater tables using GIS and RS Fazel Amir, Tayebeh Tabatabai Islamia Azad University, Iran

Flood management is important to recharge ground water tables in dry land regions where the agricultural and range lands are vulnerable to soil erosion. Remote sensing (RS) and Geographic Information systems (GIS) are effective and efficient techniques in watershed management and flood distribution over rangeland. To achieve this goal, in the first step a topographic map in 1/25 000 scale of the study area was digitalized by ILWIS program to provide a contoured map. Using the contoured map, the slope and aspect maps as well as the digital evaluation model (DEM) of the site were prepared. In the second step the satellite images (TM bands 1–7), area photos of 1/40 000 scale and data obtained from the field visits were used to provide the soil, slope, aspect and land use maps of a research site in south Isfahan province were prepared and water feeding sites were identified using a GIS system. The results indicated that out of 8545.48 ha of total study area only around 95.06 ha (1.2%) was suitable for water spreading and artificial water recharge practices. It was also concluded that the application of RS and GIS were the most applicable means to identify the artificial water recharge sites. 0060 Modeling Soil erosion and sedimentation by EPM model in the Central Part of Iran Fazel Amir1, Mohammad Reza Chaichi2, Tayebeh Tabatabai1

Matthew J Amesbury, Keith E Barber, Paul D Hughes

1

Islamia Azad University, Iran Tehran University, Iran

University of Southampton, United Kingdom

2

Abrupt Holocene palaeoclimatic events are a current research focus and may occur on decadal or sub-decadal time-scales. They are identified, but cannot be well characterised, by current peat-based palaeoclimatological methods. While recent research has demonstrated climatic control of ombrotrophic bog stratigraphy, it is possible that at fineresolution, autogenic factors or ‘noise’ may override this allogenic

Lack of information to prepare erosion maps for quantitative and qualitative sediment evaluation is a major need in watershed management in Iran. The goal of this study was to use EPM model and apply GIS to minimize the probable errors in evaluation of soil erosion and sedimentation in Ghareh Aghach watershed in central part of Iran. To achieve this goal, in the first step a topographic map in 1/25 000 scale


of the study area was digitalized by ILWIS program to provide a contour map. Using the contour map, the slope and aspect maps as well as the digital evaluation model (DEM) of the site were prepared. In the second step the satellite images (TM bands 1–7), aerial photos of 1/40000 scale and data obtained from the field visits were used to provide with geological, geomorphologic, vegetation cover, pedological and land use maps of the study area. By integration of geological, facies and slope maps and classifying them in 6 categories (0 –5%, 5 – 10%, 10 –20%, 20 –30%, 30 –40% and >40%), 174 homogenous uniform sampling units were identified to apply MPSIAC model. Model information layers comprised nine effective factors in erosion and sedimentation in the watershed site were obtained by digitalizing and classifying the basic information data in GIS program. In frequent field visits all the necessary data for EPM model were collected, checked and improved in 174 homogenous and uniform sampling units. Following of finalizing the information layers, all of them were integrated to create the final erosion map. The results of MPSIAC model indicated that 60.8% (5444.28 ha) of the total watershed area was classified at class III of erosion category with medium sedimentation and 39.2% (3510.36 ha) was classified at class IV of erosion category with high sedimentation, respectively. Basin erosion and sediment was calculated as 71169.5 ton/yr and 29260.42 ton/yr by MPSIAC model, respectively. 0373 Permanent Quaternary Hyperaridity in the Negev, Israel: Resulting from regional tectonics blocking Mediterranean frontal systems Rivka Amit1, Yehouda Enzel2, Sharon David3, Onn Crouvi3, Eric McDonald4, Ori Simhai3, Ari Matmon5 1

Geological Survey of Israel, Israel Hebrew University, Israel 3 Israel 4 United States 5 Institute of Earth Sciences, Hebrew University, Israel 2

Although various episodes of wetter Quaternary climates in the Negev were suggested in many studies in the Negev desert, here we demonstrate that Reg soils – developed on flat alluvial surfaces – sensitive to minor changes in precipitation indicate that the southern Negev has been permanently hyperarid at least since the middle Pleistocene. The wetter episodes were restricted to the northern Negev currently mildly arid. Gypsic-saline Reg soils that developed on stable surfaces during 200 ka in the southern Negev are cumulative and polygenetic, but none exhibits even the weakest development of calcic horizons. Under current climatic conditions in the Negev, calcic soils are widespread in areas with rainfall >80 mm yr−1. This indicates that the hyperarid southern Negev (100 m high are present within the Ouarzazate foreland basin along the southern margin of the Central High Atlas record a history of sedimentation and denudation that allow rates of denudation and sediment transfer to be determined. Using geomorphic mapping, sedimentology and terrestrial Be-10 cosmogenic radionuclides, the history of sedimentation and erosion within a stretch of the Ouarzazate Basin is reconstructed. The pediments and terraces in this region date from the Holocene to 250 ka. The pediment and terraces sediments were deposited during interglacials (marine isotopes stages 9c, 7e, 5e and 1) and were subsequently eroded during glacials. The terrace and pediment incision was controlled partially by a drop in base level as the outlet channel, the Draa River, progressively cut through the Anti-Atlas to the south of the Ouarzazate foreland basin. The pediment and terrace formation, however, was strongly modulated by climate change on glacial-interglacial timescales as the base level dropped due to the incision of the Draa River through the Anti-Atlas. These data clearly demonstrate a climatic control on sediment transfer and landscape denudation in this region during the Quaternary and provide a model for understanding sediment transfer in other intracontiental mountain belts. Furthermore, these data


show that mean rates of fluvial incision in this region range between 1 to 0.4 mm/a for the latter part of the Quaternary, suggesting that rates of mountain uplift is 0.78 Ma) glaciations in the southern Interior Plains of Canada has not been found. Earlier work in southern Alberta, southern Saskatchewan, and Northern Manitoba identified only normally magnetized (Brunhes Chron) glacial and Interglacial sediments. The Saskatchewan borecore data reveal two reversely magnetized lower tills (Mennon and Dundurn Formation) overlain by a sequence of 5 normally magnetized tills. Low carbonate content and elemental analyses suggest that the reversely magnetized tills were laid down by ice which moved predominantly from the north. Several outcrops of glacial sediments on the Horton Plateau northwest of Great Bear Lake were sampled for paleomagnetic analysis and provide the first evidence of reversely magnetized tills on the mainland of the northernmost Interior Plains. Four reversed tills overlain by two normal tills allow for a preliminary correlation with the Mackenzie Delta borecores, and taken together, these records indicate that continental ice was present in the northwestern Interior Plains in the early Matuyama, in contrast to the central Interior Plains of Canada where continental ice first appeared in the late Matuyama, and to the south where it was apparently absent entirely during the Matuyama. The early glaciations in the Horton Plateau region appear to have been locally sourced, as the tills do not contain Canadian Shield erratics. This, and the evidence for northern

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sources of ice for the earliest glaciations in the Saskatoon area suggest that continental ice sources were perhaps very different during the Matuyama, as compared to those of the Brunhes Chron. New data from both northern and central localities within the Interior Plains suggest that the timing, extent, and source of continental ice sheets varied considerably in the Interior Plains of Canada during the Quaternary.

0831 Carbon from biogenic opal: tracing changes in the carbon cycle using proteins in diatom silica Philip Barker1, Elizabeth Turner1, Melanie Leng2, Alayne Street-Perrott3, Dirk Verschuren4 1

0009 Archaeological site stratigraphies as geoarchives for testing models of tsunami event periodicity during the Holocene — case studies from Western Australian shorelines Anthony Barham, Sue O’Connor RSPAS, Australian National University, Australia

The coastline of Western Australia (WA) is recognised as being at high-risk from earthquake-generated tsunami. Four tsunamis have impacted on the shoreline during the last 50 years, including events on the Kimberley coastline with wave run-ups of 4-6m in 1977 and 1994. The documented European historic record of tsunami and cyclone-generated storm wave events is typically short, 50 to 10m), estimated to have return periods of 400–500 years by Nott and Bryant (2003). Our methodology arrays archaeological site data according to its potential to map the presence/absence of high energy extreme wave impacts. It includes site types which would not survive high-energy wave impact (such as built structures, walls and shell mounds) as well as well-stratified occupation deposits which are sensitive to burial, deposit-mixing or removal by wave run-up, and associated backwash. Rockshelter sequences close to AHT display episodes of deposition and hiatus against which event-dates suggested for palaeo-tsunamis can be tested. Many archaeological contexts exist where reworking is manifest – attributable to many geomorphic processes – of which tsunami or major storm wave impact activity is just one. We conclude a) better facies interpretive protocols are needed for shell and coral-rich sand deposits located within modelled palaeo-tsunami run-up zones and b) shoreline archaeological site stratigraphies should be viewed as “geoarchives”, with inherently high chronological resolution and facies sensitivity to high energy wave events, which can be used for improving strategic models of tsunami risk and strategic planning.

Lancaster University, United Kingdom NERC Isotope Geosciences Laboratory, Keyworth, Nottingham, United Kingdom 3 Swansea University, United Kingdom 4 Ghent University, Belgium 2

Stable carbon isotope analysis of lake sediments is routinely used to trace changes in lake productivity and carbon sources. One problem with this approach, especially in smaller lakes, is that inputs of higher plant materials with diverse carbon isotope signatures may overwhelm the algal signal so that changes in the supply of dissolved biogenic carbon or productivity are difficult to discern. Here we present stable isotope data from proteins included within the silica of lacustrine diatom frustules, which have the potential to overcome source influences and instead will record changes in dissolved carbon supply and utilisation. This method has previously only been used on marine sediments where different controls on isotopic fractionation apply. Modern samples from lakes have shown strong correlations with the supply of dissolved biogenic carbon from catchments (CO2) and lake productivity surrogates (Chla, P, Secchi depth). Here, we will illustrate our approach using core materials taken from Mt Kenya and Mt. Kilimanjaro, together with modern diatom samples. These lakes are the subject of intensive palaeoenvironmental investigations providing well-dated multiproxy data sets and are known to be sensitive to shifts in the carbon cycle. First stable isotope results from diatoms preserved in cores from Simba Tarn (Mt Kenya) and Lake Challa (Kilimanjaro) will be presented and compared with supporting data from these sites. We hypothesise that these proteins will reveal changes in lake carbon cycles on Quaternary time scales that will help to identify periods when these tropical lakes were net carbon sources or carbon sinks. Moreover, this approach adds to the growing arsenal of stable isotope methods hosted by biogenic silica.

0524 The role of ancient DNA in understanding glacial refugia Ian Barnes Royal Holloway, University of London, United Kingdom

An understanding of glacial refugia is of fundamental importance to Quaternary studies, contemporary conservation policy, and theoretical biology. Recent technical developments in a range of fields have provided new methods to resolve the timing and development of refugia, with the use of DNA recovered from palaeontological materials, ancient DNA, one of the most prominent. Here, I will discuss how the use of ancient DNA may provide additional insight into the mechanisms that underpin refugia, summarising the data so far generated for mammalian megafauna, and other species. I will also discuss how currently unpublished data from studies of brown bear (Ursus arctos), and woolly mammoth (Mammuthus primigenius) highlight the utility of ancient DNA in this context – combining the temporal resolution possible from radiocarbon dating, with the taxonomic resolution of molecular genetics.


0452 Constraining the Late-Quaternary glaciation extent in Kamchatka by combining geomorphology and an empirical shape–characterisation for modern ice masses Iestyn D Barr, Chris D Clark, Felix Ng University of Sheffield, United Kingdom

Controversies surround the Quaternary glacial history of Eastern Siberia. Deciphering this history for Kamchatka provides a potentially simple case-study because of the peninsula’s orientation and its abundant glacial geomorphological evidence. This regional example also highlights key issues in palaeo ice-mass reconstructions for mountain areas, notably whether glaciation style is dominated by numerous valley glaciers, or by ice caps and icefields drained by outlet glaciers. Here we follow two lines of analyses for Kamchatka to assess plausible reconstructions between these end-member scenarios. First, we use satellite images and digital elevation model data to identify and map moraines over Kamchatka. The moraine distribution, both in plan-view and with respect to elevation, suggests two distinct glaciation phases, both reflecting the influences of orographic and latitudinal palaeoclimate gradients. Second, we attempt to use the moraine distribution to evaluate palaeo-ice thicknesses, in order to address to what extent the Kamchatka mountain divide was submerged by ice in each glacial phase. This exercise invokes an empirical parameterisation of ice-surface morphology based on Nye’s (1951) theory, where a constant C characterises the parabolic fit to an observed ice-surface profile along a flowline. In particular, when estimated for ~200 modern ice masses worldwide, C is found to depend systematically on the ice-mass size (L) over a broad range L ~ 100 – 103 km. This empirical dependence then allows us to constrain the divide ice thickness and derive palaeo ELA and ice-volume estimates for Kamchatka (with known error bounds). We advocate this hybrid reconstruction approach, which combines glacial geomorphology with contemporary observations of ice masses, as a useful intermediate between subjective methodologies (ice surface topography drawn from moraine and trimline positions) and 3D numerical ice-flow models, where uncertain boundary conditions and high degrees of freedom often limit their application. 0458 Mire-oaks and north Atlantic environmental change: a midHolocene hydrological record Philip Barratt1, Paula J Reimer2, Robert Kalin3, David Brown1 1

Palaeoecology Centre, School of Geography, Archaeology and Palaeoecology, Queen’s University Belfast, United Kingdom 2 14CHRONO Centre, Queen’s University Belfast, United Kingdom 3 Environmental Engineering Research Centre and 14CHRONO, Queen’s University Belfast, United Kingdom

Tree-rings provide annually resolved environmental archives from which present and past environmental processes are inferred and modelled. Trees from mire contexts contribute significant amounts of material to the Holocene chronologies of Europe. Although we no longer have direct analogues for these environments, they were certainly marginal for tree growth. Under such conditions changes in local and regional conditions would have a significant impact upon the tree populations living there. It is commonly held that the main forcing agent behind such impacts on mire woodlands are shifts in hydrological conditions influenced by climatic forcing. Ireland is the first landfall for many Atlantic weather fronts, and ocean-atmosphere processes dominate many aspects of the islands climate. The Irish bog-oak re-

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cord thus presents a multi-millennial scale, potentially hydrologically sensitive, data set by which to examine north Atlantic environmental change. New chronologies from a mire site situated on an important fluvial outlet from one of Europe’s largest inland lakes have been constructed to test this hypothesis. Combining data from this site with existing archived tree-ring data, and applying GIS and spectral techniques, a complex picture of regional population variation and growth change is being compiled. This work is revealing significant inter-site differences as well as similarities in the tree-ring and tree-population record. Using this methodology a more detailed review of the data is being undertaken 0461 Interrogating tree-ring archives: a joined-up methodology Philip Barratt1, Paula Reimer2, Robert Kalin3, David Brown1 1

Palaeoecology Centre, School of Geography, Archaeology and Palaeoecology, Queen’s University Belfast, United Kingdom 2 14 CHRONO Centre, Queen’s University Belfast, United Kingdom 3 Environmental Engineering Research Centre and 14CHRONO, Queen’s University Belfast, United Kingdom

Tree-ring data provide indications of population dynamics and size over time periods from decades to millenia. Such data also provide annually to seasonally resolved information about changes in growing conditions. Large archives of tree-ring data thus provide valuable resources for research on environmental change. However, these archives can also present issues of management and data overload. To combat this problem techniques to reduce the data are frequently applied. Such approaches attempt to provide valid general overviews or hone in on specific, limited, sections of the data to explain or illustrate particular research questions. The bog-oak record held at Belfast, Northern Ireland, is an example of such an archive, and presents just such issues. Uses of these data in the literature often show simple composites or carefully selected dates used to correlate with other proxies. During the construction of new chronologies to test the impact of mid-Holocene regional environmental change, sections of this archive were extracted for comparitve purposes. It became apparent during this process that new methods were needed to manage and interrogate this data-set efficiently. Construction of an integrated database, GIS, and analysis software, free of formats, and available freely across multiple platforms has allowed the archive to be more easily examined spatially and temporally. Using this ‘joined-up’ system has helped highlight the potential spatial complexity of site population respones at decadal and centennial scales. It has also made analysis of selected ring-width data less laborious and has been used to detail the nearly continuous decadal scale of disturbance affecting annual growth response of the bog-oaks. These results are showing the effectivness of this system in implementing new methodologies and finding new levels of detail in existing data-sets. 1071 Absence of cooling during the Younger Dryas Chronozone in the South Pacific Ocean Timothy T Barrows, Keith Fifield The Australian National University, Australia

The last deglaciation in the North Atlantic Ocean was characterized by an abrupt return to near glacial conditions during the Younger Dryas Chronozone (YD). The YD is recorded as a cold period from 12,800 to 11,500 cal yr BP (10,000 –11,000 14C yr BP). Cooling is demonstrated

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in this interval by ice cores from the Greenland ice sheet, deep-sea sediments in the North Atlantic Ocean, and in pollen records in Europe. Glaciers and ice sheets advanced in mountainous regions of Scandinavia, Scotland and the Alps. However, the cooling becomes less discernable with distance, suggesting a link with thermohaline circulation and North Atlantic Deep Water formation. No clear YD is recorded in the Antarctic ice cores, although a brief cooling is recorded shortly before it (The Antarctic Cold Reversal). Elsewhere in the Southern Hemisphere the evidence is often contradictory. A strong case has been made in New Zealand where moraines have been dated close to the YD Chronozone. In particular, the Waiho Loop moraine deposited by the Franz Josef glacier is limited in age by many radiocarbon dates to ~13,000 cal yr BP. Similarly, moraines at Arthur’s Pass have been directly dated to within the YD chronozone. Here we present new exposure dating evidence that demonstrates that the Waiho Loop was constructed after the YD. Additionally, we show that the Arthur’s Pass moraines were deposited before the YD. We find no evidence to support the assertion that the YD is a time of pronounced cooling in the South Pacific. 0928 A Paleoclimatic Diagnostic-Features Approach to Data-Model Comparisons Patrick J Bartlein University of Oregon, United States

Assessing our understanding of the climate system through the comparison of paleoclimatic data syntheses and model simulations is a perverse enterprise—progress should be counted less by apparent agreements and more by failures (mismatches between data and simulations), because the resolution of those mismatches is what ultimately advances our understanding of how the climate system works. This success-through-failure situation makes it important to understand the limitations of the different approaches for making comparisons, measuring agreement, and identifying those features of the real climate that are indeed being adequately simulated in models. – In the inverse (or bottom-up approach), paleoclimatic data are interpreted in climatic terms, and these inferred climate values are compared with model output. This approach is limited by indeterminacy of the data (the same response can be invoked by more than one change in a potential control or set of controls), and by the need to aggregate inferred climate to the resolution of a climate model. In the forward (or top-down) approach, the output from a climate model is used to simulate paleo data (e.g. vegetation, lake status), typically using some kind of environmental submodel (but with increasing model elaboration, directly by the model). This approach is limited by the availability of appropriate submodels, and by the need to disaggregate or downscale the model output. Both approaches are also limited by the uneven spatial distribution of paleoclimatic data and because the paleo data, and in particular, the model output, are also highly spatially autocorrelated. Along with the above limitations, this creates a situation where it may be difficult to assess the significance of comparisons between data and model output using standard statistical or quantitative approaches. – An alternative data-model comparison approach focuses on atmospheric-circulation and surface-climate features that characterize present-day climate variability (such as the monsoon circulation or the “centers of action.”) In this “paleoclimatic diagnostic-features” approach, syntheses of paleo data, insights from modern synoptic climatological studies (including the extraction and analysis of climate-mode indices), and experiments with mechanistic models are

combined to project the likely responses to simulated (paleo) changes in such features, and to assess whether or not that response was recorded by the data. Although seemingly more qualitative than quantitative, this diagnostic-feature approach may give a more realistic impression of the overall capabilities of climate models than would simple pattern correlations because it focuses on the specific mechanisms through which changes in boundary conditions are registered. 0102 Developing the First Chronostratigraphic Framework for Fluvial Deposits and Associated Palaeolithic Archaeology in South-West England Laura S Basell1, Antony G Brown1, Phillip S Toms2, Robert T Hosfield3 1

School of Geography, Archaeology & Earth Resources, University of Exeter, United Kingdom 2 Geochronology Laboratories, University of Gloucestershire, United Kingdom 3 Department of Archaeology, University of Reading, United Kingdom

Considerable recent research has been conducted on the chronostratigraphy of terrace staircases in the UK and France. Such research has informed our understanding of large-scale fluvial dynamics and drainage patterns, rates of uplift, climatic cycles, archaeological chronologies, and landscape evolution. In the UK, most of this work has focussed on south-east England on the major staircase sequences such as those associated with the Rivers Thames, Severn and Avon and palaeo River Solent, most recently through work funded indirectly by the aggregate extraction industry. By contrast the terrace deposits of southwest England have been little studied largely due to a lack of commercial aggregate extraction. This paper presents the preliminary results of the Palaeolithic Rivers of South West Britain Project, which has employed a range of methods to characterise and date the terraces of targeted rivers in south-west England. The primary areas selected were the Rivers Exe, Axe and Otter, and the palaeo River Washford. The methods used have included sedimentological logging and recording of exposed sections and excavated areas, clast analyses, and the use of LIDAR and IFSAR data within ArcGIS. Where suitable deposits were present, samples for Optically Stimulated Luminescence dating were taken. These samples have generated a range of dates covering isotope stages 12 – 2, and in conjunction with the work on the terraces’ composition and form, this has allowed the development of the first chronostratigraphic framework for the fluvial deposits in the area. Our understanding of the terrace sequences has been greatly improved and it is clear that while the evolution of all the target catchments is complex, the evolution of the River Axe is anomalous. At a larger scale the focus on adjacent catchments has allowed the consideration of wider, regional landscape change. The study has also applied a recent advance in Optical dating, which involves the use of a simple intrinsic measure of accuracy that proves vital in studies where independent, corroborative chronometric data are absent. Continued work will focus on developing the predictive modelling aspects of the project and relating the development of these fluvial systems to those in the English Channel, south-east England and further afield. Such work obviously has significant implications for related areas such as our understanding of Quaternary faunal distributions and movements, including hominins.


1291 Early to Middle Stone Age site distributions in eastern Africa and their relationship to Quaternary environmental change, refugia and the evolution of Homo sapiens Laura S Basell University of Exeter

East Africa is undoubtedly important in the evolution of Homo sapiens. Palaeontologically the area has yielded some of the earliest remains of “anatomically modern” humans, and hominin remains which fall just outside the range of variability seen in Homo sapiens (e.g. Homo idaltu). The prominence of the area has been further supported over the last two decades by developments in genetic research. Several studies have indicated that East and North East Africa were of particular importance in the evolution and subsequent dispersals of our species, to the rest of the world. A theme pertinent to both these fields and frequently discussed in large-scale models of human evolution is that at some point in the last 500 000 years hominin populations underwent a bottleneck (although this was not necessarily related to a speciation event). Suggestions regarding the cause of a bottleneck have focussed on exceptional or prolonged aridity in Africa during glacial phases centring on oxygen isotope stage 4 (in combination with the postulated effects of the Toba super-eruption) and oxygen isotope stage 6. It has also been suggested that parts of East Africa acted as refugia during these periods. This paper uses published, large-scale global climatic datasets in combination with data from chronometrically dated archaeological and palaeontological sites to consider whether this latter claim can be supported. If areas in East Africa did indeed act as a refuge in times of climatic stress, we should find: 1) a correspondence between sites dated to periods associated with increased aridity, and areas that maintained conditions favourable to omnivorous bipeds and 2) a more continuous record in such areas than elsewhere. In combination, the datasets provide general support for refugia in East Africa. But the study also highlights some significant problems with the resolution of the datasets currently available, and that further studies at a site-specific and regional scale are essential in order to provide a better idea of whether this is the case. 0636 Long-term dune evolution on the Southern Cape Coast, South Africa Mark D Bateman1, Andrew S Carr2, Peter J Holmes3, Colin V Murray-Wallace4, David Roberts5 1

University of Sheffield, United Kingdom Universiyt of Leicester, United Kingdom 3 University of the Free State, South Africa 4 University of Wollongong, Australia 5 Council for Geoscience, South Africa 2

The southern Cape coastline of South Africa exhibits multiple generations of coastal aeolian deposits including 200 m high barrier dunes and parabolic dunefields. The region is thought to be tectonically stable and is currently located near the convergence of the Benguela and Agulhas ocean currents. It also lies near the modern interface of the southern Africa’s winter and summer rainfall zones and is adjacent to the extensive, shallow Agulhas plateau. It is therefore a coastal region particularly sensitive to past environmental and sea level changes and is ideally placed to explore the relationship of long-term coastal geomorphic evolution and sea-level fluctuations. Recent work on the macro-scale evolution of these aeolian deposits reveals a history extending over ~250 ka and suggests that the greatest

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intensity of coastal aeolian activity relates to interglacial/interstadial highstands. However, some of the processes controlling dune formation, as well as their sensitivity to millennial – centennial scale climatic and oceanographic changes remain obscure. For example it is unclear whether the Holocene dune forms can be considered useful analogues for the aeolian activity during previous interglacial periods. This paper presents the first intensive and detailed chronology of Holocene coastal dune deposition for this region based on optically stimulated luminescence (OSL) dating, amino acid racemization (AAR) and radiocarbon ages. Results support previous studies which reveal dune accumulation from the mid-Holocene onwards with the majority of ages post-dating the Holocene sea-level high stand at c. 7500–6000 BP. The new age ranges do not provide strong evidence for episodic regional-scale coastal dune building events, but rather demonstrate both consistent availability of shallow marine sandy sediments for deflation and a high potential for aeolian activity in all areas throughout the last 6000 years. This is particularly the case in areas such as Sedgefield on the southern South African coast, where local terrestrial sediments have been and continue to be, flushed out of estuaries into the coastal zone. This new Holocene dune record is instructive in interpreting the dune record from previous interglacials. 0186 Aeolian dynamics and shoreline mobility in the North of France Yvonne Battiau-Queney University of Sciences and Technologies of Lille, France

While the relationship between beach and foredune has been extensively studied, the role of extensive dune field has not been considered as an important one in the coastal system and shoreline mobility. The study, which was carried out in the “Picardy marine plain” tends to the opposite view. Here three main units are juxtaposed: (1) a macrotidal sandy beach; (2) an up to 3 km-wide complex of dunes with outer dunes, intermediate flat sandy plain and inner dunes; (3) a low marsh made of marine sediments. At least three phases of dune development occurred in late Holocene: the oldest Subatlantic dunes established when the shoreline was several hundred meters westward and are presently cut into cliff. The inner dunes of Merlimont have a maximum age Cal BP 480 to 290. The youngest outer dunes are still active and nourished from the beach. Correlation of dune activity with shoreline mobility is possible within the coastal system. In the studied area, prevailing winds have always blown from the sea to the land as nowadays. Spatial and temporal differences concern aeolian intensity and vegetation dynamics. Three cases happen: (1) Strong aeolian activity coupled with sparse vegetation. Large mobile dunes are shifting inland, and a great quantity of beach sand is exported outside the coastal system. If it is not compensated by marine inputs the coastal sediment budget is negative, leading to constant shoreline retreat, as it was observed in the 19th and the first thirty years of the 20th century. (2) Strong aeolian activity coupled with dense vegetation. Most part of the sand blown from the beach is trapped in the foredune. So it remains in the coastal system to be eventually removed by waves and return to the nearshore zone. The shoreline alternatively advances or retreats. This type of mobility is peculiarly well documented in Hardelot area since the middle of the 20th century. (3) Absent or weak aeolian activity on the beach, preventing foredune development. Although infrequent, this case concerns the coast south of Hardelot, where fresh groundwater keeps the beach sand wet at low tide. Here the sediment budget depends upon marine flux only. The shoreline retreat was slow but relatively constant during the last 60 years. When considering shoreline mobility, the role of the supposed increasing rising sea-level in the

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20th century appears insignificant compared to aeolian flux in the coastal system and sediment trap in dunes. 1400 Geoarcheological Survey of the Noah’s Ark, Dogubayazit, eastern Turkey Salih M Bayraktutan Botas-Pipeline Coorp. Ankara, Turkey

The Noahs Ark site, near Dogubayazit,E.Turkey has been investigated by geological and geophysical surveying methods. The Site came to existance by a local earthquake, in 1949, M=5.0(?),triggered mud-rich debris flow, down along the Uzengili Creek. Ark-shaped object (NA) has flowed downstream and finally stabilized, at currently existing location. NA is 157m long, 45m wide and 10 –15m thick. Ground penetration radar, proton magnetometer and engineering seismograph are used. Radar measurements (Baumdarner, Bayraktutan, Fasold) taken 70 profiles at 2m intervals,scanning surface, has provided some internal features. Equal interval signals recorded. Magnetic-map provided information about size of rock outcrop in centre of NA.Magnetic intensity showed a slight fluctuation around the calc-schist rock outcrop, reflecting the difference in content of Fe-minerals in calc-schist and surrounding debris comprised of ultrabasic rock fragments. Seismic measurements revealed two layers with velocities of 2400–3300m/s and 1500 m/s. This proved that deep layers are not calc-schist, rock protruding from the central-west of the formation, is not continuing down to bedrock, and floating at surface. First layer has thicknesses changing from 2.5 m to 8.0 m. Drillings were taken at 4 locations along the contral line, down to 13 m depths were not successful in coring fine fraction. Radar scanning picture showed equally spaced (3.20 m) signals which are interpreted by some researchers as the locations of arkframe, but this could not proved. Reason can be either differential weathering or diffrence in humidity. Materials comprising these vertical impressions and the area inbetween are examined, but no difference of any large scale internal structure or variation in chemical composition found. Material of ark-shaped mass is mud flow debris rich in clayey content, including subangular rock fragments.No horizontal structure found inside.V-shaped radar signals were smoothed after the topographic correction, but still the interface between the ark-shaped mass and deeper part of debris flow, is visible. Consequences of geoarcheological work briefly described in this report can be listed as; (a)Durupinar Site is an active mudflow, (b)three stage of flow recognized, (c)arkshaped object originally was located at higher altidues, d)current location is end point of journey (e)its motion prevented by the converging flow-lines, at entrance of channel, (f )no clear organized man-made structure, (g)1949 earthquake destroyed topography, activated mudflow and MA appeared. (h)western margin of valley is NNE-striking active fault, (i)the rock-outcrop at center is not connected to bed rock, it has been flowing together. Further search by 3D radar imaging and dry core-drilling are recommended, to answer mysterious questions. 1401 Palaeoclimate and Palaeogeographic Implications in Pasinler Plio-Quaternary Basin, Eastern Turkey Salih M Bayraktutan Botas-Bil. Pipeline Coorp. Ankara, Turkey

Pasinler Basin (PB) is one of the largest Plio-Holocene deposition area, located in compressional geodynamic context of E. Turkey. PB occupies attitude of great palaeoclimatic significance in the Near East,

lying within transition zone between areas with Medit-type climates and those with more continental climates. Relief increased sensitivity to past climatic variations. The PB itself occurs in headwaters of Aras River,draining eastward to Caspian. This is the area where Rivers flowing into Black Sea, Caspian Sea and the Gulf (Indian Ocean) start. Active tectonic processes modified surface and subsurface hydrology, had big influence on basin development. Mid-basin floodplain sediments reveal a series of oscillations between mineral and organic-dominated environments through Early-Middle Holocene. Damp floodplain (DFP) conditions occur at apprx 7000 BC, 4000 BC and 2000 BC. Fine mineral sediments with occasional gravel suggest lower productivity on floodplain and more variable flows, including higher peak flows. In late Holocene, sometime after the last DFP period, an incision phase followed a change in fluvial regime represented by coarse gravels. Episodes of DFP conditions in Early and Middle Holocene are widely synchronous with similar conditions identified elsewhere, in E.Turkey. This suggests that PB, was sensitive to regional climatic events. NE penetration of these events can now be better constrained. Degree of correlation declines for the 2000BC event and subsequent conditions. This may in part be due to dating limitations but spatial variability in climate cannot be ruled out. Radiocarbon and palynological dating techniques are used, to date palaeo-changes. Another factor is likely to be land use change. Archaeological investigations in the basin indicate a significant cultural shift at around 2000 BC. The PB study, although at an early stage, demonstrates the palaeoclimatic use of floodplain depositional sequences in a region where lacustrine sites are rare and partly atypical. They provide potential for understanding impact of varying human activity over long time periods. Three terrace surfaces are recognised. Youngest (valley bottom) sediments in PB, provided evidence for Pleistocene and Holocene floodplain conditions. More stable floodplain conditions occurred at around 9000, 5500 and 4000 cal.yr BP. Incision occurred sometime after 4000 BP, probably as a response to both climatic and human controls. Seismotectonic activity was very widespread within the Basin. However tectonic processes do not appear to have substantially influenced the details of Holocene palaeo-environvironmental records. Comparisons with key sites in Anatolia and beyond, suggest these changes are part of regional climatic pattern, perhaps influenced by changes in East African Monsoon. 1404 Palaeoseismic and Historic Seismicity of the Region of eastern Anatolia-south Caucasus-northwest Iran Salih M Bayraktutan1, Yousuf G Sattarzadeh2 1

Botas-Bil. Pipeline Coorp. Ankara, Turkey Tabriz Isl.Univ. Geol. Dpet., Tabriz, Iran

2

The region of study, literally called Turk-Iran High Volcanic Plateau (TIHVP) located in the north of Arabian Plate Collisional Front, undergoing a compressional geodynamic regime. This region covers eastern Anatolia-northwestern Iran and southern Caucasus, where N-S compression is compensated mainly by strike slip faulting mechanism. On the other hand, E-W thrusting, N-S extentional fracture and associated vast volcanism of Pliocene-Quaternary age, are dominant structural features. An arc-shaped (triangular) geometry of active faulting formed the seismotectonics framework, the southern side, NE side and NW side. In this report, the Quaternary Basins (QB) formed along major active fault zones, like North Anatolian, east Anatolian Faults, Erzurum Faults in Turkey, Tebriz Faults, Nakhcivan Faults in Iran-Azerbaycan, and A. Samsar Faults in Armenia. In this article, palaeo-seismicity, historic and XX century seismicity of selected Quaternary basins from threee major


part of the region are presented. The geometry, age and sense of motion along the high rank seismicty faults are comparatively, studied. Erzincan Basin, Erzurum Basin, Pasinler Basin, Mush Basin in E.Turkey, Tebriz Basin, Erdebil Basin in NW Iran, and Erivan Basin in Armenia are selected. There are trenches studied on marginal master faults, of these basins. Major earthquakes such as 1983 Horasan Eq., 1992 Erzincan Eq., 1988 Spitak Eq., NW Iran earthquakes initiated trenching work, and seismotectonic features bounding these basins. Expected maximum displacements and intensity, associated to high population areas interpreted in terms of hazard assessment. Major hazardous events associated particularly to marginal faults, during the last 10,000 years, evidences from archeological and topographical data, are well studied, and evaluated in erms of hazard prdiciton. 0926 Quantitative paleo-rainfall estimates for continental interior regions using 10Be in loess Warren Beck1, Weijian Zhou2, Alfred Priller3, Zhengkun Wu2, Maobai Chen4, Zhisheng An2, Walter Kutschera3, Feng2 1

University of Arizona, Physics and Geosciences Departments, Tucson, United States 2 State Key Laboratory of Loess & Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xian, China 3 VERA (Vienna Environmental Research Accelerator), University of Vienna, Vienna, Austria 4 Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China

Here we demonstrate a new method to derive quantitative paleo-rainfall estimates for continental interior regions using 10Be in loess. We apply this technique to derive an 80,000 year long rainfall record from the Chinese Loess Plateau. The key steps in this technique are to account for variations in 10Be flux that are due to magnetic field modulation of 10Be production rate, and to account for 10Be derived from recycled dust. Aside from these two factors, variations in 10Be flux are chiefly due to changes in wet precipitation rate. We calibrate the 10Be flux dependence on rainfall rate using 7Be concentrations in modern rainfall as a proxy. In three different 7Be vs. precipitation amount studies on three continents a similar linear relationship is found. Using the average slope in these studies we convert from 7Be to 10Be using the known 10Be/7Be flux ratio in modern tropospheric precipitation. The precipitation record we derive with this method is well correlated with the speleothem delta18O records from Dongge and Hulu caves in S.E. China, which are widely regarded as a robust record of Asian monsoon intensity. Our record indicates extremely low rainfall for the LGM and marine isotope stage 4 (MIS4), with precipitation rising gradually out of MIS4 to near modern levels during MIS3. After circa 35 ka BP precipitation began a long decline culminating in a 5 ka long minima during the LGM ending at circa 20 ka BP. Precipitation then increased stepwise in dramatic fashion at ~20 ka, and again at 14.3 ka. Precipitation was constant or decreased slightly between 13-11ka, followed by another abrupt precipitation increase culminating in a Holocene maximum at 9 ka BP. Precipitation then dropped rapidly to a Holocene minimum at 5.8 ka BP followed by a modest rise to 4 ka then gentle decay and another small rise to the present during the late Holocene. Two large precipitation increases are observed in our record which are roughly coeval with melt-water pulses 1 & 2 suggesting a coupling between high and low latitude climate dynamics during the deglacial. The low frequency component of our precipitation record resembles summer (JJA) solar insolation curve for 30°N, except during MIS3, when it more strongly resembles the insolation differential between 30°N and 30°S. This can be understood in terms of two of the chief

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elements of monsoon forcing, land/sea temperature differential, and cross-hemispheric atmospheric pressure gradient exhibited over the tropical ocean. 1220 Late Quaternary aridity changes along the middle Yellow River floodplain as recorded by dust supply and pedogenesis in the Mangshan section Christiaan J Beets1, Maarten A Prins1, Simon R Troelstra1, Hongbo Zheng2 1

Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, The Netherlands 2 School of Ocean and Earth Science, Tongji University, China

The Mangshan Plateau is located on the south bank of the Yellow River (Huang He) just west of the city of Zhengzhou, well outside the Loess Plateau in central China. We present detailed grain size, magnetic susceptibility (MS), carbonate, geochemical and stable-isotope records from a 60 meter thick loess-paleosol sequence (S0-L1-S1-L2). Mixing models of the grain-size data indicate that the loess deposits are mixtures of three loess components. Comparison of the mixing model with existing models established for a series of loess-paleosol sequences from the Loess Plateau indicate that the Mangshan loess has been supplied from a proximal dust source, the Yellow River floodplain, during major dust outbreaks. The high accumulation rates, the composition of the loess components, and especially the high proportions of a sandy loess component support this. Pedogenesis throughout the section resulted in various stages of soil development as recorded by the MS, carbonate percentage and trace element composition. Carbon isotopes in the bulk carbonate and rhizoliths confirm significant changes in moisture availability and vegetation development. Changes in the vegetation cover in the Yellow River floodplain, itself controlled by humidity changes, likely controlled the dust entrainment processes and eventually loess accumulation at the Mangshan Plateau. 1233 The penultimate deglaciation in the Amsterdam Basin, The Netherlands Christiaan J Beets1, Dirk J Beets2 1

FALW, Vrije Universiteit, The Netherlands Voorhaven 76 Edam, The Netherlands

2

The deglaciation history of the penultimate glacial to interglacial transition is recorded in high detail in lake deposits from the Amsterdam Basin. The Amsterdam Basin was formed as a result of a late-Saalian ice-surge (probably post 140 ka) and became part of a large lake covering the western and central area of the Netherlands, extending into the present North Sea. The geometry and the character of the sedimentary infill of Amsterdam Basin are well described using a large amount of drill-cores over the entire basin. The size of the ephemeral lake was on the order of 5000 square km with an average depth of 25 m. Based on varve counting, oxygen isotope and pollen analyses we could establish that in the ~2500 years preceding the Eemian, climate substantially fluctuated. A relatively warm period of ~1000 years was followed by a severely cold one of ~1500 years before the onset of the Eemian. We assign an age of 131±2ka to the start of the Eemian. The early Eemian calcareous lake deposits indicate a rapid warming of climate, resulting in stable warm conditions over a period of ~800 years. Precipitation increased just prior to transgression of the sea in the lake, causing important changes in vegetation. The top of these

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lake deposits are organic-rich (sapropelic) calcareous diatomites and form the transition to the overlying marine sequence. The first marine deposits contain boreo-artic diatom and benthic foram species indicating a northern source for the water entering the Basin. In conjuction with a light oxygen isotope signature and a Sr-isotope composition below seawater values this indicates that full-marine conditions were not yet established. The sea level maximum was reached in overlying Eemian pollen-zone E4b and E5 at ~128-129 ka. 1387 Volcanic Tsunamis in Cook Inlet, Alaska James E Beget University of Alaska, Fairbanks, Alaska, United States

Volcanic eruptions can generate tsunamis that cause extensive damage and casualties at great distances from the volcano. The 1883 Krakatau eruption, for example, produced a tsunami that resulted in more than 36,000 fatalities in the Sunda Straits region of Indonesia immediately surrounding the volcano and also produced fatalities as far away as Sri Lanka, more than 2500 km from the volcano. Augustine Volcano, located in the southern Cook Inlet area of Alaska, also erupted in 1883 and also produced a tsunami. Historical accounts and paleotsunami deposits show the 1883 wave was ca. 6–8 m high in areas 80 km from the volcano, and affected widely separated coastal sites over an area of ca. 10,000 km2 around southern Cook Inlet (Beget and Kowalik, 2006). By a stroke of luck no fatalities resulted from the Augustine volcanic tsunami, because Cook Inlet has very large tides, ranging from 6 –10 m, and the 1883 tsunami occurred near low tide. Numerical modelling and the distribution of paleotsunami deposits are in good agreement, and show waves reached 17 m in height near Augustine Island after a volcanic debris avalanche flowed into the sea on the north side of the volcano. Stratigraphic studies of volcanic ash horizons and paleotsunamic deposits preserved in coastal bluffs show that at least three additional volcanic tsunamis occurred in the Cook Inlet area of Alaska during the last 3600 years. Archeological studies indicate the native people living in the Cook Inlet area during this time interval inhabited coastal villages, and depended strongly on marine resources for survival (Klein, 1997). The largest prehistoric volcanic tsunami in southern Cook Inlet also originated at Augustine Volcano, and occurred about 1700 yr BP. This is also approximately the same time as a significant break marking the end of the Kachemak culture in the late Holocene archeological record of the Cook Inlet area. The volcanic tsunami reached at least 7 m above high tide line in areas 80 –100 km from the volcano, and may be responsible for the end of the Kachemak culture in the Cook Inlet area. 1176 Holocene Mangrove ecosystem dynamics and sea-level changes in northern Brazil

region of Pará State and Marajo Island in the Amazon mouth region. The results indicate that the hydrology of the coastal Amazonian wetlands is strongly influenced by the Atlantic sea-level. Rapid sea-level rise during the early Holocene stabilized near modern levels at ca. 7500 14C yr BP and mangroves start to develop at the modern coastal area. The retreat of mangroves after about 6700 14C yr BP reflects a lower relative sea-level. The modern mangroves developed mostly between 4000 and 3500 14C yr BP or somewhat later at the present-day coastline. On the Bragança Peninsula in eastern Pará State, mangrove vegetation started to develop at different times at the 3 sites: at about 5120 14C yr BP or later at the Campo Salgado site, at 2170 14C yr BP at the Bosque de Avicennia site and at 1440 14C yr BP at the Furo do Chato site. Since mid-late Holocene times, the mangroves covered even the most elevated area on the peninsula, which is today a salt marsh, suggesting somewhat higher relative sea-levels. 1181 Vegetation, biodiversity and fire dynamics on the southern Brazilian highland during the Late Quaternary and their implication for conservation and management of modern Araucaria forest and grassland ecosystems Hermann Behling1, Valério DePatta Pillar2 1

Department of Palynology and Climate Dynamics, Albrecht-von-Haller-Institute for Plant Sciences, University of Göttingen, Germany 2 Departamento de Ecologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil

Palaeoecological background information is needed for management and conservation of the highly diverse mosaic of Araucaria forest and Campos (grassland) in southern Brazil. Questions on the origin of Araucaria forest and grasslands, its development, its biodiversity, dynamic and stability, its response to environmental change such as climate, and the role of human impact, are essential. Further questions on its natural stage of vegetation or its alteration by pre- and post-Columbian anthropogenic activity are also important. To answer these questions, palaeoecological and palaeoenvironmental data based on pollen, charcoal, and multivariate data analysis of radiocarbon dated sedimentary archives from southern Brazil are used to provide an insight into past vegetation changes that allow us to improve our understanding of the modern vegetation and to develop conservation and management strategies for the strongly affected ecosystems in southern Brazil. 1189 Late Quaternary vegetation, biodiversity, fire and climate dynamics in the Atlantic mountain region of eastern Brazil Hermann Behling1, Hugh de Forest Safford2, Marcelo A T Oliveira3, Lydie Dupont4 1

1

Department of Palynology and Climate Dynamics, Albrecht-von-Haller-Institute for Plant Sciences, University of Göttingen, Germany 2 Laboratory of Coastal Dynamics, Federal University of Pará, Belém, Brazil 3 Center for Tropical Marine Ecology (ZMT), Bremen, Germany

Department of Palynology and Climate Dynamics, Albrecht-vonHaller-Institute for Plant Sciences, University of Göttingen, Germany 2 Department of Environmental Science and Policy, University of California, Davis, CA, United States 3 Universidade Federal de Santa Catarina (UFSC), Departamento de Geociências, Campus Universitário, Trindade, Florianópolis, SC, Brazil 4 Universität Bremen, Geowissenschaften, Forschungszentrum Ozeanränder (RCOM), Bremen, Germany

More then 10 radiocarbon dated sediment cores, studied by pollen and sediment analysis, provide a detailed insight on past environmental changes and give an outline of sea-level and its influence on mangrove development and dynamics during the Holocene in northern Brazil. We will present an overview of existing and new data from the coastal

The mountain ecosystems systems of eastern Brazil harbor the most biodiverse ecosystems on planet earth, yet we know little about why they are so biodiverse. We are especially ignorant of the role that history has played in the development of these hotspots of species endemism and richness. This contribution represents part of a long-term

Hermann Behling1, Marcelo Cohen2, Ruben Lara3, Vincent Vedel3


effort to provide detailed documentation of the natural history of the southern and southeastern Brazilian highlands, and to study linkages between past processes and modern ecological patterns. Palaeoecological studies from several sites along the Serra do Mar coastal mountain range, provide new results on vegetation, biodiversity, fire and climate dynamics during the Late Quaternary. An unknown very wet short phase during the end of the Younger Dryas period, with a decreasing intensity trend from the tropics to the subtropics (from the north to the south), reflects effects of the slow-down of the thermohaline circulation during the Younger Dryas period. Marked drier climatic conditions during the early-mid Holocene and wet climatic conditions is also reflected by vegetation dynamics in the eastern Brazilian coastal mountain region. 0360 Palaeoflood hydrology and floodwater recharge on the Buffels River (Namaqualand, South Africa) Gerardo Benito1, Varyl R Thorndycraft2, Maria Teresa Rico3, Yolanda Sanchez-Moya4, Alfonso Sopeña5, Blanca A Botero6, Alfredo PerezGonzalez7, Ofer Dahan8 1

Spain Royal Holloway University of London, United Kingdom 3 CSIC-Instituto Pirenaico de Ecologia, Spain 4 Universidad Complutense de Madrid, Spain 5 CSIC-Instituto de Geología Economica, Spain 6 CSIC-Centro de Ciencias Medioambientales, Spain 7 Universidad Complutense de Madrid, Spain 8 Ben Gurion University of the Negev, Israel 2

This study aims (1) to reconstruct long-term flood magnitude and frequency using palaeoflood hydrology in an arid ephemeral river basin (Bufflels River) in South Africa, and (2) assess long-term (decades to centuries) floodwater recharge patterns contributing to the recharge of the alluvial aquifer. Infiltration rate and recharge were monitored in order to quantify transmission losses through the deep vadose zone. The palaeoflood hydrology of the Buffels River (9000 km2) was reconstructed from slackwater deposits and palaeostage indicators in two canyon reaches located at: (1) Rooifontein, in the upper catchment, and (2) Messelpad, in the lower basin. The palaeoflood record, with more than 25 flood events over the last 600 years, shows clusters of floods at specific periods, for example A.D. 1400 –1500 (at least five events) and A.D. 1700 –1900 (at least 10 events). The largest flood (s) in the upper catchment reached a minimum discharge of 255 m3s−1 whereas in the lower basin the minimum estimated flood discharges was 510 m3s−1. The 20th century was characterised by a decrease in the frequency and magnitude of extreme events. Periods with increased flood magnitude and/or frequency in the Buffels River are strongly related to increased moisture influx and winter precipitation along the western coast of South Africa. The 1990 –2006 flood annual series for the ungauged Buffels basin was modelled using a distributed rainfallrunoff method (Tetis model, Polytecnic University of Valencia), calibrated using our own stream gauge record (2005–2006) from the upper and lower catchment. Palaeoflood data and modelled flood discharges were combined for the flood frequency analysis using the maximum likelihood estimates of the parameters for several distribution functions. The analysis provided flood discharges, volume estimates and potential infiltration losses for different return periods. Implications for long-term floodwater recharge of the Buffels river alluvial aquifer are discussed. Acknowledgements: The research was funded by EU WADE Project contract no. GOCE-CT-2003-506680) and Spanish MEC PCI 2005-A5-0208.

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0053 Glacial history of the Ellsworth Mountains, Weddell Sea embayment, West Antarctica Michael J Bentley1, Christopher J Fogwill2, David E Sugden2 1

Durham University, United Kingdom Edinburgh University, United Kingdom

2

We report here the results from a programme of geomorphological mapping and sampling for cosmogenic isotope analysis in the Ellsworth Mountains. The overall aim of the project is to establish the timing and rate of thinning of the West Antarctic Ice Sheet from its maximum extent in an area inland of the Weddell Sea embayment. In season 05/06 we worked along a 350 km-long transect, stretching from Pirrit Hills (81˚ 06 S, 85˚ 31 W) in the south to the ridge between Mt Bentley and Mt Hubley in the north (78˚ 09S, 86˚ 41 W). Most sites were on the western (West Antarctic Ice Sheet) side of the range but we also worked in the Flowers Hills (78˚ 24 S, 84˚ 31 W) on the east side of the range, adjacent to the Rutford Ice Stream. We studied the geomorphology of 11 field locations in detail, including studies of drift sheets, weathering of sediments and bedrock, plus closely-spaced sampling of erratics and bedrock along altitudinal transects at each site. Our geomorphological mapping has allowed us to determine a series of ice sheet advances and we discuss a preliminary landscape and glacial history of the Ellsworth Mountains extending from the pre-Quaternary to the present-day, including a record of Holocene thinning. We have also determined a cosmogenic 10Be and 26Al chronology for the mapped glacial fluctuations. 0090 Glacial and sea level history of the South Shetland Islands, Antarctica Michael J Bentley1, Dominic A Hodgson2, Peter T Fretwell2, Steven J Roberts2, Emma P Watcham1 1

Durham University, United Kingdom British Antarctic Survey, United Kingdom

2

We report here the first results of a programme to elucidate the glacial history of the South Shetland Islands. We worked on a number of sites between King George Island and Livingston Island to map the glacial geomorphology, map and survey raised beaches, and sample deposits for radiocarbon and cosmogenic isotope analysis. We surveyed several raised beaches using differential GPS techniques in order to map the spatial pattern of glacio-isostatic rebound following deglaciation. We have been able to identify at least one major readvance since deglaciation and it is also clear that the ice caps over the islands are now more advanced than earlier in the Holocene. We report a preliminary chronology for these fluctations, and discuss this in the context of previous work. The history of relative sea level change has been more complex with relative sea level rise in the Early Holocene reaching a mid-Holocene highstand followed by relative sea level fall. Understanding the pattern and age of raised beaches has also allowed us to provide important chronological constraints on some of the glacial history. This geomorphological work is being carried out in conjunction with a programme of lake coring that will yield records of post-glacial relative sea level and climate change.

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0318 Proposal of a stratigraphic subdivision of the Quaternary of Poland Andrzej Ber1, Leszek Lindner2, Leszek Marks3 1

Polish Geological Institute, Poland Institute of Geology of the Warsaw University, Poland 3 Institute of Geology of the Warsaw University & Polish Geological Institute, Poland 2

Multi-optional approach in studies of the Quaternary of Poland resulted many a time in introduction of new stratigraphic terminology. A significant role has been also played by stratigraphic subdivisions, applied for mapping – particularly for the Detailed Geological Map of Poland, scale 1:50,000. Both these have resulted in an immense number of terms that have not been supported by sufficient documentation. During the last 30 years several ambiguous polycyclic units were introduced, including ‘mega-glaciations’ comprising single interglacials, and ‘Mega-Interglacials’ with several ‘individual’ glaciations or coolings. The authors present a stratigraphic subdivision of the Pleistocene of Poland composed of four complexes (Preglacial, South-Polish, Middle-Polish and North-Polish). Each complex comprises a group of climatostratigraphic units of the first order, both the glaciations (coolings) and interglacials (warmings). In general, a complex is a regional lithostratigraphic unit, composed of several different beds of considerable thickness, but characteristic for their certain common feature. In geologic literature on the Quaternary of Europe the term ‘complex’ has already a long and established tradition. It was presented for the first time by Kukla and Lozek (1961) to define a set of superposed palaeosols (pedocomplexes). The term ‘complex’ was proposed by Zagwijn (1975) in a subdivision of the Dutch Cromer into coolings (Glacials A–C) and separating warmings (interglacials). It was applied among others by Gibbard et al. (1991) and also to define the main glacial episodes in Germany (Stratigraphische Tabelle, 2002). In the long pollen sequences, the term ‘complex’ is used to comprise several intervals (e.g. Kukla, 1978). In stratigraphy of the Quaternary of Poland, the first use of the term ‘complex’ dealt with main glacial and interglacial units in a morphostratigraphic sense and was applied to the present and buried landforms (Lindner, 1987). Later it was used in a chronostratigraphic scheme for a poly-interglacial formation, named ‘Czyzów Complex’ and occurring in the Kleszczów Graben in central Poland (Krzyszkowski, 1991). This term was used in a stratigraphic subdivision for the setting of the bi-optimal Augustów Interglacial (Ber et al., 1998). The proposed stratigraphic initiative of the authors neglects the inconsequent Polish stratigraphic terminology, especially for mono- and polycyclic glaciations and interglacials. It also enables compact correlation with stratigraphic subdivisions of the Quaternary of western Europe. Determination of stratotypes for subseries/subepochs of the Pleistocene in a global stratigraphic subdivision may result provide in future a more precise definition of the stratigraphic scheme for the Polish Quaternary. 0554 Seasonal structure of Holocene El Niños: high-resolution reconstruction from stable-isotope ratios in massive corals Rose D Berdin, Michael K Gagan Research School of Earth Sciences, The Australian National University, Canberra, Australia

An increasing number of climate models and proxy records for the middle Holocene indicate relatively weaker and less frequent El Niños

relative to the present. This has been largely attributed to orbitallydriven changes in the seasonal cycle of insolation, which suppressed El Niños and induced a more La Niña-like climate during the middle Holocene. How this has affected the seasonal structure of El Niño events has yet to be investigated using proxy records. In this study, we compared the seasonal evolution of Holocene El Niños based on biweekly coral 18O/16O records from eastern Samar, Philippines. Coral 18O/16O reflects the combined effect of rainfall and SST and at Samar pronounced positive 18O/16O anomalies relate to droughts and cooler SSTs during El Niños. These anomalies typically manifest towards the end of the calendar during an El Niño year. We compared coral 18O/16O anomalies at the start, peak and end of the four most recent El Niño events (1986/7, 1990-95, 1997/98 and 2002/03) with events recorded at 7.2 ka and 2.3 ka. Composite analysis of these El Niños reveals significant changes in the onset and magnitude of peak anomalies. El Niño events at 7.2 ka and 2.3 ka commenced about 3–6 months earlier, but ended in the middle of the calendar year within two months of the termination-time for present-day events. Peak anomalies are largest at 2.3 ka, consistent with a climate model and proxy records showing large amplitude and more frequent events in the late Holocene. Results from our study indicate that along with changes in frequency and magnitude, the seasonal structure of El Niños has also evolved, possibly in response to changes in orbital forcing. 0299 Holocene and Upper-Pleistocene parabolic dunes and clay dunes in central Spain Manuel Bernat1, Alfredo Pérez-González2 1

Instituto Geológico y Minero de España. c/ Ríos Rosas., 23. 28003-Madrid, Spain 2 Facultad de Ciencias Geológicas. Dpto. de Geodinámica. Universidad Complutense. 28040-Madrid, Spain

Detailed cartography made with a stereoscopic digital station and incorporated into a Geographical Information System to perform spatial analysis was combined with field morphometric measurements and sedimentological-choronological studies in order to obtain the geormophological characterization, formation environment and chronology of the two main aeolian deposits in central Spain, located in the southeastern Duero Basin (DB) and the Manchega Plain (MP). The first ones between 41˚ and 42˚ North latitude and the second ones between 39˚ and 40˚ North latitude. In both regions, the climate is Mediterranean-continental with dry hot summers and the average rainfall oscillates between 500 and 300 mm depending on location. Wind deflaction processes of the Guadiana and Júcar alluvial systems created the aeolian deposits of the MP that are mainly composed of quartz sands. However, in the San Juan alluvial plain (MP) there is a large extension of clay-dunes. In the DB, wind remobilisation of the small particles from Quaternary terraces and Tertiary arkosic sediments produced aeolian deposits of quartz-feldspar sands. Morphologically, simple and compound parabolic (U-V forms, hemicyclic, lobate and elongate), crescentic, linear, and blowout dunes have been recognised in both places. There is also lunettes in the MP that were formed by the exposure to prevalent winds of seasonally playa-lakes with salt and clay sediments. The large extension of aeolian sand sheets and the predominance of parabolic dunes (74% of dune forms) indicate the active role of sparse vegetation cover in the formation of these aeolian systems. In the DB, dunes were formed by south-western and western winds, while in the MP the prevalent winds were western and north-western. The chronology of the dune deposits is being determined with luminescence (TL-OSL) dating. Thus, the main parabolic sand dunes forma-


tion in the DB and the MP occurred between 13.5 and 7 ka BP, during the cold and arid Younger Dryas stadial and the Early Holocene cold episode around 8 ka BP. The clay dunes of the MP have been accumulated mainly from 29 to 19 ka BP that correspond with the DansgaardOescher 3-2 stadial. However, clay dunes also were formed between 13.5 and 7 ka BP. In both locations, there are reactivations in the recent Holocene, with maximum activity around 5-2 ka BP and 0.5-0.2 ka BP, the firs one probably linked to human agriculture expansion, and the second one linked to dry-cold climate during the Little Ice Age on the Iberian Peninsula. Acknowledgements: PCI-2005-A5-0208. 0388 Searching for Old Tsunamis and Earthquakes in Banda Aceh and the Application of the INQUA Intensity Scale Glenda M Besana-Ostman1, Mastaka Ando1, Fumi Kimata1, Masatomo Umitsu2, Didik Sugiyanto3, Makoto Takahashi2 1

Research Center for Seismology, Volcanology and Disaster, Mitigation, Nagoya University, Philippines 2 Department of Geography, Nagoya University, Japan 3 Syah Kuala University, Indonesia

Since the occurrence of the 2004 Sumatra earthquake, the Nagoya University (NU) team together with the Syah Kuala University (SKU) had undertaken several field surveys related to that earthquake. Most of the field surveys were related to the effects of tsunami, Global Positioning Satellite measurements, and building/engineering inspection. This study presents the results of the field surveys that were done mostly in the north and northeastern shorelines of Banda Aceh. Due to limited time and logistical constraints, the investigations in each area were mostly ocular investigations wherein measurements of wave heights and relative subsidence or uplift were estimates from other cultural monuments using a hand-held level, Brunton compass, portable GPS receivers, topographic maps, satellite imageries, and pacing. Parts of the surveys also included search for old tsunami deposits and investigations of the Sumatra fault. Based on two field surveys, tsunami effects from the 2004 Sumatra quake vary from erosion to deposition of huge boulders, sand, mud and debris from the shorelines. In Aceh city and along the northwestern shorelines, most of the damage was from the debris-laden flood-like waters while total devastation of communities were observed near and along the shore. Many communities were also lost, vast land areas were eroded and subsidence of at least 40 cm were observed extensively. On the other hand, the moderate ground shaking produced by the 2004 Sumatra quake caused extensive damage on poorly-built structures in Aceh city. Damage ranges from minor damage on walls, pancake collapse, collapse of soft floors, and structural failure of beams and columns. No liquefaction-like damage was observed. In case of the old earthquakes and tsunamis, evidence of liquefaction was found in Lhok Ngah within a massive sand layer near the shore. However, no tsunami deposit prior to the 2004 event was found in the same vicinity. Moreover, clear evidence of active faulting was observed on the western splay of the Sumatra fault in Matair and the southwestern portion of Aceh city. Application of INQUA intensity scale for this event would be attempted for uniform data acquisition/banking that could be useful for future earthquake disaster mitigation and education campaign. The local construction practices should also be given more attention to mitigate future disasters related to ground shaking.

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0921 10-Be shows that Namibian drainage basins are slowly, steadily, and uniformly eroding Paul R Bierman1, Kyle K Nichols2, Ari Matmon3, Yehouda Enzel4, Jennifer Larsen4, Robert Finkel5 1

University of Vermont, United States Skidmore College, United States 3 Institute of Earth Sciences, Hebrew University, Israel 4 Hebrew University, Israel 5 Livermore National Laboratory, United States 2

Namibia, home to the dramatic Great Escarpment and one of the driest coastal plain deserts in the world is eroding slowly and uniformly at an average rate of ~8 m/My. To estimate this overall erosion rate, we collected water-transported sand from small ephemeral stream and river beds draining the coastal plain, the Great Escarpment, and the uplands as well as from the drainage networks of two major rivers, the Swakop and Omaruru, which have their headwaters on the uplands, cut across the escarpment zone, and traverse the coastal plain. We sampled sediment from a variety of basin sizes (1 – 29,000 km2). We infer rates of landscape change from a series of 38 high precision (1 sigma, 1.3–3.2%; mean = 1.7±0.5%) measurements of 10-Be made in quartz extracted from samples of river-borne sand (250 – 850 um grain size). All samples contain significant concentrations of 10-Be (0.54 – 1.75 million atoms/g quartz) which when considered as steady state erosion rates, results in a range from 4.1 to 12.2 m/My and an average of 8.3±1.9 m/My for the dataset as a whole. Considering the small basins by province, the upland is eroding at 4.9±0.8 m/My (n=3), the lowland at 7.8±1 m/My (n=1), and the escarpment zone at 8.2±2.3 m/My (n=11). The furthest downstream samples on the Swakop (29,000 km2) and Omaruru Rivers (8000 km2) give model erosion rates of 8.8±1.0 and 8.6±1.1 m/My respectively, rates which match well area-weighted averages of tributary streams (8.9±1.6 (n= 6) and 8.3±1.3 m/My (n=4), respectively). There is no downstream pattern in the 10Be concentration along either main stem river nor is there any relationship between erosion rate and basin area in the dataset as a whole. What does all this mean? First, we find that basin-scale rates of erosion are 2X higher than those on exposed rock surfaces (as reported in Bierman and Caffee, 2001) suggesting that the presence of even a thin veneer of regolith speeds rock weathering. Second, rates of erosion estimated in fluvial sediment using 10-Be are remarkably homogeneous, varying < 3X over large areas. Third, slow rates of erosion determined cosmogenically match well those modeled from thermochronologic data suggesting steady, slow erosion over time and fourth, the new cosmogenic data provide no evidence for significant escarpment retreat over time; rather, they suggest that the escarpment, and all other mega-geomorphic features of the Namibian landscape must be long-lived, stable landforms. 0160 Radar-derived bed roughness characterization of Institute and Möller Ice Streams, West Antarctica, and comparison with Siple Coast ice streams Rob Bingham1, Martin J Siegert2 1

British Antarctic Survey, United Kingdom University of Edinburgh, United Kingdom

2

Subglacial bed conditions exert a significant control on ice stream behavior and evolution, and can usefully be characterized by determining bed roughness from FFT analysis of radar-imaged basal reflectors. In

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this paper we assess bed roughness across Institute Ice Stream (IIS; 81.5°S, 75°W) and Möller Ice Stream (MIS, 82.3°S, 65°W), West Antarctica, and compare our findings with bed roughness determined across the Siple Coast ice streams. We find that variations in bed roughness are spatially organized, and attribute this predominantly to the varying efficacy of subglacial erosion and deposition, with rougher (inland, slow-flowing) regions largely manifesting preglacial topography, and smoother (downstream, fast-flowing) regions evincing significant modification to the subglacial landscape. The observed similarities between the bed roughness characteristics of IIS/MIS and the Siple Coast ice streams suggest that IIS and MIS are largely underlain by wet, poorly consolidated sediments, and may therefore be vulnerable to the types of dynamical instabilities experienced by the Siple Coast ice streams. The connection between modern basal roughness and ice dynamics is particularly useful in judging former ice sheet dynamics from deglaciated terrain.

0846 Are pollen-based biome reconstructions a good reflection of large-scale vegetation patterns? Heather A Binney, Mary E Edwards University of Southampton, United Kingdom

At continental scales, vegetation dynamics are apparent as the appearance, fragmentation, and disappearance of vegetation formations over time. Assuming that these patterns are mainly controlled by climate, they are likely to reflect variations in key atmospheric circulation features, such as the average position of the polar jet and associated storm tracks or the strength of a monsoon system. General Circulation Models (GCMs) are most effective when simulating features at this scale. Increasing levels of atmospheric greenhouse gases are driving the need to model future climates; thus it is important to know how well models simulate climates different from those of the present day. Patterns of actual past vegetation as recorded by palaeodata can be used as bench marks to evaluate the effectiveness of model simulations of past climate. The technique of biomization allows the mapping of large-scale vegetation patterns from pollen data, and it has the advantage that results can be compared relatively easily with modern vegetation distribution (or simulated vegetation). There are, however, scaling issues inherent in biomization: pollen samples from different types of site integrate the vegetation signal over different sized areas. For example, pollen from lake sediment better reflects broad-scale patterns of vegetation, whereas spectra from local sites (moss polsters or mires) reflect the fine-scale mosaic. Spatial bias and/or uncertainty are also a function of dominant pollen types, topography, and wind. We address these issues using an updated modern pollen data set for the northern extra tropics. By comparing pollen-based biome distributions with observed modern vegetation in key regions and ecotones, we assess the success of biome assignment. The results will help inform data-model comparisons made for reconstructed palaeovegetation and model simulations.

0937 The distribution of Foraminifera in Gulf St Vincent - proxies for sea-level changes John H Cann, Mary-Anne NM Binnie University of South Australila, Australia

Port Gawler, on the northeastern coast of Gulf St Vincent, South Australia, is an area of tidal dominated bioclastic carbonate sedimentation in which foraminifera comprise a substantial component of the sediment. This study examined the distribution of species of benthic foraminifera in surficial intertidal sediments at Port Gawler. Sediment samples were collected from seven sites. These samples were washed and wet sieved to remove their mud component, and when dry, the grain size fractions 0.25– 0.50 mm were prepared for microscopic examination. Applying standard micropalaeontological procedures and techniques, >300 foraminifera tests were picked from each sample and the percentage abundances of species were determined. The most prolific species of benthic foraminifera at Port Gawler are Nubecularia lucifuga (almost 60% at site 3A), Peneroplis planatus (33% at site 3B), Discorbis dimidiatus (almost 20% at site 6B), Cribrobulimina mixta (9% at site 6B) and Elphidium crispum (5% at site 2A). Triloculina inflata and morphologically similar T. oblonga together comprise 12% at site 5F. These species are considered to be the key indicators of the intertidal seagrass environments and thus provide excellent proxies for palaeoenvironmental inferences. Less abundant species comprising less than 5% of the total in any sediment sample include the Textulariids Trochammina inflata, Clavulina difformis and C. multicamerata. Miliolid species include: Spiroloculina antillarum, S. tricosta, Vertebralina striata; three species of Quinqueloculina, Q. lamarckiana, Q. parvaggluta and Q subpolygona; three additional species of Triloculina, T. striatotrigonula, T. tricarinata, T. trigonula; and the less abundant Miliolinella labiosa, M. subrotunda and Scutuloris parri. Helenina anderseni and E. macelliforme comprise the Rotaliid species. 0116 Sea-level in Singapore since the last Interglacial Michael Bird1, Keith Fifield2, Tiong Sa Teh3, Chew Hung Chang3, Nick Shirlaw4, Wei Chong Pang5, Kurt Lambeck2 1

University of St Andrews, United Kingdom Australian National University, Australia 3 Nanyang Technological University, Singapore 4 Land Transport Authority, Singapore 5 Singapore 2

Consideration of the Quaternary stratigraphy, sea-level history and detailed bathymetry of the Straits of Singapore, the first potential barrier to dispersal between mainland Southeast Asia and Sundaland, suggests that a marine connection between the Indian Ocean and South China Sea through the Straits did not exist until the Last Interglacial Period (oxygen isotope stage 5e). A tenuous connection also existed during stages 5a and 5c, as well as possibly stage 5b. During these periods, strong currents flowed from west to east (the opposite direction to modern net flow) along a narrow palaeochannel that can be identified in the floor of the modern straits. These currents were responsible for scouring the 204 m ‘over-deepened’ basin (the ‘Singapore Deeps’) and a similar 102 m deep basin south of the southern outfall of the Riau Straits. The region has been undergoing down-warping at a rate of 0.06 – 0.1 mm/yr since the beginning of the Last Interglacial Period, and this suggests that the land bridge from Peninsular Malaysia into insular


southeast Asia may only have been severed for brief intervals in Stage 5, and thus did not act as a significant barrier to migration for most of the Quaternary. In addition we report a new high-resolution Holocene sea-level curve for Singapore based >50 radiocarbon dates from elevations of +1.43 m to −15.09 m representing sea-level index points in intertidal mangrove and shallow marine sediments deposited by sea-level rise accompanying deglaciation. The results indicate that mean sea level rose rapidly from around −17 m at 9500 cal BP to around −3 m by 8000 cal BP. After this time, the data suggest (but do not unequivocally prove) that the rate of sea-rise slowed for a period of 300 –500 years centred on ~7700 cal BP, shortly after the cessation of meltwater input to the oceans from the northern hemisphere. Renewed sea-level rise amounting 3-5 m began around 7400 cal BP and was complete by 7000 cal BP, producing a highstand 2.5 m above sea-level. The existence of an inflection in the rate of sea-level rise, with a slow-down centred on ~7700 cal BP, is broadly consistent with other available sea-level curves and is supported by evidence of stable shorelines and delta initiation elsewhere at this time. ‘Stepped’ sea-level rise occurring shortly after 7500 cal BP and also earlier during deglaciation may have served to focus significant post-glacial episodes of human maritime/coastal dispersal, into comparatively narrow time intervals. 0065 Can non-annually dated proxy archives be correlated at decadal scale? A meta-analysis of climate change c. 850 cal BC Maarten Blaauw1, Dmitri Mauquoy2 1

Earth Sciences, Uppsala University, Sweden Department of Geography and Environment, University of Aberdeen, United Kingdom 2

The spatio-temporal pattern of past abrupt climate change is often inferred through comparing proxy archives from different types of archives and multiple regions. However, many archives are non-annually dated and thus have considerable chronological uncertainties. These uncertainties can result in mistaken interpretations through age-modelling errors, subjective selection of age-models, mistaken interpretations of proxy data, tuning with other archives, or the drawing of suggestive lines to align events between archives. Two recently developed Bayesian statistical methods could avoid or reduce the above problems. The methods are applied to several high-resolution 14C dated archives which were used to infer abrupt solar forced climate change c. 850 cal BC. Using varying time-windows, we check to which extent non-annually dated proxy archives can properly answer annual to millennial time scale questions. 0196 Registration of a past climate event c. 850 cal BC: Bayesian analysis of multiple cores from within a raised bog site Maarten Blaauw1, Dmitri Mauquoy2, Bas van Geel3 1

Palaeobiology, Department of Earth Sciences, Uppsala University, Sweden Department of Geography and Environment, University of Aberdeen, United Kingdom 3 Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, The Netherlands 2

Recently Bayesian methods were developed to test for the timing of events between proxy archives (Blaauw, M. J.A. Christen, D. Mauquoy, J. van der Plicht, K.D. Bennett, 2007. Testing the timing of radiocarbon-dated events between proxy archives. The Holocene 17:

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283–288). The methods are applied to four existing high-resolution 14 C wiggle-match dated cores from within a single raised-bog complex in The Netherlands. All cores span a period of inferred climate change c. 850 cal BC, at the start of a period of low solar activity. Within-site variability, especially for small-scale macrofossil changes, can make climatic interpretations difficult. Using time-windows of varying size, we check to which extent non-annually dated proxy archives can properly answer annual to millennial time scale questions. 0610 A meta-analysis of climate change c. 850 cal BC using high resolution proxy archives Maarten Blaauw1, Frank Chambers2, Dmitri Mauquoy3, Gill Plunkett4, Graeme T Swindles4, Bas van Geel5, Dan Yeloff5 1

Palaeobiology, Department of Earth Sciences, Uppsala University, Sweden Centre for Environmental Change and Quaternary Research, University of Gloucestershire, United Kingdom 3 Department of Geography and Environment, University of Aberdeen, United Kingdom 4 School of Geography, Archaeology and Palaeoecology, Queen’s University Belfast, United Kingdom 5 Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, The Netherlands ACCROTELM members* 2

The spatio-temporal pattern of past abrupt climate change is often inferred through comparing proxy archives from different types of archives and multiple regions. However, many archives are non-annually dated and thus have considerable chronological uncertainties. These uncertainties can result in mistaken interpretations through age-modelling errors, subjective selection of age-models, mistaken interpretations of proxy data, tuning with other archives, or the drawing of suggestive lines to align events between archives. Two recently developed Bayesian statistical methods could avoid or reduce the above problems. The methods are applied to a suite of high-resolution 14C dated archives (mostly from European raised bog deposits) in order to investigate the existence, nature and extent of an abrupt solar forced climate change c. 850 cal BC. Within-site variability, especially for small-scale macrofossil changes, can make climatic interpretations difficult. Even more, some proxy types show asynchronous responses within cores (e.g. macrofossils vs. biomolecules). Using varying timewindows, we check to which extent non-annually dated proxy archives can properly answer annual to millennial time scale questions. 1029 Late Holocene hydrological change in mid-latitude Europe Dan J Charman1, Antony Blundell2, Dmitri Mauquoy3 1

University of Plymouth, United Kingdom University of Liverpool, United Kingdom 3 University of Aberdeen, United Kingdom 2

Records of late Holocene hydrological variability are well-preserved in raised bogs throughout northwest Europe. Despite a long history and increasing number of these records, there have been few attempts to synthesise them quantitatively to provide a regional summary of changes at decadal to centennial resolution, or to explore spatial variability in hydrological change across Europe. This is due to a variety of factors, including variability in the sensitivity of individual sites and locations within those sites to change, difficulties of comparing records at different sites using different proxies, and chronological uncertainties making direct correlation of records problematic. Many of

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these problems have parallels in other archives and proxy records. Here we address some of these problems by assembling a series of water table reconstructions from across Europe based on testate amoebae analyses of raised mire peat covering the last 5000 years. To minimise problems of comparability between sites, the same methodology has been applied at 6 sites in a transect running from Ireland to Estonia. Past water table change was inferred from testate amoebae assemblage data using a new transfer function based on modern taxon assemblages at the sampled sites. High precision chronologies were based on wiggle-matched radiocarbon dates, supplemented by bombspike radiocarbon, 210 Pb and spheroidal carbonaceous particles for the last 150 years of peat accumulation. The water table reconstructions were detrended to remove possible influences of long term autogenic changes of the peatland system, then normalised and expressed as anomalies compared to the same standard reference period for all records. Patterns of change at the pan-European scale are assessed and compared to a stacked water table record from northern Britain and lake level changes in central Europe.

this band differs distinctly from the rest of the stalagmite, but mirrors the changes seen in the Ethiopian sample, with a significant relative increase in vegetational biomarker input being accompanied by substantial changes in the C27/C31 n-alkane and the C24/C28 n-alkanol ratios. We therefore propose that this band represents a decline in the overlying woodland and a period of vegetational clearance. Significantly, while the lipid signals show close relationships to the overlying vegetation, they also record events that are not apparent in established stalagmite proxies such as stable isotopes. Therefore this new technique allows us to decouple vegetation records from climatic records and so identify periods of human impact on the environment.

0723 Decoupling vegetation and climatic records using lipid biomarkers preserved in stalagmites

A complex subduction situation between the converging Philippine and Eurasian Plates and the resulting arc-collision zone of the Luzon arc are responsible for the high seismicity and the formation of the compressive mountains of Taiwan. Altitudes above 3000 m are quite common, the highest peak being at 3952 m. The mean uplift of Taiwan is calculated at 5 – 10 mm/a in the last million-year timescale. The high seismicity prepares the rock for erosion by loosening the near-surface material and triggers differently scaled mass movements. In addition, the monsoon-driven precipitation regime, reinforced by seasonal typhoon events (Ø3.8 p.a.), generates high surface dynamics and denudation by landslides, debris flows and fluvial erosion. The recent values for erosion are estimated at 2 – 8.6 mm/a, but with some considerable spatial differences. Two major factors are responsible for relief formation in the high mountains of Taiwan: tectonic activity and the climate of the past and present. During the last glacial cycle the upper parts of the mountains were glaciated, the valleys below are formed exclusively by fluvial processes. Greatly reduced sediment transport in the study areas above 3000 m is obvious, as slopes and debris cones of Holocene age are well preserved. Holocene periglacial activity is documented but was probably more vigorous about 3000 years BP. The present-day critical lower limit for debris production varies between 3600 m and 3700 m. This differentiated denudation pattern is partly the result of the delayed reaction of the surface to climatic changes, but it may also be steered by a reduction of precipitation in the top areas of the mountains, which reach above the shallow monsoon circulation and are mainly influenced by the westerlies. The main precipitation here is also related to typhoon events in summer, but the pre-existing soil moisture may be reduced, and fine-grained material only occurs in small areas, reducing the slope dynamics. These observations imply that uplift and denudation are not in steady-state and that the high erosion rates have not yet reached the highest peaks and crests.

Alison J Blyth1, Andy Baker2, Asfawossen Asrat3, Paolo Montagna4, Melanie J Leng5, Malcolm McCulloch6, Jon Watson7 1

McDonald Institute for Archaeological Research, University of Cambridge, United Kingdom 2 The University of Birmingham, United Kingdom 3 Addis Ababa University, Ethiopia 4 Central Institute for Marine Research, Rome, Italy 5 NERC Isotope Geosciences Laboratory, British Geological Survey, United Kingdom 6 Research School of Earth Sciences, The Australian National University, Australia 7 Planetary and Space Sciences Research Institute, The Open University, United Kingdom

Understanding how vegetation regimes change through time is a key issue in understanding how climate change and human populations impact on terrestrial ecosystems. Here we present a new chemical tool for investigating past vegetation change, using plant-derived lipids preserved in stalagmites. Lipid biomarkers are established environmental proxies, while stalagmites provide long and easily datable profiles, protected from post-depositional disturbance. Combining the two allows high resolution records of environmental change to be obtained back to at least 500 ka. The results presented form the first high resolution lipid records to be recovered from stalagmites, and demonstrate a clear relationship with changes in the overlying vegetation. Stalagmites from Ethiopia and Italy were analysed. The former, collected from the Mechara karst, encompass the past 100 years, a time period which saw the overlying native scrub cleared to make way for agricultural crops. These variations are clearly seen in the lipid signals preserved, particularly as substantial changes in the C27/C31 n-alkane and C24/C28 n-alkanol ratios. In both cases, a switch is seen from those compounds more associated with woodland vegetation (C27 n-alkane, C24 n-alkanol) to those more commonly dominant in grasslands and crops (C31 n-alkane, C28 n-alkanol) as agricultural activity developed. The hypothesis that these lipid signals are a coherent set of signatures relating to specific environmental changes is supported by the lipid signal seen in PDS-5, a stalagmite collected from the Tuscan coast. The sample contains a distinct band of heavily laminated calcite that, based upon calcite structure and trace element analyses, represents a major disturbance in the overlying environment. The lipid profile of

0438 Differentiated Denudation in the High Mountains of Taiwan Margot Boese Freie Universitaet Berlin, Dept. of Earth Sciences, Physical Geography, Germany

0440 Geomorphological Processes in the High Mountains of Taiwan Margot Boese1, Jiun-Chuan Lin2 1

Freie Universitaet Berlin, Dept. of Earth Sciences, Physical Geography, Germany 2 National Taiwan University, Taipei, Dept. of Geography, Taiwan

The almost 4000 m high mountains of Taiwan are influenced by high seismicity, humid monsoon climate, and typhoons. Tectonic deformation by earthquakes in connection with high precipitation rates and


intensities results in rapid and intense denudation processes at slopes and strong dynamics in the fluvial system. Earthquakes, landslides, and floods constitute a high risk for the population and the infrastructure (dams, traffic routes, and settlements). The Chi-Chi earthquake in 1999 has increased the sensitivity to slope failures. Immediately after that event, about 20 000 mass movements were recorded. During the following years, extreme rainfall events, most of them linked to typhoons, induced an increasing number of landslides, and extreme sediment transport in fluvial systems occurred. As time elapsed after the earthquake the number of “new” landslides decreased, and the processes focussed on the erosion and transport of the material provided by the previous landslides.The Tachia Hsi in Central Taiwan provides an example of these dynamics. The upper catchment beween 1400 and 3742 m asl comprises different morphologic altitudinal zones. In Nanhuta Shan a Pleistocene glacial zone and a Holocene periglacial to subperiglacial zone were distinguished. At elevations above 3000 m the activity of slope and fluvial processes is restrained. Below 3000 m, landslides and debris flows provide the fluvial system with material which is deposited in the 10 km long Deji Reservoir at 1400 m asl. These accumulations are visible in the distal part. Further downstream, huge landslides affected the slopes, destroying several kilometres of the Central Cross Highway and providing the bulk of sediments for fluvial transport. Consequently two other dammed lakes at 900 m and 750 m asl have been completely filled with sediments; power stations, bridges, roads and houses have been destroyed. The flood plain was heightened, e.g. 30 m at Kukuan Bridge At present, the sediments in the fluvial channel are being eroded. 0443 Surface Exposure Dating of Glacial Boulders in the High Mountain Range of Taiwan and its Implication for the Late Glacial Equilibrium Line Altitude Margot Boese1, Robert Hebenstreit1, Susan Ivy-Ochs2 1

Freie Universitaet Berlin, Dept. of Earth Sciences, Physical Geography, Germany 2 ETH Zürich, Institute for Particle Physics, Switzerland

The High Mountains of Taiwan, with altitudes almost up to 4000 m asl, are located at the eastern fringe of the Pacific, across the Tropic of Cancer. Glacial landforms and sediments in three presently unglaciated mountain massifs, the Nanhuta Shan, the Hsueh Shan and the Yushan, located in northern and central Taiwan, support the concept of repeated glaciations of the Taiwanese high mountain range during the late Pleistocene. Previously reported Optically Stimulated Luminescence (OSL) data deriving from well-preserved glacial and glacier-related sediments suggest a glaciation, termed the Nanhuta glacier advance, during the Late Glacial or even the transition to the Holocene. Several new surface exposure data from glacial boulders in the Nanhuta Shan, using in situ produced cosmogenic 10Be isotopes, confirm a Late Glacial age of the sediments and therefore of a distinct glaciation with a well defined extent. The relationship of annual precipitation and summer (JJA) temperature is used to estimate the present theoretical (virtual) equilibrium line altitude (ELAt) at about 4000 m over the southern and 3900 m over the northern part of Taiwan, i.e. just above the present-day peaks. Considering a minimum post-glacial mountain uplift rate of 5 mm/a in the tectonically very active region, the equilibrium line altitude (ELA) was at an average of 3400 m during the Late Glacial which corresponds to an ELA depression (DELA) of 500 m during this period. Data from the local LGM or earlier are still rare, but glacial landforms and deposits indicate a possible DELA of 900 m and the ELA position at an average of 3000 m or even lower.

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0743 Termination I registered in a sequence of the Falkland Islands, southern Atlantic Ocean SJP Bohncke, HAW de Goffau Vrije Universiteit Amsterdam, Department of Paleoclimatology and Geomorphology, The Netherlands

The Falkland Islands are an intriguing area due to its position in the Southern Atlantic Ocean and its closeness to Antarctica. Paleoenvironmental data from the Falklands may potentially contribute to the debate with respect to the Antarctic Cold Reversal (ACR). A 5.60 m long core was collected from a coastal cliff at the Falkland Islands. The bottom part has been subjected to pollen analyses and Thermo Gravimetric Analysis (TGA). This analysis involves a step wise burning of the sample and in this way it separates different LOI fractions. The record starts with lacustrine clay, gradually passing in to organic gyttja at 5.34 m. This transition is dated to 12,025 + 70 BP. The gyttja, together with the riparian and aquatic taxa, argues for open water in which organic productivity was high. The LOI shows a steady increase up to this depth after which both the 330 ˚C and the 550 ˚C LOI show a drop. Probably there are still moments of minerogenic input into the lake. From 5.60 m to 4.93 m high Poaceae values are present indicating cold moist conditions. The hydroseral succession culminates in a dry phase with dominance of Empetrum and was dated to 10,200 + 60 BP. The dry phase however, starts slightly earlier, around ca. 10,450 BP, which is shortly after the end of the ACR. Here both Empetrum values and the C/N ratio increase as well as the easy burnable TGA fraction (330 ˚C). Subsequently, the TGA returns to values that were registered prior to the Empetrum phase. Simultaneously with this dry phase, pollen from the South American mainland is registered, indicating that the westerlies have descended southwards and the influence of sea ice around Antarctica has declined. 0235 Holocene bedload transport and mass wasting sedimentation in a steep coastal area, St. Lawrence Estuary, Canada Andrée Bolduc1, Mathieu Duchesne1, Calvin Campbell1, Guillaume St-Onge2, Patrick Lajeunesse3, Philippe-Xavier Normandeau4, Nicolas Pinet1 1

Geological Survey of Canada, Canada Université du Québec à Rimouski, Canada 3 Université Laval, Canada 4 École Polytechnique de Montréal, Canada 2

The integration of multibeam surveys (including backscatter index) with high-resolution (seismic and sidescan sonar) geophysical surveys and seafloor sampling is used to build a comprehensive geological framework of the Quaternary succession of the St. Lawrence Estuary (eastern Canada). The sedimentary succession locally reaches up to 500 m in thickness and likely records at least the last 2 major continental glacial and interglacial sequences. Rapid sedimentation rates in the Estuary (up to 7m/kyrs) have blanketed any glacial morphology that may have been present. Superficial coring (7.2) might be expected in the future, Australia-wide. This data have been combined with information such as the total displacement across faults in the current stress regime, fault length and distribution, and relationship of faults to contemporary seismicity, topography and landscape to assess the response of the Australian crust to the imposed stresses. The primary finding is that response is heterogeneous and Australia may be divided into a number of ‘neotectonic’ domains which are distinguished by differing active fault characteristics. The model implies that earthquakes behave similarly within the large neotectonic domains, providing a validation for the large areas of similar background rate used in probabilistic seismic hazard assessment. Furthermore, discretion should be used when applying an understanding of fault behaviour across domain boundaries, or between SCRs. The neotectonic domains proposed in this paper are a first attempt to group active faults of like characteristics. With more paleoseismicity data (to capture variability in source behaviour) and consequent refinement of domain boundaries, extrapolations may be made from well-known faults, and models describing the long term seismic behaviour of the Australian crust developed. The potential exists thereby to overcome

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the limitations of the short historic record of seismicity in Australia, upon which all current seismic hazard assessments are based. 0914 Temporal clustering of surface ruptures on stable continental region faults: a case study from the Cadell Fault scarp, southeastern Australia Dan J Clark1, Russ van Dissen2, Matt Cupper3, Clive Collins1, Amy Prendergast1 1

Geoscience Australia, Australia GNS Science, New Zealand 3 The University of Melbourne, Australia 2

A characteristic of Australian stable continental region (SCR) faults appears to be the temporal clustering of surface rupturing earthquakes. With the possible exception of active faults in the Flinders/Mt Lofty Ranges region of South Australia, active periods of earthquake activity comprising a finite number of events are separated by much longer periods of seismic quiescence. This relationship is well illustrated by the Cadell Fault, which is the most prominent example of a multiple-event Quaternary fault scarp in southeast Australia. The ~55 km long and up to 15 m high main section of the scarp is developed in the Cenozoic sediments of the Murray Basin and has been modified by fluvial processes relating to the Murray and Goulburn Rivers. Dating of relict fluvial features on the hanging wall, including palaeochannels and paired terraces, constrains the age of initial uplift to ca. 50–65 ka. A 3–4 m high tectonic terrace riser bordering the channel of the paleo-Murray River, now an airgap, is consistent with entire scarp-length rupture. At least four earthquakes of between Mw 7.0–7.3 are required to produce the observed relief, equating roughly to one event every ca. 15 kyr. Total slip in the last ca. 60 ka on the 50 degree west-dipping fault is in the order of 20 m, suggesting a slip rate of ~0.3mm/yr. Seismic reflection data image a 75 m vertical offset (~98 m total displacement) of the base of the mid Eocene Renmark Group across the fault. The base of the Pliocene to Quaternary Shepparton Formation is vertically displaced by approximately 40 m. The post-mid Eocene slip rate is therefore in the order of 0.003 mm/yr, and the post-Miocene slip rate is ~0.010 mm/yr. Hence, the slip rate calculated over the last 60 ka is one to two orders of magnitude greater than the long term slip rate. A simple sequence stratigraphic analysis of the seismic reflection data confirms temporally clustered rupture behaviour, with two distinct growth sequences of strata alternating with thick sections of no apparent fault growth. Clustered rupture behaviour poses particular problems for seismic hazard assessment, which relies on the regular recurrence of events. However, the episodic earthquake recurrence model proposed here, based upon data from the Cadell Fault, might be used to express the relative probability for the occurrence of a near-future event on an SCR active fault. 0940 Models for crustal deformation in a stable continental region setting: insight from the southwest of Western Australia Dan J Clark Geoscience Australia, Australia

In recent times, high resolution digital elevation models (DEMs) have emerged as an important tool for finding and characterising earthquake related geomorphology, and particularly fault scarps. The results of a reconnaissance investigation of two DEM datasets covering a large portion of southwest and central Western Australia are presented. A total of thirty-three new fault scarps of probable Quaternary age have

been identified, bringing the total number of neotectonic features in the area to sixty. The scarps are spatially isolated and range in length from ~15 km to over 45 km, and from ~1.5 m to 20 m in height. Most scarps where a displacement sense could be determined from the DEM data suggest reverse displacement on the underlying fault. In the few instances where high-resolution aeromagnetic data are coincident with a scarp location the ruptures are seen to exploit pre-existing crustal weaknesses. Twenty-one of the features have been verified as fault scarps by ground-truthing, and range in apparent age from perhaps less than a thousand years to many tens of thousands of years. Four have been quantitatively examined to determine source parameters (e.g. timing of events, recurrence, magnitude). This rich neotectonic record provides an opportunity to understand the characteristics of intraplate deformation, both at the scale of a single ‘active’ fault and at the scale of the entire Precambrian shield region (the Yilgarn Craton). An uniform distribution of the northerly trending scarps suggests that strain is uniformly accommodated over the Yilgarn Craton at geologic timescales, and that the easterly-trending compressive contemporary stress field has pertained for hundreds of thousands of years or more. This evidence supports a model whereby the lower, ductile part of the lithosphere is uniformly strong and deforms uniformly, and the upper (seismogenic) layer accommodates this large-scale flow by localised, transient and recurrent brittle deformation in zones of pre-existing crustal weakness. The proposed model implies uniform seismic hazard across the southwest of Western Australia, but at a timescale much greater than useful for most seismic hazard assessment applications. Palaeoseismological data on individual faults is playing an important role in bridging the gap between this seismicity model and the historic record of seismicity in Australia, upon which all current seismic hazard assessments are based. 0596 A new alpine ice core record from Pacific North America Douglas H Clark1, Eric J Steig2, Erin C Pettit3, Joe McConnell4 1

Western Washington University, Bellingham, WA 98225, United States United States 3 Cold Regions Research and Engineering Lab, Alaska, Fort Wainwright, AK 99703, United States 4 Desert Research Institute, Reno, NV 89512, United States 2

Climate in the northeast Pacific shows significant multi-decadal and longer timescale variability, with affinities to climate across the Pacific, yet the instrumental record in western North America is relatively short. Paleoclimate proxy data, therefore, are essential to understanding climate variability in this region. Ice cores offer particularly promising records for paleoclimate reconstructions in the region because they provide both high-resolution proxy data (such as 18O and ion concentrations, which reflect large scale circulation changes) and direct measures of snow accumulation. Furthermore, at high altitude sites where ablation rates are small, snow accumulation is a highly reliable measure of total precipitation. Here we report results from a new 65-m ice core from Mt. Waddington, Coast Range, British Columbia. Mt. Waddington is one of the most promising sites for an ice core at temperate latitudes in North America. At a regional scale, its location is highly complementary to several existing ice core records recovered from the Wrangell/St. Elias Range (at Mt. Logan and Eclipse Dome, Yukon Territory, and at Mt. Churchill-Bona, Alaska): precipitation, temperature, and geopotential height anomalies all tend to be opposite in sign between these sites and Mt. Waddington. By providing an inverse signal to those in the north, the Waddington ice core should substantially improve our ability to refine reconstructions of large-scale


circulation across the region. At a local scale, Mt. Waddington is wellsuited for coring: it supports a large, high (3000 m), doubly transfluent ice divide, Combatant Col. Radar and GPS surveys indicate that the ice is ~170 m deep at the site and flowing 200,000 borehole descriptions, >1500 radiocarbon dates, high resolution digital elevation maps). Data coverage is reasonably uniform and complete and made digitally assessable in ways that separate accumulated observations from aggregated interpretations. Using concepts such as classification of facies assemblages on boreholes and cross-sections, architectural elements are identified and mapped. Extensive dating campaigns have yielded the timing of onset and abandonment of individual delta distributaries and of alternating phases of clastic and organic floodbasin aggradation of varying local extent. The delta subsurface is very heterogeneous in build-up, not in the least because the depositional traces of many river courses run through the delta. Its architecture is the complex result of transgression and lagoon formation, fluvial, deltaic and coastal sedimentation and repeated switching of active sedimentation areas and channel position (avulsion). For many aspects of the delta evolution, the spatiotemporal trends within the delta have been reconstructed, e.g. the shifting of avulsion locations, the pacing of inland backfilling, shifts in the nature of accommodation space creation and sedimentary infilling, longitudinal trends in fluvial style and channel dimensions. The Rhine Meuse delta dataset today is used to help answer many practical questions, e.g. in groundwater management, archeological prospection and testing reservoir characterisation methodologies. It is also in use for reconstruction of amongst others sea-level rise at the river mouth, vegetation development and palaeoclimate conditions from trapped palynology, and rates of active tectonic subsidence (neotectonics) from deformations in buried terrace surfaces of Last Glacial age. Such usage aims to quantify the rates at which controlling forces operated, using the local record. That approach is underlain by detailed palaeogeographical understanding of the changing sedimentary environments over the last 15,000 years: the time it took to transform a wide perigla-

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cial braidplain valley system into the delta situation of today. Uniquely, delta-wide stratigraphic coverage allows to use evolving architectural properties as a proxy for shifts in controls. Our database will be on display though poster-sized maps and cross-sections as well as digitally browsable. We will present fresh results, covering topics such as methods of mapping and dating, anthropogenic increased sediment loads since the Neolithic, sedimentology of individual avulsions, sealevel rise and accommodation of deltaic wedges and our ongoing activities in Quaternary and sedimentological research. 0448 Early Holocene sea level rise and the southern North Sea basin Kim M Cohen, Marc P Hijma Dept. of Physical Geography, Fac. of Geosciences, Utrecht University, The Netherlands

Sea level rise (SLR) following Meltwater pulse 1b at the onset of the Holocene is addressed here. Reconstructing SLR for the period 11 – 7.5 ka cal BP suffers not so much from dating-difficulties, but suffers from a lack of index-point sites where this interval is completely covered. SLR methodologies that milk onshore records from modern coastal, lagoonal and deltaic plains, seldom reach to before 7.5 ka BP. SLR methodologies from glacio-isostatically uplifting regions locally allow relative SLR reconstruction, but the non-linearity of the rebound rates renders identification of SLR events other than Mwp1b speculative in these regions. SLR methodologies from offshore sites either lack sequential continuity (isolated index-points acquired from shelves) or the sequence terminates in the Early Holocene (coral reefs drown and modern reefs initiate). Hence, it is currently unknown to what extend the global eustatic SLR history between 11 and 7.5 ka BP is to be considered a story of gradual accelerations and decelerations, or if stepwise mini-meltwater pulses (1–3 m steps, occurring within a century or so) occurred superimposed on gradual trends. Data from the Early Holocene Rhine mouth into the Southern Bight area of the Southern North Sea Basin (SNB) offers insight in the nature of Early Holocene global SLR trends. Owing to a peculiar palaeogeographic setting, it is one of the few areas in the world, where Early Holocene transgressive sediments have been preserved within the modern coastal plain, at 13–20 m below O.D., deep enough to be sheltered from destruction through Middle-Late Holocene reworking. Because of topographic elevation, the SNB drowned later than adjacent shelf areas too to the SW and N. The Rhine lower valley first morphed into an estuary, due to northward transgression through the Strait of Dover. By ~8.5 ka BP, further SLR had caused the northern North Sea to connect with the Southern Bight, establishing the circulations (tides, currents) of the modern situation. When inundating, however, parts of the SNB was subsiding faster than its surroundings, as echoed by the rather basin inward preservation of rather early coastal aggradations. The explanation is that the lowlands of the SNB in the Last Glacial, did host a joint glacio-isostatical forebulge of nearby Scandinavian and British ice loads. In the Late Glacial and Earliest Holocene this forebulge collapsed, inducing subsidence rates an order of magnitude greater than background normal tectonic subsidence rates in the SNB, pulling in the Early Holocene transgression.

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0466 Measuring forebulge updoming (Last Glacial) and forebulge collapse (Late Glacial and Early Holocene): geological evidence from the southern North Sea basin Kim M Cohen Dept. of Physical Geography, Fac. of Geosciences, Utrecht University, The Netherlands

Glacial forebulges are glacio-isostatic features around ice sheet margins. Forebulge collapse takes place during and following ice sheet decay and causes extra land subsidence for some duration. Geophysical modelling of Fennoscandian and British ice loads in the Last Glacial, predict forebulge crests that are upwarped >10 m high some 200 –300 km away from the ice front. The combined isostatical and gravitational effects of the nearby ice loads cause an asymmetric radial updoming effect, with a steep gradient towards the crustal suppression zone on the ice-sheet facing side, and gentle, asymptotically reducing gradients on the outer flank. It implies that the Netherlands in the southern North Sea Basin was located on the southern flank of a forebulge in MIS-2. Such predictions need geological data to validate model-predictions and/or to calibrate model parameters (e.g. crustal elasticity and mantle viscosity). The Netherlands’ geological record provides much wanted quantitative data on magnitudes, rates and timing of forebulge updoming and collapse. Holocene relative sea-level rise (SLR) in the former forebulge crest zone shows that subsidence due to forebulge collapse amounts for several meters of the SLR signal. But only the tail of forebulge collapse is evident from SLR records. Another 4 –6 m appears to be accommodated by braidplain fluvial aggradation between the Last Glacial Maximum and the start of the Holocene. During forebulge updoming and initial forebulge collapse, the Rhine and Meuse under periglacial discharge regime, formed an exceptionally wide E-W running braidplain through the Netherlands. The braidplain architecture reveals southward migration, which testifies for lateral tilting of the outer flank of the updoming forebulge. In the Late Glacial (LG) and Early Holocene (EH), discharge regime change caused abandonment of most of the braidplain in favour of meandering channel belts (anabranching in the LG, single channel system at onset EH). During this time, northward tilting towards the former forebulge crest is evident from lateral gradients of the abandoned braidplain surface and from the position of the EH channel belt relative to abandoned LG channel belts. Considering the magnitudes of observed post-depositional tilting and the timing of inferred syn-depositional lateral forcing, glacio-isostatic upwarping during the LGM was in the order of 10–15 m and caused absolute uplift, temporarily inverting the normal tectonic situation of basin subsidence. Forebulge collapse set on ~22 ka cal BP and induced the largest subsidence rates around 15 ka BP. Subsidence rates had returned to background rates by 5 ka BP. 0031 Impact of drought periods on the Amazon mangroves during the Late Holocene Marcelo CL Cohen1, Hermann Behling2, Rubén J Lara3, Hellen Matos4 1

Geology Department, Federal University of Pará, Brazil Department of Palynology and Climate Dynamics, Albrecht-von-Haller-Institute for Plant Sciences, University of Göttingen, Germany 3 Center for Tropical Marine Ecology (ZMT), University of Bremen, Germany 4 Laboratory of Coastal Dynamics, Federal University of Pará, Brazil 2

Three sediment cores from the littoral in Pará state in northern Brazil (Coca-Cola Lake, S 00°36'/W 47°17', Atalaia Bridge, S 00°38'/W

47°18' and São Caetano de Odivelas, S 00°43'/ W 48°01') were studied by pollen analysis and AMS radiocarbon dated. The pollen data document coastal vegetation dynamics during the late Holocene. Near the Amazon mouth region, the pollen record from São Caetano indicates the dominance of mangroves between 4800 and 1100 cal yr B.P. The data show a reduction of mangrove area and an expansion of herbaceous vegetation between 1100 and 750 cal yr B.P. The period between 750 and 200 cal yr B.P. is characterized by an expansion of mangrove and a decrease of herbaceous vegetation. This trend remained until today. In the eastern Pará littoral, the sediment core from Atalaia Bridge indicates a period with poor pollen preservation between 830 and 630 cal yr B.P., which probably was caused by dry conditions. Between 630 and 330 cal yr B.P., mangroves expanded. Later until 45 cal yr B.P., the mangrove area decreased and the herbaceous vegetation expanded on Atalaia Island. During the last 100 years, probably the inundation regime associated with wet climatic conditions favored the mangrove expansion to the topographically highest sector on Atalaia Island, while the herbaceous vegetation became reduced. The pollen analytical results from Coca-Cola Lake probably indicate dry conditions reflected by the poor pollen preservation between 390 and 240 cal yr B.P. Between 240 and 60 cal yr B.P., restinga (coastal shrub and herb vegetation), Amazon coastal forest with palms dominated this region. For the last 120 years, the record indicate an expansion of mangrove area. The three pollen records suggest that in the São Caetano area, which is closer to the Amazon River, the drought period occurred earlier between 1100 and 750 cal yr B.P. than in the coastal area of eastern Pará between 830 and 630 cal yr B.P. Apparently, the second dry period occurred only in eastern Pará around the time interval between 390 and 60 cal yr B.P. Mangrove expansion occurred since the end of the XIX century. 0964 Late Quaternary development of linear and source-bordering dunes in the Strzelecki desert, Australia Tim J Cohen, Gerald C Nanson, Josh R Larsen, Brian G Jones, Maria Coleman, David Price School of Earth and Environmental Sciences, University of Wollongong, Australia

The lower Cooper Creek exits the Innamincka dome into the Strezlecki desert to form a low-gradient fan characterised by a suite of alluvial landforms that have evolved through a long history of fluvial and aeolian interaction. Linear dunes with a north-south trend are dissected by the path of the lower Cooper Creek as it meanders towards its final destination at Lake Eyre. Many of the these linear dunes are often sourced out of east-west trending indurated but denuded sand bodies that are interpreted to represent source-bordering dunes. Here we present the basic chrono-stratigraphic relationships between the fluvial and aeolian units. We demonstrate through an extensive thermoluminescence (TL) and optically-stimulated luminescence (OSL) chronology that the basal core of these linear dunes are up to OIS 6 in age but typically fall within OIS 5e or OIS 4. These basal sands are interpreted to have been sourced from adjacent fluvial sand bodies that are buried by the contemporary muddy floodplain. These fluvial sand units also date from OIS 5e and late OIS 5a or early OIS 4 and represent distinctly different hydrological conditions than at present. Unlike the mud-dominated floodplain of today these sand units represent more competent rivers transporting abundant bedload. We suggest that source-bordering sands were blown northward out of the river channels in the initial phase of linear dune development. Vertical accretion of the source-bordering dunes continued throughout OIS 3 with the


onset of linear dune extension occurring from the LGM onwards. The current configuration of linear dunes on the Cooper fan represents minor linear extension (< 15 km) since ~ 16 ka. This demonstrates that the Strzelecki desert is characterised by both relict and contemporary aeolian landforms. Furthermore, it indicates that long distance transport of sand has played only a minor role in the formation of linear dunes on the Cooper fan. We suggest that a wind-rift extension model is the dominant mode of dune formation in this section of the Strzelecki desert with the bulk of sediment sourced from adjacent swales and the upwind source-bordering dunes. 1427 Carbonate sedimentation and reefs on Australia’s western margin Lindsay B Collins Curtin University, Australia

The continental shelves of Australia’s western margin are narrow and wave-dominated in the south, and are wide ramps influenced by tides and cyclonic storms in the north. Though less continuously developed than in eastern Australia, coral reefs are present in fringing to deep ramp settings from latitudes 12 to 30˚, providing a spectrum of responses to sea-level and subsidence changes. Detailed Quaternary sealevel records have been established from some of the reef systems. A biotic transition zone, characterised by overlap of temperate and tropical assemblages, occurs between the latitudes of 26 and 30˚. The continental margin is strongly influenced by the poleward-flowing, warm nutrient-poor Leeuwin Current , which promotes overall downwelling, and strong summer equatorward-blowing winds, which generate local seasonal upwelling. Whilst the more southerly shelves are dominated by bryozoans and coralline red algae, similar to the vast cool water southern margin, the warm water ramp which comprises the Northwest Shelf is tropical in character, with a mixture of sediments of relict, stranded and Holocene origins. Ooids and peloids are conspicuous but stranded particles which formed during initial stages of post-Last Glacial maximum sea-level rise, but were terminated by less saline Leeuwin Current flow, so that subsequent Holocene sedimentation is biofragmental to planktic. As the physical, oceanographic and sealevel processes generating these modern shelf systems are evaluated more fully they are likely to assist further in the evaluation of similar ancient facies on carbonate platforms with reservoir potential. 0108 Long-term interaction between fire, vegetation and climate change in Mediterranean ecosystems: a multi-proxy case study from Lago di Massaciuccoli (Tuscany, Italy) Daniele Colombaroli1, Aldo Marchetto2, Willy Tinner3 1

IPS - Institute of Plant Science - Bern, Switzerland CNR - Istituto Italiano di Idrobiologia - Verbania, Italy 3 CNR Pallanza, Switzerland 2

At the present day, the Mediterranean Basin is one of the most fire prone regions of the world, thus representing a key area to assess postfire vegetation dynamics at decadal to centennial scale. Nonetheless, only a few multi-proxy studies are available to address interactions between vegetation, fire and climatic changes during the Holocene. With the present study we provide a multi-proxy high-resolution study of the Mid to Late Holocene period at Lago di Massaciuccoli (43˚50' N, 10˚20´ E), a coastal lake located at the limit between Mediterranean and Central European climates, where ecosystems are expected to show stronger responses to environmental gradients. We use high reso-

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lution pollen and charcoal data to investigate the response of vegetation to fire under quasi natural conditions during the Early Holocene. The detailed study of the paleo-records by time-series analyses revealed a significant link between fire and vegetational dynamics, evidencing around 6000 cal. BP a transition from high diverse forest ecosystems to less diverse shrublands communities. Surprisingly, our results suggest that evergreen oaks (which are conventionally regarded as fire-tolerant) were partly disfavored by fire. Moreover, prior to fire, fire-sensitive Southern and Central European species - that are absent today in the Mediterranean lowlands (e.g. Abies alba) - were widespread around the site. Silver fir (Abies alba) declined synchronously with evergreen oaks after fire disturbance. We then use our diatom series to detect the possible role of climatic changes at a local to regional scale. Numerical methods provide evidence that terrestrial and aquatic ecosystems were (simultaneously) affected by similar processes. On the long term, the change in diatom assemblages points to a climatic shift towards drier conditions between 6000 and 5000 cal yr BP in accordance to other palaeoclimatic studies. Besides, shorter rapid changes in aquatic and terrestrial ecosystems give evidence that changes in the trophy of the lake were related to other key factors, such as an intensification of land-use activities. We conclude that long-term data may complement modern ecological observations on the role and behaviour of Mediterranean species in fire-prone environments. Assessing the long-term sensitiveness of species to fire also provides information about possible future scenarios, assuming that climate change will affect the intensity and frequency of fire events. In this sense this study provides useful data for reality checks of quantitative simulations for predictions of vegetational dynamics under global change conditions. 1340 The Last Interglacial soil in the Po Valley Mauro Coltorti Dipartimento di Scienze della Terra, Università di Siena, Italy

The Po Valley is a classic area where pedostratigraphy could be applied, together with morpho-, litho- and chrono-stratigraphy to understand the sequence of events that characterise the signature of major Interglacials. The Last Interglacial was supposed to have generated a leached paleosoil with pseudogley, particularly well expressed over loess and fine alluvial sediments. The older terrains would be weathered by a thick red Alfisol, a relict or buried soil attributed to the previous Interglacial. The oldest soils were called Vetusols, policyclic soils so deeply weathered during the older Interglacials that, although slightly recarbonatated due to colluvial or aeolian sedimentation during glacial periods, should rapidly return to the original very deep weathering conditions during the later Interglacials. However, ESL datings of the aeolian deposits below the supposed Last Interglacial soil indicated that it evolved during an Interstadial at the beginning of the Last Glaciation. In the southern fringes of the Po valley, up to three paleosoil progressively less weathered and usually created by the colluviation of the older one, staying on a typical reddish Alfisols. The colluviated soils have been associated with the Interstadials following the MIS 5e, that is represented by the deeper and reddish one. This soil could be very thick in places but they are more frequently severely truncated by later erosional processes. In the Po Valley, there are no other soils, except the alfisol frequently named “Ferretto”, to represent the MIS 5e. Obviously, as stated by Cremaschi (1987) it could also represent much older Interglacials, but when it is found in a morpho- and litho-stratigraphic sequence it represents the Last Interglacial. This attribution has major consequences for landscape evolu-

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tion, including neotectonics, and the chronological attribution of the Paleolithic industries. 1231 Intensity and coseismic surface rupture parameters Valerio Comerci1, Eliana Esposito2, Luca Guerrieri1, Bagher Mohammadioun3, Jody Mohammadioun3, Sabina Porfido2, Leonello Serva1, Eutizio Vittori4 1

Italian Agency for Environment Protection and for Technical Services (APAT), Italy 2 Institute for Coastal Marine Environment (IAMC-CNR), Italy 3 Robinswood Consultant, France 4 Agency for Environment Protection and for Technical Services (APAT), Italy

Magnitude quantifies the size of an earthquake by interpreting a seismogram, while intensity is an empirical classification of earthquake effects on humans, buildings and the natural environment. In order to use historical information for engineering applications, intensity values are commonly converted into magnitude values by means of empirical linear relationships. Many authors have obtained log-linear correlations between earthquake magnitude and surface rupture parameters. An analogous relationship could accordingly be expected between the latter and intensity. To this end, a catalogue has been compiled containing seismological (including intensity) and fault rupture parameters for more than 300 earthquakes, distributed worldwide: the SURFIN (SURface Faulting and INtensity) catalogue. Each earthquake is described by its date, epicentral region (country and locality), latitude and longitude, kinematics, slip type, focal depth, magnitude (magnitude derived from intensity, Me, for pre-instrumental events, and Ms), intensity (scaled to MM), surface rupture length and maximum displacement. Wherever available, intensity maps have been also collected and surface areas of selected intensity degrees computed. An analysis of the whole dataset has highlighted the presence of many earthquakes with intensities supposed anomalous because too dissimilar to those generally estimated for earthquakes characterized by similar evidence of surface faulting and magnitude. In fact, nowadays there is a strong tendency to focus solely on building-related effects. So, to overcome the shortcomings of this approach concerning sparsely populated or deserted areas and the highest intensity degrees (X to XII), where damage to buildings is known to saturate, the INQUA environmental scale has been developed, based exclusively on coseismic environmental effects. The analysis made possible through SURFIN has allowed earthquakes to be selected that present intensity values apparently compatible with their faulting parameters and magnitude. All the screened earthquake data have been correlated to develop empirical relationships among intensity, surface rupture length, maximum displacement and surface areas for given intensity degrees. 0664 Holocene vegetation changes in the Caucasus Mountains: climate or humans? Simon E Connor1, Eliso V Kvavadze2, Ian Thomas1 1

University of Melbourne, Australia Palaeobiology Institute, National Museum of Georgia, Georgia

2

The Caucasus is a diverse, mountainous region situated at the crossroads of Europe, Asia and the Middle East. Previous palaeoecological research into this region of high biodiversity and ancient culture has

emphasised climate as the governing force of Holocene vegetation change. This study tests that assertion, by comparing the vegetation history of Georgia to archaeological and palaeoclimatic records. An analysis of modern analogues has been applied to fossil pollen records to reconstruct past climatic parameters for Georgia. The results agree with regional trends, indicating that arid, seasonally variable conditions prevailed between 14,000 and 11,500 cal. yr BP. Precipitation increased gradually during the early Holocene, stabilising by 8000 cal. yr BP. Conditions then became seasonally wetter and warmer during the mid Holocene, followed by generally cooler, more variable climates during the late Holocene. At several sites, the surrounding vegetation did not respond to these regional-scale climatic changes in an expected manner. While forest cover expanded in most parts of the Caucasus during the early Holocene, in the semi-arid steppes of Southern Georgia the vegetation remained stable, open and relatively treeless despite increasing precipitation. Complementary analyses of charred particles and dung fungal spores demonstrate that fire and grazing had a conspicuous presence in early-mid Holocene landscapes. The long-term effects of fire and grazing may have been sufficient to suppress afforestation in semi-arid vegetation. Not until 5000 cal. yr BP did fires cease and woodlands expand in Southern Georgia, much later than at comparable sites in the continental interiors of Western Asia. I argue that the delayed expansion of forest in Southern Georgia was primarily the result of prehistoric pastoral activities. Subsequent vegetation changes, although influenced by late Holocene climatic variations, are also closely intertwined with the region’s human history. 0822 U-series speleothem dating from Pestera cu Oase (Romania) indicates the occurrence of rapid torrential events during MIS 3 Silviu Constantin1, João Zilhão2, Erik Trinkaus3, Jerome Quilès4, Stein-Erik Lauritzen5 1

Emil Racovita Institute of Speleology, str. Frumoasa 31, RO-010986 Bucuresti 12, Romania 2 Department of Archaeology and Anthropology, University of Bristol, 43 Woodland Road, Bristol BS8 1UU, United Kingdom 3 Department of Anthropology, Washington University, St. Louis, MO 631304899, United States 4 Unité toulousaine d’archéologie et d’histoire, UMR 5608, Univ.Toulouse-LeMirail, 5, allées Antonio Machado, 31058 Toulouse, France 5 Department of Earth Sciences, Bergen University, Allegaten 41, N-5007 Bergen, Norway

The recent discovery of the oldest Homo sapiens remains in Europe (Oase 1 and 2) in a newly found cave from SW Romania has boosted the hypothesis of repeated dispersals of human populations from Asia to Europe by following the Danube’s corridor and stirred the debate over the significance of some Neanderthal-like traits on ancient modern humans. It remained, however, less known that the Oase remains were found within a massive accumulation of animal bones (mostly Ursus spelaeus), sediments, and speleothem fragments topped by cave-bear hibernation nests and newly-formed stalagmites. The human remains were discovered on top of a bone accumulation that mainly contains fossil remains of cave bears which were dated between 50 and 42 ka cal BP. The thanatocenosis mainly indicates a subadult and adult male utilization of the cavity and the heavy component of con-specific bone consumption may indicate bone processing for trace elements and/or a more omnivorous diet than is usually ascribed to cave bears. At the present stage of our researches, there is no evidence that Pestera cu Oase has been used as either shelter or burial place and no artefacts whatsoever sustain the hypothesis of cultural agency (deliberate transport to the deep areas of the system) to explain the


distribution of the bones within the passages. Instead, we rather consider that geological processes (gravity, fluviatile transport and/or flash-floods) and/or carnivore behaviour (transport of prey inside the cave) are the main processes that contributed to the current stratigraphy. In order to understand the mechanisms through which this deposit has formed, samples were collected including bones, speleothems (both interbedded and actively growing), and sediments for rock-magnetism and paleomagnetism measurements. The paper presents the results of the U-series datings of more than 40 speleothem samples, which yielded ages ranging between ~210 ka and the Holocene. One of the speleothems developed over the bone breccias (~42 ka) indicating a rapid torrential event during MIS 3 that has generated the accumulation of sediments. Speleothems in Oase Cave also suggest that clogging of the main entrances have occurred some 20 ka and 8 ka ago, respectively. The measured ages have offered a timeframe for: (i) understanding the genesis of the cave system; (ii) the timing of the torrential events (flash floods) that lead to the formation of a sediments & bones jumble; (iii) clarifying the moment when cave-bears ceased to use this cave as a hibernation den or shelter. 0828 Black Sea level fluctuations based on the study of submerged speleothems from Dobrogea (Romania) Silviu Constantin1, Virgil Dragusin1, Cristian Lascu1, Stein-Erik Lauritzen2 1

Emil Racovita Institute of Speleology, str. Frumoasa 31, RO-010986 Bucuresti 12, Romania 2 Dept. of Earth Sciences, Bergen University, Allegaten 41, N-5007 Bergen, Norway

Several speleothem samples from Piatra Cave (Dobrogea, South-East Romania) were dated by means of alpha and mass spectrometry, in order to obtain some key-points of the chronology of Black Sea fluctuations. Piatra Cave is a submerged cave located a less than 1 km far from the Black Sea shore at an absolute altitude of ~1–2 m, and displaying the whole range of speleothems normally encountered within a vadose (sub-aerial regime). Since the water level in the cave is considered to be tightly connected with that of the Black Sea, speleothem growing intervals indicate low sea stands. In spite of a low Uranium content (0.04 – 0.1 ppm), all dated subsamples showed good chemical extraction yields, thus providing analytical reliable dates. One of the stalagmites appears to have been grown very rapidly during the Eemian, between 112 ± 10 ka and 122 ± 13.5 ka (1). Another sample, yielded a TIMS-date of 597 (+108/−53) ka. Although these dates are obviously not sufficient for a detailed analysis of the Black Sea level oscillations, they reveal at least two time-periods during which the cave evolved under a vadose regime as a result of low-sea stands. The most intriguing are the samples dated from the MIS 5e stage, during which the Black Sea level is supposed to have been ~10 m higher than the present one. Since the region is known as being tectonically stable during the Quaternary, the speleothem formation may be ascribed to: (i) either a slight subsidence in the area (~15 m) since the MIS 5e; (ii) or a sea-level at least ~15 m lower than previously believed. The latter case seems to involve a certain delay of the sea-level rise during the Eemian as we know it from literature.

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0838 New data on the chronology of the Second Termination and the paleoclimate during MIS 5 based on the study of a stalagmite from Closani Cave (SW Romania) Silviu Constantin1, Stein-Erik Lauritzen2, Joyce Lundberg3 1

Emil Racovita Institute of Speleology, str. Frumoasa 31, RO-010986 Bucuresti 12, Romania 2 Dept. of Earth Sciences, Bergen University, Allegaten 41, N-5007 Bergen, Norway 3 Department of Geography and Environmental Studies, Carleton University, Ottawa, Ontario K1S 5B6, Canada

This paper presents the first isotopic profile of a stalagmite from Romania that grew during MIS 6 – 3. The stalagmite C6 was collected from Closani Cave (Southern Carpathians, Romania). This is a dry cave that shows remarkable microclimate stability with a multi-annual mean temperature of ~11°C and a relative humidity of 99–100%. A series of eight U-series TIMS dates was successfully measured on the C6 stalagmite showing that the speleothem grew continuously between c. 183 ka and c. 39 ka with low growth rates varying between 0.63 and less than 0.1 cm/kyr. The highest growth-rate, recorded between c. 183 ka and c. 103 ka, allowed a good resolution of a preliminary isotopic profile for the time-range corresponding to MIS 6 to 5c. The 18O record is considered here as representative for the variation of the average paleoclimatic conditions during the transition to the Eemian in Romania. The basal part of the profile displays several oscillations that may be attributed to MIS 6 stadials at ~180 ka and ~166 ka respectively which were recognized in several other records. A clearlymarked cooling period follows between ca. 166 and 156 ka, followed by an abrupt isotopic increase of ~3 permil during only ~7000 years which may be interpreted as the onset of the 2nd Termination. In contrast with the “classical” SPECMAP chronology which broadly places the beginning of the Eemian at some point in time between 140 ka and 130 ka, numerous speleothem records show an earlier warming. For example, the Devils Hole profile shows an early warming at ~140 ka, while studies of speleothems from North Norway have shown that the deglaciation must have occurred at high latitudes as early as 145 kyr ago. The C6 speleothem profile suggests an even earlier warming at ~45°N that may be placed as early as 155 ka, well in advance of the SPECMAP chronology. However, the C6 profile also shows a plateau during ~150 and ~135 ka followed by a short and rapid cooling recorded at c. 132 ka. This may suggests a “two-step” pattern of the deglaciation similar to the “Zeiffen-Kattegat” episode. After this oscillation, the signal shows a new isotopic increase and reaches a maximum at c. 126–123 ka which may be correlated with both “classical” MIS 5e maximum in the SPECMAP profiles and also with the isotopic signal of the LFG stalagmite from the Western Carpathians. 1185 Palaeoclimate records from stalagmites in southern Cambodia Duncan E Cook1, Paul Bishop1, Tony Fallick2, Rob Ellam2 1

Department of Geographical and Earth Sciences, University of Glasgow., United Kingdom 2 Scottish Universities Environmental Research Centre, East Kilbride, Glasgow, United Kingdom

We have collected seven stalagmites from four limestone cave systems in Kampot province in southern Cambodia in order to reconstruct palaeomonsoon dynamics in mainland southeast Asia. Diurnal measurements of cave microclimates for up to nine months have shown the

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environments in which these stalagmites have grown to be exceptionally stable and ideal for the recording of palaeoclimatic information. U-series and AMS 14C dating methods have been used to establish the chronologies of the stalagmites. A year-round study of the stable isotope chemistry of precipitation, surface water and drip water across Cambodia suggests that 18O values are controlled primarily by rainfall amount, and thus monsoon activity. Dated variations in 18O from the stalagmites have therefore been interpreted as a high-resolution record of palaeomonsoon activity, the first of its kind to be generated for tropical mainland southeast Asia. 1265 High-resolution palaeomagnetic dating bridges the gap between radiocarbon and 210Pb chronologies in eastern Australia Duncan E Cook1, Stephen J Gale2 1

Department of Geographical and Earth Sciences, University of Glasgow, United Kingdom 2 School of Geosciences, The University of Sydney, Australia

A new compilation of historical observations of magnetic inclination and archaeomagnetic data from the last c. 8000 years from eastern Australia has allowed the reconstruction of the eastern Australia inclination record (eAIR). This reveals that inclination reached its Holocene peak in the 17th to 18th centuries AD. The resultant magnetic feature may be seen in lake sediment records throughout Australia and New Zealand, and thus provides a new source of geochronological information of great importance to the dating of recent environmental sequences. High-resolution palaeomagnetic dating of the late Holocene sediment record from Tocal Homestead Lagoon in eastern Australia demonstrates how the Holocene inclination maximum may be used to bridge the gap between AMS 14C and 210Pb geochronologies in recently deposited sediments. The eAIR thus greatly improves our ability to date environmental records that span the period from immediately before to immediately after the first arrival of Europeans in Australia. 0304 The North American Drought Atlas: Tree-Ring Reconstructions of Drought Variability for Climate Modeling and Assessment Edward R Cook Lamont-Doherty Earth Observatory, United States

The North American Drought Atlas describes a detailed reconstruction of drought variability from tree rings over most of North America for the past 500 –1000 years. The first version of it, produced over three years ago, was based on a network of 835 tree-ring chronologies and a 286point grid of instrumental Palmer Drought Severity Indices (PDSI). These gridded PDSI reconstructions have been used in numerous published studies now that range from modeling fire in the American West, to the impact of drought on palaeo-Indian societies, and to the determination of the primary causes of drought over North America through climate modeling experiments. Some examples of these applications will be described to illustrate the scientific value of these large-scale reconstructions of drought. Since the development and free public release of Version 1 of the North American Drought Atlas (see http://iridl.ldeo.columbia.edu/SOURCES/.LDEO/.TRL/.NADA2004/.pdsi-atlas.html), great improvements have been made in the critical tree-ring network used to reconstruct PDSI at each grid point. This network has now been enlarged to 1743 annual tree-ring chronologies, which greatly improves the density of tree-ring records in certain parts of the grid, especially in Canada and Mexico. In addition, the number of tree-ring records that extend

back before AD 1400 has been substantially increased. These developments justify the creation of Version 2 of the North American Drought Atlas. In this talk I will describe this new version of the drought atlas and some of its properties that make it a significant improvement over the previous version. I will also argue for the North American Drought Atlas being used as a template for the development of large-scale drought reconstructions in other land areas of the Northern Hemisphere where sufficient tree-ring data exist. By doing so, the importance of this product to the modeling community will be significantly enhanced. 1003 Presentation of the Northern Australian Pollen Database Ellyn J Cook1, Sander van der Kaars1, Allan R Chivas2, Adriana García2 1

School of Geography and Environmental Science, Monash University, Australia School of Earth and Environmental Sciences, University of Wollongong, Australia 2

Knowledge of the modern distribution of pollen in relation to vegetation and climate often forms the basis for the interpretation of fossil pollen records and, increasingly, for quantifying climatic estimates from fossil pollen spectra. In Australia there exist several local or regional recent pollen data sets that facilitate comparison between modern and fossil assemblages. Wide geographic coverage for the temperate southeast of the continent is provided by the Southeastern Australian Pollen Database (D’Costa and Kershaw, 1997), regional coverage of the semi-arid zone of southwestern Australia by Newsome (1999) and, in the north of Australia, local coverage of the humid tropics region is provided by the work of Kershaw and Bulman (1994) and Crowley et al. (1994). For the remainder of the northern part of the continent, however, modern pollen distribution data are still lacking and, as increasing numbers of fossil pollen records from northern Australia are generated (e.g. Chivas et al., 2001; van der Kaars and De Deckker, 2002; Prebble, et al., 2005), the need increases for a recent pollen database for this part of the continent. This presentation introduces the newly developed Northern Australian Pollen Database, comprising one hundred and twenty four pollen spectra recovered from surface sediments of fluvial deposits, lakes, ponds and freshwater and coastal swamps from northern Australia, and intended for use as a modern reference for refinement of vegetation and climatic histories constructed for the region from fossil assemblages. The locations sampled extend from the Western Australian shrublands to the humid tropics of northeastern Queensland and, consequently, the modern pollen signatures represent a wide range of climatic and vegetational variation. Analysis of vegetation distributional data and results of multivariate analyses of the pollen spectra reveal that observed patterns of pollen representation accurately reflect modern vegetation communities as well as climatic variation, indicating the utility of the dataset for reconstruction of past climates. 1050 The Addition of Non-Pollen Palynomorphs to Pollen and Spore Analysis in Australia Ellyn J Cook1, Bas van Geel2, Sander van der Kaars1 1

School of Geography and Environmental Science, Monash University, Australia 2 Institute for Biodiversity and Ecosystem Dynamics, The University of Amsterdam, The Netherlands

Records of the past climate and vegetation of Australia are frequently constructed from analysis of angiosperm and gymnosperm pollen, and pteri-


dophyte spores alone, or in association with sediment characteristics. Occasionally some studies have integrated analyses of other biological indicators such as green algae (Singh and Geissler, 1985), diatoms (Gell et al., 1994) and ostracods (D’Costa et al., 1989, Edney et al., 1990) which have provided useful complementary records of water depth, temperature and water chemistry as well as detailed lake level and salinity histories. However, the organic residue prepared and mounted for pollen analysis generally also yields other organic walled microfossils that may be used to provide additional and somewhat independent palaeoenvironmental information. These ‘non-pollen palynomorphs’ include (but are not limited to) microscopic remains of algae, fungi, insects and other invertebrates as well as cormophytes (e.g. epidermal cells, leaf fragments) and have been used within a variety of peat, lacustrine and archaeological deposits, in many parts of the world (e.g. van Geel et al., 1989; Davis et al., 2002). Despite such demonstrated success, their analysis is still not routinely practiced in Australia. This paper presents two straightforward examples from recent work where non-pollen palynomorphs have helped to refine interpretations, thereby demonstrating their usefulness for Australian palaeoenvironmental studies. Elevated levels of fungal spores of the dunginhabiting Sporormiella type in lake cores from western Victoria have proved to be a valuable tool for indicating herbivore densities and human impact while the presence of Glomus chlamydospores and ascospores of the saprotrophic fungus Neurospora provide additional evidence for periods of erosion and local firing, respectively. In addition, remains of Gloeotrichia (cyanobacteria) provide evidence for increased trophic status during lake level decline. An assemblage of freshwater algal taxa (Botryococcus, Coelastrum, Pediastrum, Spirogyra and Zygnema) in a record from the Gulf of Carpentaria has enabled the identification of a deep freshwater lake phase during the last glacial period where uncritical analysis of the pollen alone might have led to other conclusions.

1147 Problems with using molecular data to date recent evolutionary events Alan Cooper, Jack Da Silva University of Adelaide, Australia

Recent work has indicated that molecular evolutionary rates appear to exhibit time dependency, in that rate estimates vary according to the time period over which they are measured. This is most noticeable in apparently accelerated short-term rate measurements, and can lead to a considerable over-estimate of divergence times when the molecular clock is used to estimate the timing of recent evolutionary events (eg during the Quaternary). The estimated rates appear to follow a negative exponential curve, with the most rapid estimates resulting from shortterm measurements within families or populations, and the slowest from fossil calibrations. The key issue appears to be the essential difference between rate estimates below the species level (which are primarily measuring polymorphism within populations) and the much slower rate recorded above the species level (generally calculated with a fossil date) which measure the mutation rate. The latter is the small proportion of polymorphisms that get actually fixed in a species lineage (by drift, or selective processes) over time. We have determined a mathematical equation to explain this relationship using only simple parameters and standard population genetics theory for neutrally evolving sites. The theoretical data matches empirical studies surprisingly well, and indicates that it may be possible to obtain more accurate dating estimates if population parameters are taken into account. We apply this calculation to a number of key evolutionary events and observe major changes in molecular date estimates.

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1326 Forest fires recorded at five Amazonian lakes in different time scales Renato C Cordeiro1, Renato R Rodrigues1, Bruno J Turcq2, José Carlos S Seoane3, Francisco Fernando L Simões-Filho4, Monike S Moura5, Ana Paula R de Oliveira1, Abdelfethah Sifeddine6 1

Programa de Geoquímica - Universidade Federal Fluminense, Brazil Institut de Recherche pour le Development, France 3 Universidade Federal do Rio de Janeiro, Brazil 4 Instituto de Radioproteção e Dosimetria, Comissão Nacional de Energia Nuclear, Brazil 5 Brazil 6 Institut de Recherche pour le Development, Morocco 2

Interpretations of records of biomass burn requiring a comparison among the charcoal particle fluxes in different vegetal communities. The charcoal fluxes, which are related with paleofires, represent an important disturbance to the atmospheric system. These charcoal particles emitted to the atmosphere can provide a decrease in the sunlight penetration and promote greenhouse gas enhancement, which have a large residence time in relation to the sunlight blockage. Thus, the evaluation of charcoal deposition, as a consequence of regional burns, will have great importance to determine the impact of climatic change in different tropical ecosystems. This subject will be an important contribution for understanding the dynamics among vegetation, climate and carbon cycle along the present interglacial. In this study, paleofire records were obtained through the charcoal particle fluxes analysis in sediments of five lakes surrounded by different vegetation, which represents the most spread ecosystems in Brazil. The main goals were to identify similarities in periods of vegetation burn during the Holocene and evaluate the influence of biomass availability to charcoal fluxes. Fire records were obtained through the charcoal particle flux analyses in lacustrine sediments (Lagoa da Pata, São Gabriel da Cachoeira (AM); Humaitá (AM), Lago do Saci (PA), Carajás N4, (PA); and Caracarana (RO); reservoir sediments in an intense land use change region (Alta Floresta, MT). The charcoal analyses could have also a great importance in evaluating the impact of dry climates in different ecosystems. Determination of fire frequencies and dimensions in key areas of South America, during the Holocene, is a first step to understand the global carbon transference between terrestrial and atmospheric systems. The synchronism among the fires occurrences show a good relation with the middle Holocene dry climate phase in Brazil. Discrepancy in the flux values could be attributed to differences in biomass availability provided by these ecosystems and paleofire intensity. 0334 Variable fluvial response of the Moselle River to Middle and Upper Pleistocene environmental change (France, Germany, Luxemburg) Stéphane Cordier1, Manfred Frechen2, Dominique Harmand3, Monique Beiner4 1

Université Paris 12 - Val de Marne, France Leibniz Institute for Applied Geosciences (GGA), Germany 3 Université de Nancy 2, France 4 France 2

Downstream from the Vosges Massif, the River Moselle (and its main tributary the River Meurthe) present a succession of alluvial basins in the Paris Basin and the Rhenish Massif. Several years of multidisciplinary research in the Moselle and Meurthe valleys enabled a more reliable definition of the middle and lower terrace system, including

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about 100 m downcutting between the uppermost terrace level and the bedrock of present floodplain M0. These terraces (from M8 the oldest to M1 the youngest) have been correlated by means of morphology and sedimentology. In particular, a distinction was made between terraces formed by a “Palaeo-Meurthe” River while the Upper-Moselle flowed towards the Meuse, and terraces formed after the Upper-Moselle capture allocated to oxygen isotope stage (OIS) 8. First OSL datings on sands from below the post-capture terraces M3 and M2 in the Meurthe valley gave evidence that each terrace formed during a glacial-Interglacial cycle. The main aggradational periods correlate with cold stages, triggered by the Vosgian glaciers. Field observations suggest more or less similar fluvial dynamics along the whole Moselle valley, and the distinction between aggradational periods dominated either by the Moselle or by the Meurthe (and the other periglacial tributaries). New OSL datings on feldspar and quartz taken from fluvial sands of the post-capture terraces M3 and M1 located along the Moselle valley in the Rhenish Massif (or a few kilometres upstream) have been recently obtained. This makes it possible to improve the chronostratigraphical intrepretation. The chronological data confirm the longitudinal correlations of the terraces, assuming that the Moselle valley experienced a slightly higher uplift in the Rhenish Massif since the Upper-Moselle capture than in the Paris Basin. These results especially indicate interglacial (OIS 5e) or interstadial (OIS 5a or 5c) aggradation. The Middle and Lower Moselle fluvial dynamics is not only the result of main climate change (which lead to the formation of terrace staircases along the valley). It is also influenced by rapid climatic oscillations (several ka), having local effect and being able to modify the fluvial system evolution of the Moselle and its periglacial tributaries, by generating qualitative and quantitative change in sediment composition. These new results also underline that aggradational and erosional periods result in a more complex and spatially variable combination between the fluvial dynamics of the Moselle and its periglacial tributaries. 0798 Contemporary evolution between the alluvial landscape and the prehistoric human occupation in the big valley of the River Solimões-Amazon Marcondes L Costa1, Kenitiro Suguio2, Hermann Behling3, Nestor Kaempf4, Dirse C Kern5 1

Universidade Federal do Pará, Brazil Universidade de Sao Paulo, Brazil 3 Goettingen University, Germany 4 Universidade Federal de Porto Alegre, Brazil 5 Museu Paraense Emilio Goeldi, Brazil 2

The prehistoric human occupation which left printed expressive changes in the landscape in many parts of the World, in Amazonian they left only smaller changes in the landscape. Along the great valley of the River Amazon, stage of great prehistoric occupational activity, the dark earth in its margins are the most important human changes of the landscape. The magnificent, evergreen and gigantic fluvio-laccustrine landscape of Solimões-Amazon valley that astonished the most intrepid travelers didn’t still exist when the man here arrived. To show a contemporary evolutionary history between the young sedimentation and the human occupation in the big valley of the River Amazon we use the current geological, palaeoecological e archaeological knowledge disponible for the region and our own experience of working in this region since a long time. The great east-west channel of the river SolimõesAmazon, a transcurrent fault system settled down in Paleocene-Oligocene, the Amazon alone began to be fed with Andean source sediments at Late Pleistocene. At the Last Maximum Glacial the relative sea level

met between 120 and 130 m below the current one and the Amazons River established inside of a great canyon. The sedimentation starts and the first prehistoric hunter-collectors arrives the great canyon. Neither beaches nor floodplains existed to allow agriculture, nor clay for the ceramic. The climate was dry with savannah vegetation. Finished the Last Glaciation, the sea level invade the great canyon. The river Solimões-Amazonas lost competence, release its load and fills the channel. The new humid climate established in the region and forest retake the savanna fields. The fertile floodplains sediment favors the development of agriculture, the explosion of the ceramist activity and horticulture in the Amazonas valley (4000 – 3000 years BP), the great demographic explosion of the Amazons. Coincident with Climatic Optimum of the Northern Hemisphere, started settle down the inundation of floodplains in response to slight ascent of the relative sea level, an atmosphere less hospitable and not adapted for agriculture. In the buoyant and firm lands the forest moved forward quickly on the agricultural lands, and the man, that knew only ceramic artifacts, without domain of the metal didn’t develop technological means to surpass and to oppose the largest speed of progress of the forest, as suggest the decrease of the ceramic production and dark earth.

0007 Tsunami Hazard in Portugal—Geological recognition of tsunami deposits in two areas of Portugal Pedro J M Costa1, Suzanne A G Leroy2 1

Physics Department, Lisbon Technical University, Portugal Institute for the Environment, Brunel University, United Kingdom

2

Abrupt marine invasions such as those caused by tsunamis and storms are particularly devastating for coastal areas, especially those densely populated. Tsunami and storms often leave a permanent record in coastal sediment traps. The geological study of palaeotsunamis in coastal areas will allow the identification of past events in a greater time scale than based exclusively on historical or instrumental data. The sedimentological data could be used to establish patterns of coastal flooding and to assess the hazard risk of a specific coastal area. In historical times the most destructive tsunami that affected Europe was linked to the AD 1755 Lisbon earthquake. The effects and consequences of the AD 1755 tsunami are discussed. Sedimentological criteria to identify abrupt marine invasions in the stratigraphic column are presented. This research aims to contribute to a better understanding of the signature left by abrupt marine invasions in coastal stratigraphy by investigating the nature of the sedimentary record associated with tsunamis in a region where their impact is known. A wide range of proxies was used to detected tsunami and storm deposits in two coastal areas of Portugal. The techniques used include lithological description, grain size analysis, digital and X-ray photography, magnetic susceptibility, macrofossils analysis, geochemical analysis and 210Pb and Optically Stimulated Luminescence dating. The investigated areas (e.g. Lagoa de Óbidos (Central Portugal) and Martinhal (South Portugal)) were affected by the AD 1755 tsunami. The locations have similar geomorphological features and are both susceptible to major abrupt marine invasions. Results show that an abrupt event deposited unique sedimentary units in both locations. A similar age for the event was established. A considerable number of tsunami sedimentary characteristics were detected in both units. Overlying events may be linked to large storms. However, a key outcome of this research is the demonstration of the difficulty of distinguishing between sedimentary deposits laid down by tsunamis, and those deposits resulting from storm action; consequently the geological record of tsunamis almost certainly underestimates their frequency in the Portuguese coast.


0254 The complex interplay of time with the other factors of pedogenesis Edoardo AC Costantini CRA-Research Institute for Soil Study and Conservation, Italy

The study of the “time” factor of pedogenesis serves several scientific and applicative purposes, pertinent to the fields of both Soil and Earth Sciences. The study of paleosols is not only important for cultural and scientific knowledge, but also for soil and geological mapping, for hydropedology and geohydrology, neotectonic and soil conservation, and to asses maximum tolerable soil erosion. The study of the time factor of pedogenesis however is difficult, using current dating instruments, and because of the many interactions with the other factors of pedogenesis, it is also complex. The aim of this work is to illustrate how the study of lithological and pedological discontinuities allows the creation of pedostratigraphic levels, which can be used to reconstruct soil and landscape evolution during the Quaternary, and foresee possible development during the Technocene. The Montagnola Senese study area in central Italy shows extended outcrops of paleosols and a presence of fertile soils, which have induced human settling since Palaeolithic. Human occupation of the territory increased during Etruscan, Roman and medieval times, when an agricultural landscape was created. The present pedoclimate of the area is udic and mesic (Soil taxonomy). Main outcropping rocks are quartzite and schist, poor in or without lime, and limestone. Slopes, karsts depressions and terraces are covered by sediments resulting from the weathering of the outcropping rocks, with addition of aeolian deposits. Nine soil horizons were dated by means of Optically Stimulated Luminescence and a layer was dated by means of Cromerian fauna. Geological and geomorphological mapping were combined with the study of lithological and pedogenetic discontinuities in 41 benchmark profiles, effectuated through mineralogical, micromorphological, and geochemical analyses. Four pedostratigraphic levels were created and attributed to Early Pleistocene, Middle and Late Pleistocene, and Holocene. Soil profiles, maps and a series of deep boring were stored in a GIS; a set of three-dimensional maps of the Quaternary soil cover were generated, and the spatial distribution of each level during main intervals of the Quaternary reconstructed. The results indicated that the geographical distribution of pedostratigraphic levels is related to tectonic activity throughout Pleistocene and to human utilization of the land during Holocene. The current tendency of land management, characterised by a boost in the use of heavy and powerful mechanic tools, allows us to foresee that the pedogenetic trend during Technocene will be the increase of both soil haploidisation and frequency in the number of lithological discontinuities in the profile. 1056 Pedogenesis in Quaternary aeolian deposits in the val d’Elsa river basin (central Italy) Edoardo AC Costantini1, Simone Priori2, Luca Trombino3, Giuseppe Protano4, Alexandra Hilgers5, Daniela Sauer6 1

CRA-Research Institute for Soil Study and Conservation, Italy Earth Sciences Department, University of Siena, Italy 3 Earth Sciences Department, University of Milano, Italy 4 Environmental Sciences Department, University of Siena, Italy 5 Department of Geography, University of Cologne, Germany 6 Institute of Soil Science, Hohenheim University, Stuttgart, Germany 2

The occurrence of aeolian deposits is quite easy to recognize when sediments are homogeneous and fresh, which is seldom the case in

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soils. In temperate regions, aeolian deposits of different nature are often pedogenised and mixed. Pedogenised aeolian deposits have been reported in Italy for loess, volcanic and dune sediments, and for Saharian dusts, but the actual extension of them is unknown. It is possible that they are much more widespread than reported on geological and soil maps. The val d’Elsa river basin is located in central Italy, several dozens of kilometres from the Quaternary glaciers of the Apennines, the Tyrrhenian sea and the volcanic areas of central Italy. The aim of the work was to investigate the presence, nature, origin, and extension of aeolian deposits in soils of central Tuscany. The study area was about 600 km2. Five soil profiles, all belonging to relict, polycyclic paleosols, were selected. They were located in different geomorphological positions and geological substrates. Soil 1, an Haplic Cambisol (Chromic, Thaptobathynitic), was situated inside a doline, on top of an isolated limestone relief; soil 2, a Cutanic Alisol (Manganiferric) and soil 3, an Haplic Cambisol (Hypereutric, Rhodic, Thaptoargic), were both on a plateau, the first one formed on alluvial sediments covering marine sands, while the latter developed from lacustrine limestone. Soil 2 was on the top of a small isolated mound, while soil 3 was situated in a doline. Soil 4, a Fragic Albeluvisol (Chromic) and soil 5, a Cutanic Alisol (Chromic, Thaptobathyfragic), were located on a middle and foot slope on schist. Their main parent materials were colluvial sediments and schist. The profiles were sampled for routine analyses, iron forms, elements, and heavy minerals. Undisturbed samples were taken for micromorphological analysis with mineralogical microscope and SEM. Nine soil horizons were sampled for OSL dating. Aeolian sands were identified by SEM in the first 100 cm of all profiles, in amounts of 5 up to 30%. The maximum percentages were found in profiles 1 and 4, at 60 –100 cm. If we exclude holocenic colluvial horizons, the OSL ages of horizons with aeolian grains were 16 ky (a Btx horizon), 23 and 33 ky (three Bt horizons), and 60 –70 ky (Bt, Btc, and Btx horizons). OSL ages were only partially correlated with weathering indices (iron forms, geochemistry), while micromorphology and heavy metal analyses indicated different possible sources, including reworked volcanic ashes, short and medium distance loess. 0703 Late-Glacial vegetation and climate changes in mountain areas as inferred from pollen data: the high-resolution record of the Lauza peat bog (Champsaur, southern French Alps) Mona Court-Picon1, Odile Peyron2, Jacques-Louis de Beaulieu1, Gilles Bossuet2 1

Institut Méditerranéen d’Ecologie et de Paléoécologie (UMR CNRS 6116), Europole Méditerranéen de l’Arbois, Domaine du Petit Arb, France 2 Laboratoire de Chrono-Ecologie (UMR CNRS 6565), Université de FrancheComté, UFR Sciences, 16 route de Gray, F-25030 Besançon C, France

Pollen data represent the most widely available quantitative record of past climates and are an efficient tool for the reconstruction of vegetation and its responses to abrupt climate changes. However, the application of the current methods of transfer-functions on mountainous pollen sites still yields unreliable results and quantitative estimates of the climate from mountainous records are still rare, especially for the Late-Glacial which is generally poorly recorded in these areas due to elevation. Mountainous vegetation has been yet shown to be particularly sensitive to climate changes and mountainous pollen sequences therefore represent ideal archives for the study of past climate change. The purpose of this study is to obtain robust and precise quantitative estimates of the Late-Glacial and early Holocene climate of alpine region from a high-resolution pollen record taken from the long sequence of the mid-altitude Lauza peat bog (1140 m a.s.l., Champsaur Valley,

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French Alps). Sediment cores were extracted from the deepest part ca. in the centre of the present peat bog, and is more than 7 m long, 3.5 m of these belonging to the Late-Glacial. This sequence thus provides an exceptional sedimentation rate considering the mountainous environment, especially for the Late-Glacial and early Holocene periods, offering a great opportunity to study precisely rapid climate changes and vegetation responses. We decided to focus on Late-Glacial period since the study of previous palynological data and ice-cores has shown that the transition from the last glacial period to the present interglacial was a period of special “climatic” interest characterised by alternating cold and warm intervals with rapid transitions. Past temperature and moisture parameters are estimated using several methods of transfer-functions for the longer pollen record: standard “modern analogue technique” (MAT), constrained or not by biomes, and “Plant Functional Types” (PFTs) methods. By using the results from the different methods, the magnetic susceptibility, and the oxygen isotope ratios from the Greenland ice records as an additional palaeoclimate reference, it is possible to establish a general scheme of climatic variations at Lauza peat bog. The study also shows the effectiveness of combining several reconstruction methods, increasing the confidence in the data, and thus obtaining more precise and robust climate estimates. Finally, our results are compared with recent studies carried out on high-altitude pollen sites in the alpine region, but also with those obtained for low- and mid-altitude sites in other European regions.

fine and explain the waxing and waning of settlement activity in a particular alpine environment. • Palaecological approach (mainly palynology, but also dendrochronology, plant macro-remains, fossil insects, micro-and macro-charcoal analyses, fungal spores and other microfossils) is developed in an attempt of reconstructing palaeoenvironmental evolution throughout the last ten thousand years in a small area at high spatial and temporal resolution, especially by distinguishing human impact from natural trends since prehistoric times. Cores were collected from several lakes and peat bogs situated in different vegetation structures and with respect to an altitudinal gradient in order to provide good examples of different landscape exploitations by mountain populations. • Reconstructed rhythms of landscape evolution and exploitation systems are finally related to the Holocene climate variable, inferred from lake level fluctuations in the Jura Mountains and the evolution of glacier advance in the Alps. The objectives are to detect and analyse possible interrelations between regional climate variability, human-induced changes in vegetation, and reactions of the social and economic systems.

1084 Natural and anthropogenic Holocene environmental changes in mountainous areas (Champsaur, southern French Alps) as evidenced in high-resolution pollen, NPP and macrofossil records

Marie-Agnes Courty1, Eric Boëda2, Aline Emery-Barbier2, Christophe Griggo3, Norbert Mercier4, Helene Valladas4, Isabelle Thery-Parisot5

Mona Court-Picon1, Jacques-Louis de Beaulieu1, Josep Maria Palet Martinez2, Kevin Walsh3, Florence Mocci4, Maxence Segard5 1

Institut Méditerranéen d’Ecologie et de Paléoécologie (UMR CNRS 6116), Europole Méditerranéen de l’Arbois, Domaine du Petit Arb, France 2 Institut Catala d’Arqueologia Classica, Plaça Rovellat, s/n43003 Tarragona, Spain, Spain 3 Department of Archaeology, University of York, King’s Manor, YOEP 17 York, Great Britain, United Kingdom 4 Centre Camille Julian, UMR 9968, 5 rue du château de l’horloge, F-13094 Aix-en-Provence Cedex 20, France, France 5 France

If palaeoecological studies had shown for a long time that general vegetation dynamics since the last glaciation was driven by climate variability, it is now widely accepted that human impact has been the most important factor effecting vegetation change, at least in Europe, during the last 6000 years. Conversely, human settlements and economic activity throughout the Holocene are often closely related to natural environmental changes induced by climatic variability. In France and Switzerland, there is now a growing body of evidence indicating that the ancient lacustrine cultures sensitively responded to rapid climatic modifications. However, very few works aimed to study the potential impacts of climate on populating dynamics and economic systems of mid and high mountainous environments (>1000 m a.s.l.), which are yet well-known to be particularly sensitive to climate changes. • In order to better understand anthropogenic/natural processes interactions in these mountainous ecosystems, an integrated research program based on a multi-proxy approach has recently been undertaken in a restricted area covering three neighbouring valleys of the southern French Alps. The fundamental aim of this interdisciplinary project, involving palaeoecology and archaeology, has been to de-

0663 The Umm El Tlel sequence: A high resolution pedo-sedimentary record of climate-triggered environmental changes during the Late Quaternary (OIS 5 to 1) in the Syrian desert

1

CNRS-MNHN, UMR 5198. CERP. 66270 Tautavel, France Université de Nanterre – MAE, UMR 7041, Nanterre, France, France 3 Université Joseph Fourier, Institut Dolomieu, UMR 6636, Grenoble, France 4 LSCE CNRS-CEA, UMR 1572, Gif,-sur-Yvette, France 5 Centre d’Etudes de la Préhistoire, de l’Antiquité et du Moyen-Age, rue Albert Einstein, 06560 Valbonne, France 2

The pivotal role in human history of the drastic alteration of natural resources incites to firmly establish the synchrony between cultural changes and past environmental shifts. Here we report on a detailed reconstruction of environmental changes over the last 100 000 years in the Syrian desert using the benchmark prehistoric site of Umm El Tlel. This ten meter thick sequence forms the terminal stage of an endoreic filling originated from discontinuous aeolian, lacustrine, colluvial and alluvial accumulation concurrent to soil development. The natural deposits are interlayered with 70 occupation levels ranging from the Early Neolithic to the Middle Palaeolithic. C14 radiometric dating and TL ages on burnt flints provide a coherent series of time markers from ca. 10 kyr BP to 70 kyr BP. The micromorphological study of the microstratified sequence allows to establish a qualitative dynamic model for interpreting sedimentary processes and pedogenic transformations in terms of environmental conditions. Their palaeoclimatic significance is calibrated using palynological data. The end of OIS 5 corresponds to the lower layers (IX & VIII) with development of an arboreal vegetation. The water-layered organo-mineral units with corroded calcareous clasts, gypsic-ghosts, carbonate-depleted brown soil fragments with fine aerosols, and sandy lenses indicate the stable conditions under regularly distributed local rainfall, low-evapotranspiration, weak storminess and occasional flooding. The abrupt transition to OIS 4 (unit VII) corresponds to high energy erosion of the endoreic basin due to torrential rainy episodes under inceasing aridity. OIS 4 (VI3) is marked by lacustrine biochemical sedimentation with distinctive torrential phases synchronous to human occupation. The perma-


nent availability of water resulting from the aquifer recharge during the previous wet phase has offered favourable conditions for humans. The following OIS 3 and 2 (VI2 to III) show recurrent interruption of the overall aridity synchronous to persisting aeolian erosion by torrential episodes under a stronger Mediterranean influence, and rainfall increase as marked by the alternation of palustrine layers and charredrich organo-mineral deposits. The synchroneity of recurrent wild-fires and fin-dust fall of long distance origin with the humid phases seem to chronologically match distinctive climate shifts such as the Heinrich events. Violent aeolian deflation culminates during the last glacial maximum (II) with the extensive deposition of gypsic dunes formed from aeolian reworking of the basin. The transition to the first Holocene climatic optimum (I) shows humid pulses, synchronous to occupation, expressed by the substitution of Ca-carbonates to Ca-anhydrite, and accumulation of carbonate-depleted organo-mineral lenses. 0666 High resolution timing of the 4 kyr B.P. cosmic impact and related consequences Marie-Agnes Courty1, Guiseppe Cortese2, Alex Crisci3, Xavier Crosta4, François Guichard5, Michel Mermoux3, Elisabeth Michel5, David C Smith6 1

CNRS-MNHN, UMR 5198. CERP. 66270 Tautavel, France Alfred Wegener Institute for Polar and Marine Research, Columbusstrasse POB 120161 27515 Bremerhaven, Germany 3 LEPMI-ENSEEG 1260 rue de la piscine-BP 75, 38402 Saint Martin d’Hères, France 4 UMR-CNRS 5805 EPOC Univ. Bordeaux I, 33405 Talence, France 5 LSCE CNRS-CEA, Gif,-sur-Yvette, France 6 Lab. LEME/Nanoanalysis, MNHN, 61 rue Buffon, 75005 Paris, France 2

Often identified as a 300 years long mega-drought from a few deep-sea records, data from marine and continental archives now help to consolidate the hypothesis for a cosmic impact at ca. 4 kyr B.P. in the Austral ocean along the Kerguelen plateau. Evidence for the widespread dispersion of the ejecta by-products, followed by complex processes with multiple regional expressions, emphasize the difficulty for dating an instantaneous event at geological timescales. Here we explain the novel chronological approach elaborated for achieving a high precision chronology of the 4 kyr B.P. impact-processes and linked manifestations. It is based on the complementary use of : (i) sequential analysis of pedo-sedimentary micro-stratified sequences efficient to obtaining a high resolution relative chronology of environmental events at local scales; (ii) stratigraphic correlation from local to global scales using robust time markers essential to disentangle the direct effects of impact-processes from the following feed-back responses, and indirect long-term changes; (iii) absolute dating needed to precisely frame the exact age of the instantaneous event and to support long distance correlation. High resolution sequential analysis has been at best achieved in a few continental micro-stratified sequences in which the expanded vertical signal and the spatial continuity at local scales offer unique conditions to capture the initiating manifestations and understand their linkages to impact-processes. This aspect is illustrated by the first identification in the geological record of surface disruption directly linked to the thermal blast and flash heating synchronous to the ejecta-fall, known to occur during the first minutes of an impactevent. Time markers used for stratigraphic correlation are constrained by their degree of preservation. Only the undisturbed signal helps to study the spatial variability from local to global scales of the ejectadispersion poduced by the explosive-impact in the sea. In contrast, partly to strongly reworked signals might confuse an instantaneous

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event into a long-term period, thus explaining how the 4 kyr B.P. impact is often wrongly assigned to a 300 years long drought. Unfortunately the use of C14 radiometric dating is strongly constrained by the occurrence in the 4 kyr B.P. signal of various carbon sources with different C14 activities. These exceptional conditions require preliminary analytical characterization of the carbonaceous materials (i.e. SEM observations and Raman microspectrometry) to select uncontaminated organic materials for reliable age measurement. The study of the 4 kyr B.P. event shows the need to adjust analytical strategy to the specificity of each singular event. 0771 Evidence for Buried River Channels in the Simpson Desert, Australia Robert A Craddock1, Michael Hutchinson2, John A Stein2, Stephen Tooth3, Ted A Maxwell1 1

Smithsonian Institution, United States Australian National University, Australia 3 University of Wales, United Kingdom 2

Buried river channels have proven to be valuable economic and agricultural resources. In some instances buried channels, such as those found in the Sahara, are also dramatic reminders of climatic changes that have taken place. Here we report the potential existence of buried river channels in the Simpson Desert of Australia. The Simpson Desert is part of a much larger desert complex that occupies most of the Great Artesian Basin, the lowest point of which is Lake Eyre. Lake Eyre is the focal point and terminus of the largest internal drainage system in the world, which includes major rivers such as the Finke, Todd, Hale, Georgina, and Diamantina. The geologic evidence suggests that many of these rivers are extremely old. The Finke River, for example, has incised perpendicularly through the Alice Springs orogenic uplift that is Devonian in age (~405 Mya). Because these rivers pre-date the Simpson Desert by many millions of years, it seems likely that they once flowed continuously into Lake Eyre or its larger, ancestral predecessor, Lake Dieri, which resulted from a wetter climatic optimum during the Pleistocene (20,000 –45,000 years ago). Previous analyses of topography data collected from helicopter gravity and seismic surveys suggested that abandoned stream channels from the Finke and Plenty Rivers are discernible in the topography of the Simpson Desert. However, the resolution of these data were coarse, their coverage was limited and they do not easily lend themselves to advanced computer analyses. As part of the efforts to produce a national digital elevation model (DEM) of Australia, we generated a DEM of the Simpson Desert based on a grid of ground level elevations points from national spot height elevation data taken from 1:100,000 scale topographic maps and minima values from Shuttle Radar Topographic Mission data with a spacing of 9 seconds in longitude and latitude (~250 m). To avoid erroneously high elevation information suitable elevation data was collected from between dunes, providing more accurate information about the general surface topography. As a result, the DEM reveals the broader, low frequency topography within the Simpson Desert, which reflects the landscape buried up to 35 m below the sand surface. The resulting DEM makes it possible to trace a dense network of paleochannels through the driest desert in Australia and plot the former courses of the world’s oldest rivers prior to their burial.

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0991 Late Quaternary fluvial change in the Fitzroy River, Queensland, Australia Jacky C Croke1, Dirk Platzen1, Kathryn J Amos1, John Jansen2 1

University of New South Wales @ ADFA, Australia University of Glasgow, United Kingdom

2

The Fitzroy river, which drains a diverse 140,000 km2 area in central Queensland, before discharging into the Great Barrier Reef (GBR) Marine Park is used here to discuss the nature and timing of major Quaternary fluvial change in sub-tropical Australia. The catchment consists of an extensive array of channel and floodplain types, with anabranching channels and single-thread, confined and unconfined meandering types throughout the basin. Of particular note from airphotos and satellite imagery are numerous reaches with meandering palaeochannels visible on the floodplains, and in some locations the superimposition of a multiple channel system upon a palaeomeandering channel network. The geometry of meandering palaeochannels has been measured from air photos and satellite imagery, and compared with that of the modern channels occupying those floodplains. Optically stimulated luminescence (OSL) dating of quartz sediments from several deep cores taken in floodplains of different morphologies has been used to construct a broad chronology. These results indicate a long residence time of material stored in alluvial floodplains within the basin, with a modal age of approximately 20,000 years. A period of enhanced fluvial activity is observed to correspond to climatic conditions associated with the Last Glacial Maximum (18 – 20 ka). Proxy data from elsewhere in the region suggests reduced precipitation and stream power during this time, thus these data make a valuable contribution to our understanding of Quaternary fluvial history in this region and provide some baseline data for comparing the magnitude of more recent fluvial responses to landuse change. Floodplains across a range of morphological types and throughout the major subcatchments appear to be acting as long-term sediment ‘sinks’, with fluvial deposits of both coarse and fine particles being stored in stable floodplain environments for up to two hundred thousand years. 0885 The palaeobiogeography of the Antarctic freshwater fauna Louise Cromer1, John A E Gibson1, Kerrie M Swadling2, Dominic A Hodgson3, Bernd Wagner4, Leon A Barmuta1 1

University of Tasmania, Australia Tasmanian Aquaculture and Fisheries Institute, Australia 3 British Antarctic Survey, United Kingdom 4 University of Cologne, Germany

(Amery Oasis) whose basal sediments range in age from pre-Last Glacial Maximum through to late Holocene. These lakes represent a cohesive biogeographical unit, which is geographically isolated from western and maritime Antarctica and can therefore provide important information on the palaeobiogeography of the region. Through analysis of faunal microfossils we have built up a detailed picture on the effects of both large and small-scale environmental events on Antarctic freshwater faunal communities. We will present information on colonisations and local extinctions, and provide the first direct evidence of a lacustrine faunal refuge on the Antarctic continent during the Last Glacial Maximum. 0165 Quaternary deformation in the central Mississippi River Valley Ryan M Csontos, Roy B Van Arsdale The University of Memphis, United States

The New Madrid seismic zone is the most seismically active area in the eastern United States and is the site of at least three great earthquakes during the winter of 1811–1812. These earthquakes originate from basement faults within the Late Proterozoic-Cambrian Reelfoot rift, buried deeply beneath the central Mississippi River Valley. Integration of seismic reflection, gravity, magnetics, and petroleum exploration wells has resulted in a detailed map of the N45E trending Reelfoot rift and its faults. The rift is cross cut by N65W basement faults that divide the rift into fault blocks. Four thousand nine hundred lignite exploration bore holes within the central Mississippi River valley penetrate the flood plain alluvium and provide an exceptional picture of the Quaternary unconformity at the base of the Mississippi River alluvium and the internal alluvial stratigraphy. Structure contour and isopach maps of the bore hole data reveal Quaternary stream erosion, deposition, and tectonic deformation. Specifically, the Quaternary mapping strongly suggests that the underlying northeast-striking Reelfoot rift faults have undergone Quaternary dextral shear. This shearing is responsible for the New Madrid earthquakes and has also produced compressional stepovers such as the Lake County Uplift, Joiner ridge, and the southern half of Crowley’s Ridge. These stepovers appear to have originated at intersections of Reelfoot rift faults. At a regional scale, two northeast trending blocks of the Reelfoot rift have undergone differential uplift. Landforms of the central Mississippi Valley, which have historically been explained as erosional in origin, are strongly influenced by tectonics.

2

Little is known about the origins and palaeobiogeography of the Antarctic freshwater fauna. Theories based on vicariance (species survived the Last Glacial Maximum in refugia) and dispersal (all fauna are Holocene colonisers) have been suggested, but with little supporting evidence. The lack of direct evidence for the presence of lacustrine refuges during this period had previously strengthened dispersal theories. Several lacustrine environments, however, are now documented to have persisted throughout the LGM, possibly providing refuge for a preglacial Antarctic fauna. Analysis of faunal microfossils in sediment cores from these preglacial lakes would provide information on the survival of species during this period. In addition to this, analysis of entire fossil zooplankton communities allows for the determination of a lakes palaeoecology. Here we present the palaeoecology of three lakes; Waterfall Lake (Vestfold Hills), Lake Reid (Larsemann Hills) and Lake Terrasovoje

0728 The Late Holocene evolution of the tropical Island of Inhaca, Mozambique Fortunato Cuamba1, Bjørg Stabell2, Sylvi Haldorsen3, Mussa Achimo1, João Mugabe4, Lars Været3 1

University of Eduardo Mondlane, Mozambique University of Oslo, Norway 3 Norwegian University of Life Sciences, Norway 2

The small Inhaca Island in the Maputo Bay is the southernmost of a series of sandy tropical islands along the coast of Mozambique. The island is built up by Pleistocene to Holocene dune sand, with two main NNW-SSE – trending dune cordons along the east and west coasts. Much lower dunes separated by intra-dune depressions form a series of small lakes and wetlands in the central part of the island. The lakes are groundwater-fed, and have today no surface water inlet or outlet. Nine sediment cores of length 4 –6 m from one of these lakes were sampled


with a piston corer. The analyses of the cores include diatoms, bivalves, grain-size distribution, radiocarbon datings, and stable isotopes. The bottom of all cores except one, (core 6) consists of sand with some pieces of wood, and is most likely a dune sand. There is a sharp boundary to the overlying sand, with estuarine shells (Dosinia hepatica), gastropods, some ostracods and diatoms. The d13C-values and studies of diatoms indicate a transition from brackish (estuarine) conditions at the bottom of this sand to more saline (marine) conditions in the middle and back to more brackish and almost fresh conditions towards the top. The sand is in all cores overlain by a layer of peat less than 1 m thick, the lower part being well decomposed and containing plant remains. The start of the peat deposition marks the ultimate separation from the sea and the formation of a freshwater lake. Whole and fresh shells of Dosinia hepatica from the marine – estuarine part of the core gave uncalibrated radiocarbon ages of 6500 yrs B.P. for the lowest part; 4500 yrs B.P. BP for the middle part and 2500 yrs B.P for the top. The first reconstruction indicate a sea level approximately 4 m higher than today for the middle of this. The marine phase lasted for 4000 years, ending around 2500 yrs B.P. The results accord with the Holocene transgression of along the coast of southern Africa of +3 –5 m assumed by Ramsey (1995). More than 100 diatom species have been identified in the upper part. This is to our knowledge the first detailed study of fossil diatoms in marine and estuarine Holocene records along the southeast coast of Africa. The study is a pioneer work, which may form a good background for later studies of coastal sediments in this region. 0536 Small vertebrate changes during the Pleistocene in central Spain: the record from Atapuerca Gloria Cuenca-Bescos1, Roger J De Marfà2, Maria A Galindo-Pellicena1, Juan M López-García3, Diana Ramón1, Juan Rofes1, Hugues A Blain3, Maria L Bennasar4 1

University of Zaragoza, Spain University of Barcelona, Spain 3 University of Rovira i Virgili, Spain 4 University of Rovira i Virgili 2

Six sites, located close to each other, in the Atapuerca Hill (Burgos, Spain), contain long complete sections representing major parts of the continental Pleistocene of central upland Spain. Studies of the small vertebrate assemblages show at least 7 different faunal units (FU), well differentiated by first and last appearance data (FAD and LAD). At present, the faunal list comprises 55 small-mammal taxa, including rodents, insectivores, rabbits and bats and at least 23 taxa for amphibians and squamate reptiles (the faunas are still under study, therefore the number of taxa and their classifications may change). The ATA FU 1 (Trinchera del Elefante, Lower levels) is characterized by the FAD and LAD of two Allophaiomys species, Castillomys and Asoriculus; the ATA FU 2 (Gran Dolina site, TD) by the FAD of Iberomys huescarensis, and Allocricetus, the ATA FU 3 and 4 (TD) by the occurrence of a new giant, red-tooth shrew; the ATA FU 5 by the FAD of Microtus ratticepoides and the LAD of primitive microtines; the ATA FU 6 by the FAD of derived microtines; the ATA FU 7 by the FAD of extant rodents as Iberomys cabrerae and Chionomys nivalis. Some interesting observations about this distribution are: the first hominid presence in Western Europe is recorded in Spain at ATA FU 1, Trinchera del Elefante, in Atapuerca and in Granada. The ATA FU 1 assemblage indicated an Early Pleistocene age for this datum (between 1.5 and 1.1 Ma), and points to a warm (and humid-wooded; presence of Salamandra in TE) period (?Waalian). Another European locality of Early Pleistocene age with lithic tools, Le Vallonnet, can be included in this ATA FU 1 by its

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Allophaiomys contents. In TD, the first hominids in Western Europe (Homo antecessor) lived during a warm, wet and wooded interval, probably corresponding to MIS 21 to 19 (ATA FU 4). The transition from the Early to Middle Pleistocene at Atapuerca is characterized by a palaeoenvironmental change recorded between the ATA FU 3– 4 and the ATA FU 5–6. The general opening of the landscape at the beginning of the Middle Pleistocene, characterized by the ATA FU 6 could have promoted the dispersal of Homo heidelbergensis across Western Europe. Finally, the ATA FU 7 characterizes the late Pleistocene, when the modern faunas make their first appearance, though coexisting with survivors such as Pliomys lenki, wich disappears in mid MIS 2. 0530 Of mice and men across the Holocene-Pleistocene boundary: El Mirón cave, a case study from Cantabrian Spain Gloria Cuenca-Bescós1, Lawrence G Straus2, Juan C García-Pimienta3, Manuel R González-Morales4 1

University of Zaragoza, United States University of New Mexico, United States 3 University of Zaragoza, Spain 4 University of Cantabria 2

Rodents and humans are today intimately linked: the first consume the food that humans waste. Was this the same in the past? Palaeontologists study faunal sequences without taking into account the influence of people, and this can be a good approach before humans became important in regional ecosystems. But what happened in the Late Pleistocene? Are microfaunal changes related to human inference in their common territories? Is mice, shrew and bat diversity also influenced by the human activities? In the North of Spain, there is a rich and long tradition in archaeological studies excavations beginning at Altamira dating back to 19th C. Some localities have long, stratigraphic sequences that have been studied with a multidisciplinary approach (El Castillo, La Riera, Morín, El Juyo, Lezetxiki…). One of those localities is El Mirón Cave, in the Asón Valley (Ramales de la Victoria) in the first range of the Cantabrian Cordillera. The El Mirón sequence has provided a diverse small mammal fauna, including rodents, shrews, hedgehogs, moles and bats. For this study we analysed 719 samples, ranging from the Holocene to the late Upper Pleistocene. The samples come from 67 well stratified levels dated by archaeological contents and Radio Carbon (62 dates from 41-3.5 Kyr). We recognize 24 different species of small mammals, where 14 rodents (Arvicola terrestris, A. sapidus, Terricola sp., Microtus oeconomus, M. agrestis, M. arvalis, M. gregalis, Chionomys nivalis, Clethrionomys glareolus, Pliomys lenki, Apodemus sylvaticus, Eliomys quercinus, Glis glis, Sciurus vulgaris), 7 insectivores (Sorex minutus, S. araneus, Neomys fodiens, Crocidura sp., Galemys pyrenaicus, Talpa europaea, Erinaceus europaeus) and 3 bats (Myotis sp., Miniopterus schreibersii and Rhinolophus sp). Lagomorphs and small carnivores (Mustela sp.) are also present, though they never become numerically important in the sequence. Some small mammal changes in the El Mirón sequence may correlate with major climatic and/or cultural events. During the early Magdalenian (17-13 Ky BP) there is a recovery in small mammal diversity, in relation to the impoverishment of the faunas during the Solutrean (17,000-19,000 Ky BP), though during the Magdalenian the long persisting arvicolid species Pliomys lenki, finally went extinct. The Holocene-Pleistocene boundary (end of Younger Dryas event, 11,800 y BP) coincides with the definite establishment in the ecosystem of the large, fat dormouse, Glis glis, a large rodent that requires mature woods with large, old trees. The same occurs with other forest species, Clethrionomys glareolus, Eliomys quercinus and Apodemus sylvaticus.

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0071 Late Quaternary hydrology of salt lakes in the western Murray Basin, southeastern Australia

between Law Dome and Dome C to further investigate the differences recorded by Antarctic ice cores from inland and coastal sites.

Matthew L Cupper

1156 The Blackwattle Creek Catchment, Sydney, NSW: the Evolution of a Drowned River Valley and its Geoarchaeological Implications for Aboriginal Settlement Patterns

The University of Melbourne, Australia

Sedimentary sequences of salt lakes within the Darling Anabranch dunefields of southwestern New South Wales record changes in surface-water and groundwater hydrology over the late Quaternary. High lake conditions are expressed as terraced fine-grained lacustrine sediments and sandy quartzose and gypseous beach and foredune facies. Episodes of aeolian deflation and soil development on lake floors reflect lower water-tables. A general absence of evaporites such as gypsum in lacustrine, beach and foredune sediments deposited during oxygen isotope stage (OIS) 5 (~130-75 ka) suggests that the lakes were occupied by low-salinity waterbodies. The influence of groundwater in lacustrine hydrology during this phase of basin evolution was likely to have been secondary to surface-water processes. Groundwater increasingly dominated hydrological budgets by OIS 3, with extensive deposition of primary gypsum from the period after around 59 ka showing that the salt lakes had high salinities. Basins shrank to evaporative brine pools during intervals of heightened aridity over the latter part of the last glacial cycle. Phases of complete groundwater dominance culminated in episodes of lake floor deflation and clay dune formation at around mid-OIS 3 (~48-36 ka), the last glacial maximum (LGM; ~21-16 ka), the late glacial (~14-11 ka), the early Holocene (~7.5-6.5 ka) and the late Holocene (~3-1 ka). These hydrologic changes are likely to have been driven by variations in the effectiveness of the westerly circulation delivering precipitation to southeastern Australia, coupled with changes in evapotranspiration caused by fluctuating global temperatures and atmospheric CO2. 0601 Southern Ocean atmospheric chemistry signals since the LGM as recorded in the coastal Law Dome ice core: Comparisons with the inland Dome C ice core record Mark AJ Curran1, Tas D van Ommen1, Jorgen-Peder Steffensen2, Marie-Louise Siggard-Andersen2, Vin I Morgan1, Roberto Udisti3 1

ACE CRC and Australian Government Antarctic Division, Australia Niels Bohr Institute, Denmark 3 University of Florence, Italy 2

Law Dome is situated in East Antarctica, and is a relatively high elevation coastal site, with an ice core record spanning approximately 80,000 years. It receives high snow accumulation and is situated on the most northerly coastline in Antarctica (apart from the tip of the Peninsula), and as such it is sensitive to atmospheric chemistry changes over the Southern Ocean. This is in contrast to most Antarctic ice core records covering the same time span, which are retrieved from sites further inland, and which have much lower snow accumulation rates. We present changes in atmospheric chemistry signals through the LGM as recorded in the trace ion record of the coastal Law Dome ice core. These changes are compared to those recorded in the inland Dome C ice core. Looking at the similarities and differences between the inland and coastal records we can learn about the sensitivity of atmospheric signals to climate change and better understand the influence of wet and dry deposition. This comparative work will be complimented by an ice core drilling program planned Aurora Basin during the IPY (2008/2009 summer). This program aims to retrieve an ice core

Jakub T Czastka Heritage Concepts, Australia

Aboriginal settlement patterns in Sydney and the Cumberland Plain, Eastern New South Wales, Australia, have relied on archaeological salvage excavations to generate the data on which archaeological models are based. To date, most of these excavations have not included geoarchaeological methods to assess archaeological contexts. The accepted archaeological paradigms assume existing hydrology influenced prehistoric Aboriginal settlement patterns. Consequently, archaeological testing and salvage programs in Sydney and the Cumberland Plain are based on predictive modelling that targets surface alluvial contexts, regardless of depositional history, as the most likely contexts for the location of archaeological sites. Archaeological excavations of prehistoric and historic contexts at several sites bordering Blackwattle Creek, central Sydney, employed geoarchaeological methods including sedimentary, soil, stratigraphic and radiometric techniques, complimented by pollen studies. Using results from Blackwattle Creek and other projects in the Cumberland Plain it is argued here that palaeohydrology influenced the location of Aboriginal archaeological sites, with existing hydrology affecting the detectibility of archaeological sites. This compliments methods currently employed on archaeological sites offering more efficient and cost effective techniques for the management of Aboriginal heritage and proposes a new perspective on Aboriginal settlement patterns within Sydney and the Cumberland Plain. 1045 Reconstructing the human range in Europe during the Last Glacial Maxium via Eco-Cultural Niche Modeling Francesco P d’Errico1, William Banks1, Townsend A Peterson2, Marian R Vanhaeren3, Masa Kageyama4, Pierre Sepulchre4, Gilles Ramstein4 1

CNRS, UMR 5199 Pacea, University of Bordeaux, France, France Natural History Museum & Biodiversity Research Center, The University of Kansas , Lawrence, United States 3 CNRS UMR 7041, Nanterre, France, France 4 CNRS UMR CNRS-CEA-UVSQ 1572, Gif-sur-Yvette, France, France 2

An important recent advance in the study of biological diversity has been the development of biocomputational architectures for predictive modeling of complex biodiversity phenomena and ecological niches. These tools have considerable potential for reconstructing the niches of past animal and human populations and for illuminating the mechanisms that regulated the interactions between past hunter-gatherer populations and their environment. Here, we apply this approch, termed Eco-Cultural Niche Modeling (ECNM) to the Last Glacial Maximum (LGM) in Europe with the aim of determining the limits of the human range during this period, defining the eco-cultural niches of the two main archeological cultures present in Europe at that time, the Solutrean and Epigravettian technocomplexes, and identifying the environemental and cutural factors that shaped their territories. We used the Genetic Algorithm for Rule-Set Prediction (GARP), a machine-


learning genetic algorithm originally developed for determining ecological niches of plant and animal species. GARP requires the geographic coordinates of the locations where the target species has been observed and raster GIS data layers that record landscape and environmental variables. In our application the occurrence data are the geographic coordinates of radiometrically dated and culturally attributed archaeological sites. The raster GIS data consist of landscape attributes and high-resolution climatic simulations for the LGM (grid box size over Europe of about 60 km). The model produced using both Solutrean and Epigravettian sites identifies a clear northern boundary of the potential human range during the LGM. This boundary follows the Loire valley in France, excludes the Massif Central, includes the Mediterranean regions of France, follows the southern limit of the Alps, and the northern limits of the Carpathian range. The Solutrean model predicts the presence of this culture in southwestern and southern France, northwestern portions of the Iberian Peninsula, the Ebro valley, and more sporadically in Cantabria, northwestern Italy, and the Balkans. The Epigravettian model predicts a presence of this culture in the Balkans, the Italian Peninsula excluding the most southerly regions, the Mediterranean regions of France as well as the Aude and Garonne corridors, and the Iberian Peninsula excluding its southern regions. Statistical tests shows that these results have high predictive power. The predicted Solutrean and Epigravettian ecological spaces largerly overlap while their projections onto geographical space result in distributions that are noticeably different. We interpret this pattern as reflecting the role of cultural and geographic factors in shaping cultural territories. 1406 History and evaluation of the human-environment interactions of Taihu Plain in the central Yangtze Delta, east China Xuerong DAI1, Jinlong Ding2, John Dearing3, Lizhong YU4, Yuxin SHI5 1

China Suzhou Museum, Suzhou, Jiangsu Province 215001, China 3 Department of Geography, University of Liverpool, Liverpool L69 3BX, United Kingdom 4 State Key Laboratory of Estuary and Coastal Research, East China Normal University, Shanghai 200062, China 5 Department of Geography, East China Normal University, Shanghai 200062, China 2

We attempt to provide a case study of human-environment interactions from the central area of the Yangtze Delta in east China. This area is called Taihu (Tai lake) Plain featured with lakes and rivers, in which has formed the largest city of Suzhou (Soochow) with a 2500-year history (back to Spring & Autumn Period, 770~475BC). About 20 kilometers southeast of Suzhou a largest buried settlement has been excavated from the bottom of a medium-size lake (Chenghu) in recent years. Field investigation on archaeology, geomorphology and sedimentology shows that this settlement spans ca ~5000 years, from Songze culture (6500~5500aBP) to Song Dynasty (1127~1279AD). The formation, evolution and subsequent transference of this settlement have close relations to environmental changes and human activities. Among them floods, lakeshore retreat, damages of natural vegetation and overuse of lowland (or wetlands) as farmland become the dominant causes. The word of Suzhou consists of two Chinese characters, “su” and “zhou”. Here ‘zhou’ is a common word used for a piece of low land (or just emerged from the water) on which people can settle down. But “su” can be used to express and explain the whole history of the human-environment interactions since it can be disas-

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sembled into three basic parts with individual meaning. The top part means a piece of land with reed and weed, standing for a natural ecology and environment. The lower left part is ‘fish’, indicating a water country (wetland) yielding fishes as the best natural food for people. Besides, the lower right part is ‘grain’ (or Grammineae), supporting that this land can also be cultivated with crops (as farmland). For the future human-environment system our effort is to harmonize the proportions among these three parts. (NSFC project No.40571170) 0191 Evolutionary consequences of range contraction: habitat tracking or local extinction? Love Dalen1, Veronica Nyström2, Cristina Valdiosera3, Mietje Germonpré4, Mikhail Sablin5, Elaine Turner6, Anders Angerbjörn2, Juan Luis Arsuaga3, Anders Götherström7 1

Royal Holloway University of London, United Kingdom Department of Zoology, Stockholm University, Sweden 3 Centro UCM-ISCIII de Evolución y Comportamiento Humanos, Spain 4 Department of Palaeontology, Royal Belgian Institute of Natural Sciences, Belgium 5 Zoological institute RAS, Russia 6 RGZM, Forschungsbereich Altsteinzeit, Germany 7 Centro UCM-ISCIII de Evolución y Comportamiento Humanos / Uppsala University, Sweden 2

How species respond to an increased availability of habitat, for example at the end of the last glaciation, has been well studied through phylogeography and other techniques. In contrast, little is known about the opposite process, when the amount of habitat decreases. The hypothesis of habitat tracking predicts that species should be able to track both increases and decreases in habitat availability. The alternative hypothesis is that populations outside refugia become extinct during periods of unsuitable climate. These hypotheses have so far been difficult to test empirically because it would involve genetic sampling of a species through an expansion/contraction cycle. To achieve this, we used ancient DNA techniques to examine genetic variation in the arctic fox (Alopex lagopus), whose geographic distribution was expanded during the last glaciation, and subsequently decreased during the Holocene. The results show that southern Late Pleistocene populations have not contributed genetically to present day populations. Instead, a high genetic similarity between the extant populations in Scandinavia and Siberia suggests an eastern origin for the Scandinavian population at the end of the last glaciation. We conclude that the arctic fox in mid-latitude Europe became extinct at the end of the Pleistocene, instead of tracking the habitat when it shifted to the north. These results provide new insights into how species respond to climate change, since they suggest that populations are unable to track shifts in habitat. This implies that arctic species may be particularly vulnerable to increases in global temperatures. 0270 The influence of Pleistocene sediments on actual slope stability in the Rhenodanubian Flysch Zone of the Vienna Forest (Eastern European Alps/Austria) Bodo Damm1, Birgit Terhorst2 1

Institute of Geography, University of Eichstaett-Ingolstadt, Germany Institute of Geography, University of Tuebingen, Germany

2

In general, Flysch consists of alternating sequences of sandstones, clays and marls deposited as marine deep sea sediments during the Lower Cretaceous to the Eocene periods. Along the northern margin of

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the European Alps the Rhenodanubian Flysch Zone runs in W-E direction and dips below the Vienna basin at the periphery of Vienna. In the study area, the Vienna Forest north west of Vienna the Flysch Zone is formed by Upper Cretaceous to Eocene sediments. They are composed by various layers of (calcareous) sandstones, marly shales, calcareous marls and clay shists, which are covered by Quaternary periglacial cover beds and loess deposits. The study area represents an undulating landscape of the central European low mountain regions with deeply incised valleys and is between 300 and 500 m a.s.l. The Flysch regions are considered to be susceptible to landslides. Both, petrography of the bedrock and soil mechanical properties of the Quaternary sediments control the actual slope dynamics. In particular calcareous sandstones tend to a profound decomposition under influence of humidtiy (“Mürbsandstein”). The base of the Quaternary deposits had been formed by solifluction processes, resulting in a widespread distribution of periglacial cover beds, mainly consisting of clays and marls. These impermeable layers are responsible for the occurrence of springs. The hanging layer consists of permeable loess deposits (4m) of the last glacial period. The top of the sequence is characterised by a further periglacial cover bed, composed of a mixture of loess and sandstones, originating from the Late Glacial. In a temporal context it is evident that the stability of slopes exceeding 27 degree is controlled by sequences of landscape formation. On the basis of field survey, laboratory analyses, and slope stability modelling, investigations on recent landslides give evidence of five sequences. Initial situation: The described geological profile is completely developed. First sliding phase: Sliding of loess deposits on top of basal clays and marls. Erosion phase: Downwash of the basal clays and marls, uncovering the bedrock. Decomposition phase: Profound decomposition of calcareous sandstones. Second sliding phase: Sliding of the decomposed sandstone, after exceeding a “critical mass”. Afterwards, the phases four and five reoccur in an alternating pattern. After passing phases 1–5, the stability of the studied slopes is increased, due to the different soil mechanical properties of the potential sliding masses. Now, the critical slope is at 3 – 5 degree increased. 0272 Temporal Variations of Mountain Permafrost Creep in the Eastern European Alps derived from Rockglacier Monitoring Bodo Damm Institute of Geography, University of Eichstaett-Ingolstadt, Germany

In high mountain geosystems, active rockglaciers give evidence of the present occurrence of permafrost. The kinematics of rockglaciers and their temporal variations may indicate the sensitivity to climate-induced changes. In general, parameters such as ice content and thickness, ice temperature, and changes in slope control the kinematics of rockglaciers. Variations of these parameters are influenced by the input of water, debris supply, snow cover characteristics, and temperature variations. • Monitoring in the European Alps realised by the application of ground-based and remote sensing techniques show a distinct increase in horizontal movement rates of numerous rockglaciers since the 1990s. The observed accelerations largely occurred in spite of numerous varieties in geology, topography, and regional climate of the study areas. In the eastern European Alps rockglacier monitoring was predominantly undertaken in South Tyrol (Italy) as well as in North Tyrol and Carinthia (Austria). In part, records from these areas document differentiated temporal kinematics since the 1950th. • For example, rockglacier monitoring in the South Tyrolean Alps was carried out in the Rieserferner-Ahrn natural preserve. The area, where rockglaciers are exclusively developed in igneous- and sedimentary gneiss, is located south of the Hohe Tauern range. Remote

sensing and GIS techniques as well as on-site flow rate measurements were applied to detect the temporal varieties in creep and surface deformation of active rockglaciers. Dependent on the observed sites, the mean displacement rates were about 13–18 cm/year in the period 1956–1985 and 18–23 cm/year between 1985 and 1999, corresponding to an increase of 28–36 percent. The rates oftentimes vary significantly from one year to the next. For example, during 1992–93, 1997–1999, and 2003–04 peaks of acceleration occurred. The outstanding warm summer of 2003 was followed by a strong displacement, which overtopped the rate between 1956 and 1992 by 150 percent. • In the observed areas of the Eastern Alps the parallelism between increasing permafrost creep rates and rising temperatures is largely evident. Furthermore, direct reactions to temperature changes were observed. It is therefore supposed, that the rise in temperature and the related influence on ground thermal conditions cause the temporal changes in permafrost creep, even though topographic parameters may trigger an increase in movement in particular cases. However, the variations of rockglacier kinematics in the European Alps are difficult to explain in detail as numerous parameters influence the rheology and corresponding data are so far limited. 0257 The actual environment of the lake Ifrah and the climate reconstructions since the last glacial maximum in the Middle Atlas (Morocco) Brahim Damnati1, Ali Rhoujjati2, Issam Etebai3, Maurice Taieb4 1

Faculty of Sciences and Techniques. Natural Resources and Risks obervatory. Tangier, Morocco 2 Faculty of Sciences. El Jadida, Morocco 3 Morocco 4 France

The continental reconstruction of climatic variations in past implies the study of continuous sedimentary sequences and that these sequences are well dated. The most interesting sequences for this type of studies are taken in wet zones such as lakes or peat bogs. In the Middle Atlas of Morocco, there are sites answering these criteria of bases, such as the lake Tigalmamine, the lake Sidi Ali, the lake Ifrah, and the lake Iffer. • During the campaigns of core sampling in the Middle Atlas region, a long core of 9 m and several small cores (superficial sediments) of 1 m were taken in the lake Ifrah. • The mineralogy of the recent sediments of the lake Ifrah is dominated by detrital carbonates. High percentages are observed on the borders. The organic matter mainly of amorphous type is probably of algal origin with locally ligneous fragment. The highest concentrations in organic matter in the sediments are observed in the centre of the lake. This maybe correlated with the lake stratification, and/or with the local existence of a reducing environment favorable to the conservation of the organic matter. • The geochemistry study of the major elements of the long core of 9 m, shows that the major elements SiO2 , CaO and Al2O3 are dominating. Low percentages are those of the Fe2O3 , Na2O and K2O. The evolution of these chemical elements with the depth shows two lithological units. A lower unit with high contents in SiO2 , Al2O3, and K2O. The CAO content is low. In the upper unit, it is the opposite which occurs. The total organic carbon (TOC) is small except in the base and the top of the core. The silts represent the most abundant fraction in the record. • High contents in SiO2 , Al2O3, and K2O at the lower unit would be connected probably to an important aeolian contributions charged in detrital minerals during a relatively dry period dated between 21000 years BP and 16000 years BP.


• The top Holocene unit deposited during a wet period when contributions charged in stemming carbonates directly from the lake drainage basin are more important. • Multidisciplinary study (sédimentological, palynological studies are in progress) will bring certainly the other elements of answers on the climate of the region since the last glacial maximum until the present. 0185 Palaeoecology of the Lower Bengal Basin, Calcutta, India during the Late Quaternary Sauren Das Indian Statistical Institute, India

Palynological analysis was conducted in view of previous palaeoecological reconstructions of trends in the Lower Bengal basin (West Bengal, India). Floristic compositions were derived from peat collected from Garia, located at the southern extremity of the city (88˚ 24´ to 18.36´ E and 22˚ 27´ to 58.68´ N). Garia, being one of the oldest settlements in this region, is situated by the ‘Tolly Nullah’ connecting Calcutta to the Vidhyadhari River in the east. Bore hole samples were radiocarbon dated and three successive peat layers of 7000 (±170) yrs B.P. to 2650 (+150) yrs. B.P. were analyzed for their pollen composition. Pollen data indicates the existance of typical swampy vegetation of mangrove plant community in and around Calcutta, which are presently confined to the Sundarbans forest further south. The lower most peat layer (ca. 7000 – 6500 yrs B.P.) revealed that the vegetation sequence was comparatively uniform and mainly comprised of Heritiera, Rhizophora, Sonneratia, Excoecaria, Phoenix pludosa and grasses, implying insignificant fluctuations in climatic conditions. The middle layer indicates a mixed vegetation type of fern spores, mangroves and some terrestrial plants (e.g. Suaeda, Acanthus and grass). The lower part of the middle peat layer (ca. 6450 – 6100 yrs B.P.) consisted of marshy habitat as evidenced by fern spores, whereas their absence in the upper part implies relatively dry environmental conditions. The upper peat layer (ca. 2600 yrs B.P.) is dominated by grass pollens of Rhamnaceae, Heritiera, Excoecaria, and low amounts of fern spores indicating terrestrial habitats. The pollen/spore assemblages in the three successive peat layers indicate the presence of typical mangrove vegetation, of the type currently observed in the Sundarbans region. Frequent sea water inundation mixed with fresh water flow from the northern upstream at the low lying topography of Lower Bengal Basin seems to have led to formation of the peat by deposition rather than by drifting. 1273 Lake System Response Of Nam Co Area (Southern Tibet) To Late Quaternary Monsoon Dynamics – First Results From Hydroacoustic Survey And Coring Gerhard Daut1, Roland Mäusbacher1, Ernst Kroemer2, Johannes Wallner1, Ines Mügler3, Gerd Gleixner3, Antje Schwalb4, Liping Zhu5 1

Friedrich Schiller Universität Jena, Physische Geographie, Germany Bayerisches Landesamt für Umwelt, Germany 3 Max-Planck-Institut für Biogeochemie Jena, Germany 4 Technische Universität Braunschweig, Institut für Umweltgeologie, Germany 5 Chinese Academy of Science, Institute of Tibetian Plateau Research, China 2

This study is part of a bundle of projects dealing with the hydrological cycle in the Nam Co the second largest saline lake in China, Central Tibet. We assume that the sediments stored in this high elevated lake of the Tibetian plateau are delivered from the catchment by surface runoff, linking changes in sediment accumulation in the lake directly to

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changes in the hydrological cycle especially precipitation. To detect these changes with high spatial and temporal resolution a bathymetrical and sub-bottom profiling survey was carried out using a parametric system. A subsequent piston and gravity coring was performed and the cores were analysed for their geophysical and geochemical properties. Additionally 14C-datings were performed by AMS. These data are interpreted as proxies for changes in the hydrological cycle. • The hydroacoustic survey shows that the Nam Co lake is devided into several subbasins with a maximum water depth of 95 m. The sediment infill is characterised in the subbottom profiling by three distinguishable acoustic units with a thickness of at least 25 m. One layered but intense folded unit is detected at the base and two well layered acoustic units to the top of the sequence. The seismic profiles additionally show indicators for intense lake level changes as well as indicators for tectonic activity. The piston cores cover the time span of the last 8000 years. Sedimentological changes (grain size distribution, magnetic susceptibility) detected in the cores can be well correlated to the upper units of the hydroacoustic data. The lower folded unit is not represented in the cores. The geophysical data show a remarkable change in the sedimentology which is also detected in the geochemical data like Ca/Mg or Ca/Sr ratios, that indicate a change from low salinity at the lower part of the core to higher salinity for at least the last 2000 years in the upper part of the sediment sequence. • These first results will be completed on the existing cores by a bottom-up multi proxy approach including pollen analysis, isotope ratios of ostracodes, specific terrestrial and aquatic biomarkers and their isotopic content. 1300 Ancient Lake Ohrid: Towards an understanding of its environmental and evolutionary history – evidence from subbottom profiling Gerhard Daut1, Michael Denner2, Klaus Reicherter3, Bernd Wagner4, Martin Wessels5, sungen und Naturschutz Baden-Württemberg6 1

Physical Geography, Friedrich Schiller Universität Jena, Germany, Germany Institute for Geology, University of Leipzig, Leipzig, Germany, Germany 3 Neotectonics and Natural Hazards, RWTH Aachen, Aachen, Germany, Germany 4 Institute for Geology and Mineralogy, University of Cologne, Cologne, Germany, Germany 5 Institut für Seenforschung der Landesanstalt für Umwelt, 6MesLangenargen, Germany, Germany 2

Lake Ohrid, a transboundary lake between Albania and Macedonia, is considered to be the oldest existing lake in Europe, with an age assumed between three and five million years. Although Lake Ohrid is home to more than 210 endemic species, the environmental and evolutionary history and processes leading to these unique faunas are largely unknown. Therefore a long sedimentary record from Lake Ohrid is needed that would shed more light on the understanding of the mechanisms triggering these evolutionary processes. A first shallow hydro-acoustic seismic survey on Lake Ohrid was carried out in the summer 2004 using a parametric subbottom profiling and echosounding system. With this survey it was possible to establish a new bathymetric map which improved the existing data significantly. The maximum water depth was measured with 287 m. The subbottom profiles show in general a maximum penetration of 50 m in most parts of the lake with two main acoustic units. The upper one with well layered sediments and a lower one with few or without layering. Due to limited power of the system it was not possible to detect basal reflectors. Several other acoustic facies elements indicate series of faults and

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sediment redeposition, particularly at steep sub-aquatic slopes close to the lake shore. Mass movement processes are most likely triggered by tectonic activities or significant lake level fluctuations in the past. By comparing the first dated cores (Wagner et al. 2006) with the results from the seismic survey strengthen the theory that lake Ohrid may be one of the oldest European lakes. For the years 2007 and 2008, further seismic survey campaigns using airgun, a parametric sound system, and a sidescan sonar are planned, as well as recovery of a 10 –15 m long sediment sequence from the central part of the basin. These investigations should contribute to the evaluation of Lake Ohrid as a potential deep drilling site in the near future. 1343 Temperature and grape harvest dates in France Valérie Daux1, Pascal Yiou1, Isabelle Chuine2, Nicolas Viovy1, Bernard Seguin3, Emmanuel Le Roy Ladurie4 1

Laboratoire des Sciences du Climat et de l’Environnement, Gif-sur-Yvette, France 2 CEFE, Montpellier, France 3 INRA, Avignon, France 4 Collège de France, Paris, France

Grapevine is a Mediterranean, hardy and, perennial plant. Its development annual cycle strongly depends on climate, especially temperature. Grape harvest occurs when the grape has reached maturity. Though grape harvest date, which is influenced by the socio-economical context, is not a phenological parameter, it is seems to be linked to the springsummer mean temperature. We investigate the relations between grape harvest dates and regional monthly temperatures for vines from Burgundy, Champagne, Bordeaux, Alsace and Rhônes areas since 1850. The best correlations are obtained for May to August mean temperature versus dates. The time of grape maturity depends not only on temperature but also on grape variety. Not surprisingly, the best correlations (R) (highest correlation coefficients) are obtained for regressions involving single varieties. For example, R=0.6 for harvest dates of Alsace vines combining several varieties, and R=0.9 when considering Riesling only. The slopes of the different regressions tested are all close to 0.1 °C/day : whatever the area and the grape variety, a 1°C variation in the May to August mean temperature results in a variation of ten days in the grape harvest date. The potential of grape harvest dates as a temperature proxy is thus high. However, information on grape varieties is necessary to make the most of grape harvest dates series. 0121 British and Fennoscandian Ice Sheet Interactions During the Quaternary Bethan J Davies University of Durham, United Kingdom

This project seeks to understand the dynamic interaction between the British and Fennoscandian ice sheets and to test the applicability of recent models which advocate glaciations of the British Isles during Marine Isotope Stages 16, 12, 10, 6 and 2. The work investigates of the glacigenic sediments of Co. Durham coastline in northeast England, and uses lithofacies analysis, geochemistry, heavy mineral analysis, and micromorphology to determine the genesis, stratigraphy, and provenance of the sediments. • At Whitburn Bay there are two tills separated by a boulder pavement. The Lower Till is a massive, over-consolidated diamicton with strong clast fabrics and striated, far-travelled clasts. Micromor-

phological analysis suggests it is a deformed lodgement till. It is dominated by locally sourced Magnesian limestone, but the metamorphic and igneous-derived heavy minerals indicate that the ice was sourced from the Lake District to the west, with a high percentage of sphene but low percentages of muscovite, chlorite and tremolite. • The Upper Till is a clast poor, massive diamicton. Its weak clast fabric orientation and deformed microscale structures suggest it is a deformation till. The heavy mineral suite contains high percentages of kyanite, clinopyroxenes, and baryte, and indicates a source in a crystalline, strongly metamorphosed region, which coupled with a Cheviot erratic suite, indicate a northerly ice source from the Cheviots and Southern Uplands of Scotland. • The flat, polished, striated upper surfaces of the boulders in the pavement at Whitburn indicates that they were deposited directly at the ice-subsole interface. The lithologies of the boulders indicate that they were deposited by the first ice incursion, and represent a depositional hiatus and melt-out of the boulders. They were then overridden by ice flowing from the north, which firstly lodged and then striated the boulders, resulting in their north-westerly striation sets, mirroring the Upper Till, which was deposited over the boulders. • Within the Upper Till, glaciotectonised channels of intercalated sand and clays are interpreted as anastomosing subglacial canals, with alternating periods of traction current and suspension fall-out deposition. These channels drained the sub-marginal region of the ice sheet into an intermittent, interlobate ice dammed lake situated along the Durham coast. 0652 The development of an outline late Quaternary tephrochronological framework for Greater Australia Sarah E Davies1, Valerie A Hall1, Chris S M Turney2, Peter Kershaw3 1

Queens University Belfast, United Kingdom University of Wollongong, Australia 3 Monash University, Australia 2

Tephra has become widely recognised as a powerful tool for the highprecision correlation of Late Quaternary palaeoenvironmental records in regions such as Europe and New Zealand, where tephrochronological frameworks are well established. To date, little tephra work has been carried out in ‘Greater Australia’, defined here as the Australian continent and New Guinea. Studies that have been undertaken, largely within Papua New Guinea (PNG), have tended to focus on characterisation through bulk mineral composition. Presented here for the first time are the results of detailed geochemical analyses on single glass shards derived from volcanic centres in the Western Plains region (Victoria) and the Atherton Tablelands (northeast Queensland). Tephras from a number of the younger (96%. Layers of tephra were discovered in both records and major element analyses have enabled correlations to potential sources. The results from Pejark Marsh are significant for understanding the nature of recent volcanism in the Western Plains. Furthermore, the occurrence of tephra in the Lake Wangoom stratigraphy has implications for how the palaeoenvironmental record is interpreted. Multiple visible tephra layers from three Holocene sites in the Highlands region of PNG are characterised by single shard analyses. Although many of the tephra horizons display


a compositional continuum, they can usually be distinguished from one another. In this work the geochemistry is used to effect local correlations between important archaeological and environmental sites: Kuk Swamp, Ambra Crater and Lake Aguai Ramata. This pioneering study should encourage further tephra research in Greater Australia and help improve our understanding of climatic, environmental and archaeological change in the Australian Late Quaternary. 0654 The characterisation of local and distal tephras in the northern sector of Greater Australia including some preliminary highprecision correlations between significant archaeological sites in Papua New Guinea (PNG) Sarah E Davies1, Chris S M Turney2, Valerie A Hall1, Peter Kershaw3, Simon G Haberle4, Tim P Denham3, Brent V Alloway 5 1

Queens University Belfast, United Kingdom University of Wollongong, Australia 3 Monash University, Australia 4 Australian National University, Australia 5 Institute of Geological and Nuclear Sciences, New Zealand 2

Despite a long history of volcanism, limited precision-based tephra research has been carried out in the northern sector of Greater Australia. ‘Greater Australia’ is defined here as the Australian continent and New Guinea, since these two landmasses were joined during the Late Glacial Maximum. For the first time we present detailed geochemical analyses on single glass shards from tephra layers at Kuk Swamp, Ambra Crater and Lake Aguai Ramata, in the Highlands region of PNG and also Lynch’s Crater in northeastern Australia. Importantly, the Kuk Swamp record holds international significance for understanding early agriculture in New Guinea. Previous attempts to link visible tephra layers within this site were based on largely on visual characteristics. Here we demonstrate how robust correlations can be made using major element geochemistry. It has been suggested that forest clearance during the mid-late Holocene was localised and temporally staggered throughout the Highlands. In this work we report high-precision correlations between the three late Holocene PNG records using visible tephra layers, allowing us to test the timing of vegetation change. Furthermore, a long, continuous terrestrial record from Lynch’s Crater (Atherton Tablelands), provides the main reference for Late Quaternary environmental change in northeastern Australia. A cryptotephra discovered within early Isotope Stage 4 sediments has been geochemically analysed and is consistent with a Papuan source. This is the first reported occurrence of distal tephra on the Australian continent and demonstrates the potential of tephrochronology for effecting high-precision correlations between sequences. Future work is needed to test hypotheses of synchronous climate change in the region. 0865 Towards a North Atlantic tephrochronology framework for the Last Interglacial - glacial transition Siwan M Davies1, Mattias Bigler2, Sigfus J Johnsen2, Jørgen P Steffensen2, Stefan Wastegård3 1

University of Wales Swansea, United Kingdom University of Copenhagen, Denmark 3 Stockholm University, Sweden 2

The demise of the last interglacial period serves as the most recent analogue for understanding the mechanisms, timing and environmen-

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tal responses that may lead to a glaciated Earth at the end of the current interglacial period. Reconstructing the pattern of events, however, is confounded by chronological limitations as a scarcity of precise absolute timescales and stratigraphic marker horizons impedes the precise correlation of diverse palaeoclimate archives that span this episode. One of the few techniques that has the potential to address this problem is tephrochronology. Here we report on the work being undertaken on the NGRIP ice-core to construct a European and North Atlantic tephrochronology framework for the last interglacial-glacial transition. Tephras within this record have been identified by visual inspection of the ice-core during the drilling campaign, however, in most cases, the high resolution NGRIP chemical stratigraphy obtained by continuous flow analysis, electrical conductivity measurements (ECM) and dielectric profiling (DEP) data are employed to pinpoint the presence of cryptotephra horizons (tephra horizons that are invisible to the naked eye). Thus far, this work has revealed the presence of previously unreported tephra horizons of Icelandic origin, thus adding considerably to our knowledge of Icelandic volcanism over the Last Interglacial-glacial transition. Moreover, identification of these tephra layers in the ice-cores will enable independent ages to be assigned to these events, and will form a basis for tracing coeval layers in marine and terrestrial records. 1106 Testing the synchroneity of Dansgaard-Oeschger events in the North Atlantic region using tephrochronology Siwan M Davies1, Stefan Wastegård2, Mattias Bigler3, Sigfus J Johnsen3, T Rasmussen4, Jørgen P Steffensen3, Anders Svensson3 1

University of Wales Swansea, United Kingdom Stockholm University, Sweden 3 University of Copenhagen, Denmark 4 University of Tromsø, Norway 2

Tephrochronology is fast becoming a key technique for the precise correlation of Late Quaternary records in the North Atlantic region. In recent years, the geographical distribution of signficiant tephra horizons has been extended and thus a number of tephras have become important tie-points for correlation of diverse palaeoarchives during the Last Glacial cycle. Here we report on two key tephra horizons – the Faeroe Marine Ash Zone II and III (FMAZII & III) - that have recently been identified in the NGRIP ice-core and correlate to tephras found in several marine records within the North Atlantic region. FMAZII (also referred to as the Fugloyarbanki tephra) is dated to 26 744 ± 390 b2k (1σ uncertainty) according to the Greenland Ice Core Chronology (GICC05), and constrained to ca. 23-24 14C ka BP within the marine records. This tephra falls after the warmest peak of GIS3 in both the NGRIP and marine records. The FMAZ III, on the other hand, is constrained to 33,000 14C ka BP in the marine records and 38,130 ± 720 b2k (1σ uncertainty) in the NGRIP ice-core, and falls directly on the warming limb of GIS 8. This tephra provides key evidence of the synchronous nature of this climatic transition. Both tephras represent key marker horizons for the synchronisation of palaeorecords with the highest degree of precision and suggest the close coupling of the marine and atmospheric systems during the last glacial period. Furthermore, the discovery of these horizons in the NGRIP ice-core emphasise the extensive nature of these tephras and outline the potential of tracing these events in other proxy records, particularly within terrestrial records in areas of northwest Europe that remained ice-free during OIS 2 and 3.

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1352 Understanding the Earth system and the role of the latitudinal temperature/insolation gradient

0287 Tsunamis in the Geological Record Alastair G Dawson1, Iain Stewart2

Basil A S Davis1, Simon Brewer2 1

Newcastle University, United Kingdom 2 CEREGE, France

During the mid-Holocene, lower winter insolation was associated with warmer winter temperatures at high latitudes and higher summer insolation was associated with cooler summer temperatures at low latitudes. Model simulations of mid-Holocene climate have had problems reproducing this contradictory response of the climate system to insolation forcing. We show here that these changes can be explained by an unexpected sensitivity of the climate system to changes in the latitudinal insolation gradient (LIG) that drives the Earths latitudinal temperature gradient (LTG). This is demonstrated using a reconstruction of the Northern Hemisphere mid-Holocene LTG based on a synthesis of both terrestrial and marine data, as well as a continuous record of the LTG throughout the Holocene based on a continental-scale pollen-based gridded temperature record. This LTG record is validated by comparison with proxy records of the main climate modes that would be expected to be influenced by the LTG during the Holocene, such as the summer Monsoon and winter AO. We suggest that a lack of sensitivity of climate models to LIG forcing of the LTG may also underlie problems found in model simulations of both of these main climate modes. These apparent discrepancies between model simulations and observed climate have been variously prescribed to simplifications in models of local factors such as vegetation, sea ice, sst’s and topography. While this has led to a drive for greater complexity in model design, we suggest a simpler explanation may be based on an over sensitivity of model response to direct insolation forcing, and a relative insensitivity to changes in the insolation gradient. A lack of low latitude temperature records relative to high latitudes has long made the study of the LTG particularly difficult, yet as the main driver of the atmospheric and (wind driven) ocean circulation and a key diagnostic of the climate system, we would like to encourage further research in this area. 1357 Alkenones say warmer, Pollen says cooler; Land-Ocean contradictions in Holocene climate reconstructions from the Mediterranean Region Basil A S Davis Newcastle University, United Kingdom

The Mediterranean Sea is an enclosed ocean that would suggest close coupling between sea surface and land surface temperatures. In fact, this has indeed been the case during the 20th Century based on instrumental data, but temperature records during the Holocene show a clear contradiction between land and ocean proxies that appears difficult to explain. Alkenone sst records almost universally suggest the early-mid Holocene was warmer than present, while pollen-based surface temperature records equally suggest cooler early-mid Holocene temperatures. Interestingly, the latter cooling is also reproduced in faunal sst records based on modern analogue techniques. This study outlines possible problems associated with both land and ocean proxies whilst also putting these alternative proposed climates (warmer/cooler) in the context of the wider climate system. Both alkenones and pollen are some of the most widely applied proxies in land and ocean based climate research, and resolving this contradiction could well have important implications for one or other proxy.

1

Aberdeen Institute for Coastal Science and Management, University of Aberdeen, Scotland, United Kingdom 2 Department of Geography, University of Plymouth, Plymouth, United Kingdom

A review is presented here of tsunami deposits in the geological record. It begins with a discussion of the relationships between the processes of tsunami generation and propagation and the sedimentary responses. This is followed by a consideration of the sedimentary processes associated with the passage of tsunami waves across coastlines. Attention is also given to the sedimentary processes associated with tsunami-triggered gravity backwash flows and comparisons are made with turbidity current action. We observe that despite sedimentary evidence for recent tsunamiites, geological research on ancient tsunamis have not identified stratigraphic units associated with onshore tsunami sedimentation. Equally, it is noted that nearly all published studies of sedimentary processes associated with modern tsunamis have not considered patterns of sediment transport and deposition in the offshore zone. The discussion draws on a range of examples that highlight the variability of the sedimentary record of ancient tsunamis. We draw attention to the fact that analogues for the sort of geological evidence for tsunamis in the Quaternary are unlikely to preserved in the rock record. We therefore highlight the issues relating to the offshore sedimentary record of past tsunamis, the difficulties in recognizing such records and address the issue of how such problems may be solved. 0492 A long late Pleistocene pollen record from the Urmia Lake, NW Iran Jacques-Louis de Beaulieu Institut Méditerranéen d’Ecologie et de Paléoécologie (IMEP), France

A 100 m-long core collected from hypersaline Lake Urmia, NW Iran, has been the subject of palynological and sedimentological investigations to reconstruct late Pleistocene environmental changes in northwestern Iran. Comparison of the general vegetation trend, inferred from the Urmia pollen diagram, with the long pollen records of southern and southeastern Europe suggests that the Urmia record encompasses a period ranging from mid to late Saalian through the Early Holocene. The uppermost part of the core, which corresponds to the mid to late Holocene, has been lost. During both the Saalian and the last glacial periods, hypersaline shallow to playa lake conditions existed. Dense halophytic communities, comprised mainly of various species of Chenopodiaceae, covered the extensive saline mud flats around the contracted lake. During these intervals, Artemisia and mountain steppe plants dominated the upland vegetation, with Artemisia, Cousinia, Astragalus, Nitraria, Pteropyrum, and Apiaceae (Ferula-type and Bunium-type) among the most important constituents of the steppic vegetation. Lake level appears to have been higher during the interglacials and capable of supporting a significant brine shrimp population, as suggested by the accumulation of aragonitic faecal pellets. It was probably highest during the latest Saalian and very early Eemian (OIS 5e) when brackish water dinoflagellates flourished in the lake. During this stage, Artemisia and mountain steppe vegetation was replaced by the typical Zagros open oak-woodlands and Pistacia scrubs through a transitional steppe dominated by the sub-shrubby Ephedra spp. A similar vegetation succession developped during the transition


from the last glacial to Early Holocene before the re-establishment of the open oak woodlands and peripheral scrubs. Hippophaë was the most important tree species in the later part of both glacial periods. It was then followed by a succession of Ephedra, Pistacia, and Betula during the late-glacial times. At the onset of both the Holocene and Eemian interglacials, Quercus and Juniperus are dominant, while Ulmaceae, Fraxinus, Pinus and Carpinus show minor increases. The pollen of the latter two trees likely came from the Euxinian and Hyrcanian forests in northern Turkey, Caucasus and northern Iran. A small peak of Zelkova in the Eemian Interglacial is evidence of the presence of this relict species in the Urmia region before the last glacial period. The modern hypersaline conditions of the lake began in the Early Holocene and coincide with a period of increasing tree pollen percentages. 1125 Timing and impact of early mining activities in two French Mediterranean mountains: Lozere and Durance Alps (France) Jacques-Louis de Beaulieu1, Bruno Ancel2, Christine Bailly-Maitre3, Sandrine Baron4, Martin Lavoil5, Alain Ploquin4, Maria Pulido1, Alain Véron6, 1

IMEP, UMR 6116 du CNRS, Europôle Méditerranéen de L’Arbois, Bâtiment Villemin, BP 80, 13545 Aix-en-Provence Cedex 04, France 2 S.C.S.T.I., 05120 L’Argentière-la- Bessée, France 3 MMSH, 5, rue de l’Horloge, BP 647, 13094 Aix-en-Provence Cedex 20, France 4 CRPG-CNRS, BP20 Vandoeuvres-lès-Nancy, France 5 IMEP, UMR 6116 du CNRS, Europôle Méditerranéen de L’Arbois, Bâtiment Villemin, BP 80, 13545 Aix-en-Provence, France 6 CEREGE, Europôle Méditerranéen de L’Arbois,13545 Aix-en-Provence Cedex 04, France

The global impacts of early metallurgy became a major question after the identification of a high led concentration in Antarctic ice cores during the Roman times. Here we report on collaboration between archaeologists, geochemists and palynologists to identify the environmental consequences of early metallurgy on past landscapes at local and regional scales in south-east France. Both in Mont Lozère (Cevennes) and at Fangeas, in high Durance basin, cores were extracted from peat bogs close to medieval mining sites excavated by archaeologists. Pollen analyses, led content measurements and 14C dating were applied to the cores. In the two sites a major changes in led concentration or isotopic ratio is evidenced during late Iron Age and Medieval times. The first peak does not correlate with the local archaeological evidences and could correspond to a regional influx. The environmental impact of the mining activities is difficult to disentangle from other anthropogenic activities (intensification of agriculture and pastoralism). 1422 Plant palaeogenetic and Pleistocene vegetation history Jacques-Louis de Beaulieu1, Rémy J Petit2 1

IMEP UMR CNRS 6116, France INRA, France FOSSILVA working Group 2

The survival of temperate taxa during the Pleistocene glaciations, the location of their refuges and the steps of their postglacial expansion toward northern latitudes constitute classical questions for biogeographers. Long-standing researches of palaeobotanists and palynologists brought their contribution in this debate; more recently the phylogeographical approach uses genetic markers to explore the historical roots

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of the present biodiversity. In Europe, during the last decade, research projects, combining population genetics based on modern DNA techniques and vegetation palaeomaps bases on pollen and plant macrofossils databases, shed new lights on the migration routes of tree taxa. Our goal, within the FOSSILVA project, was to extract ancient DNA from Lateglacial and Holocene remains of forest trees to trace the geographical origin of their present day lineages. Here we present an assessment of this experiment. The poor conservation rate of DNA in fossil plant remains is recalled. Our results are modest but open a door toward further studies; they give the opportunity of a larger overview on the state of the art in the field of ancient plant DNA. The FOSSILVA project “dynamics of forest tree biodiversity: linking genetic, palaeogenetic and plant historical approach” was funded by the EU (EVK2-1999-00015P).

0796 Caves palynology: analyzing taphonomic processes to better understand environmental changes in Patagonia (Argentina) María Eugenia de Porras, María Virginia Mancini, Aldo Raúl Prieto Laboratorio de Paleoecología y Palinología - Facultad de Ciencias Exactas y Naturales - Universidad Nacional de Mar del Plata, Argentina

Pollen records from caves have been largely used to reconstruct paleoenvironmental conditions in Patagonian semi-desert of Argentina. Furthermore, these caves are archives of archaeological importance related to the human occupations since ca. 13,000 14C years B.P. However, there is a great disagreement to use these pollen sequences because of the complex taphonomic processes that could have affected them. Therefore, modern and fossil taphonomic pollen studies emerge as a fundamental step toward answering some of the key questions related to these processes and the environmental reconstructions. In the present study modern surface pollen samples from two caves are analyzed to study the different processes of pollen transport, distribution and preservation. By comparing local and regional modern pollen samples from Patagonian semi-desert and inner cave pollen spectra, both preservation and concentration components of taphonomic processes and their resulting on vegetation representation have been evaluated. Inner pollen samples present excellent preservation and higher concentration values than the exterior ones. Inner spectra reflect a differential distribution of the pollen types which is strongly related to (1) cave morphology and orientation; (2) distribution and abundance of vegetation in the entrance of the cave; (3) pollination type and, (4) vectors of pollen dispersion. These spectra represent the vegetation in the caves entrance and within the ravine (local vegetation). However, some pollen types are over-represented to the rear or near the walls of the caves indicating that central and middle zones would be the best places to sample a fossil sequence inside the caves. Finally, Late PleistoceneHolocene vegetation history is reconstructed from several caves in the semi-desert between 47˚ and 49˚S, concerning the taphonomic results. The main vegetation changes are related to abiotic causes, however minor changes could be assigned to human activities and biotic disturbance. These results highlight the potential of these fossil pollen records since taphonomic processes are considered to reconstruct paleoenvironmental conditions.

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0356 Facies characterization of microtidal, high wave energy and tropical estuarine influenced Paraná Holocene regressive barrier, southern Brazil Maria C de Souza1, Rodolfo J Angulo1, Mario L Assine2 1

LECOST - Universidade Federal do Parana, Brazil Departamento de Geologia Aplicada, Universidade Estadual sPaulista, Brazil 2

At the southern Brazilian coast the 3 m sea-level drop after 7000 –5000 years B.P. postglacial maximum helped the formation of wide regressive barriers. Many papers have been published about barriers geographic distribution, sedimentary characteristics and evolution. However, little attention was given to the barrier facies. This work aims to characterize the Paraná Holocene regressive barrier sedimentary facies, identify the sedimentary environments and reconstruct the barrier evolution. The Paraná Holocene regressive barrier is located between 25 10´S and 26 00´S of latitude, it is about 6 km wide and presents conspicuous beach ridges. At present time the tidal range is 1.4 m, the wave period varies between 6 and 10 s and the significant wave height is between 0.5 and 1.5 m. The regressive barrier is 12 m thick and was formed when sea level was 1.5±0.5 m above the present level. The barrier overlies the Pleistocene substratum constituted by a lagoonal facies association. The barrier sediments are mainly quartzose fine and very fine sand with low contents of coarser sand, granules and small gravel. At the lower part of the barrier occurred very fine sand and muddy sand with vegetal fragments, debris, shell fragments and shells, in some cases articulated and in living position. There are also abundant ichnofossils, mainly Ophiomorpha and other kinds of tubes. 15 main facies were defined: planar (Sp), through (St), low angle (Sli), swaley (Ssc), sigmoidal (Ssg), tangential (Stb) and hummocky (Chc) cross stratification; massive sand (Sm); ripples and cross lamination sand (Sr); flaser (Sf), wavy (Hw), linsen (Fl) and bioturbated (Hb) heterolitic deposit; drape massive mud (Fm) and bioturbated mud (Flb). Two paleocurrent patterns, one bidirectional parallel to the paleocoastline and another transversal towards the paleocoast, were identified. There were defined five facies associations corresponding to inner shelf, shoreface, foreshore and backshore/foredune environments in a regressive sequence. The facies association indicates a regressive sequence that prograded over the Pleistocene substratum. 10 m of the barrier facies sequence were deposited below paleosealevel and 2 m above paleosea-level. The facies association suggests that they were deposited in an open seacoast with low to medium wave energy associated to high-energy wave episodes. The fine sediments and the vegetal debris were probably provided by the large tropical estuarine systems that exist at the time of the barrier formation.

interpolation technique. The results provide quantitative estimates of the palaeohydrological budget of Europe and its major sub-regions throughout the Holocene. These are discussed in relation to existing alternative proxy records such as lake level data, major forcings such as changes in insolation and the polar ice sheets, and the relationship with key climate modes such as the summer Monsoon and winter NAO. The ability of mid-Holocene climate model simulations to reproduce the observed hydrological changes on comparable continental scales is also investigated. 0444 Resilience and sustainability of Chinese agricultural landscapes: palaeoenvironmental perspectives John Dearing University of Liverpool, United Kingdom

In the context of the newly created PAGES Focus 4 programme http:// www.pages.unibe.ch/science/research/newstructure.html, the paper describes attempts to understand the ‘environmental health’ of modern landscapes through analysis of palaeoenvironmental records (lake and reservoir sediments, alluvial sequences, archaeological data, instrument records, written documents). These include the reconstruction of centennial-scale changes in land use and land cover, hydraulic engineering, climate, flooding, erosion and water quality. Two lake-catchment sites in sub-tropical SW and E China (Erhai and Chaohu) provide the case studies where a comprehensive range of historical information can be applied to questions about the evolution, resilience and sustainability of coupled lowland-upland agricultural systems, dominated by paddy field and dry terraced farming methods. What are the longterm trajectories of major ecological processes, like flooding? How have climate and human activities acted in the past either independently or together to drive change? How are the processes linked in time and space? Can sub-systems be mapped on to adaptive cycles in order to gauge current levels of resilience? How will the system respond to anticipated human and climate perturbations? Is the current state of the system sustainable? The paper reviews the success of using combined empirical-theoretical approaches to addess questions about longterm system dynamics, particularly in the context of creating a typology of modern landscape conditions. 0368 Pedogenesis of paleosols of volcanic origin from the South Central Rift Valley, Ethiopia Fikre M Debela1, Ahmet R Mermut2 1

University of Northern British Columbia, Canada University of Saskatchewan, Canada

2

1240 The palaeohydrology of Europe during the Holocene reconstructed from pollen data Basil AS Davis1, Simon Brewer2 1

University of Newcastle, United Kingdom CEREGE-Univ Paul Cezanne (CNRS 6635), France

2

An earlier analysis of the Holocene temperature of Europe based on pollen data is extended to include palaeohydrological parameters such as annual and seasonal precipitation and moisture-balance. These have been reconstructed from over 500 pollen sites using a modern-analogue transfer function based on pft scores, assimilated onto a uniform spatial grid and time-step using a 4-dimensional (3-d space plus time)

The Rift Valley has formed as a result of tectonic and volcanic activities since the Oligocene (some 37 million years ago). The valley was formed as a result of a major continental tectonic movement. Despite its age, the Rift Valley is currently filled with recent deposits that have resulted from renewed faulting activities, repeated volcanism and sedimentation. Multilayered profiles are common and thought to be a result of intermittent volcanic deposition and polypedogenes. Organic C contents are generally low in these soils. Soil pH ranged between slightly acidic and very strongly basic, but was mostly in the neutral range. Electrical conductivity values were less than 2 dSm−1, indicating that none of the pedons are salt affected. Despite the formation from pumice and other volcanic deposits, allophane and imogolite contents were comperatively low (< 6%), as


was phosphate retention (< 20%). These preclude the soils from Andisol soil order. Vitrandic subgroups in pedons studied recognize a significant influence from volcanic ash in the soils. Formation of argillic horizons is by far the most dominant pedogenic process in the pedons. Thick and continuous clay coatings were clearly seen on ped surfaces, pore walls and between the sand grains. Strongly developed paleosols are very common in the Rift Valley. All of the pedons examined were more than 150 cm deep and well developed, except the Togo pedon, which showed only a slight alteration in its recently weathered 40 cm of topsoil over 2.5 m of loose volcanic pumice parent material. The Togo pedon, however, has underlain a strongly developed paleosol, indicating that the pumice layer is a recent geological deposition. 14C analyses of organic matter in the buried A horizon gave a date of 2200 BP, which is too old to be the age of the upper volcanic ash deposit. Profile development of the upper profile appears to be much younger than 200 years. The whitish tephra layers were observed in other soils indicating that there have been many tephra depositions in the area. The most recent one is likely younger that 2200 years The upper horizons of the many soil are likely derived from the tephra deposit. 1010 Cave sediments as palaeoclimate indicators: pilot study at Mt Etna, Queensland Linda N Deer1, Gregory E Webb1, Scott A Hocknull2 1

Queensland University of Technology, Australia Queensland Museum, Australia

2

Cave environments have the potential to play a major role in Quaternary palaeoclimate research as they may record integrated, dateable records of fossil vertebrates, speleothems and pollen. Although sediments occur within almost every cave system, few studies have focused on what palaeoclimate information may be derived from those cave sediments. Cave sediments can be classified as either endogenetic (derived by internal processes) or exogenetic (derived from external sources and transported into the cave). As previous studies have shown a relationship between the mineralogy of clays produced by weathering in different climatic regimes (i.e., illite and chlorite generally reflect weathering in cool and dry conditions, whereas kaolinite and smectite generally reflect chemical weathering in humid and warm settings), exogenetic sediments may reflect external climatic conditions. We carried out a preliminary case study at Mt Etna, Queensland. Caves in this area occur within highly fractured and recrystalised limestone olistoliths that contain siliciclastic strata in places and are bound by serpentinites. We compared the clay mineralogy of cave sediments associated with:(1) rainforest vertebrate faunas, (2) more arid, open faunas, and (3) in varying positions relative to a sequence of flowstones. In each case, sediments showed no bedforms and were limited to very fine grained detritus. They are interpreted as having been deposited from suspension. Samples were analysed using X-ray diffraction after removal of visible bone and flowstone fragments. Preliminary results show no apparent difference between clays in sediments containing rainforest and more arid vertebrate assemblages. Additionally, clay compositions did not vary stratigraphically in relation to the positions of flowstone. All samples contain mixtures of illite, kaolinite, smectite and mixed layer illite/smectite. The following hypotheses are being considered to explain the uniformity of clays in the deposits. (1) Changing climate did not affect the primary types of clays produced by weathering at Mt Etna. (2) The clays at Mt Etna largely represent endogenetic sources being liberated internally through limestone dissolution. (3) The local karst environment provided a relatively uniform

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local climate regime, whereas the vertebrate faunas sampled a broader geographic area with less uniform climate. (4) Clays were diagenetically homogenised secondarily to some extent within the cave setting. 0498 Burial dating of sediments by cosmogenic 10Be and 26Al Andreas Dehnert1, Naki Akçar1, Uwe Kasper2, Peter W Kubik3, Frank Preusser1, Christian Schlüchter1 1

Institute of Geological Sciences, Universität Bern, Switzerland Institute of Geology and Mineralogy, Universität zu Köln, Germany 3 Institute for Particle Science, ETH Zürich, Switzerland 2

Sedimentary records provide important information on the climatic and environmental history, as well as on the tectonic development of a given area. To evaluate the information in a temporal context, the availability of reliable dating results is necessary. There are enormous problems, however, associated with the dating of especially Quaternary sediment sequences. Burial dating of sediments using in-situ produced cosmogenic nuclides could provide absolute ages for such deposits. This method utilises the fact that minerals were exposed to cosmic radiation prior to deposition and that individual cosmogenically-produced nuclides decay at a constant rate once sediment has been buried. In this case, the decay ratio of the cosmogenic nuclides 10Be and 26Al, which are abundant in quartz minerals, can be used to calculate the time when sediment was shielded from cosmic rays. Burial dating with 10Be and 26 Al is quite well developed in the field of cave sediments but only a few studies have attempted the dating of fluvial terraces. Further more, no published studies of dating sedimentary basin fillings are available so far. Successful burial dating of fluvial terrace formations in the Lower Rhine Embayment, Germany, shows ages of up to 2.7 Ma, which correlate well with the local stratigraphy. At present, we are working on sedimentary sequences from the Swiss Midlands. This, and a status report of our ongoing work, will be presented at the conference. 0875 Late Glacial climate dynamics of the Neotropics recorded by pollen data from a marine core from the Cariaco Basin, Caribbean Sea Irina Delusina1, Larry C Peterson2, Howard J Spero1 1

University of California, Davis, CA, United States University of Miami, Fl, United States

2

The palynological data of a deep marine sediment core from the anoxic Cariaco Basin, off the coast of Venezuela indicates unique pollen assemblages which mirror the complex altitudinal zonation of coastal vegetation and its dynamics. The Cariaco Basin acts as a natural sediment trap for rapidly accumulating sediments of marine and terrestrial origin and provides the chance to compare both signals. The pollen analyses encompass the interval from 3 to 12 m in core MD03-2620, cover the Late Glacial/BØ-èl transition, Younger Dryas and the beginning of the Preboreal. The data indicate the abrupt changes in dryness/ wetness conditions as well as cooling/warming. The correlation of pollen data with percentage of sediments lightness, oxygen isotopes, Titanium/Iron concentration of other Cariaco basin cores, as well as comparison of our data with vascular plant signals, shows that the increasing of pollen productivity might be dictated not by warming, but increasing discharge of terrigenouse material from the continent. The relative constancy in pollen assemblages and the graduate changing of percentage of counted palynomorphs, speaks to altitudinal reconstruction of vegetation. Thus, the Montana rain forest predominated over

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deciduous Montana forest or Paramo elements during the BØlling-Ållerod time, but didn’t replace them. At the end of LG and the middle of Younger Dryas time seasonally dry forest prevailed. At the end of Heinrich event (ca 15,500 cal B.P.) the deepest offset of vegetation corresponds to the other dry episode, correlated with the lakes-level drop in northern South America and hiatuses of terrestrial sedimentation. Overall, the Neotropical region wasn’t affected by the dramatic cooling at the time of cold North-Atlantic episodes as Younger Dryas, but indicates sufficient dryness. 1411 Factors Affecting the Accretion of Peat in the Sacramento-San Joaquin Delta of California Irina Delusina1, Kenneth L Verosub1, Judith Z Drexler2, Nicole Lunning1, Christian S de Fontaine2 1

University of California - Davis, United States United States Geological Survey - Water Resources Division, United States

2

The Sacramento-San Joaquin Delta is the name given to the inland estuary at the confluence of the south-flowing Sacramento River and the north-flowing San Joaquin River in the Central Valley of California. The Delta is underlain by peat deposits that started to form when the rise in sea-level decelerated in the early Holocene. The Delta is a key component in the complex system that transfers fresh water from northern to southern California, and it is a critical ecosystem. At the end of the eighteenth century, Europeans created “islands” in the Delta by raising levees and pumping out the water. The peat deposits proved to be excellent for agriculture, but exposure to the atmosphere as well as agricultural practices led to rapid oxidation of the organic material. Now the centers of many of the islands are many meters below sea-level, which raises concerns about levee failure and potential disruption of the State’s water delivery system. As a result, there is great interest in restoring the peat deposits, but little is known about the rates of peat accretion or about optimal conditions for the formation of peat. To address these questions, we collected cores from four pairs of sites throughout the Delta. Each pair consists of a drained, farmed island and a relatively undisturbed marsh island situated in an adjacent channel. The thickness of the peat on the farmed and marsh islands averaged approximately 220 cm and 640 cm, respectively. The cores were analyzed to determine organic matter content, bulk density, carbon content, magnetic properties, and pollen spectra. Basal ages for most of the cores ranged from 6200 to 6700 cal. yr. B.P. The pollen data suggest that the peat began to form under warm/wet conditions and continued under warm/dry, cool/ dry, and then warm/wet conditions, indicating that there was considerable landscape evolution. This conclusion is supported by evidence for changes in the concentration of magnetic material that can be attributed to variations in paleoenvironmental conditions. 1053 Optically stimulated luminescence chronologies of late Pleistocene permafrost deposits and tephra sequences from eastern Beringia Martina Demuro1, Richard G Roberts1, Lee J Arnold1, Duane G Froese2, Fiona Brock3 1

University of Wollongong, Australia University of Alberta, United Kingdom 3 University of Oxford, United Kingdom 2

We report on the ongoing results of our optical dating program of Beringian permafrost deposits containing fossils and sediments from

which the ancient DNA of extinct and extant species has been recovered. The particular region of study, Beringia, which includes the glacial land bridge connecting the two great landmasses of Eurasia and the Americas, presently submerged by the Bering Strait, has dictated the flow of plants and animals between the two continents over the last several million years. A number of well characterised tephra beds have been documented across Alaska and Yukon Territory, collectively known as eastern Beringia. The reconstruction of Quaternary stratigraphic sequences and palaeoenvironments in this region has benefited greatly from the study of these important stratigraphic markers. In order to test the applicability of optically stimulated luminescence (OSL) dating on perennial permafrost of East Beringia, the technique was applied to Pleistocene ice-rich loess-derived deposits associated with known-age tephra beds of the Klondike district, south of Dawson City, Yukon Territory, Canada, and neighbouring regions. Our analysis focus on a number of these important tephras, namely (i) Dawson tephra - originating from the Aleutian Arc-Alaska Peninsula - at Quartz Creek, Klondike; this particular tephra has recently been associated with highresolution palaeoenvironmental data producing evidence for the nature of local-scale vegetation composition during the onset of the last Glacial Maximum in Eastern Beringia, and (ii) Sheep Creek tephra - derived from the Wrangell volcanic field eruptions – found at Ash Bend, Stewart River, central Yukon. We report our findings of OSL measurements made on quartz extracts and the resultant equivalent dose (De) values obtained using the single-aliquot regenerative-dose (SAR) protocol at the single-aliquot and single-grain scale of analysis. This study represents the first single-grain OSL study of deposits associated with tephra beds in East Beringia. In this paper we focus on (i) the luminescence characteristics and behavioural trends of the permafrost-tephra samples collected, (ii) the applicability of the SAR method at the single-aliquot and single-grain scale of analysis, and (iii) interpretation of resultant De distributions and comparisons with established thermoluminescence (TL) and 14C ages. 0863 Human-environment interactions in the Upper Wahgi valley, Papua New Guinea: Early Holocene to present Tim Denham1, Simon Haberle2 1

Monash University, Australia Australian National University, Australia

2

The development of landscapes during the Holocene is well-documented at palaeoecological sites across the highland spine of New Guinea (including both Papua New Guinea and the Indonesian province of Papua). Archaeological records from sites in the highlands shed light on the nature and scale of human-environment interactions, i.e. the animal and plant exploitation practices, that contributed in part to the signals witnessed in the palaeoecological records. In this presentation, the archaeological and palaeoecological data is synthesised to: 1. reconstruct a generalised chronology of landscape change along an altitudinal cline within the Upper Wahgi valley during the Holocene (and with reference to the Pleistocene); 2. differentiate the varying climatic, human and tectonic components to landscape change through time and across space; and, 3. highlight the spatial and temporal variability in landscape change across the Highlands during the Holocene (and as evident today).


0676 Protocols for taphonomic data collection Christiane Denys1, Peter J Andrews2, Yolanda Fernandez-Jalvo3, Antoine Louchart4, Thalassa Mattews5, Denne Red6 1

Museum National d’Histoire Naturelle (CNRS), France The Natural History Museum, United Kingdom 3 Museo Nacional de Ciencias Naturales (CSIC), Spain 4 Universite de Lyon, France 5 University of Cape Town, South Africa 6 The Smithsonian Institution, United States 2

Time averaging, reworking, re-sedimentation are some of the research goals of TAPHONOMY that may certainly help to interpret HUMAN ENVIRONMENTS. Specimen recovery, however, is still far from being acceptable at most palaeo/archaeological sites. The unawareness of a protocol for taphonomic sampling as well as the lack of research of taphonomic disturbances on the site may have serious repercussions on dating, palaeoecological-palaeoclimatic-environmental interpretations, and human behavioural interpretations. A complete step by step description will here be described allowing the collection of specimens without destroying the features necessary to perform a complete palaeontological study. Here, three main collection methods are considered, which constitute the most common procedures: (a) Surface collection when fossils are exposed, (b) Surface collection when fossils are partially exposed (c) Excavation. Several aspects have never been considered, and they are extremely important to reduce the loss of information when picking up fossils. These procedures will allow us interpreting the past at a maximum level of resolution and prevent erroneous interpretations. Basic DNA/ dating sample recovering procedures are also included, although recent publications show the need of establishing a particular protocol for DNA sampling, which will be displayed in: protocols for palaeogenetic sample collection. 0672 The Rise and Fall of the Cretan Deer Michael D Dermitzakis1, George Iliopoulos2, Alexandra A Van der Geer1, George A Lyras1 1

University of Athens, Museum of Paleontology and Geology, Greece University of Crete, Museum of Natural History, Greece

2

A recent finding of a large antler fragment on Crete reopened our study of the extinct Cretan deer genus Candiacervus. The genus is known to us mainly by its derived forms of the Late Pleistocene. The last representative of the lineage is the smallest species, which got extinct due to extreme habitat reduction. This on its turn was caused partly by a significant sea-level rise as a side-effect of the climatic change (global warming), and partly by the human colonizers. The end of the reign of the dwarf deer is placed around 10,000 years BP. Its success had lasted nearly 0.3 million years. During its blooming period, it knew no competitors. The only other large herbivore was the dwarf elephant Elephas antiquus creutzburgi. Elephants occupy a slightly different ecological niche. It is not clear why this elephant did not reach the miniature size of the pygmy mammoth of the Early Pleistocene, but it may very well have to do with the success of Candiacervus. The deer genus radiated beyond what is seen in a comparable mainland area. Some eight species or morphotypes inhabited the island during the Late Pleistocene, each adapted to its own ecological niche. This is explained as a sympatric speciation to occupy all possible empty niches ranging from

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dense forest to prickly rocks. The coexistence of various environments has been confirmed by studies on the rich fossil avifauna. The most typical Cretan deer are the two smallest sizes, which have not only relatively and absolutely short limbs, but also long and simplified antlers; these species occupied a niche close to that of the wild goat of Crete today: barren rocks with thorny bushes, as shown by features of their osteology and goat-like body proportions. It deviated so much from mainland deer that it seemed impossible to indicate with certainty its ancestor. At least, till the summer of 2006. A large antler was found on the Lasithi plateau. The sediments indicate a middle Pleistocene age. The morphology of the antler resembles most that of Megaloceros. A megacerine ancestry was suggested already before, but now it seems validated by this finding. With this, the story of the Rise, Success and Fall of the Cretan deer is completed. 0580 Vegetation evolution in southeastern United States during the last deglaciation directly correlated with North Atlantic changes Stephanie Desprat, Jerry McManus Woods Hole Oceanographic Institution, United States

Millennial to centennial-scale climatic oscillations punctuated the last deglacial warming. The major climatic changes of the last deglaciation, which are associated with important oceanic circulation modifications, are identified as the cold-warm-cold succession Oldest Dryas-Bölling Allerod-Younger Dryas. They are largely recorded in the North Atlantic from the tropics to the high latitudes, in Greenland and Europe. North America seems to be also affected by the Younger Dryas widespread cooling. However, continental records of southeastern United States detect muted cold conditions or even warming. Furthermore, pollen and plant macrofossil records from Florida appear to show a strong antiphase relationship in the temperature variability between Florida and North Atlantic regions over the last 60,000 years. For a better understanding of the ocean-atmosphere coupling in particular during the last deglaciation, it is firstly essential to document accurately the phase relationship between vegetation evolution and oceanic conditions in the subtropical areas. Here, we present a high resolution marine pollen record of the last deglaciation from the southeastern North American margin (Blake Bahama Outer Ridge). Pollen analysis of core KNR140-2 GGC39 allows a direct correlation between vegetation changes in southeastern United States and oceanic changes in the subtropical North Atlantic, circumventing the chronological problems inherent in continental-marine sequence comparisons. 0845 Beachrocks as indicator of relative sea-level changes since the mid-Holocene on the southern coast of Turkey Stephane Desruelles1, Eric Fouache1,2, Attila Ciner3, Erdal Kosun4, Remi Dalongeville5, Yvan Coquinot6, Jean-Luc Potdevin6 1

University Paris 12 - EA 435 Geonat (Creteil, France), France UMR 8591 LGP (Meudon, France), France 3 Hacettepe University - Department of Geological Engineering (Ankara, Turkey), Turkey 4 Akdeniz University - Department of Geology (Antalya, Turkey), Turkey 5 Maison de l’Orient et de la Méditerranée - UMR 5133 Archeorient (Lyon, France), France 6 University USTL Lille 1- UMR 8110 PBDS (Lille, France), France 2

On the southern coast of Turkey, up to three beachrock levels, can be observed. Although most of the beachrocks are situated on the vicinity

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of the actual sea level, some are submerged, sometimes down to −4.5 m or emerged up to +0.5 m. Because beachrocks are formed within the intertidal zone by carbonate cementation of the beach deposits during stages of shoreline stabilisation, they correspond to different generations indicating different sea-level stands. Fourteen sites along this coast were studied and samples were analysed using a polarising microscope, cathodoluminescence and SEM. Due to the abundance of micrite in between the limestone pebbles that often compose the beachrocks, cements had to be manually extracted for AMS Carbone 14 datings. Even then only beachrocks from two sites can be dated. However, by cross-comparing these results with the geometry of the beachrocks, the position of notches, vermet reefs, abrasion platforms and archaeological vestiges together with the available tectonic data, it is possible to distinguish several areas where different relative sealevel positions are recorded. From Finike bay to the West, a post-roman relative sea-level rise is observed after a period of coastline stabilisation. The area from Kemer to Okurcalar witnessed relative sea-level rise since mid-Holocene interrupted by three phases of stabilisation corresponding to beachrock lines. Two of them have been dated: the first level between 0 m and −0.8 m from 435 AD to 733 AD and the second one between −1.5 m and −2.2 m around 659-502 BC. From Inçekum to Aydincik, the sea-level is around +0.5 m in 269 BC and later becomes stable at least since the 12th century AD as can be interpreted from archaeological vestiges. To the East, beachrocks in Gözcüler indicate a relative sea-level rise interrupted by a phase of coastline stabilisation between 2nd and 6th centuries AD. More to the South, three raised notches near Samandag at +0.4 m, +0.8 m and +2.9 m indicate the tectonic complexity of the area. Our observations reveal a very dynamic tectonic regime, especially subsidence to the West and uplift to the East since at least mid-Holocene and before Roman era. 0460 Assessing palaeomonsoon variability during the Late Quaternary: Evidence from the lake sediment archives of Yunnan Province, China Charlotte G Dew1, Richard T Jones1, Melanie J Leng2, Chris C Caseldine1, Enlou Zhang3, Peter G Langdon4 1

School of Geography, University of Exeter, United Kingdom NERC Isotopes Geosciences Laboratory, BGS Keyworth, Nottingham, United Kingdom 3 Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China 4 School of Geography, University of Southampton, United Kingdom 2

The Asian Monsoon climate is characterised by distinctive seasonal precipitation and wind patterns that produce warm, humid summers (the rainy season) and cold dry winters. The Asian Monsoon system can be subdivided into the Indian, East Asian and Western North Pacific Monsoon subsystems delineated by the line of 105˚ E longitude, which runs along the eastern flank of the Tibetan Plateau (Wang et al., 2003, Marine Geology, 201, 5–21). Any changes in the monsoon cycle may result in floods, droughts or crop failure. Characterising the extent of monsoon variability is therefore crucial to understanding the possible socio-economic and environmental outcomes that may result from climate change. Wang et al. (2005, QSR, 24 (5–6), 595 –629) contended that the acquisition of high resolution records of the Asian monsoon subsystems which are sufficiently geographically distributed across the region remains an outstanding issue which needs to be addressed by palaeoclimatologists. Palaeoclimatic research in China has largely focused on proxy records from East and Southeast China to investigate East Asian Monsoon dynamics. Very few high resolution records exist

for high altitude sites in Southwestern China and thus our understanding of the regional climate as a whole is limited. This sub-region is climatically important because it is the convergence zone of the Indian and East Asian monsoon subsystems (Yihui and Chan 2005, Meteorol Atmos Phys, 89, 117–142) and is therefore sensitive to climate change. This NERC-funded PhD research project seeks to address this outstanding issue by developing a high-resolution palaeoclimatic record of monsoon variability spanning the Late Glacial Interstadial Transition (LGIT) and the Early Holocene, focusing on high-altitude lake sediment records from Lake Shudu, Yunnan Province, China, which is located on the southeastern edge of the Tibetan Plateau. The sediments are being analysed using a range of measures of Palaeomonsoon activity (e.g. precipitation, wind conditions and vegetation dynamics) including pollen, stable isotopes (d13C) and lithological indicators. A core chronology has been derived using novel techniques including 14 C AMS dating of pollen concentrations, the results of which are also presented. Collectively the preliminary results suggest that Lake Shudu is a dynamic and productive site, with excellent potential for recording climatic changes. The pollen profile reveals a history of high productivity, characterised by an abundance of Picea, Tsuga and Pinus, coupled with high levels of organic material inferred from the LOI data. C/N and 13C values will also be presented. 0335 Mid-Holocene environmental changes and human impact in the coastal area near Rome (Italy) Federico Di Rita Dipartimento di Biologia Vegetale, Italy

During the last millennia, the coastal area near the mouth of the Tiber River has been shaped by intense geomorphic processes, producing two coastal basins (the Maccarese and Ostia ponds), which were drained out at the end of the XIX century. At present, only small stands of natural vegetation of the coastal wet environment are left in protected areas. This region experienced a long history of human occupations, testified by Eneolithic and Roman settlements, so it is particularly suitable to compare the effects of environmental changes and human activity on the vegetation structure and composition during the middle and late Holocene. To this purpose, pollen analysis of the sediments of the Maccarese pond, north of the Tiber delta, has been carried out, together with micro-charcoal and non-pollen palynomorphs analysis. During the last 6000 years four abrupt environmental changes occurred, recorded by strong variations in floristic composition and vegetation structure, as well as by proxies for water salinity. The pollen diagram indicates clear human presence in the landscape, with a significant increase of cereals, starting somewhat before 5200 cal BP, at the same time of the occupation of the nearby Eneolithic village. A sharp increase of the micro-charcoal curve, following a natural opening of the landscape, suggests an intense local fire activity correlated with domestic, agricultural and grazing practices. The presence of Tilletia spores, a parasitic fungus affecting grasses and cereals crops, indicates that fungal infections represented one of the adversities faced by the Eneolithic inhabitants of the area. During the period 5200-2000 cal BP, deep environmental changes, including relative sea levels fluctuations, are recorded by two very distinct vegetation phases, characterized by a lush alder wood and an open vegetation with many aquatics, respectively. No clear evidence of human activity is found between the Eneolithic and Roman settlements. During the middle and late Holocene this coastal area was a very unstable environment, limiting the extent and continuity of human occupations. Complex natural factors, such as sea-level fluctuations, and geomorphic and micro-cli-


matic processes appear to be the main agents for the formation of different vegetation types and ecosystems. 0859 OSL Age Constraints on Sediments in Lower Victoria Valley, Antarctica Warren W Dickinson1, Uwe Rieser1, Andrew Mackintosh1, Hamish McGowan2 1

Antarctic Research Centre, Victoria University Wellington, PO Box 600, Wellington, New Zealand 2 School of Geography, Planning and Architecture, University of Queensland, Brisbane 4072, Australia

Sediments deposited by glaciofluvial and aeolian processes occupy much of the floor of the Lower Victoria Valley floor. The system is complex and recycling of sediments occurs between a variety of sources and sinks. The absence of silt and clay reflects, (1) a supply of sediment from cold-based glaciers and (2) a removal of fines by aeolian processes. Dune sands exist because of an abundant supply of sand from streams and bidirectional winds that confine the dunes to the confluence of the Packard and Victoria Valleys. Most of the glaciofluvial sediments appear to be deposited at the terminus of the Lower Victoria Glacier but are reworked into thin sheets of sand further downstream. Large blocks of ice from glacial and proglacial ponds are often encased by these sediments. To put age constraints on this sedimentary system, 14 OSL samples were collected from shallow bore holes and stream cuts created by the 2001/2002 floods. Ages of the glaciofluvial sediments associated with large blocks of ice range between 40 and 1 ka. There is no apparent special ordering to these ages on the valley floor. The dune sands generally have ages 63 μm) of the eolian sediments. As variations in the sand-sized particle fraction within loess near the desert margin may be primarily controlled by the migration of the southern desert margin, increase in this fraction can be linked to southward

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expansion of the deserts, in turn suggesting southward retreat of monsoon rain-belt. We preliminarily propose that the oscillatory weakening trend of the East-Asian summer monsoon could have been forced by the increase in global ice-volume during the Neogene. 0809 Middle-Holecene vegetation of the Leiria region (Portugal) Filomena U Diniz Faculty of Sciences - Lisbon University, Portugal

The history of the Holocene vegetation is generaly based in palynological studies. The boring S4 Junqueira was drilled in alluvial deposits in the valley of the river Liz (Leiria, Portugal) near the littoral border and consequently related to coastal and fluvial dynamics. Work carried out in this valley has permited identification of Acheulian sites and its emplacement in the quaternary chronostratrigraphic table. The sequence in S4 is made up of black clay with plant remains and fine grey sand on the top. Palynology – from the base to 72 cm arboreal vegetation is primarily made up of Quercus forming deciduous oak forest with Corylus. Betula appears occasionally and in small percentages. Alnus is a dominat riparian element. Pinus is weakly represented. The peaks of Myrica denote phases of progressive terrestrialization. The development of Amarantaceae-Chenopodiaceae in the lower part indicates the presence of halophilous vegetation witch gives way to a more humid biotope. In the upper part (0 –72 cm) there is an abrupt increase of Pinus and a dropping of Quercus althoug Corylus maintains the same frequency. Alnus is stable and there is a small rise of Salix. Herbs reach higher levels in the middle and the top; taking account the importance of Pinus this may indicate an opening up of the vegetal landscape. The presence of mediterranean elements is generally weak throughout the diagram though there is a slight increase of Olea at the top. Ericaceae allways reaching important values. The radiometric dating relative to the top of this sequence is 1860 ± 60BP and to the bottom is 5890 ± 70BP. The present work aims the reconstruction of Middle-Holocene environmental evolution of this region based on a more detailed diagram concerning the lower part of the sequence. This new data will contribute to a better understanding of the landscape natural evolution and the eventual human influence. These results will be compared with others from North and South of Portugal. Main approaches: oak forest; antinomy Pinus – Ericaceae; “maquial” vegetation. 0704 Upper Pliocene and Pleistocene bio-climatic units of south Russia in the context of Quaternary subdivision Andrey E Dodonov, Marina V Sotnikova, Alexey S Tesakov Geological Institute of the Russian Academy of Sciences, Russia

In south Russia there are key sections which contain the late Pliocene and Pleistocene mammal faunas. These sections are crowned with rather thick loess cover with a number paleosols. This geological context provides a reasonable opportunities for bio-climatic subdivision of the upper Pliocene and Quaternary. Paleomagnetic data help for geochronological interpretations. Four biostratigraphic units, characterized by the Khaprovian, Psekupsian, Tamanian and Tiraspolian faunal complexes, are basically in use for this time interval. Their stratigraphic position corresponds consequently to the middle and late Villafranchian, Galerian and Cromerian biostratigraphic units of Western Europe. The Khapry faunal assemblage contains remains of Archidiskodon meridionalis gromovi, large horses of the stenonis group, and advanced mimomyan voles. The carnivore fauna demonstrates the

typical middle Villafranchian association with Homotherium crenatidens, Pliocrocuta perrieri and Nyctereutes megamastoides. The transitional Psekupsian mammal assemblage is characterized by the appearance of Archidiskodon meridionalis meridionalis and very hypsodont voles of the mimomyian group. The most characteristic elements for the Tamanian complex are A. meridionalis tamanensis and microtine voles with rootless dentitions (Allophaiomys, Lagurini). The widespread Canis (Xenocyon) lycaonoides, C. mosbachensis and Homotherium latidens also occurred. Paleomagnetically, this complex corresponds to the upper part of the Matuyama Chron. Its lower boundary slightly predates the Jaramillo Subchron. Tiraspolian complex contains Mammuthus trogontherii, and documents adaptive radiation of voles of the genus Microtus. It corresponds to the lower part of the Brunhes Chron. Climatostratigraphic subdivision of loess-paleosol series in southern Russia is based on the pedologic approach in combination with paleontologic and paleomagnetic data. A series of paleosols have a relatively well substantiated stratigraphic support: the so called Mezin (MIS5), Inzhava (MIS11-?) and Vorona (MIS13-15-?). The lack of the reliable absolute dates for the upper part of loess section would stimulate a further investigation using a new dating technique. According to available data six or seven pedocomplexes are established in the Brunhes Chron corresponding to the middle and upper Pleistocene. In that time, loess sedimentation was intensively developed in southern Russia and loess horizons are distinctly pronounced. During the early Pleistocene, loess has just started to deposit covering the watersheds and being reworked by paleosol processes resulting in the pedosediment formation like red clays. In south Russia, this formation is termed the Scythian clays; they have a multi-factor origin and can be dated in the range of late Pliocene – early Pleistocene. 1394 Environmental setting and the human colonisation of Australia John Dodson1, John Hughes2, Sue O’Connor3, Sean Ulm4 1

ANSTO, Australia Bristol University, United Kingdom 3 ANU, Australia 4 University of Queensland, Australia 2

The palaeo-environmental setting behind human migration patterns is complex. The broad shallow seas north of Australia and around SE Asia underwent major changes in land/sea areas in relation to sea level change at the critical times of first human migrations into the region. These, associated with climate change, had profound effects on the vegetation structure and hence distribution of food, water and other resources. These provided significant environmental opportunities and constraints that had to be confronted by people during the journey even before they reached Australia. Once people reached Australia they not only had to cope with climate trends and a different kind of climate variability but also there was the problem of adapting to new biomes and food resources, and water availability patterns. The palaeo-environmental record, combined with astute use of tuned and fully coupled global climate models and climate-vegetation models, provides broadscale views of habitat distribution. Employing generalised models of hunter-gatherer cultural ecology we may be able to derive conceptual models of what kinds of regions presented opportunities, and when, and also identify those areas unsuitable for long-term settlement. Here we aim to test conceptual models of human-environment interactions by seeking out concordance and mismatch between the archaeological evidence and presumed best regions for human settlement based on models and palaeo-environmental analyses . It is most unlikely that migration was always a forward movement of people to new settle-


ments but rather a network established and supported by forward and backward migration in relation to opportunities and conditions. Ultimately we aim to create one or more models of the colonisation of Australia in a way that might be tested by future work.

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0430 Petrographic composition of boulders and pebble from glacial and glaciofluvial deposits of Volhyn, Ukraine Kateryna Dorosh

0076 Understanding tsunami risk in the Australasian region

Institute of Geochemistry, Mineralogy and Ore Formation NAS of Ukraine, Ukraine

Dale Dominey-Howes1, James Goff2

Study of boulders and pebble from glacial and glaciofluvial amberbearing sediments of Volhyn Polessye yields the following results. Fragmental material from glaciofluvial sediments of the Dnieper age in the Slutch-Ubort interfluve is represented by flints from underlying Cretaceous rocks. In the Styr-Goryn interfluve local rocks (Cretaceous flints) ammount to 80% of the whole pebble composition of terminal moraines, with 20% represented by erratic volcanic and metamorphic rocks. An increase in number of Scandinavian boulders (up to 25%) is observed in the terminal moraines of the Stokhod-Styr interfluve. The biggest number of Scandinavian boulders is observed in the narrow Zapadny Bug-Pripyat interfluve. The boulders are represented by Aland rapakivi, rapakivi-like granite and its varieties, red and brown Baltic quartz porphyry, plagioclase gneiss, amphibolites. Devonian and Lower Carbonian limestone is also present in big quantities and local Cretaceous flints amount to 30% of the whole pebble composition. In the central part of the Turya-Stokhod interfluve Upper Cretaceous pebble-beds amount to 90% of the fragmental material of terminal moraines. Scandinavian boulders and pebble consist predominantly of brown and red Ionian sandstones. Presence of amber in the terminal moraines and glaciofluvial deposits that were formed mainly at the expense of local rocks permitted to draw a conclusion that placers of amber in Volhyn are mostly of local origin. Presence of some erratic boulders and pebble point to the fact that some quantity of amber could be redeposited from outside Ukraine.

1

Macquarie University, Australia 2 National Institute of Water & Atmospheric Research, New Zealand

The 2004 Indian Ocean tsunami demonstrated that large destructive tsunami are not confining to the Pacific. Two decades of geological research in New Zealand and Australia has demonstrated that both countries are at risk from local, regional and teletsunami. Sources range from the Indian to the Pacific to the Southern Ocean. Both countries have extensive records of past events, most occurred in the Holocene but some earlier tsunami have been documented. Here we summarise the reported tsunami record for New Zealand and Australia and pay careful attention to separate palaeotsunami and historic tsunami records. From these records, we outline what is known and more importantly, what is not known, about regional tsunami hazard and risk. We identify a series of key research priorities for the region and suggest that much can be learnt from a collaborative effort to explore trans-Tasman tsunami risk. 0077 Preliminary catalogue of Australian tsunami Dale Dominey-Howes Macquarie University, Australia

The Indian Ocean tsunami (IOT) of 2004 has resulted in significant interest within Australia about the record of tsunami for the continent because an understanding of tsunami hazard begins with catalogue of past events. Here, a preliminary catalogue of tsunami affecting Australia is presented. The catalogue contains entries for 57 tsunami events. The oldest event is dated at 3.47 Ga, the most recent is the July 17th 2006. Forty-four tsunami were recorded on the New South Wales coast although the NW coast of Western Australia records a significant number of events. Forty-seven events have affected Australia since AD1858. Maximum run-up for an historic event is +6 m asl whilst the maximum run-up for a palaeotsunami event is reported at an elevation of at least +100 m asl. Twenty-three percent of historic Australian tsunami were generated by unknown causes and Papua New Guinea, the Solomon Islands and Indonesia collectively represent the most important source area of historic tsunami for Australia. Geological records for palaeoand historic tsunami are identified and summarised. The geological record of tsunami represents a potentially important source of information for Australian tsunami. However, at the present time, the geological record is both limited and controversial and future research should seek to re-examine proposed geological evidence of tsunami. From an analysis of this preliminary catalogue of Australian tsunami, a series of key research priorities have been identified to guide future research in the region.

0528 Future Climate Change: Implications for Radioactive Waste Diane L Douglas San Diego State University and URS Corporation, United States

Our study examined the potential for future climate change to raise the water table in west Texas and affect dispersal of low level radioactive waste. The study was based on the assumption that variations in earth’s orbital parameters are the primary force affecting Glacial/Interglacial cycles. Astronomical theory holds that if the sun’s output of solar radiation is assumed to be constant, the amount of solar radiation reaching the top of earth’s atmosphere at any given latitude during any given season is fixed by three elements of the earth’s orbit, eccentricity (100,000 years), obliquity (41,000 years) and precession (23,000 years). Obliquity affects the nature of seasonality at high latitudes and precession affects the nature of seasonality at low latitudes. Operating within this assumption, we reconstructed the past 40,000 years of climate for west Texas, New Mexico, Arizona and Colorado using floral data derived from 210 packrat middens and correlated these reconstructions with earth’s orbital parameters. The midden data were derived from a USGS databank (http://esp.cr.usgs.gov/cgi-bin) and organized in an Excel spread sheet by longitude, latitude and elevation. The temperature and precipitation constraints of species represented in each midden assemblage was identified and average minimums, average maximums and annual averages of temperature and precipitation were assigned to each assemblage. This information was used to reconstruct climate for Arizona to west Texas at 1 – 3 ka, 6 – 8 ka, 10 – 12 ka, 15 – 18 ka, and 20 – 40 ka for low (< 975 msl) and high (1200

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– 2100 msl) elevation sites. The environmental lapse rate (0.6C per 100 m) was used to evaluate the congruity of climate reconstructions for different elevations for each time period. These climate reconstructions were evaluated relative to the orbital parameters that existed at each time period; orbital parameters were derived from http://aom. giss.nasa.gov/srorbpar.html. Correlation analysis was performed on orbital parameters for the past 40,000 years and the next 100,000 years to estimate when climate conditions would be similar to 1 to 3 ka, 6 to 8 ka, 10 – 12 ka, 15 – 18 ka, and 20 – 40 ka. Although the orbital parameters that occurred within the past 40,000 years will not occur within the next 100,000 years, moderate correlations occur that help estimate extreme highs and lows that might raise the ground water table and result in dispersal of low level radioactive waste. 1223 The impact of increasing horizontal resolution on the simulation of LGM climate: an evaluation using vegetation data Rachel V Downey1, Sandy P Harrison2, Ayako Abe-Ouchi3 1

University of Leicester, United Kingdom University of Bristol, United Kingdom 3 University of Tokyo, Japan 2

An assessment of whether increasing the horizontal resolution of an atmospheric general circulation model (AGCM) produces a more realistic simulation of regional climate patterns has been made using an equilibrium vegetation model (BIOME4) to translate the simulated climate changes from three AGCM simulations (at T21, T42 and T106 resolution) into simulated vegetation patterns to facilitate comparison with observations. Increasing resolution has a large impact on the simulation of northern hemisphere extratropical climates and vegetation. The vegetation patterns produced using output from the T42 version of the model are in better agreement with observations than those produced from the T21 version. There is insufficient data from key regions (e.g. central Siberia) to determine whether the increase from T42 to T106 produces an improvement in the simulated regional climates. Increasing resolution has little impact on the simulated climate and vegetation across the tropics, although again the T21 simulation appears to produce the worst match to observations. The comparatively small change with increasing resolution in the tropics is due to the largescale atmospheric controls on regional climates. Increasing resolution appears to have relatively little effect on southern hemisphere extratropical climates, reflecting the fact that the simulated climate changes are relatively unimportant. These analyses suggest it is not necessary to use the highest-resolution models for palaeoclimate simulations; adequately representative regional climate changes can be obtained using T42 resolution models. 1213 Late Quaternary Sediment Delivery to Offshore Shelf Edges, Slopes, and Basins, in the Gulf of Papua: Testing the Basic Principles of Sequence Stratigraphy during the last glacialinterglacial sea level cycle Andre W Droxler1, Gerald R Dickens1, Jason M Francis1, Brooke E Carson1, Stephan J Jorry1, Gianni Malarino2, Luc Beaufort3, Bradley Opdyke4 1

Rice University, Earth Science, United States Pan-Terra Geoconsultants B.V., The Netherlands 3 CEREGE CNRS, France 4 Australian National University, Earth and Marine Sciences, Australia 2

The continental margin of the Gulf of Papua forms one of the world’s largest active tropical mixed siliciclastic-carbonate depositional systems where rivers supply large amounts of terrigenous sediment to a shelf with substantial neritic carbonate production and a series of isolated long-lived carbonate platforms. Over the last 150 kyr, corresponding to a full glacial-interglacial sea level cycle, the composition and flux of sediment shed to and accumulated on the shelf edges and surrounding slopes and basins (Ashmore and Pandora troughs) have changed dramatically through time according to the different sediment sinks. Flux of siliciclastic sediment dramatically increased during the early sea level regression across all of Ashmore Trough. From the end of MIS 5e about 110 ka to the end of MIS 5 in the distal cores when sea level had fallen to ~ 40 – 50 m, and to the mid-MIS 3 approximately 40 ka in the central part of the basin when sea level had dropped to ~ 70 m. These parts of the basin become sediment starved during the late sea level regression and lowstand (late MIS 3 and MIS 2). Proximal cores on the northern Ashmore slope continued to receive a high flux of siliciclastic sediment through the lowstand (early-MIS 2) when the coastline had migrated to the modern shelf edge, though a large volume of sandy and muddy sediment was bypassing this part of the basin and accumulating in the adjacent deeper (1700 m), flat-floored and enclosed central part of Pandora Trough. In this basin, the MIS 4-2 sedimentation was characterized during the lowstand by numerous siliciclastic sandy turbidites and high fluxes of fine siliciclastic mud. The timing of a calci-turbidite accumulation and the first appearance of bank-derived aragonite and Mg-calcite in the fine carbonate fraction in both Ashmore and Pandora Troughs coincide during Meltwater Pulse 1B when sea level had risen to ~ 50 – 40 m, with the first re-flooding of Boot, Portlock, and Eastern Fields Reefs, modern atolls that remained exposed for most of the glacial stages. Earlier highstand intervals, in particular MIS 5e but also MIS 5c-5a, are characterized by the occurrence and high fluxes of aragonite and Mg-calcite. Finally, the sea level transgression during last deglaciation created favorable conditions for the establishment and growth of coralgal reefs along the modern shelf edge using as substratum the former lowstand glacial siliciclastic coastal deposits such as beach ridges and delta lobes. 0711 A uranium-series chronology of sub-orbital climatic events in the North Atlantic region during Termination II and Marine Isotope Stage 5 based on multiple speleothems from Corchia Cave (Italy) Russell N Drysdale1, John C Hellstrom2, Giovanni Zanchetta3, Anthony E Fallick4 1

The University of Newcastle, Australia The University of Melbourne, Australia 3 The University of Pisa, Italy 4 Scottish Universities Environmental Research Centre, United Kingdom 2

The Termination II-Marine Isotope Stage 5 (MIS 5) period represents one of the most important climatic intervals of the Late Quaternary, yet important questions remain unanswered. Was the deglaciation sequence similar to that of the Last Glacial termination? Which parts of the Earth first experienced post-glacial warming and post-interglacial cooling? How far afield were the direct effects of post–Interglacial North Atlantic cooling events felt? Robust radiometric chronologies from both hemispheres are required to address these important issues. To date, we still have no complete radiometrically dated, high-resolution terrestrial sequence covering this period for southern Europe, a region strongly affected by conditions in the North Atlantic. Speleothems are one of the few archives capable of providing such records. We present a precisely dated, high-resolution stable isotope record based on multiple stalag-


mites from Corchia Cave (Italy) covering the period 140 to 75 ka. The chronology of our stacked isotope time series is fixed by over 100 multi-collector ICP-MS U-series ages. The isotope time series shows a clear ‘pause’ through Termination II at 131-129 ka, similar to the Younger Dryas of Termination I, followed by a brief 2-3 kyr period of ‘optimal’ climatic conditions early in MIS 5e, when speleothem growth rates were at their highest. A sequence of post-Last Interglacial cold events, which are well-documented in marine, ice and pollen records, but by and large poorly constrained chronologically, are preserved in these stalagmites as major isotopic excursions. The most significant of these is event C24, dated at between 112 and 109 ka, which represents the end of the Eemian forest phase in southern and western Europe. Our record provides the first complete chronology of MIS 5 cold events. This will allow refinement of age models for numerous regional marine and continental records covering this period, and represents a starting point for investigating inter-hemispheric synchroneity of climate shifts through this interval.

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domains (Grenvillian basement, Palaeozoic St. Lawrence Platform and Appalachians). We recognize seven Quaternary seismic units, organized in 2 main packages, lower and upper, and 2 independent units that all have variable seismic reflection characteristics. Isopach maps show that the distribution of the Quaternary seismic units is closely linked to the topography of the underlying geological domains. Within the Quaternary succession, the lower package (seismic unit 1 and, in the eastern (downstream) part of the Estuary, seismic units 1 and 2) has a highly variable thickness and fills up most of the topographic depressions of the bedrock. The upper package (seismic units 3, 4 and 5) covers the entire Estuary, including the Laurentian Channel shoulders, suggesting that it was deposited in an environment similar to the present-day physiographic setting. The other two seismic units are the result of local geological processes and mostly occur along the northern flank of the Laurentian Channel: the sedimentation of submarine fans (seismic unit 6) and mass wasting deposition (seismic unit 7). Lithological and geochronological controls are now required to correlate these seismic units and to understand their geological significance. This is the focus of current research.

0516 The Grain-size Distribution Charateristics of Red Sandy Sediments in Dongjiang River valley, Southern Nanling Mountains during MIS2

0886 Is mixing and contamination of samples from arid environments a concern for optical dating?

Shuhuan Du, Baosheng Li

Geoff AT Duller

School of Geography Department, South China Normal University, China

Layer LJ3 of Linjiang stratigraphic section in Dongjiang River valley in the south of Nanling Moun-tains is a set of red sandy sediments. Measured by TL dating it was found to be formed in MIS2 9500±800 a —19600±1800a B P.Analyzed by the grain sizes of the 16 samples (LJ3-100 to LJ3-85) in this layer, it was discovered that: (1) The contents of each grain group in different samples are similar.(2) The values of Md,Mz, s,Sk and Kg swing from LJ3-100 to LJ3-85 in a narrow range.(3) The segments of each samples in the accum -ulative curves extend parallel with similar slopes. All the three aspects reveal the aeolian characteristics of Layer LJ3. Hereby,we can see that Layer LJ3 is made up of red sandy sediments formed in MIS2 in the south of Nanling Mountain,reflecting the arid climate at that time. 0349 3D architecture of the Quaternary succession in the St. Lawrence Estuary, Canada Mathieu J Duchesne, Nicolas Pinet, Andrée Bolduc, Denis Lavoie Geological Survey of Canada, Canada

The St. Lawrence Estuary (eastern Canada) is a narrow Quaternary basin with a deep central channel, the Laurentian Channel, which comprises seven stacked sedimentary units. The bedrock geology of the Estuary has controlled the architecture of the sedimentary succession. Consequently, the detailed interpretation of the Quaternary succession has to take into account feedback effects between the inherited geometry of the Estuary, glacial erosion processes, topography, sedimentation, isostatic rebound, sea level change and seismic activity. The geological framework previously available for the Estuary relied on conceptual models developed from sparse or poor quality datasets. Recently, high-resolution seismic-reflection surveys were conducted to improve our understanding of the regional geology of the St. Lawrence Estuary. Data show that the basin is filled by a wedge-shaped Quaternary succession that thickens from less than 50 m to the northeast to > 400 m at the mouth of the Saguenay Fjord, more than 200 km to the southwest. The seismic sections image the geometry of the top of the three underlying bedrock

University of Wales, Aberystwyth, United Kingdom

Traditionally it has been thought that sediments from arid environments, especially desert dunes, are ideally suited to optical dating because it should be reasonable to assume that all mineral grains were exposed to sufficient daylight at deposition to reset their luminescence signal to zero. In many instances this confidence has been borne out by highly reproducible optical ages. For instance, optical dating of samples from linear dunes on the northern margin of the Namib Sand Sea has yielded a stratigraphically consistent set of ages, ranging from a few decades to several thousand years. Combined with ground penetrating radar, these ages have provided clear insight into the geomorphological processes involved in linear dune formation and the Holocene dynamics of these specific dunes. Over the last 5 –10 years an increasingly sophisticated range of methods have been developed within the field of optical dating to assess the reliability of the ages generated. In more complex depositional environments (e.g. glacigenic or fluvial) incomplete resetting of the luminescence signal, post-depositional mixing, and contamination have all been major issues. In such settings one tool that has been developed to assess the homogeneity of samples has been to reduce the scale of analysis from many thousands of grains, to hundreds of grains or less. The ultimate limit of this is the measurement of single sand-sized grains. This approach has not commonly been applied to samples from arid environments because of the assumption that they have been well bleached. However, optical dating results from a number of studies show that contamination of samples with unbleached grains and mixing of sediments can still be a problem. Measurements of the luminescence signal from single sand-sized grains from samples in the Nile valley show that such problems may exist in arid environments. For these samples, conventional measurements based on many thousands of grains would yield erroneous ages, but numerical analysis of single grain data may enable accurate ages to be obtained.

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0889 Optical dating of Middle Stone Age sites in Kenya and Zambia Geoff AT Duller1, Jeong H Choi2, Mayank Jain3, Sumiko Tsukamoto1, Ann G Wintle1, Stanley Ambrose4, Larry Barham5 1

University of Wales, Aberystwyth, United Kingdom Korea Basic Science Institute, Korea 3 Risø National Laboratory, Denmark 4 University of Illinois, United States 5 University of Liverpool, United Kingdom 2

Obtaining an accurate chronology for Middle Stone Age (MSA) archaeological sites in Africa is a key prerequisite for understanding the nature, rate and pattern of human behavioural evolution during this crucial period. A substantial portion of the MSA is beyond the limit of conventional radiocarbon dating, and so other geochronological methods are needed. In recent years luminescence dating of sediments based on the analysis of the optically stimulated luminescence (OSL) signal from quartz has played an increasingly successful role, with ages from sites such as Blombos in South Africa being key to realising the significance of the archaeological finds. However, the methods developed for those samples are not suitable at all archaeological sites. In Zambia at Kalambo Falls, and in Kenya at sites around Narok and Lake Elementaita, additional challenges exist related to the local geology. At both sites the high level of natural radioactivity of the sediments means that saturation of the ‘fast’ OSL signal used for dating occurs in a shorter period of time than at sites in South Africa where dose rates are only one third or one fifth as high. This limits the time period for which conventional optical dating can be applied. Additionally, at the sites in Kenya, the nature of the quartz is such that only some of the samples contain the ‘fast’ OSL signal suitable for dating using conventional methods. This paper describes the challenges of applying optical dating to these sites, and presents results from the application of novel methods employed in an effort to obtain accurate ages for these key MSA sites. In the case of the samples from Kenya, the major challenge has been to isolate the ‘fast’ OSL signal, and this has been achieved using numerical analysis of the luminescence data. At Kalambo Falls the quartz has excellent properties, but because of the antiquity of the site and the high dose rate, the conventional ‘fast’ OSL signal cannot be used to date all of the archaeological deposits. A new method, based on a different luminescence signal from quartz, has therefore been applied to samples from this site. 0764 Land-atmosphere-ocean linkages around the tropical South Atlantic during deglaciation Lydie M Dupont1, Hermann Behling2, Frank Schlütz3 1

Geosciences University of Bremen, Germany Department of Palynology and Climate Dynamics, Albrecht-von-Haller-Institute for Plant Sciences, University of Göttingen, Germany 3 University of Göttingen Jung-Hyun Kim Gerrit Heil 2

Vegetation records from marine sediments indicate different responses and climate mechanisms operating during deglaciation. (1) The pollen record of core GeoB 3910 shows that in north-eastern Brazil humid gallery forest and small patches of montane Atlantic rain forest occurred together with a dry forest synchronous to an increase of tropical Southwest Atlantic sea surface temperatures (SSTs). At the same time, the temperature difference between the tropical Southwest Atlantic and the temperate Northeast Atlantic increased. Together with other South American records, it strongly suggest a southward shift in the yearly migration of the Intertropical Convergence Zone. (2) In Angola

the expansion of montane Podocarpus forest indicating cool and humid conditions parallels the low SSTs in the tropical Southeast Atlantic as recorded at ODP Site 1078. Rise in SSTs correlates with the increase of lowland forest. (3) In Namibia, a rise in SSTs parallels the increase in savannah and the decrease in desert vegetation until the end of the Antarctic Cold Reversal. After that, southeast Atlantic SSTs no longer influenced the vegetation development in the Kalahari. Stronger trade winds during the Antarctic Cold Reversal and the Younger Dryas period probably caused increased upwelling and lower SSTs off the west coast of southern Africa. A southward shift of the Atlantic anticyclone could have resulted in both stronger trade winds and reduced impact of the Westerlies on the climate of Namibia. 0353 Postglacial sea level curve in the Rías Baixas (Galicia, NW Spain) Ruth Durán1, Raquel Diez2, Federico Vilas2, Soledad García-Gil2 1

Instituto de Ciencias del Mar (CSIC), Spain Universidad de Vigo, Spain

2

Since the first relative sea-level curve in the Iberian Atlantic Coast based on radiocarbon dating, the interpretation of sea-level position during the last postglacial period has remained uncompleted. This may be explained by the lack of sediments in the continental shelf, which can be classified as sediment starved. Due to the morphology of the rías, they represent sedimentary traps of transgressive sediments and offer an excellent opportunity to study the relative sea-level changes during the last deglaciation. In this context, the aim of this study is to develop the relative sea level curve of the Rías Baixas since the Last Glacial Maximum (aprox. 18 ky BP). It has been developed, based on high resolution seismic data, radiocarbon dates of marine sediments and the main post-Last Glacial Maximum sea level changes. The last glacial cycle was characterized by climate fluctuations which have associated with changes in global sea level. Previous studies of the sedimentary infill of the rías reveal an important change in the relative sea level that is related with the Younger Dryas event. New data allow identifying other events during the last transgression. The discussion of their significance and their comparison with global sea level changes and other records around the North Atlantic coast make it possible to define a relative sea level curve for the Rías Baixas. The curve compiles the main relative sea level changes identified in the sedimentary infill of the Rías Baixas. An important transgressive surface has been correlated with the large melting event (Melwater Pulse 1a). The presence of prominent progradational units and a toplap surface at 60 and 30 metres bpsl are related to slow downs or even stillstands of sea level during transgression (Younger Dryas and the cold event at 8.2 ky BP). Shorter stillstands are also recognized at different depths (aprox. 70, 65 and 45 m bpsl). 1085 Global Sea Level During the Last Interglacial Andrea Dutton, Kurt Lambeck The Australian National University, Australia

The magnitude and timing of temporal variability in sea level during the Last Interglacial (LIG) highstand has been subject to debate due in part to the inherent difficulties in reconstructing small, meter-scale fluctuations in sea level on relatively short timescales. To address this outstanding question, we have combined glacio-hydro-isostatic mod-


els and observational data from multiple sites to evaluate the relative position of sea level between the beginning and the end of the last interglacial period. We have drawn upon existing relative sea level data consisting of precisely dated corals from two tectonically stable regions, Western Australia and the Bahamas. These are the most complete data sets available for relative sea level position during the LIG because they have a population of U-Th ages that span the duration of the highstand. Relative sea level curves generated from these observational data suggest a reasonably constant sea level position during the LIG. However, model simulations demonstrate that both sites are subject to isostatic adjustments from water loading as the ice sheets melt. Hence, when both data sets are considered in the context of these glacio-hydro-isostatic changes, we extract a eustatic sea level signal that indicates a 5-meter rise in sea level between the beginning and the end of the LIG. Although most of this sea-level rise could have been accommodated by melting from the Greenland ice sheet, it is likely that the Western Antarctic ice sheet also contributed some component of this sea level rise. 1072 Possible connections between prehistoric anthropogenic burning and the change to a cultural landscape in Northwestern Germany Eileen Eckmeier1, Guido LB Wiesenberg2, Jan O Skjemstad3, Jutta Meurers-Balke4, Michael WI Schmidt1, Renate Gerlach5 1

University of Zurich, Department of Geography, Winterthurerstr. 190, 8057 Zurich, Switzerland 2 University of Bayreuth, Lehrstuhl für Agrarökosystemforschung, 95440 Bayreuth, Germany 3 CSIRO Land and Water, PMB 2, Glen Osmond, SA 5064, Australia 4 University of Cologne, Institute of Pre- and Protohistory, Laboratory of Archaeobotany, Weyertal 125, 50923 Köln, Germany 5 Rheinisches Amt für Bodendenkmalpflege, Endenicher Str. 133, 53115 Bonn, Germany

During Late-Neolithic (3500-2200 BC), a strong human impact was visible in nearly all terrestrial archives in the Lower Rhine Basin (NWGermany), e.g. extensive changes in plant composition; the natural landscape was transformed into a cultural landscape. At the same time, agricultural practice changed from plough-less agriculture to a presumably fire-based livestock farming. To obtain more information about these transformations, we investigated dark soils in the Lower Rhine Basin following a 33 km long pipeline trench and at 16 archaeological large-scale (0.5 – 5 ha) excavations. The soil horizons were always connected to anthropogenic pits, and most of the pit fillings contained macroscopic charcoal. Our main research questions were: (i) could the investigated dark soils have been formed by anthropopogenic burning?, and (ii) can we prove soil amendments (manure) via organogeochemical analyses? The proportion of charred material in soil organic matter was examined by isolation and identification of black carbon via UV photo-oxidation and 13C NMR. Isolated black carbon material and hand-picked macro-charcoal was dated by 14C AMS. Phosphorous concentrations and the distribution of lipids (n-alkanes) were compared for the dark material and the surrounding soil material. Large proportions of the organic matter taken from the dark soils consisted of charred organic matter (19 to 46 % of soil organic carbon). The radiocarbon ages of charcoal and black carbon indicated the presence of fires from 7530 – 7200 calBC to 675 – 780 calAD. In half of the cases the amount of phosphorous was higher in the black soil material than in the surrounding soil. The proportion of total lipids compared to total organic carbon was lower in the dark soils, presumably

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because lipids were preferentially destroyed by burning. All samples showed a particular high abundance of short-chain and even carbonnumbered n-alkanes. Temperate deciduous forests could not be easily ignited by natural causes. Thus, mainly human induced fires are very likely the sources of the charred organic matter, but an increased input of organic matter, e.g. from manure was not detected in all pit fillings. The unexpected distribution of n-alkanes could result of a still unknown process of decomposition of plant material, maybe degradation during biomass burning. We concluded that the investigated dark soils are relics of prehistoric agricultural burning activities in NW-Germany, possibly providing the basis for the change to a cultural landscape in Late-Neolithic. 0726 Biotic and human history at Ketilsstaðir, southern Iceland, and the enigma of multiple peat-cut pits Kevin J Edwards1, Egill Erlendsson2, Tim Horsley3, Paul C Buckland4, Andrew J Dugmore5, Ian A Simpson6, Guðrun Sveinbjarnardóttir7 1

University of Aberdeen, United Kingdom University of Iceland, Iceland 3 University of Bradford, United Kingdom 4 Bournemouth University, United Kingdom 5 University of Edinburgh, United Kingdom 6 University of Stirling, United Kingdom 7 National Museum of Iceland, Iceland 2

An area of southern Iceland centred upon Ketilsstaðir would appear from surviving records to have a complex environmental and human history. Unlike other areas of Iceland, the first Norse (Viking) settlers were met by a vegetational landscape which was already relatively unwooded as a result of natural processes. Human colonization is denoted by archaeological remains and historical documentation, while fossil evidence (especially pollen and peat stratigraphy) reflects increasing cultural activity. The anthropogenic environmental record is initially muted and has to be disentangled from the impacts of tephra falls - especially that of the massive (20 cm local thickness) Katla-1357 ash. Apart from palynology, the sedimentology, soil micromorphology and insect evidence contribute to an assessment of the Viking and Medieval age geoarchaeology of the area. A particular focus is upon the significance of pit-like features found in a drained, peat basin. The pits are explored geophysically, stratigraphically and palaeoecologically and the geophysical surveys reveal a complex of discrete regular anomalies, consistent with pits cut into the peat and filled with tephra. The tephra deposits constrain pit use to between AD 1341 and 1357. Adopting a multiple working hypothesis approach, the paper enquires as to whether the features at Ketilsstaðir might be former peat cuttings and hence accidental or intentional receptacles for volcanic ash, and/or whether they had a primary purpose as hemp or flax retting pits. An additional interest lies in the deposition of cut turves which lie directly on top of the Katla-1357 ash. The turves may be the debris from peat-cutting activities, with surface sods placed at the contemporary surface of the peat bog at the time of cutting, or they may represent an attempt at reinvigorating a land surface made temporarily sterile by the deposition of ash.

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1163 Late-Quaternary dynamics of arctic thermokarst lakes contribute feedbacks to deglacial climate warming Mary E Edwards1, Katey M Walter2, Guido Grosse3, Sergei A Zimov4, Patrick J Bartelin5, Paul J Valdes6, F Stuart Chapin2 1

University of Southampton, United Kingdom University of Alaska - Fairbanks, United States 3 University of Alaska - Fairbanks, Germany 4 Northeast Science Station, Pacific Institute for Geography, Russia 5 University of Oregon, United States 6 University of Bristol, United Kingdom 2

Unglaciated lowland regions of Siberia and northwest North America are characterized by deep, fine-textured surficial sediments of Pleistocene age. These deposits contain massive ice bodies, including syngenetic ice wedges that grow apace with accumulating sediment and may be tens of metres deep. During cold, dry periods, the land surface remains largely frozen and accumulates ice and sediment containing organic carbon; under warm, moist conditions, thawing leads to thermokarst erosion, which lowers the landscape via loss of water and subsequent collapse, and thermokarst (“thaw”) lakes are formed. The last deglaciation, ca 15-8 ka B.P., saw the widespread initiation of thermokarst as northern climates became warmer and moister than those of the preceding glacial period. The onset of thermokarst lake development can be identified in exposures and lake-sediment cores via a range of sedimentological features and radiocarbon-dated. Thermokarst developed regionally in Siberia and northwest North America from ca 14 ka B.P., and many lake initiation dates fall in the period ca 11-8 ka B.P. The earliest onset coincides with a hemispheric shift to warmer, moister conditions, and it occurred prior to the inundation of exposed ocean shelves due to deglacial sea-level rise. The later, large pulse of lake formation coincides with the early-Holocene thermal maximum in the western Arctic, which was largely insolation-driven. Active thermokarst lakes are high methane emitters because freshly thawed and eroded carbon-rich materials are decomposed in lake bottoms. Calculations based on modern observed emission rates, the temporal pattern of lake development, and changing shelf area indicate that thermokarst lakes can account for a considerable portion of the late-Quaternary boreal atmospheric methane observed in ice-core records. The development of numerous lakes across the landscape (cover may be 40% of the land surface in some regions) also influences the surface energy balance. Experiments with a regional climate model (RegCM) demonstrate that the presence of lakes slightly cools growing-season temperatures. Thus while the direct effect of lake development is a negative feedback to regional climate change, there is a much stronger indirect positive feedback to global climate via methane emissions. Anthropogenic warming in the 21st century has the potential to modify thermokarst dynamics further; feedbacks to that warming are thus possible and require investigation via earth-system model simulations and field observations. 1030 3D modelling of Quaternary buried channels in Hamburg, Germany Juergen Ehlers, Jens Kroeger Geologisches Landesamt Hamburg, Germany

The Quaternary glaciations shaped the landscape of the North European lowlands. The influence of the glaciers was not restricted to the land surface. Subglacial meltwater drainage cut up to 500 m deep into the

underlying sediments. Most of the deep buried channels were formed during the Elsterian glaciation. Towards the end of the glaciation they were partly refilled with sand. Consequently, they form important aquifers. However, as they are not visible on the surface, their reconstruction relies on borehole records and geophysical investigations. In the BurVal project, geologists from Denmark, the Netherlands and North Germany worked together to improve the understanding of those features. Tools were developed to map the buried valleys. The 3D modelling of Quaternary buried channels in Hamburg presented on this poster is part of that project. Using the program GOCAD, a 3D model of the underground in the area of the Ellerbeker Rinne was constructed. The aim of this 3D model was not only to show the geological structures of this area, but also to validate, control and integrate all available data produced by several different methods over a long time with quite different quality standards. The 3D model shows the hydrostratigraphy of the Ellerbeker Rinne and the adjacent Tertiary layers. In order to improve the information, additional maps and profiles were incorporated. The initial model was then combined with seismic profiles and electromagnetic measurements from a helicopter (HEM and SKYTEM). It turned out that in the NW the channel is relatively shallow and symmetrical, whereas towards the SE it gets increasingly deeper and asymmetrical with steep flanks on the SW side and gently dipping NE flanks. In the SE also the relationship of the channel to the underlying salt dome could be demonstrated and some faults were detected in the underlying substratum. Comparison of seismic with borehole data reveals, that the borehole data often suggest far too shallow channel depths. However, in most areas no better information is available. Only where seismic profiles could be used, some of the borehole data could be corrected. The resulting model demonstrates that 3D modelling is a powerful tool to improve the understanding of irregularly shaped subsurface features like buried channels. 1035 Biomarker Analysis of a Holocene Mangrove Peat Core from Spanish Lookout Cay, Belize Jennifer L Eigenbrode1, Marilyn L Fogel1, Natalie M Monacci2, Matthew J Wooller2 1

Carnegie Institution of Washington, United States University of Alaska Fairbanks, United States

2

Mangrove peat hold paleoecological records of mangrove responses to Holocene environmental changes such as sea-level fluctuations. We used lipid biomarkers to assess the relative proportions of different mangroves in a past habitat at Spanish Lookout Cay, Belize. Biomarkers were extracted from 16 sub-sets of an 800 cm core (BT-79) that represent an ~8000 calendar-year-before-present record. Lipid biomarkers in BT-79 were compared with biomarkers extracted from modern mangrove specimens. All three species of mangroves in Belize (Rhizophora mangle, Avicennia germinans, Laguncularia racemosa) have normal alkanes from C-17 to C-35, with a maximum at C-29 and an odd-to-even carbon chain preference. Modern microbial mats from Belize contained novel branched hydrocarbons, in addition to the normal alkanes up to C-33. In BT-79, both mangroves and mats contained the isoprenoids, pristane and phytane, although the mangrove tissues had relatively higher concentrations of phytane than microbial mats. In peat, the lipid signature of branched compounds resembled mangrove biomarkers in a majority of the core samples. Steroid and pentacyclic triterpenoid hydrocarbons were found in all extracts from mangroves and peat. Microbial mats contained a different set of lipid biomarkers corresponding to bacterial hopanoids. Ratios of specific mangrove biomarkers (about 12–15 individual compounds) are being investigated as a record for the relative abundances of Rhizophora: Avicennia: Lagun-


cularia. At present, we can detect a higher relative abundance of Avicennia at ~800, and again at ~350 cm depth. Mangrove roots, fine and coarse, have biomarker signatures different to leaves. Fine roots contained a suite of compounds with lower molecular weights, extensive branching, and very high abundance of n-C29 relative to the other normal alkanes. Coarse roots had biomarkers similar to Avicennia leaves, but different from Rhizophora leaves. There is no clear evidence of fine Rhizophora roots in the biomarker record; however, it is highly likely that coarse roots provide input into lipid composition. At depths with high subfossil leaf area (e.g., 400 – 440 cm), mangrove biomarkers dominated with no indication of microbial or fine root input. At this time, peat was accumulating rapidly. At the end of the slow accumulation period, (~500 cm) ~7000 cal. yrs BP, subfossil leaf area is very low and corresponds to an abundance of microbial hopane biomarkers. We propose that an enriched concentration of microbial biomarkers indicates shallow, interior ponds that are the current habitat at the site. 0715 The Bering Land Bridge: A moisture barrier to the dispersal of steppe-tundra biota Scott A Elias Royal Holloway, University of London, United Kingdom

The Bering Land Bridge (BLB) connected the two principle arctic biological refugia, Western and Eastern Beringia, during intervals of lowered sea level in the Pleistocene. Fossil evidence from land bridge organic deposits dating to the last glaciation indicates that this broad, lowland region was dominated by shrub tundra vegetation, and had a mesic climate. The dominant ecosystem in Western Beringia and the interior regions of Eastern Beringia was steppe-tundra, with herbaceous plant communities and arid climate. Although Western and Eastern Beringia shared many species in common during the Late Pleistocene (e.g., woolly mammoth, Pleistocene musk-oxen, and Pleistocene horses), there were a number of species that were restricted to only one side of the BLB. Among the vertebrate fauna, the woolly rhinoceros was found only to the west of the BLB, North American camels, bonnet-horned musk-oxen and some horse species were found only to the east of the land bridge. There were all steppe-tundra inhabitants, adapted to grazing. The same phenomenon can be seen in the insect faunas of the Western and Eastern Beringia. The steppe-tundra beetle fauna of Western Beringia was dominated by weevils of the genus Stephanocleonus, a group that was virtually absent from Eastern Beringia. The dry-adapted weevils, Lepidophorus lineaticollis and Connatichela artemisae were important members of steppe-tundra communities in Eastern Beringia, but not found on or west of the BLB. The leaf beetles Chrysolina arctica, C. brunnicornis bermani, and Galeruca interrupta circumdata were typical members of the Pleistocene steppe-tundra communities of Western Beringia, but absent from Eastern Beringia. On the other hand, some steppe tundra-adapted leaf beetles managed to occupy both sides of the BLB, such as Phaedon armoraciae. These biogeographic patterns are difficult to interpret, but ongoing research on the ancient DNA of steppe-tundra beetles preserved in permanently frozen sediments from Beringia should shed new light on the comings and goings of Beringian beetles during the Pleistocene. Modern floristic evidence suggests that there may have been a north-south moisture gradient on the BLB, with moister. In general, the fossil beetle evidence indicates that Western Beringia was much more uniformly covered by steppe-tundra during Pleistocene glaciations than was Eastern Beringia. At least during the Last Glaciation, fossil evidence from southwestern and northwestern Alaska suggests that mesic tundra dominated these regions, whereas the fossil

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evidence from the interior parts of Alaska and the Yukon clearly point to steppe-tundra environments. 0039 Combating Flood Crisis with Geographic Information System (GIS): An Example from Akure, Southwest Nigeria O A Eludoyin1, O M Akinbode2, O A Ediang3 1

Department of Geography, Obafemi Awolowo University, Ile-Ife, Nigeria, Nigeria 2 Obafemi Awolowo University, Nigeria 3 World Maritime University, Malmo Sweden, Nigeria

Flood is a natural environmental disaster which could be aggravated by manâè™s unguided development. It may subsequently cause destruction of properties and loss of life. Therefore it needs to be controlled and human influences controlled. This study attempts to describe an application of GIS as decision support to flooding problems in an urban area in Nigeria. The objective of the study is to describe the efficacy of GIS in monitoring of development on floodplains in an urban area in Nigeria. Topographic features were digitised from an existing 1:5,000 topographic map of Akure, with some position data collected and map updated using a handheld GPS. A database was created using both cartographic and attributes data collected from these and other sources. Spatial analyses were carried out using a PC based Integrated Land and Water Information System (ILWIS), version 3.2. The results obtained implicated dumpsites within the river channel as well as structural development within the River Ala floodplain as the major causes of inundation in this section of the city, especially, in the wet season. The study concluded that GIS could provide adequate decision support information to policy makers. 0081 Late Quaternary relative sea-level change and crustal movements of the eastern seaboard of the United States Simon E Engelhart1, Benjamin P Horton1, Wm Richard Peltier2, E Robert Thieler3 1

University of Pennsylvania, United States University of Toronto, Canada 3 United States Geological Survey, United States 2

High quality relative sea-level (RSL) data reveal spatial and temporal variations in crustal movements since the Last Glacial Maximum (LGM). Current concerns regarding the potential eustatic sea-level rise associated with anthropogenic warming of the atmosphere and oceans and its impacts on coastal resources have resulted in increased interest in former RSL fluctuations. Rates of sea-level rise obtained since the LGM represent the fundamental basis for comparison with the historical and present day changes. Reconstructions through the Holocene allow modellers to quantify lithospheric thickness and mantle viscosity and establish lateral variations in mantle structure across the continental/oceanic margin. Reconstructions of crustal subsidence/uplift on a regional basis allow for the development of site-specific coastal management regimes to proposed rates of eustatic sea-level rise during the 21st century. There is an urgent need to re-evaluate the quality of the United States Atlantic coast RSL record, because of the apparent inability of the best currently available Glacial Isostatic Adjustment (GIA) models to fit the earliest portions of the Holocene records at most sites south of Boston. Initial results from Delaware and North Carolina demonstrate this significant misfit between the early

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Holocene records and the predictions of the latest generation models. There is a difference of 1mm yr −1 between the late Holocene subsidence rates at Delaware and North Carolina (1.9±0.1mm yr −1 and 0.8±0.1mm yr −1 respectively). This is in disagreement with GIA models, which predict that the Delaware and North Carolina coastlines exhibited similar crustal movements during the last 4000 cal yrs BP. 0785 The influence of river inundations on quantitative chironomidinferred temperature reconstructions on OIS-3 floodplain sediments Stefan Engels1, Johanna AA Bos1, Sjoerd JP Bohncke1, Oliver Heiri2 1

Vrije Universiteit, Amsterdam, The Netherlands Universiteit Utrecht, The Netherlands

2

Many projects have focused on the abrupt climate changes during Oxygen Isotope Stage (OIS)-3. However, the mechanisms driving these dramatic climate shifts are still poorly understood. Quantitative reconstructions of environmental parameters can form a major contribution in our attempt to discriminate the driving processes behind these climate changes. The opencast lignite mines in eastern Germany provide for a fragmentary record covering the early OIS-3, and a multi-proxy study using both chironomid-based numerical inference models and the plant indicator-species approach reveals that climate warming was the most likely cause for the formation of the studied thawlakes. The fossil chironomid and botanical assemblages and the sedimentological record all suggest that the palaeolakes were situated on a river floodplain. Modern lakes where high-discharge events of nearby rivers or streams can reach the lake are however not usually included in modern calibration sets and it is presently unclear to what extent river inundations can affect chironomid-based environmental reconstructions. In order to investigate this potential influence of river inundations in a modern analogue situation, 13 regularly inundated sites and 20 closedbasin lakes were sampled during a fieldwork in Finnish Lapland. Preliminary results reveal that river inundations have only a minor influence on the chironomid assemblages of these shallow lakes. Instead, lake depth seems the more relevant factor for the distribution in these floodplain lakes. The results indicate that the fossil chironomid records encountered in eastern Germany can be used to quantitatively infer past changes in mean July air temperatures without the results being adversely affected by the proximity of a river. In a next step, a chironomid-temperature inference model will be applied to the assemblages in order to quantify the intraregional variability in chironomidbased inferences and to test more rigorously whether chironomid-based reconstructions are potentially biased by riverine influence. 1077 Reconstruction of soil erosion and human-environment interactions from lacustrine sediments – an example from Frickenhauser Sea (central Germany) Dirk Enters1, Bernd Zolitschka2, Walter Dörfler3 1

UMR CNRS 5204, EDYTEM, Université de Savoie - Technolac, F-73376 Le Bourget du Lac, France, France 2 Geomorphology and Polar Research (GEOPOLAR), Institute of Geography, University of Bremen, Celsiusstr. FVG-M, D-28359 Bremen, G, Germany 3 Institut für Ur- und Frühgeschichte, University of Kiel, Johanna-MestorfStraße 2-6, D-24118 Kiel, Germany, Germany

Lake sediments provide excellent archives to extend instrumental and historical records of environmental change into the past. However, the

discrimination between climatic and human forcing factors is difficult due to their complex interaction. Frickenhauser See, a small and eutrophic lake in central Germany, provides a 12.75 m long sediment record that covers approximately the last 2000 years. Starting in the 11th century, natural sedimentation processes of organic sediments are replaced by an event-dominated sedimentation of minerogenic turbidite deposits, which are caused by forest clearing and subsequent soil erosion in the catchment area. Turbidite thicknesses and frequencies show two phases of higher process activities between 1150 and 1300 AD as well as between 1650 and 1850 AD. The latter phase correlates with increased flood frequencies of the Werra River, located 16 km to the northeast. However, a detailed comparison between sediment and flood records is mainly hampered by the limited time range of the historical flood record but also by the lack of a “modern analogue” depositional system for the lake. The chronological uncertainties which are related to 14C dating also prevent to assign a particular depositional event in the sediment record of Frickenhauser See to known historical floods. Around 1870 AD, land-use change reduces the minerogenic input into the lake and calcareous varves formed under permanent anoxic conditions. Although parts of the catchment area were still used for vegetable gardening until the 1930’s, this cultivation method did not lead to the excessive soil erosion as observed in previous centuries. In the case of Frickenhauser See, the deposition of turbidites is primarily caused by the sensitivity of the catchment area to erosion. This depends on multiple factors including varying human land-use intensity as a response to population pressure, changing agricultural techniques as well as different climatic triggers such as extreme rainfalls events or snowmelt. Although observed turbidite layers are likely the result of climatic forcing factors leading to increased soil erosion, it is human impact that makes the catchment area susceptible for erosion. Human influences on sedimentation rates and sediment properties resemble lake responses to climatic controls and these two forcing factors also interact with each other. The discrimination between climatic signals and anthropogenic effects therefore still represents one of the major paleolimnological challenges for the future. 0454 Quantification of Holocene floodplain sedimentation in the Rhine Valley Gilles Erkens Department of Physical Geography, Faculty of Geosciences, Utrecht University, The Netherlands

During the Holocene, the vegetation cover in the Rhine catchment and surrounding NW Europe developed initially in response to postglacial climatic warming and later under increasing human influence. These spatio-temporal developments make the history of sediment delivery to the Rhine and its floodplains a complex one. From several smaller Rhine tributaries, it is known that floodplain sedimentation amounts varied significantly over time as a result of changes in, particularly, vegetation cover. It is therefore expected that a large parts of the increased river loads of fine sediments due to agricultural deforestation got trapped on floodplains along the Rhine trunk river. The Rhine is a large river, however, and up till now it the magnitude of floodplain sedimentation increase along the trunk river was unknown. Likewise it was unknown whether there was a stepwise or gradual increase, or if there was a time lag between the response in upstream (Upper Rhine Graben) and downstream (Rhine-Meuse delta) reaches. We have quantified the amounts of floodplain sedimentation per millennium over the timescale of the Holocene. We distinguish three main sinks of Holocene floodplain sediments along the Rhine trunk river: the Upper Rhine


Graben, the Lower Rhine Embayment and the Rhine-Meuse delta. New collected field data and borehole data from extensive databases allow to calculate the thicknesses and ages of floodplain sediments. This information is used to calculate sedimentation rates and to perform sediment budget analyses for the complete catchment. The results are coherent for different parts of the drainage basin and show a shift from a natural controlled to a human modified fluvial system. First results show an initial increase in overbank sedimentation rates in all study areas since 4000 cal BP, and a three-fold increase after 2000 cal BP. Response in all three sinks is remarkably similar. This implies that early human land-use already modified sedimentation patterns in large catchments such as the Rhine system. The calculated floodplain sedimentation rates allow to determine the response of the Rhine system to changes in its drainage basin on an interglacial time scale. This may be of major importance to better understand the special scale and magnitude of fluvial system response to predicted global climate and land use changes in the future. 0758 Lateglacial and Holocene fluvial response to climate- and humaninduced vegetation changes in the northern Upper Rhine Graben, Germany Gilles Erkens1, Koen P Volleberg1, Marjolein TIJ Bouman1, Wim Z Hoek1, Rainer Dambeck2 1

Department of Physical Geography, Faculty of Geosciences, Utrecht University, The Netherlands 2 Department of Physical Geography, Faculty of Geosciences, Johann Wolfgang Goethe University Frankfurt am Main, Germany

The northern Upper Rhine Graben (south-west Germany) hosts a well preserved Rhine terrace sequence of Late Glacial and Holocene age. These terrace levels differ in elevation, fluvial style, overbank sediment characteristics and soil formation. Climate variability and human impact are considered to have been major external controls on fluvial development in the area, because they are known to have impacted vegetation cover in the drainage basin and the discharge regime. The aim of this study was to describe and quantify fluvial development during the last 15,000 years in the northern Upper Rhine Graben and correlate this to human- and climate-induced changes in vegetation cover. For a representative valley segment (12 km length), results from previous surveys were integrated with newly obtained borehole data and digitized elevation data to construct maps and cross-sections. We dated terrace surfaces directly with OSL and indirectly with pollen assemblage biostratigraphy and radiocarbon dating from channel fills. Detailed grain size analysis (laser diffraction) was used to characterise variation in floodplain sediment composition. In addition, fluvial response to external forcing was quantified using GIS to calculate floodplain sedimentation rates throughout the Holocene. Changes in vegetation cover during the last 15,000 years were reconstructed using palynological analyses. Finally, we compare vegetation development in the river valley and the wider drainage basin with observed fluvial development and changing sediment characteristics. Because we could establish how specific element of the fluvial system responded in time, this allows us to distinguish between direct and indirect response to external factors, and intrinsic river behaviour. First results indicate that initial terrace formation was caused by climatic warming after the Last Glacial Maximum, although fluvial response to climate change was slow and continued until the Middle Boreal. In the Middle Holocene, intrinsic response of the system combined with the tectonical background situation and wetter conditions in the floodplains caused changes in fluvial style and associated overbank lithofacies. During the

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last part of the Holocene, human impact became dominant, resulting in an increase in floodplain sedimentation rate and volume and a change in grain size distribution. The results indicate that the spatio-temporal response of the River Rhine is non-uniformly to external and internal factors, but the general trend is a major shift from a natural controlled to a human modified fluvial system. 1126 Holocene floodplain sedimentation trends in the Lower Rhine Embayment (Germany) Gilles Erkens1, Thomas Hoffmann2 1

Department of Physical Geography, Faculty of Geosciences, Utrecht University, The Netherlands 2 Department of Geography, University of Bonn, Germany

During the Holocene, climate and human impact have profoundly altered the erosion, transport and deposition of fluvial sediments in central Europe. It is therefore suggested that Holocene climate- and human-induced vegetation changes in the upstream drainage basin influenced the sediment flux to the River Rhine and consequently sedimentation rates in the floodplains of the River Rhine. Calculated sedimentation rates allow for determining the response of the Rhine system, expressed in floodplain sedimentation, to changes in its drainage basin on a millennial time scale. The study area is the Lower Rhine Embayment, one of the largest Holocene sediment sinks in the Rhine catchment. We investigated Holocene floodplain sedimentation with three separate approaches, all based on an extensive database of 14C samples and borings. The 14C data were used to calculate: (i) sedimentation rates and (ii) phases of fluvial activity and stability. Based on boreholes, we constructed valley-wide cross sections, from which we (iii) quantified floodplain sediment volumes for successive Holocene time slices. The results of the 14C probability frequency analysis suggest a tendency towards stable fluvial and colluvial systems during the Early and Middle Holocene and increased activities during the Late Pleistocene and the last 4000 years. In general, phases of increased fluvial activity coincide with phases of decreased slope stability (and vice versa) suggesting a strong response of the fluvial system to external forcing. The estimated sedimentation rates based on the 14C ages varied in three phases during the last 14,000 years, whereby the first phase (until 8000 years BP) is characterised by relatively high floodplain sedimentation rates. The second phase with decreased sedimentation rates coincidences with more stable environmental conditions during the Middle Holocene climatic optimum. The third phase from 4000 years BP onwards, shows a strongly increased sedimentation rate. Tentative results of the calculated floodplain sediment volumes suggest a minor increase in sedimentation between 4000 and 2000 cal yr BP compared to the Middle Holocene, and a strong increase after 2000 cal yr BP. This trend is visualised by all three approaches, and it exceeds amplitudes expected from intra-Holocene climatic forcing. Therefore, the results imply a coherent early shift from a naturally controlled to a human dominated fluvial system. Recognising that human impact already modified floodplain sedimentation in large catchments such as the Rhine from 4000 cal yr BP onward, may put the response of fluvial systems to predicted future global climate and land use changes in perspective.

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0184 Coral U-series ages: U in corals and in the oceans Tezer M Esat1, Yusuke Yokoyama2 1

Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Australia 2 Department of Earth and Planetary Sciences, University of Tokyo, Japan

A by product of U-series dating of corals is the 234U/238U ratio in the oceans at the time the coral was growing. The expectation is that this ratio remains invariant in the oceans over the U-series time scale, of at least 500,000 years, and hence it can be used to detect itinerant U or Th through the sample over time. Often, a suite of corals from a reef section show an intriguing, approximate 1:1, correlation between the 234U/238U ratio and age. This pattern can arise by the addition of almost equal amounts of external 230Th and 234U into the coral over an extended period. Currently, the favoured explanation postulates addition of equal amounts of 230Th and 234Th. The latter has a very short half life of about 25 days but the advantage that during aqueous transport it should not fractionate from 230Th. There are at least three prescriptions for removing the extraneous added components, based on the difference between the measured and expected 234U/238U ratio, to derive a corrected or “true” age for the sample. However, there is growing evidence that 234U/238U may not have been invariant in the oceans through Glacial-Interglacial transitions. In addition, some of the correlated data sets cross over to values of 234U/238U lower than in the present ocean thus requiring both the removal and addition of 230Th and 234Th, in neighbouring corals, which is not easy to explain. We will present data from Huon Peninsula coral reefs that show much more complex behaviour than the so far recognised 1:1 linear trend. Firstly, during major sea-level transitions the 234U/238U ratio shifts from low to high values in step with rising sea-levels. There are several well documented examples of this type of behaviour. Secondly, the variability in 234U/238U is amplified during rapid changes in sea-level. Candidates for this type of behaviour occur during rapid sea-level changes associated with Heinrich-events and also during the OIS6 to OIS5 transition. At these times, there is a direct correlation between sea-level change and U as the 234U/238U ratio shifts between high and low values in step with sea-level. This type of behaviour cannot be explained by extraneous 230Th-234Th infusion or through any other plausible diagenetic process. Conversely, these results cast doubts on the 230Th-234Th addition explanation for the 1:1 234U/238U-age trend in the data and more so on the so-called corrected ages calculated from them. 0246 New insights on seismic hazard in the southwest of Australia from paleoseismological studies Beatriz E Estrada1, Dan Clark2, Karl-Heinz Wyrwoll1, Mike Dentith1 1

University of Western Australia, Australia Geosciences Australia, Australia

2

The southwest of Western Australia is one of the most seismically active parts of the Australian stable continental crust. Three historic moderate to large earthquakes have generated scarps which disrupt the otherwise topographically subdued landscape of the region. Recent field work guided by interpretation of high-resolution digital elevation models (DEMs) resulted in the recognition of additional linear scarps that are potentially related to large pre-historical surface breaking earthquake events. Paleoseismological investigations of two of these scarps, the newly recognized Dumbleyung Scarp, and the previously recognized Lort River Scarp, not only confirmed their association with

surface rupturing paleo-earthquakes but also indicated events with likely magnitudes of ~M7.0. Two trenches excavated across the 36 km long Dumbleyung Fault scarp, located about 230 km southeast of Perth, show that the scarp is developed in Quaternary alluvium which has been displaced across a west dipping reverse fault. Structural and stratigraphic relationships suggest that the fault has generated at least one large event (>Mw7.0) and a smaller event in the last several tens of thousands of years. Two trenches excavated across the 40 km long Lort River Scarp, located at about 540 km southeast of Perth, show that the scarp is developed in deeply weathered gneiss that has been displaced by an east dipping thrust fault. The scarp is partly buried by slope colluvium derived directly from the scarp. Structural and stratigraphic relationships suggest that the faulting has displaced both the weathering profile and the colluvial material on top of the scarp, suggesting at least two events. One event is likely to have been of large magnitude (>Mw7.0). The large single event displacements inferred from these paleoseismological investigations provide a robust base for defining the maximum credible magnitude earthquake for Western Australia. The occurrence of similar fault scarps across the region suggests that the potential for large surface-breaking earthquakes has been significantly underestimated. 0948 Radiocarbon Dating of Rice Husk Material from Temple Bricks at Angkor, Cambodia Damian H Evans1, Quan Hua2, Dan Penny1, David Fink2, Christophe Pottier3, Roland J Fletcher1, Charles Mifsud2 1

University of Sydney, Australia Australian Nuclear Science and Technology Organisation, Australia 3 École française d’Extrême-Orient, France 2

It has long been thought that the medieval city of Angkor, in Cambodia, collapsed in the middle of the second millennium CE due to the environmental consequences of urban expansion and the intensification of rice agriculture. Recent archaeological surveys have provided a measure of support for this hypothesis. Studies of remote sensing data have revealed traces of a vast network of village temples, occupation mounds and hydraulic infrastructure stretching between and far beyond the well-known monuments of the central zone. However, the Angkor area has been occupied continuously for at least two millennia and there are serious chronological issues with the new data. Several hundred of the newly discovered temple sites consist of little more than scatters of brick rubble and are virtually impossible to date using conventional (art historical, architectural, or inscriptional) approaches, while scientific excavations of a significant number of sites will likely take many years, if not decades. This paper details an alternative method of dating the most common surface material, brick. During the Angkor era, rice husks, a by-product of the annual harvest, were added to the clay mix as temper during brick manufacture in order to enhance the structural properties of the fired product. Brick kiln technology was rudimentary, and in most cases small traces of this organic material remain within the unevenly fired bricks. In partnership with AINSE/ANSTO, the Cambodian archaeological authority (APSARA) and French researchers, we have successfully developed a method of extracting husk material from bricks, and have used the small-mass 14C analysis capabilities at ANSTO to acquire radiocarbon age determinations from extremely small fragments. This paper presents the preliminary results of that work, which has the potential to provide direct, absolute dates for Angkorian temple structures for the first time and to add considerably to our understanding of Angkor’s growth and decline. The work has been funded by an AINSE Postgraduate Research Award.


0113 Surging glacier landsystem of Tungnaárjökull, Iceland David JA Evans1, David R Twigg2, Brice R Rea3 1

Geography Department, Durham University, United Kingdom Department of Civil and Building Engineering, Loughborough University, United Kingdom 3 Department of Geography, University of Aberdeen, United Kingdom 2

Tungnaárjökull is a 17km wide surging glacier lobe of the western margin of Vatnajökull, Iceland. Historical surges on to ice front-parallel bedrock ridges have produced landforms and sediments diagnostic of surging, providing us with the ideal opportunity to assess processform relationships in glacial geomorphology through the landsystems approach. The landform-sediment assemblages on the Tungnaárjökull foreland conform to the surging glacier landsystems model of Evans and Rea (1999, 2003), which recognizes three overlapping geomorphic zones. The outer zone (A) of thrust block moraines, hill-hole pairs and push moraines can be identified along the former margins of the 1880 –1890, 1945 and 1995 surges, although the high glacier ice-content of the weakly consolidated pre-surge sediments has resulted in the development of ice-cored hummocks throughout most of the thrust masses. The intermediate zone (B) of hummocky moraine located on the down-glacier sides of topographic depressions and often draped on the ice-proximal slopes of the thrust block and push moraines is particularly well developed. This reflects the nature of the pre-surge deposits, which were typically glacifluvial outwash draped over buried glacier ice from previous surges. Due to the restrictions placed on sandur development by the proximity of the bedrock ridges to the receding glacier snout, the burying of glacier ice by outwash was more widespread than on most other surging glacier forelands. The 1915 –1920 surge limit is demarcated on by an arc of faintly fluted ice-cored hummocks. The inner zone (C), comprising long, low amplitude flutings produced by subsole deformation during the surge and crevassesqueeze ridges produced at surge termination, is also well developed throughout the whole foreland despite the fact that proglacial outwash has extensively dissected and reworked it. Zig-zag or concertina eskers are rare. Intrazonal forms of surging include ice-cored, collapsed outwash, which is located in areas where proglacial outwash fans and streams were prograded over portions of the stagnant snout. This is concentrated in the south of the map area where additional evidence of older ice-cored outwash, which has been proglacally thrust during subsequent surging, occurs as ice-cored hummocks. 0195 Controlled moraines: characteristics, genesis and preservation potential David JA Evans Geography Department, Durham University, United Kingdom

Glacial geomorphologists have identified linearity in end moraine sequences in a wide variety of settings ranging from cirque basins to the former margins of ice sheets in continental interiors. This has not always been explained by marginal pushing, dumping or glacitectonic disruption but rather as the preservation of former englacial debris concentrations after complete ice melt-out. As such these landforms qualify as “controlled moraines”, where moraine form and pattern is controlled by englacial/supraglacial organization of debris concentrations. Such interpretations have significant implications for palaeoclimatic reconstructions in that glacier dynamics are inferred to be characterized by mass stagnation, even though the development of en-

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glacial structure is related to more dynamic behaviour such as englacial thrusting. Similarly, the impact of supraglacial reworking must be negligible in order to preserve moraine form. Only vertically or near vertically inclined debris concentrations may produce significant linear ridges, and as most debris-rich ice facies are manifest as up-glacier dipping folia, such linearity should be expected only in a few situations (e.g. subglacial crevasse-squeeze ridges). Assessment of the preservation potential of controlled moraine in the Quaternary landform record is accomplished through the analysis of the process-form relationships of recently deglaciated terrains in Iceland, Svalbard and Ellesmere and Baffin islands in the Canadian arctic, where glacier snouts display clear controlled moraine development and historical moraine systems have evolved from the downwasting ice. It is apparent that englacial structure may be represented in only crude form as low amplitude moraine belts that lack the intricate crenulations of marginal push moraines. Additionally, the occurrence of controlled moraine of late Pleistocene age in the permafrost of northern Canada provides a clear illustration that sharply defined linearity in controlled moraine is a supraglacial feature that may survive through large parts of interglacials as permafrost. 0553 Cosmogenic nuclide calibration: The Baltic Ice Lake drainage Derek Fabel1, Arjen P Stroeven2, Svante Björk3, Marc Caffee4 1

University of Glasgow, United Kingdom University of Stockholm, Sweden 3 Lund University, Sweden 4 Purdue University, United States 2

During retreat of the Fennoscandian ice sheet, a large ice-dammed lake formed along its south-eastern margin. The ice damming this Baltic Ice Lake (BIL) was breached at the northern tip of Mt Billingen, resulting in a catastrophic drainage of ~8000 km3 of meltwater and an associated lowering of the BIL by ~25 m. This event occurred at ~11,500 calibrated 14 C yr, determined using bio-, litho, and chrono-stratigraphic data from numerous lake and bog cores in the immediate vicinity of Mt Billingen and the varve chronology from the Baltic Sea tied to the GRIP 18O record. The dramatic fall in the level of the BIL is recorded by raised shorelines, isolation of lake basins, and changes in the characteristics of marine sediments. We collected material for a pilot study from (1) scoured bedrock directly in the path of the meltwater outflow, (2) large (> 2m x 2m x 2m) sandstone boulders derived from the northern tip of Mt Billingen and transported by the flood, (3) bedrock from a meltwaterscoured area further down-current (called Klyftamon), and (4) cobbles from the surface of thick floodwater deposits downstream of the scoured Klyftamon bedrock surface. The results of 10Be analysis of these samples are internally consistent between the sampling locations, and we compare these to the available 14C data in order to assess the validity of the site as a potential calibration site for cosmogenic nuclide methods. 0588 Natural Variability and Anthropogenic Influence on Climate: Surface Water Processes in the Indonesian Seas Stewart J Fallon1, Thomas P Guilderson2, Chris Charles3 1

Australian National University, Australia Lawrence Livermore National Laboratory, United States 3 Scripps Institute of Oceanography, UCSD, United States 2

Radiocarbon has been used as a tracer of ocean circulation and marine geochemistry since the discovery of carbon-14 dating. 14C has been

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used to study global ocean circulation through the distribution of natural and bomb-derived 14C. Two expeditions, GEOSECS (1970s) and WOCE (1990s) identified spatial gradients in both the surface and deep-water 14C, which define large-scale ocean circulation. The main limitation of these studies is that they provide only a “snap shot” of 14C variability. In order to get a complete picture of the temporal variation of 14C, proxy records, such as those provided by corals are needed. Corals can provide time series of seasonal and interannual 14C variations of the surface ocean over time scales of hundreds of years. Bimonthly radiocarbon values have been recovered from corals in the Indonesian Seaway (Makassar Strait) and the outflow to the Indian Ocean (Lombok Strait) in order to better understand seasonal, interannual and decadal variability in the surface water masses that contribute to the Indonesian Throughflow (ITF). Both coral records have a prebomb (30 cm sea level rise in the next century, the equilibrium of the coastline would be restored only by means of a higher fluvial supply (after the elimination of two dams), as well as the inversion of the subsidence over more than 400 km2 (CO2 and Methane injections). 1070 A millennial scale palyno-succession, its implication in climatic and sea level variability since 26 ka from Bay of Bengal, India Farooqui1, D Reddy1, Venkateshwara M Rao2 1

India National Institute of Oceanography, India

2

High-resolution palynological investigation was carried out in a 5.4 m deep gravity Core (SK-187-GC-18; Off Nizamapatnam, Bay of Bengal) retrieved from about 1500 m water depth. The study was supported by two Radiocarbon dates obtained between 5.3-5.4 m (26,430 ±720 yrs. BP) and 2.1 to 2.2m depth (4136 ± 120 yrs. BP). The net rate of sedimentation calculated with these dates reveal slow rate of sedimentation prior to latter part of Middle Holocene which increased 3–4 times since then. The small volume and restricted communication of the Bay of Bengal with the open ocean, moreso, represents excellent monitoring sites for even the smallest climate perturbations in the area. The objective of the study was on ecological perspective and therefore, the successional comparative account of high or low percentage of the terrestrial and marine forms were evaluated that provide an understanding of the external forces such as climate and relative sea level fluctuations along the south-east coast of India. The area of study is presently more influenced by North-east monsoons. Based on the rhythmic cyclicity in percentage of allochthonous and autochthonous organic debris major 5 phases of relative sea level highstands and 5 phases of lowstands were demarcated since 26, 430±720 yrs. BP. While the highstands prior to Middle Holocene are of higher magnitude intercepted by longer duration of lowstand, it is of low magnitude intercepted by shorter duration of Lowstand after 4136±120 yrs. BP. However, small highstand and lowstand peaks show rhythmic cyclicity of events during the major 5 lowstand events recorded. Results suggest that during the glacial period, the winter monsoon played a major role in the flux of sediment off shore. The forest cover with arboreals was low except for few Rhizophoraceae pollen recorded during highstand of highest magnitude sometime around 11 to 12 ka. The abundance of Botryococcus and Chrozophora, a herb, that grows during or after the winter hydroperiods indicate the dominance of North-east Monsoon during the ice age. Longer duration and high peaks of allochthonous plant matter from land indicate three prolonged winter monsoon periods of high intensity with intermittent low intensity monsoon periods exhibiting a cyclicity in series of fluctuation. The study establishes the temporal relationship between records from land and those from the sea by offering insight into the contemporary land-climate conditions, its intensity, nature, timing and magnitude since the LGM.

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0849 Two mid-Pleistocene glacial cycles (MIS 14 to 10) from lacustrine sediments in the Valles Caldera, northern New Mexico Peter J Fawcett1, Jeff Heikoop2, Scott Anderson3, Linda Hurley1, Fraser Goff1, Catrina Johnson1, John W Geissman1, Craig D Allen4 1

University of New Mexico, United States Los Alamos National Laboratory, United States 3 Northern Arizona University, United States 4 US Geological Survery, United States 2

A long-lived middle Pleistocene lake formed in the Valle Grande, a large moat valley of the Valles Caldera in northern New Mexico, when a post-caldera eruption (South Mountain rhyolite) dammed the drainage out of the caldera. The deposits of this lake were cored in May 2004 (GLAD5 project, hole VC-3) and 81 m of mostly lacustrine silty mud was recovered. A tentative chronology has been established for VC-3 with a basal tephra Ar-Ar date of 552±3 kyr, a correlation of glacial terminations V and VI in the core with other long Pleistocene records (SPECMAP) and the recognition of two geomagnetic field polarity events in the core (14D and 11D) which can be correlated with globally recognized events. This record spans a critical interval of the middle Pleistocene from MIS 14 (552 kyr B.P.) to MIS 10 (~350 kyr B.P.), at which time the lacustrine sediments filled the available accommodation space in the caldera moat. Multiple analyses including core sedimentology and stratigraphy, sediment density and rock magnetic properties, organic carbon content and carbon isotopic ratios, C/ N ratios, and pollen content reveal two glacial/interglacial cycles in the core (MIS 14 to MIS 10). Glacial terminations V and VI and complete sections spanning interglacials MIS 13 and MIS 11 are captured at a high resolution. In the VC-3 record, both of these interglacials are relatively long compared with the intervening glacials (MIS 14 and MIS 12), and interglacial MIS 13 is significantly muted in amplitude compared with MIS 11. These features are similar to several other midPleistocene records. Of particular interest is relatively large amplitude hydrologic variability evident in the interglacial MIS 11 section. Here, prominent wet-dry cycles with a ~11 ka duration are shown by correlative changes in sedimentology (laminated vs. mudcracked horizons) and in lake productivity (organic carbon, biogenic silica). We hypothesize that this variability arises from a split-precessional cycle that modulates the strength of the southwest North American summer monsoon and hence summer rainfall amounts during this extended interglacial period. Similar periodicities are not found during the glacial periods, as the lake moisture source is dominated by westerly frontal systems and a southerly deflected polar jet stream. 0383 Ancient dunes and paleosols of the Sahel and Sahara in East Niger as archives of Pleistocene and Holocene climate changes in NW Africa Peter Felix-Henningsen Institute of Soil Science and Soil Conservation, Germany

Fossil and relict paleosols found in extremely arid to semiarid climatic regions of the Sahara desert can provide evidence of past humid climatic periods. These soils developed in eolian sands and can be used to indicate the age and distribution of ancient dunes formed during dry climatic phases that occurred prior to humid periods. Two generations of ancient dunes were found with paleosols along a SW-NE traverse covering 20 study sites from the southern Sahel of East Niger to the

Ténéré desert and Tchigai mountainous region, and up to the southern border of Libya. They are overlain by recent, active eolian sand sheets and dunes. OSL dating revealed that the accumulation of Upper Pleistocene ancient dunes, mainly found in the Sahel and Sahara of East Niger, began at 29.3 BP and ended at 9.5 BP. Paleosols on these dunes display red-brown to yellow-brown Bw horizons and are more than 200 cm thick in the Sahel and about 100 cm (or less) in the Sahara. Therefore they are classified as Luvic Arenosols (Sahel) and Cambic Arenosols (Sahara), respectively. The structure of the soil horizons is stabilized by pedogenic cementation and shows frequent effects of bioturbation. The migration of moderately soluble constituents, such as silica or carbonates, suggests that the high humidity of the climate during the period of soil formation caused leaching of soils, interflow and formation of groundwater and paleo-lakes. Near the shores of extended paleo-lakes, the terrestrial paleosols changed into Gleyic Arenosols. The former shore lines are frequently marked by seams of goethite rhizoconcretions (“bog iron ores”). Within the paleolake depressions, bleached ancient dune sediments caused by gleying are covered by siltrich lacustrine sediments. A second dune generation of lesser extent, and mainly preserved in the wind shadow positions of escarpments and inselbergs, developed under arid conditions with an end in sedimentation between 4.5 and 3.5 BP. The data indicate a further humid period at ~ 4 ka, whereas most African proxies show a virtually abrupt change to modern dry climate conditions as early as ~4 ka. During this humid period, weak Cambisols also developed on the younger dune generation. Artifacts from the Upper Neolithic on the lacustrine sediments indicate that the paleo-lakes did not reach their fullest original extent during the mid-Holocene period. 1033 TIMS dating of very young carbonates (0 –500 years) Yue-Xing Feng1, Jian-Xin Zhao1, Ke-Fu Yu2 1

Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Qld 4072, Australia, Australia 2 Centre for Microscopy and Microanalysis, University of Queensland, Australia

Recent development in multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) has greatly enhanced sample throughput for U-series dating and U-series age precisions for samples of >200 ka old due to its ability to correct for mass bias on Th isotopic measurements. However, comparing with MC-ICP-MS, the traditional thermal ionization mass spectrometry (TIMS) still has some advantage, in our opinion, in dating carbonate samples of very young ages, due to its very low background noise on the ion detector, the absence of carry-over blanks, practically higher abundance sensitivity (as a result of better vacuum), excellent linearity for small ion currents, increased Th ionization efficiency with small sample loads on filaments, which are particularly advantageous for measuring extremely small 230Th signals in young samples. Our long-term monitoring of baselines at half-mass-unit next to 229Th, 230Th, 234U shows they are below 0.2 cps on the Daly detector, identical to the electronic dark noise of the 14-year old Sector 54 machine. Our graphite loading blank is also negligible, with the on-peak signals for mass 229, 230, 233, 234, 235 and 236 being identical to the dark noise (i.e. no additional signals above the dark noise) after the pre-degassed filament was conditioned at 5.0 A in the TIMS for 5 –10 minutes. The only detectable signals include ~60 cps 232Th and ~2 cps 238U probably from the graphite. The same test was also applied to degassed zone-refined rhenium filament ribbons, which show no signals at all across the Th-U mass range. Our U-Th procedural blanks were also routinely monitored. 238U and 232Th


blanks are both less than 5 x 10 −12 g, whereas 230Th blank is ~3.3 × 10 −17 g, which contributes only ~4 weeks (~0.07 year) to the calculated 230Th ages for samples with 3 ppm U (e.g. corals). Because of such excellent conditions, we are capable of routinely dating young corals of 3000 kilometres from Australia’s primary dust source regions and lying within the dominant southeast dust plume pathway, New Zealand is ideally located to examine dust emissions from central and eastern Australia in response to environmental variability.

In this study we present a ~7000 year record of Australian dust deposition in New Zealand extracted from an alpine ombrotrophic peat bog. The Australian origin of dust deposited through the core is established using a trace-element provenance model that allows the source to be determined on a catchmentgeologic scale. For the majority of the record Lake Eyre in central Australia was the predominant source of dust reaching New Zealand except during the early to mid Holocene (7–5000 BP) when dust was sourced from other regions in Australia. At this time sediment records from Lake Eyre indicate that it was in a prolonged lacustral phase, implying that it was too wet to act as a dust source. Following drying and the commencement of modern playa conditions around 4000 BP Australian dust flux in the core increased 4 fold, while the provenance model indicated that Lake Eyre was the main source of this dust. Increased dust flux after 5000 BP is also coincident with a number of global proxies that suggest ENSO type conditions commenced at this time. Similarly, a second increase in dust flux at 2500 BP occurs in conjunction with other records which suggest ENSO variability reached a maximum at this time. These results attest to the sensitivity of dust as a palaeoclimate proxy. Importantly, it appears to be a particularly useful measure of ENSO type climate variability in the region because of the close association between ENSO and the hydro-meteorology of the Lake Eyre Basin – Australia’s largest and most active dust source. 0701 Constraining ice sheet dynamics in North West Scotland using cosmogenic nuclide analysis Hannah E Mathers1, Tom Bradwell1, Derek Fabel2, Martyn S Stoker1 1

British Geological Survey, United Kingdom University of Glasgow, United Kingdom

2

We present work forming part of a larger palaeoglaciological project in Scotland. This research has been developed to critically assess the previous evidence constraining the dimensions and dynamics of the last British Ice Sheet in NW Scotland. Specifically this project will address: evidence for ice-sheet limits (both vertical and horizontal); the validity

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of palaeo-nunataks; reconstruction of former ice-flow dynamics; and chronological constraints on ice-sheet retreat. Previous work has identified the signature of a palaeo-ice stream in The Minch draining ~15,000 km2 of NW Scotland. This has key implications for former ice-sheet surface altitude and ice-divide migration. This new reconstruction indicates a dynamic western ice sheet margin, confirmed by multibeam bathymetric data from around the Summer Isles. In combination with high-resolution NEXTMap surface models onshore we have mapped, in detail, the recession of the ice sheet back to the fjords of NW Scotland. Recent 10Be cosmogenic data constrains the retreat chronology of this sector of the British Ice Sheet. Dynamic oscillations immediately after the North Atlantic iceberg-discharge event (Heinrich 1) occurred c. 16– 17 ka BP. New cosmogenic exposure ages suggest that ice-sheet retreat occurred rapidly in this region, probably in response to sea level rise associated with Northern hemisphere meltwater pulses. 0118 From the Pleistocene incision of a palaeo-valley until the Holocene formation of sandbanks: the Quaternary evolution of a shelf with low accommodation potential (Belgian Continental Shelf, southern North Sea) Mieke Mathys1, Cecile Baeteman2, Marc De Batist1 1

Renard Centre of Marine Geology, Ghent University, Belgium Belgian Geological Survey, Belgium

2

With respect to the Quaternary deposits, the Belgian Continental Shelf (BCS) was one of the last unmapped and unknown areas of Belgium. Because of the absence of a distinct shelf break and the virtually complete lack of subsidence, the BCS has very little accumulation space to accommodate and preserve Quaternary sediments. The Quaternary on the BCS is very patchy and discontinuous, and has a maximum thickness of only 45 m. From this fragmented record it was very difficult to produce a coherent reconstruction of the Quaternary evolution, in times when only analogue data were available. At present, > 16.000 km of analogue high-resolution seismic profiles have been scanned, converted into digital ‘segy’ format, and integrated with almost 500 core descriptions, enabling us to develop a genetic model for the Quaternary evolution of the BCS. The seismic data show seven seismicstratigraphic units, in agreement with previous studies on one of the sandbanks of the BCS. Two basal units fill in the deepest parts of a large incised valley (the Ostend Valley), and have possibly been deposited in an estuarine or fluvial environment. The third and fourth unit, separated by an erosional surface, completely fill up the incised valley, and even extend beyond it. They are assumed to have been deposited in an estuarine and tidal flat setting, respectively. The fifth and sixth unit are interpreted as nearshore and coastal sandbank deposits, and the seventh unit represents recent tidal sandbank and swale deposits. Thanks to the integration of all the available sedimentological core data with the seismic stratigraphy, it became evident that this 7-unit seismic-stratigraphic sub-division of the Quaternary cover has indeed a regional validity. Based on seismic-stratigraphic evidence, it is assumed that for instance unit three and four were initially deposited across a large area of the BCS and were subsequently affected by erosion and the formation of sandbanks. Probably, the formation and infill of the Ostend Valley is the result of a combination of erosive phases during successive glacial sea-level lowstands, and tidal scouring and infilling during the last interglacial highstand and early Holocene. The younger units are deposited in a straightforward vertical facies succession reflecting an overall transgressive context: first a tidal environment was established, followed by the formation of coastal, wave-dominated sandbanks, after which offshore tidal sandbanks

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formed under the current macro-tidal regime, and the continuing –but slowing- rise of the sea level. 0609 Different directions and rates between the long-term (geological) and the short-term (geodetical) vertical deformation in the northeastern Japan arc Tabito Matsu’ura1, Akira Furusawa2, Hidetaka Saomoto2 1

Active Fault Researh Center, AIST, Japan Japan

2

Crustal uplift rates of the central part of the northeastern (NE) Japan forearc are estimated using Late Quaternary terrace surfaces. The ages of terrace surfaces are correlated to marine isotope stages (MIS) by tephrochronology and 14C dating. Along the Pacific coast, uplift rate determined from a MIS 5.5 marine terrace surface is estimated to be 0.13–0.16 m/ky. At Isawa upland, inland of NE Japan, the latest and older fill terrace surfaces were correlated to MIS 2/1 and MIS 6/5, respectively. The incision rate, estimated as 0.16 m/ky from the relative heights of the fill terrace surfaces, agrees roughly with the uplift rate along the Pacific coast. In contrast, geodetic surveys (leveling surveys) and GPS observations show that subsidence along coastal area and at Isawa upland reaches to −1 mm/yr and −5.5 mm/yr respectively. This short-term subsidence is different direction of the long-term uplift. Furthermore, the short-term subsidence is nearly one order of magnitude larger than the long-term uplift at Isawa upland. Thus forearc subsidence can not be extrapolated to long-term tectonic movements. We interpret short-term geodetic subsidence as elastic deformation of the forearc crust caused by interplate coupling between the Pacific and the Eurasian plates. 1054 Modern owl pellet and small carnivore scat collections as analogues for the interpretation of fossil micromammal assemblages along the southern coast of South Africa Thallassa Matthews1, Curtis W Marean2, David L Roberts3, Erich Fisher4, Jocelyn Bernatchez2 1

Iziko South African Museum, South Africa Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, United States 3 Council for Geoscience, South Africa 4 University of Florida, United States 2

Regurgitated owl pellets and small carnivores scats are frequently deposited in, or between, the depositional layers of paleontological and archaeological sites. The pellets and scats disaggregate over time leaving pockets of micromammals within the fossil and/or artefact-bearing horizons. These micromammal accumulations frequently prove extremely useful for paleoenvironmental research as micromammals have small home ranges, do not migrate, and many species can provide detailed information about the vegetation and/or substrate of the area in which they live. Ascertaining the predator/s responsible for a fossil micromammal accumulation is essential if the assemblage is to be used for paleoenvironmental research as different accumulators have varying predation ranges and prey preferences that impact species abundance. Under the auspices of the SACP4 (South African Coast Paleoclimate, Paleoenvironment, Paleoecology, Paleoanthropology) project centred on Pinnacle Point at Mossel Bay, modern comparative owl pellet and small carnivore scat assemblages are being collected from a number of public and private nature reserves along the south

coast of the Cape Province, South Africa. A diversity of ecological settings are represented, defined in large measure by geological and climatic factors. The species representation of micromammals in owl pellet and small carnivore scat assemblages are compared to a variety of ecological settings through the use of remote sensing imagery, ground truthing, and GIS-based analysis. This material will provide taxonomic, taphonomic and environmental analogues for the interpretation of fossil micromammal collections. This will facilitate the interpretation of the various fossil micromammal assemblages from the Pinnacle Point caves, some of which have been accumulated by owls and small carnivores. 1171 Long-term forest-savanna dynamics in the Bolivian Amazon: implications for conservation Francis E Mayle1, Robert P Langstroth2, Rosie Fisher3, Patrick Meir1 1

University of Edinburgh, United Kingdom URS Dames & Moore de Mexico, Mexico 3 University of Sheffield, United Kingdom 2

The aim of this presentation is to evaluate the respective roles of past changes in climate, geomorphology, and human activities in shaping the present-day forest-savanna mosaic of the Bolivian Amazon, and consider how this palaeoecological perspective may help inform conservation strategies for the future. To this end, we review a suite of palaeoecological and archaeological data from two distinct forestsavanna environments in lowland Bolivia: Noel Kempff Mercado National Park (NKMNP) on the Precambrian Shield and the ‘Llanos de Moxos’ in the Beni basin. We show that they contain markedly contrasting legacies of past climatic, geomorphic, and anthropogenic influences between the last glacial period and the Spanish Conquest. In NKMNP, increasing precipitation caused evergreen rainforest expansion, at the expense of semi-deciduous dry forest and savannas, over the last three millennia. In contrast, pre-Hispanic indigenous cultures were instrumental in facilitating recent forest expansion in the Llanos de Moxos by building a vast network of earthworks. Insights from mid-Holocene palaeodata, together with ecological observations and modelling studies, suggest that there will be progressive replacement of rainforest by dry forest and savanna in NKMNP over the 21st century in response to the increased drought predicted by General Circulation Models. Protection of latitudinal landscape corridors may be needed to facilitate these future species reassortments. However, devising appropriate conservation strategies for the Llanos de Moxos will be more difficult due to its complex legacy of palaeoindian impact. Without fully understanding the degree, to which its current biota has been influenced by past native cultures, the type and intensity of human land-use appropriate for this landscape in the future will be difficult to ascertain.


0643 Late Glacial and Holocene hydrological and west wind variability in southeastern Patagonia inferred from multiple proxies of Laguna Potrok Aike Christoph C Mayr1, Andreas Luecke2, Torsten Haberzettl3, Michael Wille4, Nora I Maidana5, Christian Ohlendorf6, Frank Schaebitz4, Bernd Zolitschka6 1

GeoBio-Center, University of Munich, Germany ICG V: Sedimentary Systems, Research Center Juelich, Germany 3 Geoscience Center, University of Goettingen, Germany 4 Seminar for Geography and its Didactics, University of Cologne, Germany 5 Depto. Biodiversidad y Biología Experimental, Universidad Nacional de Buenos Aires, Argentina 6 GEOPOLAR, Institute of Geography, University of Bremen, Germany 2

The sediment record of the maar Laguna Potrok Aike (52°S, 70°W) provides a unique continuous archive of Quaternary climate variability. Parameters investigated on a sediment core from the 100 m deep lake center reflect the environmental changes during the last 16,000 years. Bulk sedimentary organic matter has been characterized with different geochemical methods (stable isotopes, Rock Eval, C/N ratios). These data suggest that gradual (millennial-scale) as well as rapid (centennial to decadal-scale) fluctuations occurred with respect to both the contributions from different organic matter sources to the sediment and the lacustrine primary productivity. A prominent and rapid shift in most of these parameters (e.g. bulk nitrogen stable isotopes, oxygen isotopes of endogenic calcites, C/N ratios, bulk organic carbon isotopes) occurred around 8700 cal BP coinciding with an increase in sedimentation rate. Ratios of long-distance transported forest pollen to local steppe pollen as well as pollen flux imply that an increase in strength or frequency of westerly winds might have been the reason for a climatic shift at that time. Increased west wind intensity was accompanied by a severe drought as indicated by oxygen isotope records of endogenic carbonates and dated subaquatic lake level terraces. In contrast, radiocarbon dates of exposed lacustrine sediments and oxygen isotope ratios characterize the second half of the last millennium as an extraordinary moist period. Anomalous climate episodes inferred from the Laguna Potrok Aike record are suggested to be linked to changes in atmospheric circulation patterns such as latitudinal shifts of the Southern Hemispheric Westerlies and to changes in the extension of the Antarctic sea ice. 0522 Iroquoian farmers, wild geese, herb charcoal and the Little Ice Age: a sediment record at Crawford Lake, Ontario John H McAndrews1, Charles L Turton2 1

University of Toronto, Royal Ontario Museum, Canada

Palynological analyses record two farming intervals and forest succession due to prehistoric climate change and historic human impact. Throughout the second millennium CE the now meromictic lake deposited varves. Before 1300, the varves were bioturbated by detritovores such as ostracodes but since then well-preserved varves indicate that the onset of meromixis excluded detritovores. The Iroquoian Zone, AMS dated to 1268-1500, contains DNA-determined dung pellets of wild Canada geese. Concentrated in the pellets are cultigen pollen -maize (Zea), sunflower (Helianthus) and squash (Cucurbita) and weed pollen -- grass (Poaceae), purslane (Portulaca) and nightshade (Solanum) (McAndrews and Turton 2007 Palynology 31). Charcoal of herbs is also abundant in the dung pellets. We believe that in the autumn,

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migrating geese accidentally ingested pollen and charcoal while feeding on burned Iroquoian fields and then roosted on the lake where they cast dung pellets. Some pellets dissolved to provide nutrients for the eutrophication recorded by fossil diatoms and rotifers (Ekdahl et al., 2004 Geology 32:745–748. Turton and McAndrews 2006 Rev Palaeobot Palynol 141:1–6). Eutrophication led to meromixis that has since persisted. Archaeological investigations around the lake record Iroquoian-farming villages that about 1500 migrated to lower elevations by Lake Ontario, probably in response to climatic cooling. Transfer functions applied to tree pollen, assuming a pollen lag of 50 to 100 years, indicate a cool climate beech-maple forest preceded Iroquoian farming. Subsequently during a time of oak (Quercus) ascendancy in a warmer climate, Iroquoian farming flourished. A cooling of the climate signalled by the decline of oak and expansion of white pine (Pinus strobus) coincides with the Little Ice Age. The Iroquoians response was to move to lower elevations with a longer growing season. A second interval of human impact, the Canadian Zone, began in the early 19th century. Palynological analysis features maize together with weedy grass, sheep sorrel (Rumex acetocella) and ragweed (Ambrosia). Chimney-generated charcoal is abundant. Pine pollen declines to be replaced with birch (Betula) and elm (Ulmus), which flourished after logging. Since 1960, elm declined due to disease. There is a pulse of diatoms and rotifers but because goose dung pellets are absent, the eutrophying nutrients were likely delivered in the ground water from a local farmyard. 1413 Coral reefs: the silent sentinels of global change Malcolm T McCulloch Research School of Earth Sciences, The Australian National University, Canberra, ACT, 0200, Australia

Coral reefs are subject to the threats from global climate change as well as local degradation of their marine environment from land-based pollution, both of which are now occurring at unprecedented rates. Locally, landuse changes in river catchments, wetlands and estuaries is leading to increased supplies of sediment and nutrients to many inshore coral reefs. In some cases this, together with pressures from other activities such as trawling and overfishing, is resulting in an evolutionary trajectory that may ultimately result in an abrupt phase shift from a coral to a macro-algae dominated ecosystem. On global scales, increased frequency of unusually warm events is also causing mass coral bleaching, such as occurred in 1998 and 2002. Rising levels of atmospheric carbon dioxide from fossil fuel burning is also increasing ocean acidity, which may ultimately result in reduction of coral calcification due to the decreasing carbonate saturation state of seawater.

In the absence of mankind’s footprint, there is however good evidence that warmer periods, such as those that occurred during the Last Interglacial period, can in fact lead to more prolific coral growth, especially in high latitude reefs. However these periods were characterised by higher sea levels but also importantly, levels of pCO2 that were lower than today, and substantially lower than those predicted for the future. Nevertheless, such observations clearly demonstrate that an understanding of the processes that are driving environmental changes at local as well as at global scales is essential, if coral reefs as we know them today are to have a sustainability future. Here, we examine geochemical archives preserved in fossil as well as modern long-lived massive corals, to help decipher the complex

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interaction between local anthropogenic impacts and global climate change. 0794 Climatic inferences from glacial and palaeoecological evidence for the Last Glaciation and early Holocene in southern South America Robert D McCulloch, Chris J Fogwill School of GeoSciences, The University of Edinburgh, United Kingdom

A synthesis of glacial and vegetation records from Fuego-Patagonia tells of climatic changes, in particular latitudinal shifts in the focus of the southern westerlies, that affected sub-Antarctic regions from the Last Glacial Maximum (LGM) and through the Late-glacial / Holocene transition. Here we present a revised chronology based on 14C assays, cosmogenic isotope analyses and tephrochronology. The LGM is marked by multiple advances that culminated at 25,100-23,100 cal BP. This pattern of an early LGM is found elsewhere is southern South America. A less extensive glacier advance culminated before c. 17,700 cal BP along the southern Andes and was followed by rapid and widespread glacier retreat and the southward migration of the westerlies. However, the Fuego-Patagonian glaciers persisted and advanced between 15,500 and 11,770 cal BP coinciding with the Antarctic Cold Reversal and nourished by an increase in precipitation. The early Holocene (c. 11,300–9500 cal BP) is dominated by an extreme arid phase in Patagonia. This phase coincides with the absence of the George VI ice shelf on the Antarctic Peninsula and may suggest that the southward migration of the westerlies ‘overshot’ South America and moved into the Drake Passage leading to a rise in sea surface temperatures along the Antarctic Peninsula. The return of more humid conditions in the Magellan region at c. 8000 cal BP and the reforming of the George VI ice shelf suggest the return of the westerlies to their present day location. 1037 Late Holocene summer warming in the Southern Hemisphere: terrestrial temperature records from the subantarctic islands of New Zealand Matt S McGlone1, Janet M Wilmshurst1, Chris S M Turney2 1

Landcare Research, New Zealand University of Wollongong, Australia

2

The subantarctic islands of New Zealand lie within the stormy Southern Ocean and experience an intensely oceanic, cool, cloudy windy climate. Their vegetation ranges with altitude from low forest through scrub and grassland to tundra-clad tops. They are of volcanic origin, mountainous and nearly completely covered with deep peaty soils. These soils have yielded long, well dated pollen records of late-glacial and Holocene vegetation change extending back to 18,000 cal BP. We have established transects of peat cores extending from near sea level to the tundra zone crossing the regional tree line on Auckland (50°S) and Campbell (53°S) Islands. Tundra, grassland and low scrub prevailed until 9000 cal BP when forest and scrub similar to that of the present developed and continued to increase in density and altitudinal range until 1000–2000 cal BP. Reliable records of summer temperatures have been developed through quantification of these pollen profiles via transfer function and modern analogue techniques. Lowland subantarctic island summer temperatures initially track ice core and marine temperature reconstructions, including features such as the

Antarctic Cool Reversal, moderate warming across the Younger Dryas chronozone, pronounced warming at the beginning of the Holocene and an early temperature maximum between 12,000 and 11,000 cal BP. However, the subantarctic island records then diverge, as the early temperature maximum is followed by a cooling between 11,000 and 9000 cal BP, and then a steady warming to reach present temperatures by 6000 cal BP. This pattern is not obvious in the Antarctic ice core or marine records. High altitude sites at tree line show summer warming continuing until at least 2000 cal BP. Our results strongly suggest that seasonality of temperature has played a major role in high latitude southern terrestrial records. We propose that summer temperatures lagged winter warming and thus the late-glacial and early Holocene were times of extremely oceanic conditions in the south and warm winter oceans. From 9000 cal BP onwards, warming summers and cooling winters resulted in increasingly seasonal climates, although the net effect was towards declining mean annual temperatures from 6000 cal BP onwards. Our results suggest that marine temperature reconstructions are biased towards the winter half year whereas high latitude and high altitude terrestrial vegetation records are biased towards the summer months. The timing of the Holocene increase in summer warmth is consistent with direct solar forcing. 0567 Mid-Holocene aridity in southeastern Queensland, Australia: evidence for an ENSO driven super drought? Hamish A McGowan1, Lynda M Petherick2, Patrick T Moss2 1

School of Geography, Planning and Architecture, The University of Queensland, Brisbane., Australia 2 University of Queensland, Australia

In February 2004, a 4 m core spanning the last ~ 40 ka was retrieved from Native Companion Lagoon (NCL), southeast Queensland, Australia using a Russian D-section corer. Analysis of the top 1 m of the core, which represents the Holocene, identified a pronounced increase in aeolian sedimentation commencing at ~5700 cal BP with peaks in the deposition of wind transported sediment of 12.5 g m−2a at 4690 cal BP and 10.8 g m−2a at 3890 cal BP before decreasing to 0.3 g m−2a at ~2000 cal BP. The increase in aeolian sedimentation ~5700 cal BP was coincident with a pronounced increase in charcoal content of the core, thereby indicating that fire was most likely a key agent in the destabilisation of the local dunes. Geochemical provenance of the long traveled dust component of the record identified western Queensland and southwestern New South Wales as the dominant source areas. Analysis of pollens from the core indicate a reduction in aquatics similar to that reported by Donders et al. (2006) for Lake Allom, Fraser Island, while there was also a reduction in rainforest and pteridophytes. As a result, we believe that this period of increased aeolian sedimentation was caused by prolonged and severe drought possibly linked to the onset of ENSO type conditions in the mid-Holocene as reported by Moy et al. (2002) and Gagan et al. (2004). Through analogy with contemporary ENSO events, precipitation bearing southeasterly trade winds would have been suppressed and replaced by more frequent and dry west to southwesterly winds as indicated by the provenance of far traveled dust to west and southwestern source areas. Importantly, the NCL record identifies southeast Queensland as a region susceptible to prolonged and severe drought as a consequence of more persistent ENSO type conditions. Recent modeling studies suggest that ENSO type conditions may transform from their current interannual variability into the mean climate as a consequence of global warming. Our results suggest that if this was to occur, then southeast Queensland may experience the onset of another arid phase.


0557 Coral microatoll records of variability in El Niño-Southern Oscillation during the early to mid-Holocene Helen V McGregor1, Colin Woodroffe2, David Fink3 1

School of Earth and Environmental Sciences, University of Wollongong and the Australian Nuclear Science and Technology Org., Australia 2 School of Earth and Environmental Sciences, University of Wollongong, Australia 3 Australian Nuclear Science and Technology Organisation, Australia

El Niño events in the Pacific, co-varying with the Southern Oscillation in the southern hemisphere, give rise to the El Niño-Southern Oscillation (ENSO) phenomenon. This quasi-cyclic variation has farreaching effects on climate in the Pacific region, and it has become increasingly clear that it is highly correlated with climate in the Australian region, influencing flood and drought conditions. Christmas Island, Kiribati in the central Pacific is ideally placed to record occurrence and intensity of ENSO because it experiences pronounced El Niño-related SST anomalies, indeed El Niño was first recognised by Bjerknes based on precipitation records from Canton in Kiribati. Palaeoclimatic proxies provide an essential tool to extend the historical instrumental record to sufficient length to indicate long-term variability in phenomena such as ENSO and to detect trends and interpret causes. Coral palaeoclimatology, particularly reconstruction of former sea-surface temperature (SST) using oxygen isotope analysis (d18O), is one of the most important sources of longer-term tropical climate data. Christmas Island lies within the dry equatorial zone of the central Pacific (157˚30'W, 2˚00'N); it is a particularly dry and desolate atoll (average annual precipitation 936mm), but lies on a steep precipitation gradient, and receives heavy rainfall during El Niño events (eg 3686 mm during 1997 El Niño). This makes it uniquely sensitive to El Niño. d18O variations in corals track SST and rainfall which are both closely related to El Niño, and correlation with the NINO3 Index is strong (the NINO3 Index is an index of SST anomalies for 90˚W–150˚W, 5˚S–5˚N, used to define El Niño events in the instrumental records). Preliminary d18O analyses of fossil microatolls from Christmas Island indicate that El Niño was less intense around 3000 BP but more intense around 1700 BP. In this study we extend our analysis of El Niño events as recorded at Christmas Island using a series of AMS 14C dated fossil microatolls, with individual microatolls clustered in age around 1600 to 1900 BP, 3300 to 3700 BP, and one dated to 4000 BP. 0979 Rapid 20th-century increase in coastal upwelling off northwest Africa Helen V McGregor1, Mihai Dima2, Helmut W Fischer3, Stefan Mulitza4 1

School of Earth and Environmental Sciences, University of Wollongong & the Australian Nuclear Science & Technology Organisation, Australia 2 Faculty of Physics, University of Bucharest, Romania 3 Institute of Environmental Physics, University of Bremen, Germany 4 DFG Research Center Ocean Margins, University of Bremen, Germany

Coastal upwelling areas are important for biological productivity and are of economic significance due to the large commercial fisheries in these regions. There is some evidence that upwelling is being impacted by increases in greenhouse gases through changes in land-sea temperature gradients increasing the strength of upwelling-favourable, alongshore winds. However, with most evidence based on short instrumental

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records and very few long, high-resolution records from upwelling regions it is difficult to assess the extent of this trend, and the likely impact of further increases in atmospheric CO2. This study investigates upwelling variability off the Moroccan coast, in the heart of the Cape Ghir upwelling system, using the alkenone sea surface temperature (SST) proxy, measured in samples from near-decadal resolution sediment cores spanning from 2500 BP through to the 1990s. The most recent part of the two alkenone records overlap with the instrumental period for the last 100 years, and shows a steady cooling trend of approximately 1.2°C over this time. This result is consistent with windspeed observations for the latter part of the 20th century that show pronounced upwelling intensification in the Canary Current region. The last 100 years of the GeoB6008 alkenone records, when viewed in the context of the gravity core record for the last 2.5 millennia, shows that the strong decrease in SST observed for the last century is larger and more rapid than any other change seen in the entire record. In addition, the alkenone SST records are anti-phased compared to Northern Hemisphere temperature reconstructions for the last 2000 years and show a relatively warm Little Ice Age and cool Medieval Warm Period. We hypotheses that hemispheric-scale temperature variations could manifest as a greater change in land surface air temperature (SAT) compared to SATs over the ocean, affecting land-sea pressure gradients, alongshore winds and therefore upwelling. Together, these results suggest that coastal upwelling varies with NHTs, and upwelling off northwest Africa may continue to intensify as global warming and atmospheric CO2 levels increase. 0949 Species-area curves & morphoclimate models as tools in forecasting effects of climate change on vertebrate communities Jenny L McGuire, Anthony D Barnosky, Marc A Carrasco University of California at Berkeley, United States

Anthropogenically induced global climate change, habitat fragmentation and species introductions all have many potentially significant impacts on ecosystems. However, we currently lack robust models and metrics that enable us to identify critical climatic effects on the mammalian component of ecosystems, which in turn limits forecasting the ecological effects of climate change. As a first step, it is critical to know if currently observed changes in mammalian biodiversity, species ranges and species compositions are normal oscillations or anomalous events. It is also critical to know the details of how climatic parameters affect the involved species. To address the first challenge, we first take a macroecological approach and build species-area curves for selected time slices, using data from the MIOMAP and FAUNMAP databases. We use those curves to determine whether extant biodiversity is within normal past ranges and examine trends in past species richness. To better understand the relationship between climate and species distributions—which ultimately underlie any climatically-induced changes to biodiversity—we then focus on an ecologically important small mammal in California ecosystems, the California vole, Microtus californicus. We develop what we term a morphoclimate model, which maps intraspecific morphological variation onto climate across space through time, while accounting for previously unaddressed cofactors including interspecific interactions and dispersal barriers. This approach integrates data from geometric morphometrics obtained from modern and fossil specimens with climate and paleoclimate models. Finally, through the combined use of species area-curves and morphoclimate models, we explore the ecological and evolutionary implications of climate change in explaining observed deviations

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from the “natural” baseline of mammalian biodiversity as it has fluctuated through thousands and millions of years. 1011 Late Quaternary erosion in lowland and mid-altitude Tasmania in relation to climate change and first human arrival Peter D McIntosh1, David M Price2, Rolan Eberhard3, Adrian Slee4 1

Forest Practices Authority, Australia University of Wollongong, Australia 3 Department of Primary Industries and Water, Australia 4 University of Tasmania, Australia 2

Although erosion at many Tasmanian lowland and mid-altitude sites has been previously documented and dated, establishing a chronology of landscape stability and instability and assigning causes to erosion has been complicated by the small number of ages obtained, errors in dating methods, and the difficulty of distinguishing between climatic and anthropogenic processes. In this paper we critically assess previous Tasmanian studies, calibrate published 14C ages considered to be dependable, present new 14C and thermoluminescence (TL) ages for 18 sites around Tasmania, and consider the evidence for the hypotheses that erosion processes at low and mid altitudes have been: (1) purely climatically controlled; and (2) influenced both by climatic and anthropogenic (increased fire frequency) effects. Of the 58 ages obtained for erosion accumulations (comprising dunes, colluvium, alluvium and loess-like aeolian deposits) only three fall in the period 45–100 ka. Plots of all finite ages (calibrated for 14C and ‘as measured’ for TL and optically stimulated luminescence (OSL)) indicate a slight increase in erosion between 45 and 35 ka and a sustained increase of erosion after 35 ka, within the OSL-dated 40–31 ka dry period defined at Lake Mungo (Bowler et al. 2003) and the 14C-dated moist Tullabardine Interstadial defined in Tasmania. Evidence for climatically controlled erosion periods similar to those recorded in loess deposits dating to c. 350 ka in New Zealand has not been found. We consider three possible biases that may have affected the age distribution: the limitations of 14C dating, sampling bias, and preservation bias. We suggest there may have been a tendency towards the sampling of more recent dune strata, but that 14C dating and preservation biases are unlikely to have affected the age distribution obtained. The absence of widespread erosion before 35 ka, the abrupt beginning of erosion around this time, the frequent association of erosion products with charcoal, the arrival of people in Tasmania at 40 ka BP, and the known use of fires by Aborigines to maintain patches of non-climax vegetation suggest that ecosystem disturbance by anthropogenic fires, in a drier climate than that presently prevailing, contributed to erosion in lowland and midaltitude Tasmania. This model of ecosystem disturbance and erosion following human arrival is similar to the ‘alternative’ model proposed by Roberts et al. (2001) to explain megafauna extinction, i.e. ecosystem disruption preceding extinction, with climatic factors also having an influence. 0956 Retreat history of the West Antarctic Ice Sheet since the Last Glacial Maximum from deep-basin and sub-ice shelf sediment cores in the South Western Ross Sea Rob M McKay1, Gavin Dunbar1, Tim Naish2, Peter J Barrett1, Lionel Carter1 1

Antarctic Research Centre, Victoria University of Wellington, New Zealand GNS Science/Antarctic Research Centre, Victoria University of Wellington, New Zealand 2

Three gravity cores from beneath the McMurdo/Ross Ice Shelf and three piston cores from beneath seasonally-open water to the north and west of Ross Island display a characteristic succession of sedimentary facies that document the retreat of the Ross Ice Sheet since the Last Glacial Maximum (LGM). The succession of facies records a transition from sub-glacial to open-marine environments that comprises in ascending stratigraphic order: (1) normally consolidated, clast-rich muddy diamict dominated by clasts derived from the Transantarctic Mountains and interpreted as melt-out from the basal debris layer proximal to a retreating grounding zone; (2) sparsely-fossiliferous (containing reworked diatom frustules) and mud lacking lonestones, interpreted as a sub-ice shelf facies; and (3) diatom-rich mud and diatom-ooze with lonestones indicative of open water conditions with iceberg rafting. We present a chronology based on radiocarbon dates from the acid insoluble organic fraction of post-LGM sediments, which indicates that lift-off of the grounded Ross Ice Sheet in deep basins surrounding Ross Island began at ~10,000 BP. Retreat of the grounding line from the outer Dryglaski Trough (using the chronology of Domack et al., 1999; GSA Bulletin) to Ross Island was rapid and occurred within ~1000 years. By ~8900 BP, there was open water immediately to the north of Ross Island, and the calving line of the Ross Ice Shelf was established in its present position. Our data suggest the position of the calving line has remained relatively constant since then despite ice core evidence for mid- and early Holocene climatic optima 1–2.5 ˚C warmer than present (Steig et al. 1998; Annals of Glaciology). Our revised chronology implies an earlier and more rapid retreat of the Ross Ice Shelf than previously reported, and may correlate with global eustatic sea-level pulses mwp-1A and 1B. 1429 Relative climate stability during marine isotope stage 11 (MIS 11) Jerry F McManus1, Delia W Oppo1, James L Cullen2, Heather Benway1 1

Woods Hole Oceanographic Institution, United States Salem State College, United States

2

We present new evidence from sites in the Atlantic and Pacific ocean in order to assess the relative stability of global and regional climate during Marine Isotope Stage 11 (MIS 11). These sites include ODP Sites 980 (55˚N, 15˚W, 2.2 km) and 983 (60˚N, 24˚W, 2.0 km) in the North Atlantic, ODP Site 925 (4˚N, 43˚W, 3.0 km) in the tropical Atlantic, ODP Site 1238 (8˚N, 84˚W, 1.4 km) in the eastern tropical Pacific, and ODP Site 806 (0˚N, 159˚W, 2.5 km) in the western tropical Pacific. Oxygen isotope ratios in multiple individual planktonic foraminifera display muted variability during the peak warmth of MIS 11. Although it is extremely difficult to date this interval, several lines of reasoning indicate that the warm, stable interval lasted tens of thousand of years. Both benthic and planktonic oxygen isotopes from sites in the Atlantic ocean also indicate a long interval of relative sea level stability at approximately modern levels. We will consider mechanisms that might reconcile these observations with the possibility of 20 meter higher sea levels during MIS 11. These include a greater salinity contrast between the Atlantic and Pacific oceans. This contrast is maintained today by asymmetric atmospheric water vapor transport and by differing salinities in the northern and southern deep waters that combine to fill the deep Pacific. In order to test whether the modern salinity difference was greater during MIS 11, we compare isotope records from sites in the Atlantic and Pacific. The benthic oxygen isotope records from the Atlantic display no measurable difference between MIS 11 and Holocene, while the Pacific records are more variable, but suggest that MIS


11 values are lower by approximately 0.1 per mil. The results are not easily consistent with a 20-meter higher sea level, but they do allow a smaller rise combined with a greater salinity contrast between oceans. 0976 Relationships between Australian dust, phytoplankton growth and CO2 drawdown in the Southern Ocean: present day support for Quaternary correlations Grant McTainsh1, Albert Gabric2, Harry Butler3, Roger Cropp1, Bronte Tilbrook4 1

Australian Rivers Institute, The Griffith School of Environment, Griffith University, Nathan, Queensland, Australia 2 The Griffith School of Environment, Griffith University, Nathan, Queensland, Australia 3 Australian Centre for Sustainable Catchments, Faculty of Sciences, University of Southern Queensland,Toowoomba, Queensland, Australia 4 CSIRO Division of Marine and Atmospheric Research, Hobart, Tasmania, Australia

In High Nutrient – Low Chlorophyll (HNLC) regions such as the Southern Ocean to the south of Australia, mineral dust-borne micronutrients, such as iron (Fe), are thought to limit primary production, control phytoplankton species composition, and potentially transfer carbon to the deep ocean, thus, affecting atmospheric CO2 concentrations. There is good Quaternary evidence from the Antarctica and the Southern Ocean of correlations between glacial (arid) phases, high dust activity, increased phytoplankton and reduced CO2 concentrations, but the present day process support for these Quaternary correlations is more equivocal. The austral spring-summer of 2002–03 was characterised by unusually high dust storm activity in Australia, which presents an opportunity to examine these relationships between dust and Southern Ocean biota. We present a suite of data on: dust activity on the continent (measured and modelled), dust transport offshore (modelled), satellite ocean colour and aerosol optical depth data, suggesting that dust plumes were transported into the Southern Ocean, as far south as 50°S. In addition, contemporaneous data are available on surface ocean chlorophyll from several cruise transects between Hobart and Antarctica that corroborate the satellite ocean colour data. These data sets point to the occurrence of several large-scale natural ocean fertilization events during 2002-03, supporting the results of various artificial perturbation experiments conducted in the equatorial Pacific and Southern Ocean. We conclude that mineral dust from the Australian continent exerts an important influence on the Southern Ocean ecosystem, and together with other continental sources, may provide a key climate feedback loop linking the lithosphere, atmosphere and ocean. 0138 Holocene environmental changes at Groenvlei, Western Cape, South Africa: chronology, sedimentology, molluscan palaeoecology and stable isotope geochemistry Michael E Meadows1, Brian McK Chase2, Kelly Kirsten Sardinha1, Grant Cornish-Bowden1, Caroline Duncan3 1

University of Cape Town, South Africa Oxford University Centre for the Environment, United Kingdom 3 Quaternary Dating Research Unit, South Africa 2

This paper presents results of a palaeoenvironmental reconstruction of Holocene sedimentary accumulations evident in the Wilderness Lakes area of the southern coast of the southwestern Cape. Although the area has been the focus of considerable previous scientific attention in this

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regard through the pioneering work of ARH Martin, recent advances in palaeoecological, sedimentological, geochemical and chronological techniques suggest that further palaeoenvironmental study of area would be potentially valuable, more particularly if several proxies are applied to the sedimentary sequences. The aim of this paper is to present multi-proxy evidence based on the analysis of sediments sampled from Groenvlei, and to apply the evidence to a more robust reconstruction of Holocene palaeoenvironments for the Wilderness Lakes area and beyond. Specific objectives of the study are, in relation to Holocene sediments (i) to report on the results of vibracoring activities at Groenvlei and several of the other Wilderness Lakes; (ii) to establish the chronology of sedimentation using radiocarbon and optically stimulated luminescence methods; (iii) to describe the sediment physical characteristics; (iv) identify molluscan assemblages and their palaeoenvironmental affinities (v) to identify key elements of stable isotope geochemistry of the sediments; (vi) interpret the sediment physical, chemical and biological attributes in the context of changing environmental conditions, specifically in relation to changing climate, sea level and human activity during the Holocene. The record reveals considerable detail as the nature of Holocene climate and sea level change. This information is then placed in the context of contemporary and future management policies for the Wilderness lakes and wetlands. 0563 New radiocarbon dates from sapropels in three Holocene lakes of the Coorong coastal plain, southeastern Australia Aija C Mee1, David M McKirdy1, Martin A Williams2, Andrew Smith3, Evelyn S Krull4 1

University of Adelaide, School of Earth & Environmental Sciences, Australia University of Adelaide, Geographical and Environmental Studies, Australia 3 Australian Institute of Nuclear Science and Engineering, Sydney, Australia 4 CSIRO Land and Water, Adelaide, Australia 2

Contrary to earlier perceptions that the Holocene was a period of relative climatic stability, a growing body of evidence now shows that there were frequent and often rapid fluctuations in climate throughout the Holocene at a variety of temporal scales. The environmental fluctuations in Australia during the latest Quaternary glacial-interglacial cycle conceal substantial local and regional variations, showing that we need to study sites that are sensitive to both regional climatic fluctuations as well as local hydrological influences. The Coorong lakes region of South Australia offers excellent potential for such work. These lakes contain up to five discrete sapropel (organic-rich) horizons developed during the Holocene. Numerous studies across the world have linked sapropel deposition to abrupt changes in palaeoclimate, notably to changes in precipitation. The hydrological reasons why certain lakes show multiple sapropel horizons and others only a few need to be clarified. We here report the results obtained from AMS radiocarbon dating (n = 25) of single cores from three Coorong lakes (here termed A, B, C). The 6400 cal BP (6.4 ka) onset of sapropel deposition in Lake A indicates its isolation from the open Coorong Lagoon. In Lake B, the onset of sapropel formation at ~4 ka coincided with the transition from lagoonal to perennial lacustrine conditions as the sea withdrew from the inter-dune corridor. Lake C was never directly connected to the marine system. Here, organic matter from near the base of the lowermost sapropel, dated at ~4.1 ka, provides a minimum age for the onset of lacustrine conditions. Sapropel deposition recorded within these lacustrine sequences ceased earlier in Lake A (~5 ka) than in Lake B (~2.6 ka) and Lake C (~1.9 ka). This may simply reflect a marked local climatic gradient (drier in the north, wetter in the south).

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Alternatively, it may indicate that these shallow lacustrine sapropels, unlike their marine and deep-lake counterparts, do not form only during times of high precipitation but may be triggered by other processes such as the enhanced aeolian influx associated with climatic desiccation. Sapropel formation in two of the lakes coincides with recognised periods of rapid global climate change, previously unrecorded in southern Australia, each characterised by cool poles and dry tropics, lending some support to our inference that the episodic influx of aeolian dust may have triggered sapropel formation. 0784 History of glaciation of the Hunza tributary valleys in the Batura Muztagh and the Misgar-Kilik valley and the Haramosh Muztagh, N.W. Karakoram Sigrid Meiners Department of Geography, University of Goettigen, Germany

The post to late glacial glaciation history of recently glaciated tributary valleys of the Hunza- and the Indus valley is closely linked with the scientific discussion about the maximum extent of glaciation during the LGM in the main Indus valley. Investigations are focused on the reconstruction of glacier stages between the Postglacial and the Late Glacial to the Last Glacial Maximum according to the principle of their positional relationship. The calculation of the snow lines after the method of Kuhle (1988) yields evidence of climatic change. In detail two still glaciated tributaries of the Hunza valley can be shown as characteristic examples, the Bar valley on the Batura SW side and the Kilik valley (Misgar), north of the Karakoram main ridge and the HaramoshKutwal valley in conection to the Indus valley. Today, the recent avalanche fed glaciers come down from high lying catchment areas with average altitudes of 6200–6800 m and terminate at c. 3000 m. Snow line runs at 4600–4700 m in the steep flanks, which is common in the Karakoram Mountains. In the Bar valley one can differentiate four stages (except subrecent stages) marked by different lateral moraine level but there are no endmoraines preserved. Late glacial moraines at the valley outlet allow a snow line depression of c. 800 m. In contrast, the recent snow line in the Kilik valley is at c. 5000 m with small valley glaciers and lower catchment areas. While the postglacial stages do not reach far from the recent positions, there are extraordinary widespread moraines of Late Glacial. For the Haramosh valley five stages can be reconstructed after the former glacier joins the Indus glacier. The valley outlet moraine indicates a snow line depression of 600–700 m and seems to be the latest stage of Last Glacial. For the Postglacial the great lateral moraine (GLM) is prominent which frequently reached down 2.5–5 km away from the recent glaciers with a calculated snow line depression of c. 300 m in maximum. 1353 Holocene and Latest Pleistocene Alpine Glacier Fluctuations in Western Canada and United States Excluding Alaska Brian Menounos1, P Thompson Davis2, Gerald Osborn3 1

University of Northern British Columbia, Canada Bentley College, United States 3 University of Calgary, Canada 2

Almost 20 years have passed since INQUA XII, for which a special session was convened to consider the worldwide evidence for Holocene glacier fluctuations. During the past two decades, mountain glaciers in western North America have continued to retreat from extended downvalley positions reached some 300 to 150 cal. yr BP.

This retreat has exposed wood in glacier forefields and composite moraine stratigraphy that provides a unique opportunity to constrain the ages of glacier fluctuations. Surface exposure dating and the recovery and analysis of proglacial lake sediment records have likewise added to our understanding of glacier activity over the past 13,000 cal. yr BP. Glaciers at several sites in western Canada and the Lower 48 of the United States advanced during the Younger Dryas (YD) Chronozone (~ 13,000-11,500 cal. yr BP). The evidence and magnitude of the YD advance differ substantially across the western Cordillera, and these differences may relate to: (a) regional differences in atmospheric circulation patterns; (b) site specific conditions such as late melt out of late Pleistocene ice; or (c) destruction in some cases of the deposits by later advances. Evidence that includes tephra incorporated in moraines indicates that glaciers in western Canada and the northwestern United States advanced at ca 6000-5000, 3500-2000, and after 1500 cal. yr BP. At least some glaciers underwent a minor advance around 85008000 cal. yr BP in western Canada based on terrestrial and lacustrine sediment studies, but evidence for glacier advances dating to this period in the American Cordillera has not been published. The long-term trend in Holocene glacier extent indicates that glaciers were less extensive in the early and middle Holocene than in the late Holocene. Most glaciers reached their maximum downvalley positions about 300-150 cal. yr BP. The long-term expansion of alpine glaciers in the Canadian and American Cordillera matches the decline in summer insolation at mid-to-high latitudes during the Holocene. 0699 A comparison of lake sediment data and other archives to reconstruct climate change over the last 2000 years Sarah E Metcalfe1, Matthew D Jones1, Sarah J Davies2, Georgina H Endfield1, David W Stahle3, Jose Villanueva Diaz4 1

School of Geography, University of Nottingham, United Kingdom Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, United Kingdom 3 Department of Geosciences, University of Arkansas, Fayetteville, United States 4 INIFAP, Durango, Mexico 2

Climatic changes over the last 2000 years, preserved in the laminated sediments of the Laguna de Juanacatlán, near the Pacific coast of Mexico, are compared with prehispanic and Hispanic archival sources, as well as the expanding number of tree ring records from this tropical region. This integration of sources provides a unique perspective on drought history in this area. Details of the full Juanacatlán sequence are presented in Jones et al. (this meeting). Ti data from the top of the core have been compared against the available meteorological data. The closest meteorological site (Mascota) has about 30 years of incomplete data, but the precipitation record from Guadalajara, which starts in 1881, is consistent with the Mascota data and can be compared with the Ti record over the longer term. Based on this assessment and limited catchment monitoring, Ti appears to be a reasonable proxy for runoff reflecting overall monsoon strength. Plotting the Ti data over the last 2000 years shows a number of drier intervals including the late Classic period, the 13th to 15th centuries, ca. 1690–1710, the 1780s and around 1810. The occurrence of drought in the terminal Classic (the Maya collapse) has been clearly recorded at a number of sites in the Yucatan Peninsula and our record confirms its presence in the central highlands of Mexico. Drought episodes in the period prior to the Spanish conquest are recorded in Aztec codices and in glyphs from the Maya region and seem to have been associated with epidemics in a number of cases. Periods of drier climate indicated for the colonial period are supported by documentary evidence, particularly from


Guanajuato and Michoacan. Many of the drier intervals recorded in the lake sediments are also present in tree ring records, but a direct comparison is not straight forward. Studies of the modern NAM have highlighted a number of ocean-atmosphere configurations that affect the strength of the monsoon. As described in Jones et al. (this meeting), ENSO and PDO cyclicities are present in the Juanacatlán core and their effects can be identified. The possible role of solar forcing has been investigated by comparing the Ti record against reconstructed solar output. There is a good match indicating the dry conditions in the monsoon region correspond to periods of low solar output. The combination of proxies used here provides both a long term perspective on drought and insights into its impacts. 0369 Late Glacial and Holocene environmental history of a buried icewedge system, Barrow, Alaska Hanno Meyer1, Jerry Brown2, Lutz Schirrmeister1, Kenji Yoshikawa3, Andrei Andreev1, Dirk Wagner1, Hans-W Hubberten1 1

Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Germany 2 International Permafrost Association, United States 3 Institute of Northern Engineering, University of Alaska, United States

The Barrow, Alaska area is one of the best-studied arctic regions, including permafrost research. However, stable isotope techniques have been used only sparsely, especially to characterise different types of ground ice. The application of hydrogen and oxygen isotopes for palaeoclimate studies in ice wedge ice is useful for reconstructing winter temperatures, whereas pollen reflect summer conditions. Ice wedges are principally formed by repeated frost cracking and percolation of meltwater of winter snow into frost cracks, forming ice veins, containing, under certain circumstances, the winter signal of the year of its formation. The current study provides new information related to environmental changes during the late Glacial — early Holocene transition. A small permafrost tunnel was excavated in the early 1960s by a team lead by one of the authors (Brown). The 9-meter long excavation into a massive complex of vertically foliated ice at the 3–6 m depth revealed organic residues in the ice that were radiocarbon dated at between 11,000 and 14,000 years BP. The excavation was reopened in 2003 and sampled in 2004 and 2006 by the Potsdam team for stable isotope, sedimentological and palynological analyses. Since in the 1960s neither AMS dating techniques nor stable isotope studies were readily available, the first step was to refine the age estimate of the buried ice in order to improve our understanding of the genesis of the buried ice within the tunnel. Isotope geochemistry indicates the intersection of two, isotopically different, ice wedges (18O of –24‰ and –26‰, respectively), suggesting different phases of the regional climatic history, and also as reflected in methane contents of wedge ice. Five direct AMS dating of organic matter (lemming droppings, leaves) within the ice wedge ice of between 12,370±60 and 10,290±45 14 C years indicate ice wedge growth at the end of Late Pleistocene (Bølling-Allerød). An AMS date of 21,670±500 14C years at the lateral contact of the wedge and the surrounding sediments reveals a possible extension of the chronology beyond the Late Glacial Maximum. The ice wedge is buried under 2–3 m of ice- and organicrich sandy silt of Early Holocene age (10,380±50 and 9930±40 14C years), The upper-most section contains a cryoturbated, organic-rich soil and ice-rich permafrost (945±40 14C years) with large, active ice wedges.

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0040 The INQUA scale project: results and future directions Alessandro M Michetti Università dell’Insubria, Como, Italy INQUA ScaleProject

Macroseismic intensity is today, and will remain in the future, a key parameter in seismology, engineering seismology and earthquake geology, primarily because (A) it allows to derive quantitative information on source characteristics for historical seismic events, and (B) it is a critical information for obtaining attenuation relationships in seismic hazard analyses. The most widely used intensity scales, such as the de Rossi-Forel; MCS, the Omori, the Modified Mercalli, and the MSK scales are based on a hierarchical classification of effects regarding (a) humans, (b) built environment and (c) natural environment. The diagnostic effects for the lower degrees are essentially those on people and animals, for the intermediate degrees those on objects and buildings, for the highest degrees those on the natural surroundings. The effects on the ground reported in the scales include primary, tectonic features such as landscape modifications due to regional uplift/subsidence and faulting, and secondary, mostly shaking-induced phenomena, such as ground cracks, slope instabilities, and liquefaction. These effects are often cited in historical and contemporary reports and have the advantage of not generally being influenced by human practices, many of them depending on source parameters and local geology alone. The outstanding progress of paleoseismological and Quaternary geology research in the past decades makes available an entirely new knowledge for understanding the response of the physical environment to seismicity. In fact, today in many cases, and especially for the epicentral area of the strong seismic events, observation on ground effects provide more consistent intensity measurements than observation on damage, which is strongly influenced by the cultural and socio-economical situation of the affected area. This has been the rationale for developing the INQUA scale, a new intensity scale based only on coseismic environmental effects, introduced at the 2003 XVI INQUA Congress in Reno, USA. The INQUA scale project has been developed in order to test this scale for a trial period of 4 years; the final version of the scale will be presented during the XVII INQUA Congress in Cairns. This paper will take advantage from the several case studies examined by project participants worldwide for analyzing the critical features of the INQUA 2007 scale, and the impact that this new tool can have for the understanding of Quaternary seismicity and the mitigation of future earthquake effects on the society. 1135 Active shortening, Quaternary capable faults, and seismic hazard in the Western Southern Alps, Italy Alessandro M Michetti1, Cipriano Carcano2, Francesca Giardina1, Franz Livio1, Karl Mueller3, Sergio Rogledi4, Giancanio Sileo7, Eutizio Vittori5 1

Università dell’Insubria, Como, Italy ENI Exploration and Production, S.Donato Mil.se, Italy 3 University of Colorado, Boulder, United States 4 ENI Exploration and Production, S.Donato Mil.se, Italy 5 APAT - Geological Survey of Italy, Roma, Italy 2

Two damaging historical earthquakes with estimated magnitude in the order of 6.0 to 6.5 struck the central Po Plain during the Middle Ages:

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the Jan. 3, 1117, Verona and the Dec. 25, 1222, Brescia events. These are the strongest known historical earthquakes in the Northern Po Plain. Due to the high population density and concentration of industrial facilities, the Po Plain is arguably the most vulnerable area in Italy in terms of seismic hazards. Based on geological and geomorphological field mapping and reinterpretation of Po Plain subsurface data from the ENI oil company, we identify evidence of Quaternary compressive tectonics in the Western Southern Alps, the structural domain, which includes the epicentral area of the Dec. 25, 1222, earthquake. The recent evolution of the Western Southern Alps is characterized by a belt of segmented, 10 to 20 km long, fault propagation folds, controlled by the Plio-Quaternary growth of out-of-sequence, north and south verging thrusts. Most of this belt is concealed beneath the Po Plain. We show a typical example of such mostly buried structures that is very well imaged by ENI subsurface data in the Castenedolo area near Brescia. However, in the Lombardian foothills fault propagation folds with evidence of Quaternary deformation are locally exposed to the surface, as illustrated by the Albese con Cassano structure near Como. Pleistocene uplift rates for both the Castenedolo and Albese con Cassano anticlines are in the order of 0.1 – 0.2 mm/a, which suggest slip-rates on the controlling thrusts in the order of some tenths of millimeters. Based on fault length, geometry, the thickness of seismogenic crust, slip rates, and the comparison with similar earthquake sources in the Eastern Southern Alps, these thrusts seem capable of producing surface deformation and faulting during future moderately-sized earthquakes (e.g., Mw 6.0–6.5). Our preliminary results therefore indicate that the whole Western Southern Alps piedmont belt, between Lake Maggiore and Lake Garda, is being actively shortened, even if under relatively low strain rates, and can experience significant local earthquakes. As a working hypothesis, it is possible to consider the Dec. 25, 1222, Brescia event as a “characteristic” earthquake for this structural domain in terms of earthquake magnitude and effects. Consequently, analyses available in the literature appear to severely underestimate the seismic hazards of the study region. 0984 Quaternary geochronology in the Mojave Desert, USA: innovations and applications to dating landscape response to climate triggers David M Miller, Kate Maher, Shannon A Mahan, John P McGeehin, Lee Amoroso, John A Barron U.S. Geological Survey, United States

The U.S. Geological Survey is mapping and dating Quaternary deposits of the Mojave Desert to improve knowledge of ecosystem function, climate history, and neotectonics. High-resolution geochronology allows us to map deposits at time scales that illuminate history of landscape response to climate variations. Widespread alluvial fan deposits present the greatest challenge for dating due to paucity of organic material. To date these deposits we use luminescence and U/Th series methods as well as soil carbonate coat thickness to supplement limited radiocarbon dating. Luminescence methods appear to be reliable for fan deposits, that incorporate significant fractions of eolian sand. U/ Th-series ages from soil silica, using microbeam facilities, provide minimum ages for Pleistocene fan deposits. The rate of carbonate coat accumulation on clasts is roughly linear with age; calibration of coating thickness with deposits dated independently shows promise for this method of estimating ages. We used the new techniques on alluvial fan, fluvial, lake, and groundwater-discharge deposits. We find that the Mojave Desert depositional record during the Holocene is similar to previously determined climate-landscape records of the region. Ephemeral

rivers and lakes record periods of sustained stream flow during the Little Ice Age (ca. 1300–1850 AD) and at about 1150 AD, as well as during the early neoglacial, all of which are driven by winter storm patterns. Periods of alluvial fan aggradation across the desert are approximately 3–6 ka and 11–15 ka, matching the nearby Sea of Cortez marine records of dominance by tropical diatoms and silicoflagellates. Perhaps periods of extra warm waters in the Sea of Cortez supports more frequent and more intense summer and fall monsoons and hurricanes. Sustained alluvial fan aggradation may be driven by these kinds of intense summer storms. The position of the Mojave Desert near the Pacific coast may promote a partitioning of landscape process response to climate forcings, with Pacific frontal storms creating ephemeral lakes and sustained monsoons creating alluvial fan aggradation. 1395 Separating the impacts of climate change and human colonization on the flora and fauna of Pleistocene Australia Gifford H Miller1, John W Magee2, Marilyn L Fogel3, Michael K Gagan2, Seth D Newsome4, Stephen B DeVogel5 1

Univeristy of Colorado, United States Australian National Univesity, Australia 3 Geophysical Laboratory, United States 4 Carnegie Institution of Washington, United States 2

Australia rifted from Antarctica ~50 Ma, allowing ecosystems to evolve along separate pathways from the rest of the planet. Lacking placental mammals, marsupial mammals evolved to fill most familiar niches. As the continent drifted into the subtropics, rainfall decreased, and monsoonal circulation dominated across northern Australia. The flora and fauna of the continent evolved to meet these new conditions. At the onset of the Quaternary, short-term, high-magnitude oscillations began, with relatively warm, wet conditions during global interglacials and cold, arid conditions during global glaciations, resulting in additional ecosystem adjustments. Recent studies demonstrate that large vertebrates adjusted to these changing conditions without dramatic loss of species diversity. In this larger context, the loss of all large and many smaller marsupials as well as other large vertebrate species in the Late Pleistocene has challenged our community for over 150 years to develop a coherent explanation for the extinction based on solid evidence with a consistent theoretical underpinning. Climate reconstructions suggest that primary resources should have varied markedly on millennial timescales for most of the Quaternary, possibly amplifying in the mid Quaternary. Conditions during late Quaternary were similar, other than the colonization of the continent by humans about 50 ka. Our research focusses on teasing apart the impacts of climate change and human colonization on the flora and fauna of Pleistocene Australia. We rely on isotopic tracers of diet, drinking water, and moisture stress preserved in the eggshells and teeth of large vertebrates to evaluate ecosystem response to climate change prior to human colonization, compared to changes following a human presence on the landscape. This requires continuous time-series of paleoecological proxies that extend from the present back 50 to 100 ka before human colonization. Our results from four large and widely separated regions representing arid to semi-arid climates provide compelling evidence for an unprecedented and irreversible decrease in plant diversity between 50 and 45 ka, shortly after humans colonized Australia and about the same time as megafaunal extinction. Independent climate reconstructions indicate an intermediate climate regime without rapid oscillations 60 to 40 ka, minimizing the possibility of a climate-mediated impact. Dietary intake exhibits only minor variability in response to climate changes over the 100 ka prior to human colonization. With a climate driver for


ecosystem change and megafaunal extinction no longer tenable, the core question centers around what exactly humans did that resulted in the unprecedented changes to Australia’s flora and fauna. 0225 Reconnaisance mapping of transported regolith in the Appalachian Mountains, USA Hugh H Mills Tennessee Technological University, United States

Surficial geology maps are best compiled by extensive field work aided by topographic maps and stereo aerial photos. Where funding for field work is lacking, as has been the case in many parts of the Appalachians, preliminary surficial geology maps may be made from soil maps supplemented by a minimum amount of field work. This procedure is becoming easier and more rapid with the increasing availability of digitized soil maps. This poster provides examples of such mapping from the central and southern Appalachians. The basic approach is to transform the polygons on soil maps into surficial geology polygons, thereby avoiding the arduous task of drawing in boundaries of surficial deposits from scratch. Some of the transformation can be handled simply by directly recoding a soil unit on the soil map to a unit on the surficial geology map. For the majority of cases, however, the relationship between soil and surficial units is more tenuous, and individual polygons must be visited in the field. Even so, the use of soil polygons makes the process of mapping surficial units much faster than would otherwise be possible. As an example, three relative ages of fans were mapped in the Blue Ridge of North Carolina based on degree of weathering and soil development. Independently a county soil map was produced by the USDA. A comparison showed that the Hapludult Thunder series commonly occurs on young and intermediate-age fans, but also are widespread on sideslopes, headslopes, and drainageways. This soil unit hence is almost a necessary condition of young and intermediate fans, but is not a sufficient condition. In contrast, the Paleudult Dillsboro series is found over much of the old fan surfaces, and can be said to be almost a necessary condition for an old fan. Two other examples presented show surficial maps made from digital soils maps. One weakness of this approach is that whereas the soil maps may clearly delineate fans and terraces, they may not address the relative age of these features. Hence, field work is required to determine which polygons of, say, fan deposits, should be designated young and which designated old, assuming the assignment of two relative ages is desired. Venn diagrams are used to portray the various degrees of correspondence between soil and surficial units. 0827 Late Holocene climatic, environmental and limnological records from volcanic crater lakes in western Uganda, East Africa: preliminary results Keely Mills, David Ryves, John Anderson Loughborough University, United Kingdom

Western Uganda (lying on the equator at ~30˚E) has approximately 100 crater lakes of varying size, depth and salinity along a climatically-driven gradient from freshwater to hypersaline. The lakes also vary in the extent of recent human impact in their catchments, from lakes in protected areas to deforested and agricultural landscapes. These lakes provide a unique and exciting opportunity to study the response of tropical lake systems to climate and environmental changes in an important region of East Africa, for which palaeoenvironmental data are

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sparse. Through the use of multiproxy indicators extracted from crater lake sediment records, this research aims to assess the shorter-term, regionally specific archives of climate variability; examining questions of spatial and temporal heterogeneity of climate change in the context of growing human impacts on the landscape over the late Holocene. A detailed study of short cores and longer, continuous sedimentary sequences from lakes in the south of the crater lake region, which share the same geology and climatic regime but whose catchments range from relatively undisturbed (within protected forest reserves and National Parks), to those heavily modified by agriculture and settlement outside has been carried out using a multiproxy approach (fossil diatoms, phytoliths, pollen, 13C and 18O isotopes, sediment properties, AMS 14C, 210Pb). A reference set of around 50 crater lakes from western Uganda is being developed to link contemporary diatom assemblages from surface sediments to present-day limnological parameters (e.g. conductivity, stratification pattern) and catchment conditions (e.g. human disturbance) and will be used to interpret the fossil diatom record from lakes in the region. Initial results from this multiproxy approach provide evidence of regional variations in climate (in terms of effective precipitation) and environmental/catchment changes as a result of both natural and anthropogenic factors. Such changes can be linked to archaeological evidence for societal and cultural developments during the late Holocene to help understand the interplay between societal and environmental change in East Africa. 0134 Testing the feasibility of past glaciation in eastern Lesotho using glacier reconstruction approaches Stephanie C Mills1, Simon J Carr2, Stefan W Grab1 1

University of the Witwatersrand, South Africa Queen Mary University of London, United Kingdom

2

The high Drakensberg and eastern Lesotho highlands have received considerable attention concerning the authenticity of landform interpretations which postulate past glaciation. The high Drakensberg is one of the few remaining environments where there has been a long-standing uncertainty regarding the occurrence of Quaternary glaciation. Recent published work has primarily focused on macro-scale data, climatic extrapolations and age determinations to support a glacial origin for sites in the southern Drakensberg. However, Quaternary glaciation at these sites implies that specific climatic conditions would have been required to sustain active glaciers. The application of a glaciological approach to model former glaciation permits the calculation of palaeoglacier mass balance, total velocity and basal slip, which in turn may be compared to modern analogues. Linear ridges, interpreted as having formed through glacial activity, have been observed at four sites in eastern Lesotho, for which glacier reconstruction techniques are applied. Reconstructed equilibrium line altitudes (ELAs) for the sites range from 3081 to 3171 m a.s.l. and three of the four sites owe their existence to snow-blowing northerly winds. The results imply that mean palaeotemperatures during the summer months ranged between 2.4 and 2.9 ˚C at the sites, and that palaeoprecipitation was approximately 1500 mm per annum. The glacier reconstruction approach indicates that the mass balance characteristics of the palaeoglaciers at the four sites are comparable with modern analogues and therefore reflect areas of marginal glaciation. It is generally accepted that the summer rainfall region of southern Africa was drier during the Last Glacial Maximum (LGM), however these results suggest a higher winter precipitation during the LGM. Previous work has suggested an increase in the occurrence of cold fronts during LGM winter and spring months over the southern African coastal areas and adjacent interior, which would have produced heavier snowfalls

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and in turn increased snow cover at high altitudes. These results do not suggest evidence for widespread glaciation, but indicate that specific areas were capable of sustaining small glaciers based on microtopographic and particularly microclimatic factors. 0022 An ostracod-inferred large Pleistocene freshwater lake in the presently hyper-arid Qaidam Basin (NW China) Steffen Mischke1, Ulrike Herzschuh2, Zizhen Qiao3, Naida Sun4, Zhencheng Sun4 1

Institute of Geological Sciences, Freie Universitaet Berlin, Germany Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Germany 3 Headquarter of Petroleum Exploration and Development of Qinghai Province, Dunhuang, China 4 China University of Petroleum, Department of Earth Science, Beijing, China 2

The early and middle Pleistocene environmental and climatic evolution of the Tibetan Plateau and surrounding regions is largely unknown in contrast to the late Pleistocene and Holocene development in Central Asia. The Qaidam Basin at the northern margin of the Tibetan Plateau is one of the largest hyper-arid intermontane basins on Earth, characterised by playas, alluvial fans, pediment surfaces and a thick succession of sediments within the basin. These sediments are considered to have recorded the complex history of Quaternary environmental and climatic change in relation to the glaciation history of surrounding mountain ranges and regional hydrological changes. We performed optically stimulated luminescence (OSL) dating and uranium–series measurements (TIMS), ostracod analysis and grain size determinations on sediments from a prominent escarpment in the eastern central Qaidam Basin. In addition, an ostracod-based transfer function for Recent Tibetan lakes was applied to the fossil ostracod assemblages for a quantitative salinity reconstruction. Laterally continuous finegrained lake sediments containing a diverse ostracod fauna provide evidence for the existence of a large freshwater lake in a place with a present-day mean annual precipitation of less than 50 mm. Transferfunction derived salinities are about 1 g l−1 on average and generally not higher than 3 g l−1. Dating by OSL and TIMS techniques indicate a late middle Pleistocene formation of the freshwater lake. Whether much higher precipitation, runoff from melting glaciers or frozen ground, or large hydrological changes in the catchment area led to the establishment of the large freshwater lake in the Qaidam Basin remains to be solved. 1067 Long-term Satluj river flow records from tree rings in Kinnaur, Himachal Pradesh, India Krishna G Misra, Ram R Yadav Birbal Sahni Institute of Palaeobotany, India

Hydrological resource availability is one of the main concerns for future development and economic activities including hydroelectricity, irrigation and tourism. Atmospheric changes can affect the global climate and hydrologic cycle, in turn affecting precipitation and solar regime of a given region. The vulnerability of the Indian subcontinent to changing climate is of vital importance for its impact on hydrology affecting water resources and agriculture. Careful long-term planning and management of water resources requires understanding of variability in river flow in longer perspective beyond the instrumental window. It is essential to understand the variability of the river flow on

time scales of decades to centuries to assign reasonable recurrence probabilities of extreme events. However, our understanding of river flows in India is limited, based on observational records available for the past few decades only. High-resolution proxy records are the only tools to extend the observational records back to several centuries. Satluj River arises from beyond the Indian borders in Tibetan plateau from Mansarover and Rakastal Lake at an elevation more than 4500 m. Satluj is largest among the five rivers in the Himachal Pradesh and flows through different topographic and climatic regions. It leaves Himachal Pradesh to enter the plains of Punjab at Bhakra, where the world’s highest gravity dam has been constructed on this river. The samples of Himalayan cedar (cedrus deodara) were collected from six moisture stressed sites with steep slope in Kinnaur district of Himachal Pradesh. The increment cores were collected from old trees, which have crown dieback with umbrella shaped top indicating old age and climate stress. Pattern matching (skeleton plotting) was used to precisely date the tree-ring sequences. The ring-width chronologies extending from AD1607–2005, AD1580–2005, AD1480–2005, AD1388–2005, AD1388–2005 and AD1353–2005 were prepared from six respective sites. In the development of chronologies, individual ring width series were detrended using cubic smoothing splines with a 50% frequency response cut off width equal to 2/3 of series length. These chronologies showed strong positive correlation with total monthly river flow at Bhakra for February to July. The reconstruction back to 1660 AD was performed using principal component regression technique. This provides the first record of long-term river flow reconstruction from the Himalayan region. High year-to-year and interdecadal variability in river flow have been noticed. The reconstruction indicated relatively high flows during mid 19th and late 20th century and provides evidence of prolonged low flows during 1770–1820 and 1860–1920. 0337 Comparison of proxy methods of reconstructing mire water tables from plant macrofossils Fraser JG Mitchell1, Pirita O Oksanen2, Bettina Stefanini1 1

Trinity College Dublin, Ireland University of Bristol, United Kingdom

2

The reconstruction of mire water tables has been widely used in northern and western Europe as a proxy for past net precipitation. Plant macrofossils are one of several proxies used in this respect. The two most widely used approaches have been the summation of subjective qualitative weightings applied to taxa based on broad ecological ranges (e.g. the Dupont index) and the use of ordination axis scores from detrended correspondence analysis (DCA) when an axis appears to correlate with a moisture gradient. There are several problems with these approaches; they are subjective, they generate a relative index of mire surface wetness rather than actual water table depths and their precision is not apparent. In this paper we explore alternative approaches to quantitative water table reconstructions from plant macrofossils and compare them to these traditional methods. The EU funded ACCROTELM project has delivered a detailed macrofossil analysis of a mire site in central Ireland covering the last 5000 years. One alternative approach to reconstructing past water tables uses non-metric multidimensional scaling (NMS) to derive a water table index that is more closely aligned to ecological indicators than is possible with DCA. A second, more quantitative approach will also be reported, which uses a transfer function method based on field data of water tables recorded in a range of vegetation communities from mires in central Ireland. These proxies will be compared to results from the same dataset analysed using traditional methods. The proxies will also be compared to water


tables derived from testate amoebae and peat humification analysis from the same core. This comparison aptly illustrates the added benefit of the multiproxy approach over reconstructions based on a single proxy. 0962 Filling the gap between radiocarbon and K-Ar chronology using coupled AMS radiocarbon measurements and red thermoluminescence dating for Quaternary tephra Yosuke Miyairi1, Yusuke Yokoyama2, Sumiko Tsukamoto3, Hiroyuki Matsuzaki4 1

Department of Earth and Planetary Sciences, University of Tokyo, Japan Department of Earth and Planetary Sciences, University of Tokyo also Japan Agency for Marine-Earth Science and Technology, Japan 3 Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, United Kingdom 4 Department of Nuclear Engineering and Management, University of Tokyo, Japan 2

A widespread tephra layer is often used as a “time marker bed” in geology and geography. They can be dated by radiocarbon on organic materials to determined the timing of volcanic events occurred up to ca. 50 ka. However, the lack of suitable material (e.g. burial wood) for radiocarbon dating is often an obstacle to directly estimate the timing of tephra deposition. An alternative option is using K-Ar, yet considerable uncertainties for dating of younger samples (< 100 ka) and limitations on the dating materials, namely the requirements of high K minerals, prevent this methods from being ubiquitously applicable for tephra dating. Although the period between 50 to 100 ka is very important for various studies such as Paleoclimatology and Archaeology, a “dating” “gap” has existed. A trapped radiation charge dating technique will potentially solve these problems. We focused on development of the red thermoluminescence (RTL) dating for tephra since we observed that it captures a stable and high intensity RTL signal. We established a dating protocol to deal with tephra to conduct RTL dating. Radiocarbon and K-Ar dating results agreed very well with RTL showing reliability of our newly developed experimental protocol. The uncertainties of the RTL ages were comparable to the other radiometric dating results. This new technique as well as some applications will be discussed. 1432 Unusual earthquake-related uplift process of the Sanriku coast on the fore-arc of the Northeast Japan arc Takahiro Miyauchi1, Hideaki Maemoku2, Masanobu Shishikura3, Tomoo Echigo4 1

Earth Science Department, Graduate School of Science, Chiba University, Japan 2 Graduate School of Education, Hiroshima University, Japan 3 Active Fault Research Center, AIST, Geological Survey of Japan, Japan

The coastal areas of fore-arcs in plate convergence boundaries are characterized by a flight of late Quaternary marine terrace repeatedly uplifted by co-seismic crustal movements. We demonstrated a dynamic diagram of inter-seismic subsidence and coseismic uplift to explain the emergent process in the Sanriku coast of the Northeast Japan arc, using Quaternary and geomorphological methods. The obtained results are as follows. Pleistocene marine terraces are recognized along the coast, but Holocene ones are poorly distributed. 14C dates and lithofacies of

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geologic cores indicate the tendency of successive subsidence and the maximum subsidence rate of 3 mm/a in Holocene. Recent tidal data show faster subsidence rate of 5 to 9 mm/a in the past 50 years. The sedimentological situation has abruptly changed in mid Holocene, from bayou or lagoons to shallower beach or river beds. The recent rapid subsidence in rate of 5-9 mm/a results from the drag of the overriding plate by the coupling of Pacific plate and Eurasia plate. Comparatively, the seeming subsidence rate in Holocene is remarkably lower than that in the last 50 years. The diagram of 14C dates and heights of Holocene sediments suggests that an unusual coseismic uplift intermittently occurred about 5000 years ago during continuous crustal subsidence, accompanied by vertical uplift of more than 10 m along the northern Sanriku coast. The dislocation fault model requires that the source fault is 30-50 km offshore-reverse fault branching from the plate boundary fault. This episodic co-seismic uplift probably excelled the inter-seismic subsidence by the coupling of plates, and the totally plus balance has produced the sequence of Pleistocene marine terraces corresponding to interglacial high sea-level stands. 0207 Climate reconstruction experiments using pseudoproxies with pre-determined spectra Anders Moberg1, Rezwan Mohammad1, Chris Turney2 1

Department of Physical Geography and Quaternary Geology, Stockholm University, Sweden 2 Department of Physical Geography and Quaternary Geology, Stockholm University, Sweden 3 GeoQuEST Research Centre, School of Earth and Environmental Sciences, University of Wollongong, Australia

Pseudoproxy data are by purpose distorted climate time series obtained from output from a simulation with a climate model, where the distortion is applied in order to make the resulting time series having similar statistical characteristics as a real climate proxy time series. The primary practical use of pseudoproxies is for evaluating different paleoclimate reconstruction algorithms. Previous work has focussed on large-scale pseudo-reconstructions for the Northern Hemisphere. The distortions applied in these cases have been either white or red noise, to mimic real proxies in the sense that they only account for a fraction of real climate variability. Here, a further step is taken to also account for the fact that different real proxies have different power spectra. A wavelet based technique for constructing pseudo-proxies with pre-determined spectra is developed, as part of the European Union project Millennium. Examples of results are given for both the Southern and Northern Hemisphere. 0533 Late Holocene and present sea level changes Nils-Axel Mörner Paleogeophysics & Geodynamics, Sweden

The theories of geoid changes, global isostasy and rotational redistribution of ocean masses changed the old concept of eustasy, and made the search for “global simultaneous changes in sea level” futile. Up to about 5000-6000 BP, the sea level changes were dominated by a glacial eustatic component of rising sea level. After this time, the sea level changes seem to have been dominated by local to regional redistribution of the water masses due to ocean current changes driven by changes in the Earth’s rate of rotation, and steric effects driven by changes in water temperature and salinity.

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Is there a “a global rise in sea level” as we so often hear media announce? Well, there was a rise from about 1850 up to 1930/40, which might have been in the order of 1.1 mm, judging from European records and the Earth’s deceleration. It might have less, but it can hardly (not to say; certainly not) have been more. Satellite altimetry showed no (or just minute) rise from 1992 to 2000. Later, a significant rise was introduced to the same record and its extension up to 2003. But this factor was adopted from tide gauge data, not satellite reading. So, in fact, there are no general data supporting “a global rise in sea level”. When we examine the individual records, the picture gets even more free of true observation records of any alarming sea level rise. The sea is not in a rising mode in the Maldives, nor in Tuvalu or Vanuatu, all previously notorious sites of “flooding”. Even in Venice, a slowly subsiding area, the sea level records show no traces of any acceleration, rather the opposite. In the North Atlantic, the sea level changes are strongly driven by the redistribution of water masses (due to Gulf Stream beats driven by rotational changes) and steric effects. In view of this, it seems strange to talk about “a global rise in sea level”. This idea seems primarily to originate from models, not observation. 0531 The Maldives during LGM and the subsequent periods Nils-Axel Mörner

sea level was reached and followed by a series of rapid sea level oscillations up to the present. Six paleotsunami events are recorded. 0532 Paleosesmology; application of the INQUA Intensity Scale on a number of paleoseismic events in Sweden Nils-Axel Mörner Paleogeophysics & Geodynamics, Sweden

Up to today, we have recorded, dated and described 56 paleoseismic events in Sweden (the Paleoseismic Catalogue of Sweden). 50% of the events date from the deglacial period with an extremely high rate of glacial-isostatic uplift. Still, 11 events occurred with in the last 5000 years. Only events of a magnitude M>5.5–6.0 are recorded. Some events must have had magnitudes of M>8. Also, the frequency was high; so, for example, 6 events were recorded in 100 years (10,500– 10,400 varve years BP). In this case, it has even been possible to trace segmentation along an old faultline. In order to assess the feasibility to apply the INQUA Intensity Scale also on paleoseismic events, a number of events were selected and analysed; viz the events dated at 10,469 vBP, 10,430 vBP, 9663 vBP, 6100 cBP and 3250 cBP. The result of this exercise will be presented in a cartoon of maps with inferred intensity values as arrived at from structural data, liquefaction, slides and tsunamis.

Paleogephysics & Geodynamics, Sweden

The Maldives, now a group of about 1200 small atoll islands grouped in about 20 larger atolls, consists of corals, coral debris and coral sand. Previously, they were held to have been formed by Holocene catchreefs. This is no longer tenable. The Holocene reefs seem largely to be a thin apron upon older reef bodies (>40,000 BP). Significantly, the atolls are surrounded by shore-marks from the LGM low-stand and several subsequent sea levels from a punctuated sea level rise. Also, the old reef structures, exposed for sub-aerial weathering during lower sea level stands, are extensively karstified with systems of submarine caves. This calls for a completely new history of the islands not only with respect to sea level changes but primarily with respect to their environmental conditions during LGM to Younger Dryas period. At LGM, some 20,000 BP, sea level was at about –150 m, indicating that the geoid trough was even deeper then. The Maldives now consisted of 20 large islands, around their edges being surrounded by reef “chimneys” of about 150 m height and with a flat inland depression at around 100 m above sea level. Climate was warm and wet judging from the strong karstification. The inland depressions must have been crossed by river systems and covered by a dense rainforest. Surely many land animals and birds lived in the forest; but which ones we have no records of at present. The strong carts weathering contributed to the global carbon budget. There is a prominent sea level halt with deltas and shore cuts at around –65–70 m. This may represent the Younger Dryas period. The inland lowlands, now only some 10–20 m above sea level, were crossed by rivers debouching between the coastal rim of reef “chimneys”, now about 60–70 m high. The environment must have changed significantly. But rain forests may still persist. After this stage, sea level rose rapidly with some consistent levels of distinct marks of more stationary sea level positions. When the inland basins were flooded, flora and fauna diminished drastically and only the coastal “chimneys” remained above sea level. A quite remarkable scenery of rows of steep and high “chimneys” of older coral reefs (presently reaching –5 m and possible +2 m). At 4000 BP, the present

1132 Geophysical prospection for Late Holocene skeletal remains, Coorong, South Australia Ian Moffat1, Lynley A Wallis2, Kate Domett3, George TrevorRow4 1

Ecophyte Technologies Pty Ltd, Research School of Earth Sciences, The Australian National University, Australia 2 Department of Archaeology, Flinders University of South Australia, Australia 3 School of Veterinary and Biomedical Sciences, James Cook University, Australia 4 Coorong Wilderness Lodge, Australia

A multiple technique geophysical survey was used to locate evidence of subsurface skeletal material within an aeolian dune from Hacks Point in South Australia. This area was identified on the basis of surface skeletal material eroding from the dune and dated between 2060– 1880 cal BP. Excavation of the feature revealed the presence of two elderly individuals approximately 4 m apart. Some of the bones of the second individual had eroded (presumably in the pre-contact period) and had been reinterred nearby. Of three geophysical technques employed, ground penetrating radar was the least effective at locating evidence of skeletal material or burial activity. This data set displayed a large number of false positives probably caused by the intensely bioturbated nature of the geological setting. In contrast, magnetic intensity mapping showed a strong positive signal from the stratigraphic unit observed to contain skeletal material, as did the magnetic susceptibility response from electromagnetic induction surveying. The calculated EC values from electromagnetic induction surveying did not show any evidence of skeletal material or burial activity. Geochemical testing of the sediment aims to resolve the nature of the magnetic intensity and susceptibility anomaly. The strong association between this anomaly and the location of the skeletal material suggests that it may be the result of burning activities traditionally carried out as part of the burial practices of the Ngarrindjeri.


0137 Coastal geomorphology and luminescence chronology of the coastal dunes in Maputaland, Mozambique Fátima Momade1, Mussa Achimo2, Sylvi Haldorsen3 1

Direcção Nacional de Minas, Ministério dos Recursos Minerais, Mozambique 2 Departamento de Geologia, Universidade Eduardo Mondlane, Mozambique 3 Department of Plant and Environmental Sciences-Geology Group, The Norwegian University of Life Sciences, P. O. Box 5003, N-1432, Norway

Maputaland, the most southern part of Mozambique coastal plain, is largely covered by a veneer of Quaternary sand dunes. This is the first detailed investigation to be undertaken in this area, and is concerned with the improvement of the actual knowledge on the coastal geomorphology and ages of the sand dune cordons. The study is based on aerial photos and satellite images interpretation, with ground control. Optical stimulated luminescence (OSL) method was applied to date, for the first time, sediment samples from the sand dune cordons. Based on the major morphological features, Maputaland has two major geomorphological units: (1) the high vegetated coastal dunes cordon and, (2) inland dune complex. The high vegetated dunes cordon follows closely the present coastline, and it is in form of ridges of continuous irregular crest running NNE over a distance of 100 km. The dune cordon has a maximum width of around 2 km at the headlands, being only interrupted only at Ponta Dobela by an intermittently outlet from Piti Lake. They may attain locally a height of over 100 meters above the surrounding terrain. The coastal dune cordon is often punctuated by blowouts, and locally by washover sands. The sediments are mostly loosely packed of well-sorted, angular to sub-angular medium to fine sand, which rest on older dune cores, mostly Aeolianites and beachrocks. The inland dune complex has a flat to undulating topography with various palaeodunes cordons. The dune cordons are not continuous being often interrupted by corridors of coastal lakes, lagoonal marsh and alluvium, and small pans with peat that occupy the topographic lows between the dune cordons. There is a considerable variation in dunes relief, ranging from a maximum height of about 80 meters to a minimum around 20 meters. The sands are loosely packed of well sorted fine sand at the upper parts of the dune and become semi-consolidated at depth. The OSL age determinations indicate considerable age difference between the sampling sites within the inland dune complex, which ages ranges from 100 ± 9 to 31 ± 2 ka. The OSL age determination for the coastal dune cordon indicate an age of 5.4 ± 0.5 ka. The coastal geomorphology and the OSL ages indicate that during the Last Interglacial Maximum, Maputaland coastal plain may have evolved as a coastal barrier island complex, where sand ridges separated to each by tidal inlets were backing a lagoon and/or an estuarine system. 0234 Paleoecological responses of Belizean mangroves during Holocene sea-level change Natalie M Monacci1, Ursula Meier-Gruenhagen2, Bruce P Finney1, Hermann Behling3, Matthew J Wooller4 1

Institute of Marine Science, University of Alaska Fairbanks, United States Niedersaechsisches Institut fuer historische Kuestenforschung, Germany 3 Department of Palynology and Climate Dynamics, University of Goettingen, Germany 4 Alaska Stable Isotope Facility, University of Alaska Fairbanks, United States 2

Belize, located in Central America on the Caribbean Sea, has extensive mangrove ecosystems both onshore, along the coast, and offshore, on

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mangrove islands. Environmental change, such as sea-level variation, prompts these ecosystems to adapt over time. We conducted multi-proxy analyses of mangrove peat cores taken from Spanish Lookout Cay (core BT-79, 8 m) and from mainland Belize (core SR-63, 8.5 m), providing ~7000 year records. Within the peat, fossilized Rhizophora mangle L. (Red mangrove) leaves are preserved and are used for stable isotopic analysis. The stable carbon (13C) and nitrogen (15N) isotope compositions of these leaves were used as a proxy of this plant’s past physiology and stand structure. Dwarf R. mangle are generally phosphorus limited due partially to a lack of inundation of seawater while tall R. mangle have constant seawater replenishment. In the past, the BT-79 site is seen to have been predominantly a tall stand (13C 0.95) at 8000, 5000, 3300 and 1470 years. The 1470-yr cycle is the most significant, with the exception of the records reflecting climatic or environmental changes on land that show statistically significant 3300 and 8000 frequency bands. Once the main frequency bands were extracted from the proxy records, leads and lags between those with a D/O periodicity were calculated in the time domain. Accordingly, possible land–sea interactions can be identified and located in the frame of the temporal succession of the different climatic processes. Surprisingly, Saharan dust supply from Northern Africa appears to lead high-latitude climate changes suggesting that low-latitude feedback processes were involved in forcing the millennial climatic variability in the westernmost Mediterranean. 0026 Mid- and late Holocene changes in sea level and shoreline on Rarotonga, Cook Islands Hiroshi Moriwaki1, Mitsuru Okuno2, Toshio Nakamura3, Masashi Chikamori4 1

Kagoshima University, Japan Fukuoka University, Japan 3 Nagoya University, Japan 2

A Holocene coastal plain characterised by beach ridges and swamps, which provide excellent data on sea level and shoreline, is developed on Rarotonga of the Cook Islands in the south Pacific. We present here a model for mid- and late Holocene changes in sea level and shoreline for Rarotonga based on micro-landforms and surface deposits in the coastal plain, using air-photographs, level-equipment, power shovel, hand-borer and radiocarbon dates as well as general field survey. Sealevel change obtained is as follows: Sea level attained near-present levels c. 6000 BP, following early Holocene rapid sea-level rise. A gradual rise occurred until c. 4000 BP, when +1.5 m maximum height was attained. Sea level was essentially stable c. 4000 to c. 600 BP. Since c. 600 BP sea level has fallen to the present-day level. The sea-

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level curve is similar to others obtained in Polynesia. Hydro-isostatic movement is plausible to be responsible for this highstand, while recent sea-level fall since c. 600 BP is likely related to climatic change as discussed in western Polynesia. Shoreline changes have been greatly dominated by the sea-level change. Marine transgression attained most inland points c. 5000–6000 BP when sea level ceased rising rapidly and reached near-present sea levels. The shoreline began to prograde c. 4000 BP, which matches the culmination of sea-level rise. Coastal plain has expanded to the present coast conspicuously on northeastern coast, providing low flat area most suitable for human settlement. Post 600 BP sea-level fall resulted in slight emergence of the coastal plain, which had widely developed. This mid- to late Holocene coastal evolution helps to properly evaluate its relation to human occupation history as well as early human settlement in the Cook Islands. 0073 Holocene tephra beds in southern Kyushu, south Japan: their application to precise chronology of coastal evolution and human occupation Hiroshi Moriwaki1, Akio Ohira2, Yoshiaki Matsushima3 1

Kagoshima University, Japan Miyazaki University, Japan 3 Kanagawa Prefectural Museum, Japan 2

Coastal region on Kagoshima bay of southern Kyushu lies in a peculiar environment in the context of relative sea level, coastal evolution and human occupation, because it consists of a volcano-tectonic graben, which is dominated by some gigantic calderas and many intra-caldera volcanoes. Numerous Holocene tephra beds derived from those volcanoes make it possible to make precise correlation between coastal landforms, Holocene marine deposits in the coastal plains and archeological sites in this region. Here we present a precise correlation model based on tephra identification for relative sea-level change, coastal evolution and their relation to human occupation through the Holocene. The data for this aim are obtained from many bore holes and direct observation of surface deposits in coastal lowland and many archaeological sites on the lowland and surrounding upland, which contain several marker tephras. Tephras were identified with some stratigraphical, petrographical and chemical methods. We conducted diatom, molluscan-shell analyses to get palaeo-environments. Main results are as follows. Sea-level at around Younger Dryas aged by a marker tephra -Sakurajima-Satsuma tephra- is ca. -50m below the present sea level, while maximum elevation of sea level at around climatic optimum -7000 cal BP- aged by Kikai-Akahoya (K-Ah) tephra attains ca. +15 m above the present sea level. Mid-Holocene sea-level heights suggest upwarping of Aira caldera, one of the most active calderas, suggesting that volcano-tectonic activities of Aira caldera have been distinctly responsible for the coastal deformation in the Holocene. The studies on coastal evolution provide fundamental data to assess future volcanic eruptions in the Quaternary volcanic fields of this region. Distinct coastal progradation has occurred through the Holocene in this region, due to a great deal of sediment supply not only from several big tephra eruptions, but also from unconsolidated Quaternary ignimbrites widely occurring around coastal plains. Most distinct one is K-Ah ignimbrite eruption. We can widely recognize thick ash fall deposits of this tephra and secondary ash sediments in the marine deposits of coastal lowlands. Tephrochronological correlation between archeological remains, and coastal landforms and deposits precisely documents the human-occupation process in the coastal lowlands. Human occupation from upland to coastal lowland started at the

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beginning of emergence of lowland immediately after the culmination of marine transgression and has expanded associated with the coastal progradation.

0959 AMS C14 dating using pollen concentrate for sediments with low organic content in the tropics of Australia

1301 The Tibetan Plateau during the Holocene – forests or no forests?

Patrick T Moss1, Grant H McTainsh2, Gavin Dunbar3, Gerald Dickens4, Geraldine Jacobsen5

Volker Mosbrugger1, Xinmiao Li2, Tandong Yao2 1

Senckenberg Research Institute and Natural History Museum, Germany Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), China 2

The Holocene vegetation history is still a matter of debate. Pollen records seem to indicate that between 8000 and 5000 BP trees and forests covered major parts of Tibet up to 5000 m. Then, successive aridisation processes presumably led to a continuous decrease of forests; thereby an increasing human impact due to grazing may also have played a major role. On the other hand it is argued that long-distance transport of pollen is a major factor in pollen floras of Tibet and that forests never have been widely distributed above 4000 m. To solve this problem we investigate not only Holocene pollen floras but also present-day air-flow of pollen around NamCo in Central Tibet in combination with climate modelling. Our study indicates that there were indeed forests during parts of the Holocene and that climate change was not necessarily the only cause for a reduction in forest distribution. 0124 Mangrove development and decline on the northeastern Australian continental shelf for the last million years Patrick T Moss The University of Queensland, Australia

The ODP 820 marine core, situated on the continental slope, provides a high resolution record of both marine and terrestrial environment change for the humid tropics of northeastern Australia for the last million years. In particular, it provides a detailed picture of the response of mangroves (through fossil pollen) to alterations in sea-level over this time period. There is evidence of Rhizophoraceae-rich mangrove forests generally flourishing during transgressive events and being virtually absent during regressive events. A model has been developed that explains this pattern of mangrove development and decline. This models suggests transgressive events are characterized by a gentle gradient of drowning continental shelf (as sea level rises), availability of suitable environments (drowning estuaries and muddy sediments from rivers) and suitable climatic regime (i.e. increased precipitation), which allow extensive mangrove development. In contrast, regressions are typified by a lack of suitable environments (area of drowning estuaries is reduced due to falling sea level), lack of suitable sediments (sand rather than river muds), and reduced precipitation, which limits the scale of mangrove development. However, there are interesting exceptions to this model that deserve further attention. In addition, the development of the Great Barrier Reef within the last million years may have facilitated a progressively greater representation of mangrove forests in general by providing a more sheltered continental shelf environment for colonisation.

1

The University of Queensland, Australia Griffith University, Australia 3 Victoria University of Wellington, New Zealand 4 Rice University, United States 5 ANSTO, Australia 2

This study discusses the results of using pollen concentrate for AMS C14 dating of sediments with low organic content for two sites in the tropical north of Australia. The first site from the Mitchell Plateau in the Kimberly region of Western Australia is a swamp deposit within a small enclosed drainage basin, with a high content of inorganic sediments. Seven AMS C-14 dates have been obtained for the first 70 cm of this record, which provides a relatively consistent age chronology that stretches back 1670 BP and can be directly compared with pollen data from the same depths. The second site, ODP 820, from the humid tropics region of northeastern Queensland consists of marine sediments with high values of Calcium Carbonate. Several AMS C-14 on foraminifera have been obtained for this record, which provide a consistent age chronology for the first 8 m of the core and which is thought to cover the last 44,000 BP. More recently, seven AMS C-14 dates based on pollen concentrate have been obtained and have been directly compared with the forminiferal derived ages, as well as the core’s pollen record. The dates and concurrent pollen data provide a better understanding of the sedimentological processes, both marine and terrestrial, that have been operating in the region, as well as providing insight into the nature of the reworking of pollen grains in marine sediments. 0101 Neotectonics and genesis of shelf’s ferromanganese nodules (FMN) of Quaternary by the example of Finland Gulf (Baltic Sea) Andrej P Motov1, Natalia S Nikolskaya2, Andrej A Smyslov2, Irina A Kudinova2, Ivan A Popov2, Svetlana G Masepina2 1

JSC “PETROTRANS”, Russia

The acquired summary is based on the research data of the bottom sediments of the Finland Gulf, received from 25 000 sea-stations of their geological approbation. This work has been done by JSC “Petrotrans” in order to solve the problem of the Russian sector FMN reserves of the Finland Gulf search and estimation The FMN are located among Neocene sea sediments on the underwater terraces and canyons in depths of 21-75 m. The neotectonics role in genesis of these deposits is shown by the following facts: 1. The geochemical auras of FMN deposits are crossed by narrow linear raisings of the sea-bottom.

2. The linear form of the deposits extended in north-west direction, which is parallel to a direction of prodeleting of tectonic breaks in pre-Quaternary rocks of coast of Finland Gulf. 3. The FMN-ore deposits are located in the units of crossing of linear raisings and lowerings of the sea-bottom. 4. The non-facial heterogeneity of lithological profile with attributes of the creeps phenomena and occurrence of the tectonics gruss among terrigenous sediments.


The neotectonics processes attributes in aquatoria of the Finland Gulf are found by other authors while analyzing satellite photographs, the geophysical fields, structure and age of Quaternary sea-sediments. The FMN have modern origin, which is testified by numerous finds of modern artefacts (anchor circuits, screwnuts etc.), covered by these nodules. The ore-forming role of neotectonics is shown in creation of vibration fields, which provoke the fall-out of iron- and manganese-hydrooxides from sea water. The richest manganese-contenting nodules (Mn 15–30 weight %) are located in the narrow linear underwater canyons, controlled by linear breaks. In ore deposits, having isometric and irregular form, in which neotectonics processes are not very clear, the average Mn contents are lower (5–15 weight %). The meaning of the relationships between neotectonics processes and the genesis of the FMN of Finland Gulf is a follows: 1. It enriches our concept of geological localization links of shelf ferromanganese ores, what expands our estimation criteria of shelfaquatoria ore richness. 2. It makes the attitude towards designing of engineering communications at the bottom of Baltic sea, in particular, to projecting of North-European gas pipeline, which can be influenced by neotectonics processes, more attentive. 3. It emphasizes the exclusive position of FMN-ore as renewed mineral resource, the extraction of which stimulates ore-bearing. 0152 Positive influence of shelf ferromanganese nodules (FMN) developing on Baltic Sea ecology Andrej P Motov1, Natalija S Nikolskaya2, Andrej A Smyslov2, Irina A Kudinova2, Ivan A Popov2, Svetlana G Masepina2 1

JSC “PETROTRANS”, Russia

The conclusion about positive influence of shelf FMN mining from of Baltic Sea bottom seems paradoxical at first sight but only for those who do not know the composition and and the origin of FMN. FMN are products of modern ore-formation. It can be proven by different modern found artefacts (electrodes, anchor circuits, metal nails), covered with FMN. The speed of formation of FMN on these things is by experts calculations is about 0,15 per mm year. The main reason for FMN ore-formation is local supersaturation of Baltic sea waters with iron, manganese and phosphorus. These ore components are bound in FMN in special sites of neotectonics intensity. Neotectonics processes (particulary, vibrating) are the natural catalysts of fall-out of ore components from sea water. The places of modern ore-formation are outside of forage reserves of fish, in canyons and on sea terraces depths of 24-75 meters. The high contents of phosphorus in Baltic sea water is one of the main ecological problems, which is caused by wide usage of phosphatic fertilizers in Baltic countries in agricultural areas. During the XX century the phosphorus-content level in Baltic sea waters has increased in 5 times. This fact has led to increase of eutrophication of Baltic Sea waters, to spreading of seaweed, to superfluous organic formation, to destruction of organisms of benthonic layers, including fish. Comparison of the phosphorus content in FMN to phosphorus dissolved in Baltic sea water, indicates enormous phosphorus-capacity of FMN. According to our research, the FMN resource in Baltic sea makes 30 million tons FMN wet (15 million tons dry). The average

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phosphorus content in FMN of Gulf of Finland is equal to 1.75 weight % (3.98 weight % P2O5). Baltic Sea FMN contains 263 thousand tons of phosphorus. This mass of phosphorus, keeping in mind that its average content in Baltic Sea waters is 0,04 mg/l, is spread in volume 10520 km3. The volume of Baltic sea waters amounts to approximately 21000 km3. According to Brusendorff (2006), a reduction of the phosphorus contents by 35% in Baltic Sea waters must essentially improve condition of sea water. FMN phosphorus content with two-multiple excess provides the clearing of Baltic sea water to these 35%. Thus, extraction of self-renewed manganese ores of the Baltic Sea shelf zone can lead to improvement of an ecological conditions of Baltic Sea water. 1434 The skeleton of Palaeoloxodon antiquus from Eemian sediments from Belarus Alexander Motuzko Belarus State University, Geographical Faculty, Belarus

In the autumn of 2006, during construction of underground in Minsk at a depth of 9 meters from a surface the fossil remains of Palaeoloxodon antiquus (Falconer et Cautley) were found. The cranium of an animal with the left tusk was kept safe. The right, frontal and parietal bones were not kept. In a skull both from the right and from the left side a change of molars - M2 to M3 is observed. The bottom mandible with last change of molars (M3) remains untouched. Penultimate change of radical (M2) teeth is lost. Places of an attachment of these teeth in the bottom mandible were kept untouched. The bones of the post skeleton were partly damaged. The left humeral bone was completely undamaged. Only top articular surface of the right humeral bone is present. Radius and ulna bones were destroyed. Among metacarpus and carpus bones there is left the third metacarpus bone (metacarpus III), two carpus bones in the anatomic order and phalanxes: the two phalanx I, one phalanx II and one hoof phalanx. Pelvic bones were well preserved. Among bones of back extremites only the left litle tibia bone is present. Vertebre were kept safe and are submitted with: thorax vertebras – 7 pieces, lumbar vertebras – 4 pieces and sacral vertebras. Besides there are 21 ribs. At the moment the rests of Palaeoloxodon antiquus are on restoration in Laboratory of Taxidermy of the Zoological Museum of Belarus State University. Preliminary research of morphology of teeth of Palaeoloxodon antiquus has yielded the following results. The right M3 has length of crown 332 mm, width of crown −98.4 mm and heath of crown −162 mm. Number of plates on M3 is equal to 21. Frequency of plates −5.5 −6. Thickness of enamel is within the limits of 2.8–3.2 mm. The enamel sine is expressed poorly only in a back part the erased plates. For right M3 of the top maxilla there are such morphological characteristics: length of crown −332 mm, width of crown −91 mm, heath of crown −198 mm, number of plates −21, frequency of plates −6,0 and thickness of enamel −3.2–3.8 mm. The right M2 is strongly erased; therefore there are only 10 plates. Frequency of plates it is equal to 8.0 and thickness of enamel −2,5 mm. Width of crown M2 −94 mm.

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0679 Compound-specific hydrogen isotopes of sedimentary biomarkers to reconstruct Nam Co lake system response to Quaternary climate change Ines Mügler1, Gerd Gleixner1, Roland Mäusbacher2, Gerhard Daut2, Britta Schütt3, Antje Schwalb4, Tandong Yao5, Baiquing Xu5 1

Max Planck Institut für Biogeochemie, Jena, Germany Institut für Geographie, Friedrich Schiller Universität, Jena, Germany 3 Institut für Geographische Wissenschaften, Freie Universität Berlin, Germany 4 Institut für Umweltgeologie, Technische Universität Braunschweig, Germany 5 Institute for Tibetan Plateau Research, Beijing, China 2

Variations of the Asian Monsoon system affect the terrestrial environment at different spatial and temporal scales. One regional indication of monsoon strength fluctuations are lake level changes that are described for several Chinese lakes during the past 30000 years. Thus, lake sediments from Nam Co, Central Tibetan Plateau, covering the Holocene, were analysed for sedimentological, geochemical and biologic parameters in order to assess past monsoon induced lake sediment dynamics. As an upcoming proxy for palaeoclimate studies hydrogen isotopes of sedimentary biomarkers were determined in association with sedimentological parameters. This integrated approach based on different palaeoclimate proxies serves to improve the interpretation of biomarker isotopic signatures. Our results indicate that compound-specific hydrogen isotope ratios of aquatic and terrestrial derived sedimentary n-alkanes record the isotopic content of lake water and precipitation, respectively. Increased evaporation causes enrichment of deuterium in the residual lake water and leads to an isotopic difference between terrestrial and aquatic derived n-alkanes. This isotopic difference reveals both opposite directions and different ranges in humid and arid climate conditions. In contrast to the 30‰ enrichment of terrestrial n-alkanes relative to aquatic derived n-alkanes that are known for modern surface sediments in Central-European humid climate, the terrestrial n-alkanes from Nam Co are depleted by 50‰ relative to n-alkanes of aquatic origin. Taking into account the direction of the isotopic difference, this characterizes the general hydrology of lake systems. The application of this isotopic relationship between terrestrial and aquatic derived n-alkanes to the lake sediment sequence reveals phases of positive precipitation to evaporation (P-E) ratios associated with increasing lake levels. These can be distinguished from periods with negative P-E ratios during the Holocene. If the absolute value of this difference is considered, n-alkanes may serve as basis to quantify evapotranspiration rates and thus provide a new proxy for palaeo-evapotranspiration. This is a contribution to the research program ‘The Tibetan Plateau – Geodynamics and Environmental Evolution’ within the framework of a SinoGerman co-operation. 0680 Lake System Response Of Nam Co Area, Central Tibet, To Late Quaternary Monsoon Dynamics Ines Mügler1, Gerd Gleixner1, Roland Mäusbacher2, Gerhard Daut2, Britta Schütt3, Antje Schwalb4, Mosbrugger Volker5, Yao Tandong6 1

Max Planck Institut für Biogeochemie, Jena, Germany Institut für Geographie, Friedrich Schiller Universität, Jena, Germany 3 Institut für Geographische Wissenschaften, Freie Universität Berlin, Germany 4 Institut für Umweltgeologie, Technische Universität Braunschweig, Germany 5 Senckenberginstitut Frankfurt, Germany 6 Institut for Tibetan Plateau Research, Beijing, China 2

The hydrological cycle that controls Nam Co, the second largest saline lake in China, Central Tibet, is spatio-temporally assessed in order to

quantitatively reconstruct the past Asian Monsoon variability and its influence on lake sediment dynamics. This study presents first results addressing water balance changes as one indicator for variations of the Asian Monsoon circulation. Sub-bottom profiling and pilot coring provided initial information about the sedimentary history of the lake. Lake sediments from several long and short cores covering the Holocene were analysed for seismic, sedimentological, geochemical and biologic parameters that allow identifying phases of environmental change. Additionally, experimental and modelling work was carried out to reconstruct the isotopic signature of the lake. Thus, in a bottomup multi proxy approach including isotope ratios of ostracode valves and specific terrestrial and aquatic biomarkers the isotopic signature of the lake water and precipitation is reconstructed directly. These approaches are coupled with water balance reconstructions based on fluvial and littoral deposits along the lake margin. The integration of all these methods indicates that the hydrology of Nam Co changed before and after the Last Glacial Maximum. Beach ridges within the catchment imply pre-LGM high stands and the coarse sandy basement of the sediment sequence suggests lower lake levels before 8000 cal BP. Geochemical parameters point to a freshwater driven sedimentation until about 2000 cal BP with subsequent increasing aridity in the study area. The forthcoming synthesis with supporting proxy data on recent and past vegetation changes based on palynological analyses and detailed 14C dating will serve to interpret these primary results with regard to local and global aspects of Late Quaternary climate change. This is a contribution to the research program ‘The Tibetan Plateau – Geodynamics and Environmental Evolution’ within the framework of a Sino-German co-operation. 0683 Reconstruction of past asian monsoon variability on the Tibetan Plateau using compound-specific hydrogen isotope ratios of biomarkers from lake sediments Ines Mügler1, Gerd Gleixner1, Tandong Yao2, Baiquing Xu2, Guangjian Wu2 1

Max Planck Insitut für Biogeochmemie, Jena, Germany Institute for Tibetan Plateau Research, Beijing, China

2

The current monsoonal system over Central Asia provides precipitation for the Tibetan Plateau from air masses being developed at different moisture sources. Precipitation is therefore characterized by distinct compositions of its stable water isotopes (2H and 18O). As terrestrial archive for isotopes in precipitation, in this study lake surface sediments from a SE to NW transect along the Tibetan Plateau were analysed in order to reconstruct these hydro-climatic patterns. Isotopic ratios of H/D from organic biomarkers namely n-alkanes were determined and the 2H and 18O values of lake water and precipitation were measured. The 2H values from surface sediments from 5 lakes on the Tibetan Plateau and lake surrounding vegetation were then related to isotope data of environmental waters in order to (1) strengthen the interpretation of biomarker d2H data by establishing a transfer function between biomarker d2H value and precipitation and to (2) contribute to the understanding of the actual pattern of air masses and water vapour sources based on the isotopic approach. Compound-specific isotope ratio data along the transect covering an additional moisture gradient reveal that dD values of terrestrial and aquatic n-alkanes record the isotopic content of lake water and precipitation, respectively. An isotopic difference between terrestrial and aquatic n-alkanes resulting from the enrichment of either aquatic or terrestrial derived n-alkanes indicates the general hydro-climatic conditions of lake


systems with a positive direction in humid climate conditions and a negative direction in environments characterized by increasing aridity. 0301 Immediate vegetation response to abrupt Dansgaard—Oeschger climate change in the eastern Mediterranean region Ulrich C Mueller, Ulrich Kotthoff, Joerg Pross Institute of Geosciences, Goethe-University Frankfurt, Germany

To study the impact of abrupt climate change on Quaternary ecosystems in the eastern Mediterranean region, we performed a new coring campaign in the basin of the classical Tenaghi Philippon site (NE Greece). The core consist of fen-peat, lake-marls and intercalated tephra layers. Core recovery is 98%. Here we present a high-resolution study of the new core comprising continuously the interval of MIS 1 to MIS 4. To reconstruct the vegetation response to Dansgaard-Oeschger climate changes as known from Greenland ice-cores, we performed a palynological study with decadal- to centennial-scale resolution. The sample spacing varies between 1 and 5 cm, yielding an average temporal resolution between 45 and 220 years. The new pollen record reveals an immediate response of eastern Mediterranean vegetation to Dansgaard-Oeschger climate fluctuations. Even the shortest Dansgaard-Oeschger interstadials (such as Dansgaard-Oeschger interstadials 2 and 3) are reflected in a strong spread of tree taxa (including Quercus species) and a decrease of steppe elements such as Chenopodiaceae and Artemisia. It appears that the investigation site is located in a region of glacial plant refugia. Hence, plant-migration lags can be neglected in contrast to the more northerly Central European pollen records of the last glaciation. Furthermore, the new pollen record shows that the vegetation in the eastern Mediterranean region during the Last Glacial was predominately controlled by moisture availability. Dansgaard-Oeschger interstadials were linked to increased precipitation in the eastern Mediterranean region, whereas the stadials experienced a return of drier conditions. We conclude a very strong and direct coupling between the eastern Mediterranean region and the North Atlantic climate system during the interval of the last glaciation. 1416 Detecting environmental change and anthropogenic activities on the Laikipia plateau, Kenya Mwihaki Veronica Muiruri1, Marchant Robert Alstair2 1

National Museums of Kenya, Palynology Department, Kenya University of York, United Kingdom

2

Pollen, spore and charcoal analysis from Marura and Rumuruti swamps on the Laikipia Plateau Kenya reveals anthropogenic activities and climate variability in the Late Holocene. Specifically, a shift to open woodland dominated by Acacia and grasses and an increase in herbaceous taxa is indicative of an increase in disturbance. This ecosystem disturbance is likely to result from a period of clearance and agriculture intensification and/or Late Holocene climate variability. The reduction of Afromantane taxa such as Podocarpus, Olea, Rapanea, and the increase of Justicia and Asteraceae further imply an increase of human activities as surrounding forests were cleared for agricultural production. 1154 Paleoclimatic studies in India — An overview Prithviraj Mukundaraj Department of Science & Technology, India

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The last 2 decades had seen significant studies being carried out on palaeo-climatic studies, in India. Although these studies although have generated enormous quantity of data from different parts of the country viz. Himalaya, Indo-Gangetic Plain, Thar Desert, Gujarat Alluvial Plain, East and West coasts of India, Continental Shelves, etc., they still produce a rather sketchy palaeo-climatic history of the country. Paucity of absolute dates has been a major handicap in providing a firm chronology as high resolution palaeoclimatic data are not available from several parts and a few promising areas still remain unattended. Therefore, initiatives are being taken for consolidating the available information on the palaeoclimatic trend as perceived from glacial, fluvial, lacustrine and marine records. The basic understanding of the monsoon variation over the sub-continent, over the last 20,000 years and its projected trend, is another very important scientific problem having implications on the population of India as it has a profound influence on catchment hydrology and glacier related hazards. The response of fluvial systems to Late-Quaternary climatic changes is still poorly known as to the reasons for lags and leads in the fluvial responses, lake levels, sedimentation. One of the very important themes in future studies are also to separate changes caused by tectonic activity from changes that would have occurred primarily because of climatic variations. This paper attempts to consolidate some of the important outcomes of the research supported by the Department of Science and Technology (DST) in the area of Quaternary Climatic Studies in the last couple of decades and also present the recent initiatives in promoting co-ordinated research in this very important area of Earth Sciences in the coming decade. 0289 Vegetation and climate change of Quaternary sediments of Central Narmada Valley, India Ramachandra Rao Mulagalapalli1, Rajeev Patnaik2, Poonam Verma1 1

Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow, India CAS in Geology, Panjab Univesity, Chandigarh, India

2

The Narmada river of central India flows along an E-W lineament bounded by Vindhyans in the north and Satpuras to the south. The Quaternary deposits of Narmada Valley have recorded a variety of spore-pollen, mammals, vertebrates that can be utilized in reconstruction of vegetation and climate. These deposits are divided into Pilikarar, Dhansi, Surajkund, Baneta, Hirdepur, Bauras and Ramnagar Formations ranging in age from Early Pleistocene to Holocene. Based on the preliminary pollen analyses, a broad inference of vegetation vis a vis climate change around this area could be drawn. The pollen proxy recorded from Surajkund Formation has revealed that the area in the vicinity was covered with sparse grassland vegetation, chiefly constituting Poaceae, Asteraceae, Chenopodiaceae and Artemisia and the sediments were deposited under arid climatic condition. On the basis of the pollen/spores recovered from the samples from the Baneta Formation inferred between 24,000 to 20,000 BP, the area was covered with open vegetation constituting the grasses, Chenopodiaceae/Amaranthaceae and Asteraceae along with sparsely distributed trees viz., Symplocos and Holoptelea. The record of marshy elements such as sedges (Cyperaceae) and Polygonum together with the aquatic elements Potamogeton and Typha and algal spores such as Spirogyra and Zygnema denotes the existence of water bodies/ponds /lakes in the close proximity of the site of investigation. The overall vegetation assemblage is suggestive of the prevalence of a cool and dry climate regime during the period of sediment deposition. This vegetation scenario and corresponding climatic event is equivalent to the Last Glacial

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Maximum episode which has been globally documented between 18,000 to 22,000 BP. At 8740  450 BP, the area may have been covered with a dry deciduous forest represented by Terminalia, Mimosa, Pongamia and Artemisia under amelioration of climate when precipitation was some what higher than the earlier formations. Potamogeton and the frequent presence of algal spores also supports the view. This inference was also corroborated by the record of mammal assemblages comprising Stegodon namadicus, Equus namadicus, Hippopotamus namadicus, Sus namadicus and Cuon alpinus, suggests a warm climate with intermittent arid-humid phases in the late Middle Pleistocene. Vertebrate assemblages including cyprinid fishes, crocodiles, Hippopotamus palaeindicus, Elephas hysudricus may indicate a warm climate in the Early to middle Upper Pleistocene but the terminal part of the Upper Pleistocene may have become dryer as indicated by the presence of wild ass (Equus hemionus khur) and ostrich (Struthio camelus). 0670 A world bibliography of „Maars“ Dirk Müller1, Jörg F W Negendank1, Hermann Kaufmann2 1

c/o: GeoForschungsZentrum Potsdam, Germany GeoForschungsZentrum Potsdam - Sektion 1.4 Fernerkundung

2

Since 1970 Maars are in the focus of volcanic, limnological, paleoclimatological, paleoenvironmental as well as paleontological studies (world famous fossil grounds like Messel and Eckfeld (Germany) for the Eocene, China for the Miocene, etc.). In several countries Maar regions have been developed as Unesco Geoparks (Huguang Maar, China / West Eifel Volcanic field, Germany) and the first Maarmuseum was established at Manderscheid, Germany, where in 2000 the first International Maar Conference took place, covering all aspects (geological to touristic) of Maar craters. Therefore, it is our intention to develop a worldwide bibliography on Maars by visualizing it in google earth. The following proceedings have to be done: Collection and ordering of literature due to subjects. Programming of a .kml file to load into google earth for visualisation of the maarlocation on the planet. This file allows to search the respective maar and its corresponding information and literature. It is intended to establish a chronological order for the literature (Holocene, Pleistocene, etc.). First results are visible at the homepage: http://maarworldmap.gfz-potsdam.de. e.g.: Fischer, H., Kumke, T., Lohmann, G., Flöser, G., Miller, H., von Storch, H., and Negendank, J. F. W. (Eds.). (2004). The Climate in Historical Times: Towards a Synthesis of Holocene Proxy Data and Climate Models: Springer-Verlag, 488p.; Martin, U., Németh, K., Lorenz, V. and White, J.D.L. (2007). Maar-diatreme volcanism and associated processes, Journal of Volcanology and Geothermal Research 159(1–3): 1–312.; Negendank, J. F. W. and Zolitschka, B. (Eds.). (1993). Paleolimnology of European Maarlakes (Vol. 49): Lecture Notes in Earth Sciences, Springer-Verlag, 513 p.; Negendank, J. F. W. & Brüchmann, C. (Eds.). (2000). International Maar Conference MAAR 2000. August 20 – 23, 2000, Daun, Vulkaneifel (Vol. 2000/6): Terra Nostra, Alfred-Wegener-Stiftung, Berlin, 549 p. (Main Topics: Architecture of Maar Volcanoes, Formation of Maar Volcanoes, Maar Lake Sediments, Paleontology of Maar Lake Sediments, Hydrogeology of Maar Volcanoes – 80 extended abstracts).

0288 New study on the Late Pleistocene testate amoebae fauna from the Laptev Sea coast, Arctic Siberia, Russia Stefanie Müller1, Anatoly A Bobrov2, Lutz Schirrmeister3, Andrei A Andreev3, Pavel E Tarasov1, Frank Riedel1 1

Freie Universität Berlin, Institute of Geological Sciences, D-12249 Berlin, Germany 2 Moscow State University, Faculty of Soil Science, 119992 Moscow, Russia 3 Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, D-14473 Potsdam, Germany

The ongoing project dealing with the Late Quaternary interstadial and interglacial periods in the Eurasian Arctic aims to reconstruct environmental history of the region based of microfossil remains from permafrost sequences of NE-Siberia. In the current presentation we discuss newly obtained results of testate amoebae analysis from the Cape Mamontovy Klyk at the Laptev Sea coast covering the last 50 14C kyr. Testate amoebae (Protozoa: Rhizopoda, Testacea) often occur in moist environments and in peat bogs but they are also frequent in soils, especially in soils with a high organic content. They are one-celled micro organisms with a distinct organic shell (testa) and well-defined ecological preferences. This and good preservation of fossil shells provide a basis for the rhizopod analysis as a method for reconstruction of past environments and climates. As a result of the analysis differences of Pleistocene and the Holocene climatic conditions are reconstructed from the testate amoebae fauna. The main characteristic of fossil rhizopod complexes of Mamontovy Klyk is the dominance of eurybiotic soil genera, including Centropyxis, Cyclopyxis, Plagiopyxis and Phryganella. Fluctuations in species abundances and diversity make it possible to determine warm/cold and wet/dry periods during the late Pleistocene, in particular the Karginsky interstadial 50–30 kyr 14C BP and Sartan stadial 130–10 kyr 14C BP. It is obvious that climate changes were more drastic during the Pleistocene period. These changes were at least partly responsible for the disappearance of some rare testacean species (e.g. Argynnia sp., Paraquadrulla irregularis). Considering that the species diversity is a result of ecological and climatic conditions, we assume that the environments at the Laptev Sea coast were more favourable during the Karginsky interstadial with higher species diversity, and the climatic conditions were not that extreme as during the Sartan stadial. 0759 A deglaciation climate and ice sheet history of the Weddell Sea region from the Berkner Island ice core Robert Mulvaney1, Carol Arrowsmith2, Jean Marc Barnola3, Trevor McCormack1, Laetitia Loulergue4, Dominique Raynaud4, Volodya Ya Lipenkov5, Richard C A Hindmarsh1 1

British Antarctic Survey, United Kingdom NERC Isotope Geosciences Laboratory 3 Laboratoire de Glaciologie et Géophysique de l’Environnement, France 4 Laboratoire de Glaciologie et Géophysique de l’Environnement, France 5 Arctic and Antarctic Research Institute, Russia 2

A recent drilling project on Berkner Island, Antarctica, succeeded in retrieving a 948 m ice core to the base of the ice sheet, and penetrated a further 0.5 m into the basal sediment, recovering a sample of fine pure quartz sand. Initial analysis of the water stable isotopes and iceentrapped methane shows that the Berkner ice core contains a record of climate change spanning the last glacial cycle. The transition from the Last Glacial Maximum to the Holocene spans a depth of 300 to


350 m above the bed, allowing a well-resolved record of the deglaciation period. We present the initial data, including stable isotopes, gases, and soluble chemistry, and discuss the potential to determine the climate history of the Weddell Sea region (a source of cold bottom water to the Atlantic). Results suggest that Berkner Island may not have been over-ridden by ice from the AIS as in some ice sheet models, and it was likely to have been an independent ice rise throughout the glacial cycle. However, preliminary total air content results, supported by a large glacial to interglacial shift in stable isotope data, suggest that the Berkner ice sheet was considerably thicker at the LGM, though probably not as thick as models have suggested. We calculate the likely contribution to sea level rise during the deglaciation, and the timing of the ice thinning and retreat from this region. 0841 Investigating post-glacial environmental gradients with lacustrine sedimentary records: an example from the Uinta Mountains of northeastern Utah, U.S.A Jeffrey S Munroe Middlebury College, United States

The physiography and location of the Uinta Mountains in northeastern Utah provide a unique opportunity to investigate the evolution and/or persistence of environmental gradients during the post-glacial period. The mountains form the longest east-west oriented range in mid-latitude North America (~150 km), allowing paleoenvironmental records to be compared between slopes with north and south aspects. The range also straddles a modern climate boundary, with the eastern part receiving more than half its annual precipitation from the summer monsoon, while the western sector receives the majority of its precipitation from Pacific frontal systems during winter months. Thus paleoenvironmental records from the opposing ends of the range offer the potential for illuminating past changes in precipitation patterns. To capitalize on these opportunities, continuous sediment cores were retrieved from 20 lakes clustered in six parts of the range: east, central, and west across both the north and south slopes. The lakes range in elevation from 2960 to 3475 m, from 4 to 20 m in depth, and from 1 to 45 ha in area. Retrieved cores range from 140 to 370 cm in length; the upper ~10 to 100 cm was too loosely consolidated to be successfully retrieved with the percussion corer. Age control is provided by more than 100 AMS radiocarbon dates on terrestrial macrofossils, daphnia ephippia, and pollen concentrates. Basal sediment in the cores dates to the latest Pleistocene, while core tops range from 2000 to 500 years old. Loss-on-ignition at 550 ˚C was calculated at 1-cm intervals for all cores as a proxy for organic matter content, yielding a dataset of over 5000 samples. Analysis of these records reveals that mean LOI per lake is inversely proportional to elevation. Nearly all cores penetrated deep enough to record the transition from inorganic to organic sedimentation in their respective lakes. This switch occurred ca. 12 ka BP in most lakes, and appears to have taken less than 1000 years. Lakes from the monsoon-dominated eastern Uintas record enhanced inwashing of terrestrial material during the early Holocene, consistent with heightened monsoon activity during the insolation maximum. Many LOI records from lakes in the drought-sensitive western Uintas record a pronounced LOI minimum between 4.4 and 4.0 ka BP, synchronous with a climate reorganization noted in the northern Rocky Mountains and a major drought event in middle North America. Efforts to investigate additional proxies in these cores, including biogenic silica and C:N ratios, are ongoing.

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0786 Basal conditions beneath a West Antarctic ice stream Tavi Murray1, Andy M Smith2, Keith W Nicholls2, Keith Makinson2 1

Swansea University, United Kingdom British Antarctic Survey, United Kingdom

2

The nature of a glacier’s bed affects both its flow and the landforms that are left behind when it retreats. Direct observations from beneath ice masses are, however, rare. Particularly poorly constrained is the degree to which a glacier is de-coupled from its bed and moves by basal sliding, or is coupled to its bed and deforms the sediments beneath it. We present repeat seismic observations from beneath a modern ice stream in West Antarctica, and use the acoustic impedance across the basal interface to map the basal topography, and spatial and temporal changes in the porosity of the basal sediments, High porosity sediments are interpreted as actively deforming whereas low porosity regions represent lodged sediments, over which the ice mass is sliding. The surveys reveal both deformation and sliding occurs beneath the ice stream. We identify regions of both mobilisation and increased compaction of basal sediment between surveys, with associated hydrological changes within the bed. Topographic changes show erosion at a rate of 1 m a-1 beneath the ice stream, followed by cessation of erosion and the formation of a drumlin from fully mobilised sediment. All these changes occurred on timescales of a few years or less. The spatial variability shows the ice stream bed consists of a patchwork of sliding and deformation, and the temporal variability that an ice stream can reorganise its bed rapidly. Present models of ice dynamics may not yet simulate all the relevant subglacial processes. 1417 Fluvial responses to vertical crustal movements Late Weichselian climate changes: the Berettyó Körös System, E-Hungary Annamária Nádor, Árpád Magyari, Edit Thamó-Bozsó, Edit Babinszki Geological Institut of Hungary, Stefánia ut 14, H-1143 Budapest, Hungary, Hungary

This paper presents a case study from a subsiding setting in the eastern part of the Pannonian Basin on the evolution of fluvial systems during the Late Pleniglacial and Late Glacial times. Fine-grained sandy-silty channel-belt and floodplain deposits of the Berettyó-Körös rivers, a main eastern transverse tributary system of the modern Tisza river in the eastern part of the Pannonian Basin, were deposited during the Late Pleistocene under net subsiding conditions. The palaeo-drainage network pattern of a 2500 km2 large part of the alluvial plain was reconstructed based on interpretation of airborne photographs and analysis of 18th century topographic maps, which show the natural river patterns. The investigation showed that a large meandering river system, with two main channel belts surrounding a floodbasin, entered the alluvial plain from the northeast, and a braided river entered the alluvial plain from the southeast. Sedimentary logs of seven continuous corings and several sand and clay-pit sections were used to characterize different alluvial units. Optical luminescence dating (OSL) of 25 quartz samples and four 14C datings showed that the sediments are of Late Pleniglacial to Late Glacial age. Transport directions inferred from heavy mineral analyses combined with the OSL ages suggest that the large meandering system represents the palaeo-Tisza river, which supposedly flowed along the northeast-southwest striking Érmellék depression during the Late Pleniglacial. The interpretation of seismic profiles, field measurements of neotectonic activity, and variations in thickness of sediments along the studied profile revealed that river development was largely controlled by subsidence along the Érmellék depression until 14 to 16

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ka, and by uplift of the southeastern part of the catchment area. The studied fluvial successions also document the response of the palaeoTisza and Körös system to the climate changes of the Weichselian Late Pleniglacial – Late Glacial period. Much of the sand from the meandering zones was deposited during the Bølling-Allerød and Ságvár-Lascaux interstadials, whereas some dated sand units from the braided zone represent the Older and Younger Dryas. The error ranges of OSL dates, which often exceed the duration of Weichselian substages and subdivisions, prevented an unambiguous correlation of the studied sections with the millennial-scale climate changes of the last 25 ka. Meandering and braided river activity coexisted under different climate conditions, whereas locations of the main channel belts are related to subsidence anomalies. The results of our study thus clearly indicate that tectonics was the primary control on river development. 0778 Paleoproductivity changes during the Holocene in the inner shelf of Cabo Frio, Southeastern Brazilian Continental Margin Renata H Nagai, Silvia HM Sousa, Michel M Mahiques, Leticia Burone, Daniel PV Alves Institute of Oceanography of the University of São Paulo, Brazil

Sedimentological and microfaunal analyses of a core collected in the inner shelf of the Cabo Frio upwelling zone, were used to understand productivity changes along the Holocene in the Southeastern Brazilian Continental Margin. Grain size analysis was carried out and AMS radiocarbon datings were obtained. The 125 µm and 63 µm size fractions were analyzed for benthic foraminiferal composition, and foraminiferal test accumulation rates (BFAR) values were calculated. This index was obtained as a product of sedimentation rates and the number of dead specimens in 10 cm3 of sediment. Statistical analysis was also applied for definition of microfaunal assemblages. Between 9000 and 7000 years B.P., under conditions of sea-level lower than the present, the occurrence of a Pseudononion atlanticum assemblage and the high BFAR values obtained, indicate higher nutrient availability, related to a more conspicuous continental input, lower oxygen levels and relative low sand content probably derived from a less intense local circulation. Since 7000 years B.P., under sea level conditions similar to the present, changes in the microfaunal composition (Globocassidulina subglobosa - Bulimina marginata assemblage) as well as variable BFAR values are observed. This probably reflects a smaller continental influence and an alternation between periods of low and high nutrient availability, probably linked to more intense circulation conditions, as shown by the Globocassidulina subglobosa frequencies and increase of sand content. Periods of increasing productivity observed in the last 5000 years may be associated to the intensification of the upwelling regime in the area. 0253 Stratigraphy and age of Quaternary basaltic lavas around the Chongok-ni Paleolithic site, Korea Shinji Nagaoka1, Tohru Danhara2, Tetsumaru Itaya3, Tetsuya Sakuyama4, Mitsuhisa Watanabe4, Kidong Bae5, Kazuto Matsufuji6 1

Nagasaki Univ., Japan Kyoto Fission Track Co.Ltd., Japan 3 Okayama University of Science, Japan 4 Tokyo Univ., Japan 5 Hanyang Univ., Korea 6 Doshisha Univ., Japan 2

The stratigraphy and chronology of Quaternary basaltic lavas, which originated from Ori Volcano, around the Chongok-ni Paleolithic site, are based on the field survey, XRF, EPMA, and K-Ar and fission track dating. The basalts are subdivided into two stratigraphic units: the Chongok basalt and the Chatan basalt. The former is older than the latter. There is distinct uncomformity such as erosive valley and soil between the Chongok and the Chatan basalts. They are typical alkali olivine basalts and their phenocrysts compositions and grandmas are almost same. They can be distinguished only by whole-rock major and trace element composition, but the differences are very slight. For example, wt% of SiO2 in the Chatan basalt is just 1% higher than that of the Chongok basalt. The results of plagioclase K-Ar dating of 18 samples from both basalts and fission track dating of 4 burnt soil show that the Chongok basalt is 0.5 Ma old and the Chatan basalt is 0.15 Ma old. The Chongok-ni Paleolithic site is on the Chongok basalt. The age of the site is in 0.5-0.15 Ma. Based on basal topography of the two basalts and fluvial sediments, the Hantan River near the Chongok Paleolithic site changed the channel from northwest to southeast during the last 0.5 Ma. 1044 Impact of the Kikai-Akahoya eruption (7.3 ka cal BP) in Osumi Peninsula, southern Kyushu Island, Japan Toshiro Nagasako1, Hiroshi Moriwaki1, Mitsuru Okuno2, Mariko Matsushita3, Yoshiaki Matsushima4, Akiko Matsubara5, Fusao Arai6, David J Lowe7 1

Kagoshima University, Japan Fukuoka University, Japan 3 Human and Forest Laboratory, Japan 4 Kanagawa Prefectural Museum of Natural History, Japan 5 Keio University, Japan 6 Deceased, Japan 7 University of Waikato, New Zealand 2

Five large rhyolitic calderas and associated central volcanoes form an aligned volcanic front in middle to southern Kyushu Island, southwest Japan. The latest eruption with accompanying voluminous pyroclastic flow (pfl) from these calderas was the Kikai-Akahoya (K-Ah) eruption, which occurred in southernmost Kikai Caldera c. 7.3 ka cal BP. The K-Ah tephras (VEI 7) represent the largest Holocene eruption for Japan. Both the natural environment and human societies suffered serious damage from the climax Koya pfl especially, but detailed understanding of the extent and duration of such damage is limited. For example, it appears that earthenware style was discontinued and that lucidophyllous forests, destroyed by the Koya pfl, took ~1000 years to recover. Recent archaeological studies deny the discontinuity theory of earthenware, however. Therefore, this study aims to reveal the extent and duration of this volcanic impact and recovery process in the Kimotsuki River basin, where thick alluvial deposits provide the most comprehensive archives for Holocene landscape evolution in southern Kyushu. The K-Ah event provides a key marker for environmental change in this fluvial succession. A composite stratigraphy of alluvial and coastal sediments has been synthesised from mapping tephras and sediments and from the Kushira-Yoshimotobashi core. During mapping, the continuity of outcrops and sections was emphasized to enable correlations to be made. The main findings are as follows. (1) Although the K-Ah eruption undoubtedly had big impacts on land surfaces dynamically, and played an important role in sediment supply, such impacts endured for fewer than a few hundred years, and the landscape system had recovered and attained its equilibrium adapted to contemporary climate/sea-level conditions (2) Landscape recovery comprised


three steps: (i) mass-wasting (re-working of tephra until stable conditions were attained); (ii) appearance of temporary adaptations (continuation of desolate environments); and (iii) maturation (increase of ecological diversity). Limited resolution of the palaeoenvironmental archives means that the timing or duration of these steps is imprecise. (3) Because the Koya pfl aspect ratio was low - i.e. similar to that of a pyroclastic surge – it did not affect land environments uniformly in the area of reach nor in neighboring locations. An understanding that this physical impact was not uniform spatially is essential for evaluating the impact on ancient human society. 0252 Environmental records for recent decades in Jinheung Pond sediments (Jeongeup, Jeollabukdo, Korea) Wook-Hyun Nahm1, Gyoo Ho Lee2, Dong-Yoon Yang1, Ju-Yong Kim1, Kenji Kashiwaya3 1

Korea Institute of Geoscience and Mineral Resources, Korea Korea Gas Corporation, Korea 3 Institute of Nature and Environmental Technology, Kanazawa University, Japan 2

This paper describes the mean grain-size data of the 137Cs-dated sediment core BS-3 (35 cm long) recovered from Jinheung Pond with a dyke built in 1945, located in the southwestern part of the Korean Peninsula. Grain-size analysis of Jinheung Pond shows a clear climate signal for the past 60 years. Instrumental records of annual rainfall and excess 50 mm rainfall (annual summation of the excess of more than 50 mm per day), which are reflecting the energy available for sediment transport, correlate well with the mean grain-size distributions measured from core BS-3. The most plausible mechanism for this response in mean grain-size is variation in the annual amount and intensity of precipitation. Generally, heavy precipitation would enhance the soil erosion over the catchment area and increase the transport capacity of streams and/or rivers, and in consequence coarser mean grain-size reflects increased precipitation rates, and vice versa. However, in the grain-size distribution of core BS-3, the increased grain-size peaks attributed to increased annual precipitation are not so conspicuous. This is partly due to that the dyke obstructs the outlet flow to remove fine particles from the pond. Therefore, the mean grain-size value represents somewhat larger sediment altogether with fine clays. The results of this study make the sediments of pond and/or lake with dyke highly suitable for further past environmental investigations with a very high time resolution, especially for the record of declines in precipitation. 0366 A new high-resolution, Quaternary glacimarine stratigraphic record of Antarctic glacial and climate history: a preliminary stratigraphic framework and cyclostratigraphy for the ANDRILL McMurdo Ice Shelf Project drill core Tim R Naish1, Ross D Powell2 1

GNS Science and Antarctic Research Centre, Victoria University of Wellington, New Zealand 2 University of Northern Illinois, United States

In the austral summer of 2006–2007 the ANDRILL Program undertook its first drilling project on the McMurdo Ice Shelf in the northwest part of Ross Ice Shelf where it has been pinned by Ross Island for the last ~8ka. The drillsite was situated above a flexural moat basin adjacent to Ross Island that had formed in response to Quaternary volcanic loading of the crust, superimposed on more regional subsidence asso-

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ciated with Neogene extension of the Terror Rift. Multichannnel seismic reflection surveys linked to a regional stratigraphic framework implied accumulation of a succession over 1km-thick spanning the last 5–10 Ma. The drill rig was sited on an 85m-thick ice shelf floating over an 840 m-deep seawater column. The rig employed a wire-line diamond-bit coring system through a tide-compensated sea-riser, which was kept free from the ice shelf, by a hot-water over-reamer. Drilling recovered a 1285 m-thick succession of probable Late Miocene to Recent, cyclic glacimarine sediment with interbedded volcanic sediments, lava and tuffs contributed from the surrounding alkalic volcanoes of the McMurdo Volcanic Group. Core recovery rate was better than 98%. An integrated chronostratigraphy based on 40Ar/39Ar numeric ages on primary volcanic deposits, a paleomagnetic stratigraphy, and a diatom biostratigraphy provides a preliminary age model for the upper 500m, and implies a detailed record spanning the Middle and Late Pliocene, and Middle to Late Pleistocene. The stratigraphic architecture of the core is strongly cyclic, with three dominant cycle motifs reflecting oscillations in glacial proximity. Repetitive vertical successions of facies bounded by ice contact surfaces show regular fluctuations between subglacial, ice proximal and ice distal open marine environments. Pleistocene cycles are characterized by a thick interval of subglacial massive diamictite passing up into a thin interval of grounding-line proximal interstratified mudstone, sandstone and volcanic sandstone. Early-Middle Pliocene cycles display subglacial to ice proximal massive and stratified diamictites in their lower parts passing up into proglacial interstratified sandstone and mudstone followed by open water, ice distal mudstone. The Middle to late Pliocene is dominated by strongly cyclic alternations between diamictite and diatomite of probable Milankovitch duration. An ~100 m-thick Early-Middle Pliocene interval of diatomite shows no apparent glacial cyclicity and represents an extended period of ice-free conditions. 0404 Regulation of the monsoon climate by two orbital forcing rhythms Takeshi Nakagawa1, Masaaki Okuda2, Hitosh Yonenobu3, Norio Miyoshi4, Toshiyuki Fujiki5, Keiji Takemura6, Shoji Horie6 1

Department of Geography, University of Newcastle, United Kingdom Natural History Museum and Institute, Chiba, Japan 3 College of Education, Naruto University of Education, Japan 4 Faculty of Science, Okayama University of Science, Japan 5 Graduate School of Environmental Studies, Nagoya University, Japan 6 Institute for Geothermal Sciences, Faculty of Science, Kyoto University, Japan 2

The 100 ka eccentricity cycle is the dominant control of global glacialinterglacials through the late Quaternary, while the 23 ka precessional cycle often appears to be more influential in longitudinal tropical sea surface temperature gradient and monsoon intensities. Although both cycles can be explained by independent orbital rhythms, their relationships and interaction are not fully understood. The long pollen profile from Lake Biwa (the largest lake in Japan) covers the last four glacialinterglacial cycles (0 – 450 ka). Analysis of this record indicates that the temperature in the region typically oscillated on eccentricity timescales (100 ka) following the global trend of glacial-interglacial cycles. In contrast, precipitation was predominantly controlled by precession (23 ka), the dominant control on insolation over Japan. A key to understanding this phenomenon lies in the land-ocean temperature gradient. Though temperatures of land and ocean air masses both show dominant

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100 ka cycles, the gradient between them shows stronger 23 ka (and 41 ka) cycles. This is because the 100 ka cycle does not discriminate between land and ocean, and therefore cancels itself out when the gradient is calculated. Unlike the glacial-interglacial cycle, direct solar forcing is able to heat land and ocean differentially, because the heat capacities are different. For this reason, the temperature changes of land and ocean air masses at precession (23 ka) and obliquity (41 ka) bands do not cancel out. This generates change in the land-ocean temperature gradient, directly driving the monsoons. This interpretation is consistent with observations, particularly for the period when the amplitude of insolation change (which is linearly controlled by eccentricity) is relatively large. When the amplitude is low (i.e. eccentricity is low), glacial-interglacial changes appear to take control over monsoon changes. The threshold between those two conditions lies at the eccentricity value of 0.024. 0555 PolyCounter ver.1.0 & Ergodex DX-1: a cheap and very ergonomic electronic counter board system Takeshi Nakagawa Department of Geography, University of Newcastle, United Kingdom

How to count pollen grains quickly is one of the principal concerns of all palynologists. Due to image recognition systems still being at the experimental stage, we normally need to count pollen grains with our own eyes. Some people take their counts directly onto paper which is an obviously time-consuming process. Banks of tens of mechanical counters are a considerable improvement. However, the problem remains of transcribing the counts onto paper and/or typing them into a computer. A few computer programs have been proposed to make use of ordinary keyboards (or ten keys) as a bank of counters. These programs did not succeed in getting large appreciation in the community mainly because (i) computer keyboards are not ergonomically suitable for blind use as counter boards, and (ii) ten keys are insufficient to count large numbers of fossil pollen taxa. Here we propose a solution. PolyCounter ver.1.0 is newly developed PC software, which allows us to use a computer keyboard as a set of 45 counter keys plus 3 shift keys. By combining counter and shift keys you can count up to 135 (= 45 x 3) taxa by a very quick single action and save the results in an Excel spread sheet. Ergodex DX1 is an ideal keyboard developed by an American venture, which enables us to enjoy full performance of PolyCounter. It is literally a 100% customizable, amazing keyboard with which you can place any key in any position you like. Therefore, you can choose perfect ergonomic alignment of counter and shift keys. Using this keyboard, you can minimize the risk of pressing wrong keys (and even if you did it, the software has an “undo” function). Demonstration of both the PolyCounter software and Ergodex DX-1 keyboard will be available at the poster presentation. Upon request we will also demonstrate Polygon 2.0. This is an updated version of Polygon, the user-friendly free PC software for pollen-based quantitative climate reconstruction and calibration of the reconstruction results. PolyCounter and Polygon can be downloaded free of charge from our website (http://dendro.naruto-u.ac.jp/~nakagawa/). Ergodex DX-1 is available at around $200 plus shipping cost. Distribution is worldwide (http://www.ergodex.com/mainpage.htm). 0520 Double-L channel: an amazingly non-destructive method of continuous sub-sampling from sediment cores Takeshi Nakagawa Department of Geography, University of Newcastle upon Tyne, United Kingdom

If you have ever recovered sediment cores by yourself and sub-sampled from them at high-resolution, for more than three different people for different analyses, perhaps you can clearly remember and will never forget the disappointment in seeing the cores appear thoroughly exhausted. Worse still, the cores no longer appear tidy. Instead, they are full of cracks and are not in suitable condition for further high-resolution or continuous sub-sampling. There is a solution. A newly developed “double-L channel” technique, which is a sort of modified U-channel technique, allows you to take as many continuous sub-samples (of any size) as you like without disturbing the rest of the core. All you need is a pair of L-channels and a fishing line. You simply insert two L-channels one by one from the core surface, so that they make a U shape in section, and cut it off from the core using fishing line. Unlike U-channels, double-L channels allow you to repeat sub-sampling from the same core very easily. This is achieved by applying one new L-channel to protect the shoulder and inserting another one so that they again become a U shape in combination. Moreover, sub-samples recovered in double-L channels are extremely easy to cut and transfer to your test tubes. By sliding one channel downward the samples will be fully exposed sitting on the remaining L-channel, protected from only two sides instead of three, which is the case with U-channels. 0542 Synchronous Holocene onset between the North Atlantic and Japan (Suigetsu updates following IntCal04) Takeshi Nakagawa1, Christopher Bronk-Ramsey2, Hiroyuki Kitagawa3, Yoshinori Yasuda4 1

Department of Geography, University of Newcastle, United Kingdom Research Laboratory for Archaeology and the History of Art, University of Oxford, United Kingdom 3 Faculty of Science, Nagoya University, Japan 4 International Research Centre for Japanese Studies, Japan 2

The floating tree ring chronology of Kromer et al. (2004) together with IntCal04 brought about a significant impact on Lake Suigetsu climate reconstruction studies, by showing that the overall agreement between Suigetsu and Cariaco 14C data series (which was the basis of discussions around synchrony and asynchrony of late glacial climate changes between the North Atlantic and Japan) had to be lost. Given this, and assuming that the radiocarbon calibration model has become almost free from the marine reservoir effect down to the c. 14,100 BP horizon, we made an attempt at revising the correlation model using d14C wiggles and Bayesian approaches for wiggle matching (Bronk-Ramsey in press). The result showed the Holocene onset in Japan clearly marked by an abrupt rise in temperature at c. 11,550. Within error, this was synchronous to the Holocene onset in the Cariaco Basin grey scale record, but was substantially later than the Holocene onset in the NGRIP d18O curve (c. 11,750 BP). Some minor climatic oscillations at bicentennial time scale during the Bolling/Allerod equivalent warmer period (SGPI-1) also became synchronous to N. Atlantic minor cooling events. Onset of the Younger-Dryas equivalent cold reversal episode in Japan (SGPS-1) was more gradual than abrupt, unlike in the circum Atlantic regions. The beginning of the transition phase was also synchronous to that of Cariaco basin. However, the completion of the transition was lagging behind Cariaco by c. 250 yrs. Based on this evidence, we hypothesise that the North Atlantic ocean circulation and solar changes both control climate of circum Atlantic regions and Japan. However, the relative importance of solar forcing in Japan is higher than in the North Atlantic where the solar factor tends to be overwhelmed by the ocean circulation factor. When those two forcing agents work in opposite directions, the climatic response in Japan


becomes more gradual, as is typically the case for the YD onset. When by contrast they operate in the same direction, it is reflected as abrupt climate changes in Japan too. 1222 14 C dating and tree-ring analysis of wood circle monuments excavated at the Mawaki archeological site, Ishikawa prefecture, Japan Toshio Nakamura1, Katsuhiko Kimura2, Hiroshi Nishimoto1, Hideki Takada3 1

Center for Chronological Research, Nagoya University, Japan Faculty of Education, Fukushima University, Japan 3 The Noto-machi Board of Education, Japan 2

The Mawaki archaeological site, in the middle of the Noto Peninsula, located in Ishikawa prefecture, Japan, is located on an alluvial coastal plain of about 11 ha, facing Noto Bay in the south, and surrounded by hills in all other directions. According to the excavation surveys conducted in 1982/83, it was recognized that the site was occupied almost continuously for ca. 3500 years from the early Jomon to the latest Jomon periods (5900 cal BP to 2400 cal BP). Ten years after the first excavation survey, a second survey was initiated in 1997. During the second survey, traces of several wooden circles were clearly recognized. One of the wooden circles is 7 m in diameter outlined with ten half-cut wooden poles, with the largest pole 93.6 cm diameter. The four poles were found in this survey, but the other six poles forming the wooden circle were reported in the previous survey. These 10 wooden poles are all chestnut trees. To investigate the archaeological meaning of this ancient wooden circle remnant as well as its complete structure from the chronological viewpoint, we have conducted 14C dating and tree-ring width analysis of the excavated woods. First, we have radiocarbon-dated the four newly recovered woods to be from 2518±34 to 2665±34 BP, which are quite consistent with each other to suggest their simultaneous construction. To estimate more accurate date of the construction of the circle remnant, we are preparing to estimate dates of cutting the woods by 14C wiggle-matching method. For wigglematching and ring-width analyses, we separated tree-ring sections in radial possessing all tree rings from woods forming the wood circle, by using a handy electric saw. Each ring width was analyzed with a microscope in 0.01mm precision. In addition, to obtain ring-width data for previously excavated half-cut woods in 1982/83, we took a photograph of cross sections of tree trunks, and measured ring-widths on the computer images. The ring-width data of a wood were tried to match to those of other trees to test the overlapping period when both trees were grown simultaneously. Among the woods used to construct the circle, we recognized that two pairs of them grew in the simultaneous period. These chronological data will provide the important data to investigate when and how the seven wooden circles were built and re-built each other at around 900 to 800 cal BC. 1087 An alternative way to transport iron from inland area to open ocean and its implications for past changes in ocean productivity – Intermediate Water Iron Hypothesis Takeshi Nakatsuka, Jun Nishioka Institute of Low Temperature Science, Hokkaido University, Japan, Japan

Most of paleoceanographers believe that an indispensable micro nutrient for phytoplankton growth, iron, is supplied to open ocean as atmosphere aerosol from inland areas. Here, we present a new hypothesis

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that open ocean ecosystem is supported not only by atmospheric iron but also by intermediate water iron flowing from coastal areas. This hypothesis is based on our ongoing research “Amur-Okhotsk Project” by Research Institute of Humanity and Nature, Kyoto Japan. Amur River is the largest river in Russian Far East and discharges about 300 km3/a of water. Because there are many wetlands in Amur River watershed, dissolved iron concentrations of river water are about 1mg/l, which is 1 million times higher than that in open ocean surface. Most of the riverine dissolved iron precipitates by flocculation around river mouth located at the northwestern shelf of Okhotsk Sea. Oceanographers have been considering that iron precipitated at river mouths is isolated by sedimentation and cannot be utilized by phytoplankton. However, in fact, the precipitated iron does not deposit on the shelf, but is re-suspended on bottom by strong tidal current and penetrating into offshore intermediate layer. The reason why the shelf bottom water penetrates into the intermediate layer is that it is very dense due to brine water rejection by sea ice formation. The particulate iron discharged into the intermediate layer does not settle down easily, because of scarce numbers of organisms there, which scavenges fine iron particles, and can be transported not only to the whole Okhotsk Sea but also to the northwestern North Pacific being equilibrated with dissolved iron. As a result, we can detect extremely high concentrations of dissolved and particulate iron in the intermediate depths of northwestern North Pacific. The upward flux of intermediate water iron by eddy diffusion and upwelling can explain very high primary productivity there without considering atmospheric iron supply. This iron transport through intermediate layer depends on combination of uniqueness of Amur River and Okhotsk Sea, but has many implications for paleoproductivity in regional and global scales (1) Past productivity changes in northern North Pacific must be evaluated relating to this system, because the intermediate water iron actually regulates present productivity. (2) Land-ocean linkage through atmospheric iron must be reconsidered because intermediate depth flows from shelf and slope supply certain amounts of iron to world open ocean and oceanographers have not reached reliable budgets of atmospheric iron in oceanic surface waters. 1140 Late Quaternary glacial history and paleoenvironmental changes from the Eastern Arctic Ocean Seung-Il Nam1, Ruediger Stein2, H K Lee3, J J Bahk1, S W Chang5, Christoph Vogt4, Jens Matthiessen2 1

Korea Institute of Geoscience and Mineral Resources, Korea Alfred-Wegener-Institute for Polar and Marine Research, Germany 3 Department of Industrial Chemistry, Sangmyung University, Korea, Korea 2

Stable isotopes of planktonic foraminifera N. pachyderma sin., organic-geochemical proxies (C/Norg ratios, stable carbon and nitrogen isotopes of organic matter and rock-eval pyrolysis), bulk mineralogy and grain-size distribution (including IRD contents) were investigated on two sediment cores PS66/321-4SL and PS66/325-3SL taken from the Eastern Arctic Ocean during the “Polarstern” ARK-XX/3 expedition (2004). This study is mainly to reconstruct late Quaternary glacial history and paleoceanographic changes along the Svalbard continental margin underlying the Atlantic water inflow. Moreover, organic-geochemical proxy data were used to delineate characteristics and origin of organic matters being deposited in the Arctic glaciomarine sediments. Based on the stratigraphic framework, both sediment cores revealed distinct paleoenvironmental changes related to the repeated waxing and waning of Svalbard/Barents Sea ice sheet (SBIS), Atlantic water inflow and sea-ice coverage during the past 200 ka. In general,

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glacial stages are distinctly characterized by increased TOC coinciding with high C/Norg ratios, light 13Corg values (24.5‰) and 15Norg values (7‰). 0130 Middle to late Quaternary alluvial and aeolian stratigraphy of the Channel Country, central Australia Gerald C Nanson1, Jerry C Maroulis2 1

University of Wollongong, Australia

The Channel Country rivers of central Australia have undergone cyclical flow-regime changes broadly associated with the global climatic cycles of the Quaternary. They are characterised by mixed-load sandy stratigraphies representing the more humid interglacials and interstadials, and muddy surficial cappings mostly deposited during the drier glacials and stadials. Periodic episodes of lateral channel-migration in association with gradual vertical accretion has resulted in sequential reworking of the overbank muds and the formation of an extensive Quaternary-age sand body (the Katipiri Formation) now underlying most of the floodplains. These sands are presentative of Oxygen Isotope Stages >19 to 6, during which the entire (up to 60 km wide) floodplain was reworked. The last period of substantial sand transport on Cooper Creek occurred during the last interglacial (mid-Stage 5, ~100 ka), although only about half the floodplain was reworked. Central Australia appears to have become progressively drier and less fluvially active over the past several glacial cycles. Some sand transport has continued through to late Stage 4 (~65-60 ka) but this greatly declined in early to middle Stage 3 (60 to ~35 ka). There has been an increasing proportion of alluvial mud deposited that is representative of reduced flow energy from Stage 4 onwards, with the contemporary system almost entirely mud dominated. Remarkably, these extensive fines are transported as bedload aggregates, not dispersed as suspended load. This characteristic, along with the swelling properties of the clays, has led to the unique array of flood-channel styles and gilgai patterns that are diagnostic of the present Channel Country. During the fluvial sandtransporting phases of Stages 5 and 3, source-bordering dunes were formed, the remnants of which protrude through the mud-capped floodplain. These dunes are stratigraphically connected to their parent fluvial-sand bodies, aeolian evidence of conditions significantly wetter, not drier, than the present. Australia is now too arid and not sufficiently seasonal for source-bordering dune formation. Despite the aridity since their formation, these dunes have not migrated, further proof of the exceptional stability and longevity of the Australian dunefields. The Channel Country is a vast largely-unexplored repository of diverse evidence for Australian Quaternary climate and flow regime changes. 0131 Climate change and linear dune formation in Australia Gerald C Nanson1, Cameron Hollands2 1

University of Wollongong, Australia

Broad-crested linear dunes cover about 40% of Australia and constitute about 40% of the world’s dune area. Given this extensive distribution, it is surprising that so little is known as to how they actually form. In cen-

tral Australia, the easterly extent of the MacDonnell Ranges borders the Simpson Desert. In Camel Flat basin, widely spaced strike ridges intercept and isolate pockets of broad-crested linear dunes. Between about 75 ka and now, regional changes in Late Quaternary climate and flow regime associated with periodic avulsion of the Todd River have destroyed portions of the older dunefield, producing desert surfaces and associated dunes of younger age. This chronological diversity has enabled a study of the evolution of linear dunes. Large, widely-spaced fine-grained red dunes, 75–65 ka in basal age, occur on the western floor of the basin that has been isolated from fluvial activity. They are ramped against the footslopes of the Train Hills that block their migration northwards. The paucity of aeolian sand accumulated against this range, and the detailed luminescence chronology of the dunes in the basin, indicate negligible downwind sand and dune migration over this considerable period. We propose three models of possible linear dune formation: (1) long distance sand transport with linear extension; (2) windrift linear-extension; (3) windrift vertical-accretion. Linear dunes in the northwestern Simpson Desert are formed mostly by wind rifting involving the vertical accumulation of sand swept from adjacent swales and dunes (Model 3) and some linear extension as sand becomes trapped in the lee of the nose of the existing dune (Model 2), but not as has been previously proposed by long-distance sand transport with linear extension (Model 1). Linear dunes evolve by becoming larger and more widely spaced, growing by vertical accretion (Model 3), as they cannibalise adjacent, smaller, more closely-spaced dunes. 1423 Mid and late Quaternary changes of the climate and hydrology of Australia; where, when, why and by how much? Gerald C Nanson University of Wollongong, Australia

Although not glaciated to any significant extent, there is no doubt that Australia has experienced dramatic climatic and hydrological changes during the mid and Late Quaternary. Rivers in the more humid regions carried channel-forming discharges during OI Stages 5 and 3 that were at least 5-6 times larger than those of our present interglacial (Holocene), whereas rivers in the now arid interior have almost certainly changed proportionately more. Stages 7 and 6 appear to have been even wetter and more fluvially active, suggesting that Australia has been drying out since the mid Quaternary. This presents clear evidence for past periods of substantially greater rainfall over much of the continent. Although temperature changes and their impact on ice volumes and global sea levels are well documented, it is much less clear why there have been major changes in the moisture regimes of the mid latitude continents of South America, Australia and Africa. Some researchers in Australia have invoked changes to the monsoon, and changes in vegetation influencing changes to the monsoon. But in the present interglacial, Australia’s monsoon is relatively weak and nowhere on the globe today, over vegetated or unvegetated terrain, do monsoonal weather systems pay more than infrequent visits to the mid latitudes. Even today, Australia’s largest river basin, the Murray, can be profoundly affected by snowmelt. Throughout the vast majority of the mid to Late Quaternary Australia was substantially cooler than at present, providing an environment even less likely than today’s to have been penetrated by the monsoon. Yet the rivers of these cooler periods required sustained rainfall to form to a size their palaeochannels show they regularly achieved. This presentation looks at the present synoptic weather systems causing flooding in Australia, it proposes how these would have changed during times of higher and lower global tempera-


tures, it assesses where and when on the Australian continent rivers were substantially larger, and it suggests where this additional moisture could have to come from. Onto this mid latitude continent of greatly fluctuating climate and hydrology, humans arrived in the Late Quaternary, and some of our megafauna became extinct. Controversy abounds as to what cause what, where, when and by how much. Critical to resolving these arguments, or indeed possibly showing that they can’t be resolved by simple chronological correlations, is an understanding of global continental palaeohydrology (GLOCOPH). 0939 The evolution and stability of peat-swamp channels, Barrington Tops, New South Wales, Australia Rachel A Nanson Australian National University, Australia

Geomorphology, geochronology, palynology and hydrology are used to assess the development and stability of two channeled swamps on the Barrington Tops plateau. Channel stage-data demonstrate regular water exchanges between the contemporary channels and adjacent swamp watertables, indicating a dynamic but stable hydrological relationship between them. Stratigraphic data indicate the incision of Edwards Swamp at ~1200 BP and 800 BP along Edwards Creek and the Barrington River, respectively, and the incision of Polblue Swamp at ~1000 BP. Two swamp units are identified: the upper floodplain, comprised entirely of peat, and the inset floodplain, underlain by interbedded peat and fluvial sediments. Radiocarbon dating indicates rapid vertical growth of the inset floodplain on the Barrington River from ~800 BP to ~530 BP, following incision, and palynological data indicates a change from saturated pre-incision to wet swamp flora postincision. Bankfull stage-height is remarkably consistent along the length of each swamp channel, is achieved many times in a year and limits swamp floodplain growth rates and height by controlling swamp water-table height and hence the growth rates of swamp vegetation and peat. These data suggest the likely control of channel dimensions on inset swamp unit height and the co-evolution of the inset alluvial swamp and channel reaches. 0450 Tephrostratigraphy of deep East Antarctic ice: current knowledge and perpectives Biancamaria Narcisi1, Jean Robert Petit2 1

ENEA, Italy CNRS-LGGE, France

2

Air-fall tephra layers preserved in south polar ice represent excellent tools to (1) solve stratigraphic and dating issues, (2) infer past air mass trajectories, and (3) reconstruct the explosive history of Southern Hemisphere volcanoes. Systematic tephra investigations have recently been accomplished on the last 200,000 year sections of the Vostok, Dome Fuji and EPICA-Dome C core records, East Antarctic Plateau. These records have provided a wealth of detailed information on the evolution of climate, environment and atmosphere over the last glacialinterglacial cycles. Results of tephra studies indicate that these cores, which are up to 2000 km apart and are located in different positions with respect to Quaternary volcanic sources, show similar magnitude of recorded tephra frequency (1–2 per 20 ka). Sources of volcanic ash, identified by geochemical match, are South Sandwich volcanoes in the Southern Atlantic Ocean, Southern Andes, South Shetland Islands (close to northern Antarctic peninsula), and Antarctic provinces. The

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preponderance of events originating in the south-western part of the Atlantic region supports the picture of efficient westerly winds spiraling towards the Antarctic interior deduced from remote sensing and continental dust studies. Through comparison of chronostratigraphic and geochemical features, a few distinctive ash layers have been traced in more than one ice core, allowing precise stratigraphic links and independent comparison of palaeoclimatic records across the East Antarctic Plateau. Ongoing studies are directed towards extending tephra correlations to newly recovered Antarctic ice cores (e.g. EPICA-Dronning Maud Land, Talos Dome) and circumpolar marine archives, and towards prolonging the regional tephrostratigraphic framework to older ice sections. Isotopic dating of East Antarctic core tephra is hampered to the very low amount of available ash material and fine grain size, nonetheless tephra events can provide independent age constraints for ice flow dating models, when they are tied to radiometrically dated eruptions. This is the case of the core tephra that has recently been correlated with a 92 ka well-dated eruption from Marie Byrd Land province, West Antarctica. This essay, representing the first identification of a dated volcanic horizon in deep East Antarctic ice core sections, demonstrates the potential of tephra studies for improving the ice record chronology. Finally, East Antarctic glass shard fingerprinting provides evidence for previously undocumented tephra-productive eruptions, thus improving the volcanic stratigraphy of remote Antarctic and subantarctic vents. 0018 Documentary evidence of climate variability in the Kingdom of Lesotho, Southern Africa, 1824–1900 David J Nash1, Stefan W Grab2, Stephanie C Mills2, Puleng Morake2 1

University of Brighton, United Kingdom University of the Witwatersrand, South Africa

2

This paper presents the first nineteenth century climate history for the Kingdom of Lesotho, southern Africa, derived from documentary evidence. The primary data sources were unpublished English-, Frenchand Sesotho-language materials archived in Lesotho, South Africa and the UK. These included letters, journals and reports written by missionaries and colonial authorities, which were supplemented by published newspapers, diaries, travelogues and other historical sources. Each of the sources was read in chronological order, with any climate information recorded verbatim. This included details of catastrophic events such as droughts, floods or snowstorms, general observations of weather, and indirect evidence of climatic variability such as harvest failure and river levels. French- and Sesotho-language materials were subsequently translated into English. Individual quotations were sorted into chronological order according to the date/period to which the documentary evidence referred. Annual records were then classified into five categories (Very Wet, Relatively Wet, ‘Normal’, Relatively Dry, and Very Dry) based upon the predominant climate during each ‘rain-year’ (July to June) to produce an overall annual nineteenth century climate chronology for Lesotho. The latter portion of this chronology was then compared for accuracy against available precipitation data from 1886 –1900, with which it showed broad agreement. The results yield a continuous record of climate information from the early 1830s (following the arrival of the first French missionaries in Lesotho) to 1900. Prior to this, observations are more sporadic. Data are mostly restricted to lowland areas, but reveal extended drought or relatively dry episodes in 1833–34, 1841–43, 1845–47, 1848–51, 1860– 63, 1867–69, 1876–80, 1882–85 and 1895–99, the most severe of which occurred in 1848–51 and 1860–63. Extended wet periods or flood episodes were identified in 1835–36, 1838–39, 1840–41, 1847–

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48, 1854–55, 1863–65, 1873–75, 1880–81, 1885–86 and 1890–92, including widespread flooding in 1840–41 and 1890–91. Other weather phenomena, such as heavy snowfalls, severe frosts, ‘whirlwinds’ and ‘tornadoes’, are also reported. The climate chronology is compared with similar records for South Africa and Botswana, and possible forcing mechanisms such as teleconnections associated with the El Niño-Southern Oscillation considered. 0359 Earliest co-cultivation of foxtail millet and rice from the middle of Yangtze River basin, central China Hiroo Nasu1, Arata Momohara2, Yoshinori Yasuda3 1

The Graduate University for Advanced Studies (Sokendai), Japan Faculty of Horticulture, Chiba University, Japan 3 International Research Center for Japanese Studies, Japan 2

This study shows earliest evidence for co-cultivation of foxtail millet (Setaria italica) and rice (Oryza sativa) from the Chengtoushan archaeological site (ca. 5800 cal BP), Hunan Province, central China, and discuss its significance for the development of Yangtze River Civilization in this area. Chengtoushan archeological site is located on the loess terrace which juts out above the alluvial plain of the middle of Yangtze River basin. This site is known as one of the oldest cities of the Yangtze River Civilization in China. The moat and fortification surrounding the site, which has a maximum diameter of 360 m, belong to the Qiujialing culture (ca. 5300–4500 cal BP). Within and stratigraphically below the Qiujialing fortification, three pairs of older fortifications and moats that belong to three stages of the Daxi culture (ca. 6400–5300 cal BP) have been excavated. Macrobotanical analysis was completed on sediments from these three stages of moats of the Daxi culture. A total of 18,500 cm3 of moat deposits were washed in water and total of 121 grains of foxtail millet, numerous remains of rice (155 carbonized grains and 764 uncarbonized glumes) and 100 perilla (Shiso: Perilla sp.) fruits were found. In addition to these cultivated crops, we found a lot of accompanying weeds from same samples. The weed assemblages shows farmland and ruderal weeds increased from early stage to the end of Daxi culture. These results indicate that rice agriculture was started on the alluvial plain surrounding the site from early Daxi culture, and millet agriculture was probably started from middle of Daxi culture (ca. 5800 cal BP) on the loess terrace in this site. Millet cultivation on the loess terrace is practiced possibly against natural disasters as flood from Yangtze River. Co-cultivation of millet and rice caused sustainable food supply for people living around the site and possibly contributed development of Yangtze River Civilization. 1366 Preliminary paleolimnological data from a Santiago Island coastal lagoon, Galapagos Archipelago, Ecuador Ashley Natt1, Simon Haberle2, Geraldine Jacobsen3 1

Environmental Biology, University of Adelaide, South Australia, Australia Department of Archaeology and Natural History, Australian National University, Canberra, ACT, Australia 3 Australian Nuclear Science and Technology Organisation, Menai NSW, Australia 2

The Galapagos Islands are arguably the most famous islands in the world. This fame derives from the Islands’ rich biological history and unique locality that provides opportunities for research in the fields of evolution, geomorphology and biodiversity. Furthermore, the unique geographical location of the archipelago has in the past and continues

to provide excellent potential for palaeoclimatology, palaeolimnology and palaeoecology. In particular the location of the islands within what is essentially the heart of the ENSO region ensures the islands are frequently influenced by El Niño driven precipitation events. These El Niño precipitation events are extremely influential, given that the islands location within the Pacific Dry Zone (PDZ) ensures the islands have a semi-arid climate ( MIS 9.3 > MIS 11.3 > MIS 1 > MIS 7.5. This order is nearly similar as that recorded by oxygen isotope curve of Lisiecki and Raymo (2005) and the hydrogen isotope curve of the EPICA Dome C ice core, but differs from those of hydrogen isotope, carbon dioxide and methane concentrations in the Vostok ice core and oxygen isotope of the Dome Fuji ice core in Antarctica. Relative sea-levels during the last five interglacial peak plateaus as well as during warmest event in each plateau were estimated using a mean slope (i.e., 5 m sea-level change = 0.1‰ oxygen isotopic change). The estimates suggest that the sea-levels during warmest events at middle MIS 1 and 5.5 were higher by 2.7 m and 6.9 m respectively than during average MIS 1 and probably higher than present sea-level. These sea-level estimates at MIS 1 and 5.5 appear consistent with previous results of sea-levels and paleoceanographic reconstructions for seas surrounding Japan. The average sea-levels at MIS 5.5, 9.3 and 11.3 were higher than during average MIS 1, although more high-resolution oxygen isotope analysis is still needed in particular between MIS 7 and MIS 11. Further, for reliable predictions of the future trends in Earth’s climate forced by global warming, detailed investigations particularly focusing MIS 5.5 and MIS 11.3 are essential. 0488 Middle Stone Age artefacts from Sterkfontein Caves, South Africa Christine A Ogola1, Christine A Ogola2, Kathleen A Kuman2 1

NATIONAL MUSEUMS OF KENYA, Kenya UNIVERSITY OF THE WITWATERSRAND, South Africa

2

Middle Stone Age (MSA) lithic assemblages were first reported from Sterkfontein Caves in the 1950s and 1960s by R. J. Mason and J. T. Robinson, who excavated an assemblage from an upper surface rubble


and colluvial deposit. Mason classified this assemblage as later Pietersburg – a younger phase of the South African MSA. Through decalcification pockets within older breccia, this assemblage has in places infiltrated the Member 5 East early Acheulean infill, creating a mixed assemblage. In the 1990s, additional MSA deposits were identified by Kuman and Clarke in an area slightly west of the sample published by Mason called the Post-member 6 Infill. The material in this Post-Member 6 Infill is richer in quartz artifacts and bi-polar technique and may belong to an earlier phase of the MSA than the later Pietersburg described by Mason. This younger infill appears to be continuous with the adjacent Lincoln Cave deposit in the northwest portion of the site, which has been studied by S.C. Reynolds. While the Lincoln Cave North deposits have not yielded MSA artifacts, two flowstones were dated with the uranium series method to the MSA period: 116,000 years for the upper flowstone and 252,000 years for the lower flowstone. Although the Lincoln Cave South deposits have not been dated, they do contain some MSA-diagnostic stone tools. This paper provides a comprehensive discussion and technological evaluation of the MSA material from these various contexts at Sterkfontein.

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lake: lake level decreases during periods with persistently high wind speeds from westerly directions whereas it increases during periods with more frequent easterly winds. On a synoptic scale these situations are linked to a strengthening of the Southern Hemispheric Westerlies and to a more frequent occurrence of so-called polar outbreaks from the South Atlantic. Since lake volume controls the potential for autochthonous lacustrine carbonate precipitation, the sediment carbonate content can be used to reconstruct recurrence patterns of these weather conditions along an extended timescale. A reconstruction for the last millennium based on a gravity core highlights the potential of applying this approach to improve the interpretation of the sedimentary record. 0470 Influence of the spread of Picea abies on the late-Holocene Scandinavian fire regime Mikael Ohlson1, Richard HW Bradshaw2, Kendrick Brown3, Greger Hörnberg4, John B Birks5 1

Norwegian University of Life Sciences, Norway University of Liverpool, United Kingdom 3 Geological Survey of Denmark and Greenland, Denmark 4 Swedish University of Agricultural Sciences, Sweden 5 University of Bergen, Norway 2

0221 Monitoring meteorological, hydrological and geochemical processes – a tool to quantify effects of climatic forcing on lacustrine sediments (Laguna Potrok Aike, Argentina) Christian Ohlendorf1, Torsten Haberzettl2, Andreas Lücke3, Christoph Mayr4, Gabriel Oliva5, Frank Schäbitz6, Michael Wille6, Bernd Zolitschka1 1

Geomorphology and Polar Research (GEOPOLAR), Institute of Geography, University of Bremen, Germany 2 Geoscience Center, University of Göttingen, Germany 3 Institute of Chemistry and Dynamics of the Geosphere, ICG V: Sedimentary Systems, Research Center Jülich, Germany 4 GeoBio-Center, LMU Munich, Germany 5 Estación Experimantal Agropecuaria Santa Cruz (INTA), Argentina 6 Seminar for Geography and its Didactics, University of Cologne, Germany

The 100 m deep maar lake Laguna Potrok Aike (52°S, 70°W; 113 m a.s.l.; diameter: 3.5 km) is one of the few permanent lakes in the dry steppe of south-eastern Patagonia, Argentina. This terminal lake is sensitive to changes in the hydrological regime as evidenced by terraces above and below present day lake level. Our process studies demonstrate that changes in the water volume of the lake lead to changes in the carbonate system, which in turn can be traced in the past using the sedimentary record. One major prerequisite for this approach is a thorough understanding of the causes for lake level variations in relation to overall climatic conditions and to sediment forming processes. Here we demonstrate how the comparison of calculated and measured lake level data enhances our possibilities to interpret the sedimentary record of Laguna Potrok Aike. Investigations rest upon an extensive monitoring program in and around the lake established since AD 2002. This includes an automatic meteorological station in 990 m distance to the lake shore and a mooring located at the deepest, central part of the lake with a pressure sensor recording lake level fluctuations and thermistors in different water depths, both logging continuously, as well as two integrated sediment traps. Based on water chemistry, bathymetric information and calculations of the local radiation balance we performed hydrological balance calculations by combining an energybudget with a bulk-transfer method. The calculated lake level changes closely follow measured data determined by the pressure sensor. These data indicate that lake level variations are mainly driven by the precipitation/evaporation-ratio. Among meteorological factors, wind strength and wind direction influence the hydrological balance of the

Climate variability has been proposed as the chief driving force for changes in fire regime, though changes in vegetation composition and structure are also known to exert regulatory control. Understanding the relative importance of these factors is important in forecasting the likely future fire risk associated with climate change. To assess the relative roles of these factors, a spatially extensive network of 75 forest soil profiles was collected throughout Norway and Sweden. The soil samples were analysed for their concentration of large charcoal fragments and scanned for spruce pollen. Large charcoal fragments were targeted for analysis because they are representative of local burning. Our data show that the invasion of Picea abies, a forest tree that rose to dominance in Scandinavia during the late Holocene, was significantly associated with reduced local fire incidence over a sub-continental area. Our findings indicate that a change in the biotic components of the forest ecosystem alter fire regime, largely independent of regional climate change. Models that forecast fire risk should take vegetation composition into account. This is an example of a significant biological feedback to the global climate system acting through the rate of carbon transfer from the land surface into the atmosphere. 0098 Regional development of river basins in the Olkiluoto-Pyhäjärvi area, SW Finland Antti EK Ojala, Hanna Virkki, Jukka-Pekka Palmu, Kalevi Hokkanen, Juha Kaija Geological Survey of Finland, Finland

Biosphere assessment forms one of the main components in Posiva’s Safety Case portfolios of nuclear waste management. It includes analyses of terrain and ecosystem development, such as shoreline displacement and changes in surface hydrology. This paper describes the regional development of the Olkiluoto-Pyhäjärvi area in the time period 2000 BP – 8000 AP taking into account changes in the surface flow patterns of the Lapinjoki and Eurajoki river basins. A hydrological model, EULA, was developed and applied to investigate the past and future hydrological regimes and changes in the Olkiluoto-Pyhäjärvi study area. As detailed assessment of erosion and sedimentation

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effects were not within the scope of this study, only their general effects were evaluated. The digital elevation models (DEM) for different time stages (2000, 1500, 1000 and 500 BP; 100, 300, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 6000, 7000 and 8000 AP) were compiled taking into account the post-glacial land uplift and tilting of the Earth’s crust. With the aid of sophisticated GIS tools, the boundaries of the main river basins, the flow patterns of rivers and development of lakes during each stage were modelled. The yearly discharge rates of rivers Eurajoki and Lapinjoki were also evaluated with the assumption stable climatic features prevail during the modelled time-slices. Finally, the probability of significant changes in the surface water flow routes and development of possible future lakes in the Olkiluoto vicinity were estimated during different stages. The EULA model for 2000 BP shows an additional river basin between the Ancient Lapinjoki River basin and the Ancient Eurajoki River basin that becomes part of the Ancient Lapinjoki River basin between 1500 and 1000 BP. Between 2000 BP and the present, the shoreline has slowly transferred towards the SE due to land uplift and tilting of the basin, but the largest watercourses, lakes Pyhäjärvi and Köyliönjärvi have remained unchanged. Olkiluoto Island will become a part of the mainland and the Future Lapinjoki River basin within the next 100 years. A major change in the hydrological systems occurs between 500 and 1000 years AP when the river basins will form a single hydrological unit called the Future Eura-Lapinjoki River basin. The tilting causes gradual transfer of the Lake Pyhäjärvi shoreline towards the SE, but according to the EULA model for 8000 AP the Future Lake Pyhäjärvi will still be draining towards the NW into the Future River Eura-Lapinjoki. 0241 Quaternary geology of earthquakes: the new horizons Koji Okumura Hiroshima University, Japan

Geologists and geomophologists have been studying active tectonics including the source faults of hazardous earthquakes for many decades. However, it is only a decade or two that seismologists took geologic information on yet-to-happen earthquakes into their databases. In Japan, for example, earthquake hazard maps and insurance rates had been based only on instrumental and historic catalogs until 2005, 10 years after the 1995 Kobe earthquake. The 1995 disaster from an unexpected source finally let the hazard community to take Quaternary geology into account. The 1995 Kobe earthquake had been forseen because it did rupture a mapped fault, but not publicly forecasted. Most Quaternary faults have been mapped in Japan by 1990, but the significance of those faults were recognized only after 1995. Since 1995 intensive studies on paleoearthquakes were conducted in a very much interdisciplinary manner. As to on-fault paleoseismology, trenching are often impossible because many Quaternary faults in Japan are either erased by human activity or concealed. Then various methods of geophysical investigation, bore-hole and geoslicer transects, sedimentary and structural analyses and many other techniques are integrated on fault. Off-fault paleoseismology brought important finding on shaking records and on subduction interface earthquakes. Cooperation of geologists with archaeologists and historians made the time-series of Nankai trough earthquakes more complete. Together with those shaking records in archaeological sites and tsunami records in coastal marshes, now we are able to differentiate types of subduction earthquakes as a multiple segment event, a slow-slip tsunami-genic event, or a smaller event. The finding of a paroxysmal subduction earthquake

in the southern end of the Kuril trench is another important finding. The investigation by GS Japan was started from the discrepancy between uplifted Pleistocene marine terraces and consistent recent subsidence recorded by tide gauges. The hypothetical 17th century paroxysmal subduction event was confirmed first by sedimentological analyses of tsunami deposits with tephrochronology, and then micropaleontological analyses of coastal marshes. The latter data revealed detailed coseismic and postseismic vertical movements of the coastline. Finally, tsunami distribution and height, geologic gauging, and historic information on the tsunami are integrated to model the paroxysmal earthquake. Similar to the study of the great 1700 Cascadia earthquake, the study on the southern Kuril paroxysm marks the significance of Quaternary science in mitigation of extreme hazards. Though we cannot rule out all epistemic uncertainties and limitation, integrated multidisciplinary research is the key to learn more about the natural hazards. 0500 Comparison of pollen spectra during interglacial periods since MIS11, obtained from marine clays of 300-m cores offshore Kobe, Japan Nobuo Ooi1, Naoko Kitada2, Keiji Takemura3 1

Onp Laboratory, Japan Geo-Research Institute, Japan 3 Kyoto University, Japan 2

Two 300-m cores offshore Kobe, interbeded several marine clay layers of Osaka group, since c.a. 500,000 years ago. Marine clay layers were deposit during the periods of high sea level, that is, warm phases of climatic oscillation. Fossil pollen assemblages of these clay layers, thus, recorded the vegetation changes during interglacial periods. Marine clay layers of study cores are correlated to Ma8 to 13, which number is assigned to marine clay layers of Osaka Group from bottom by geological studies. Ma9 of Osaka group is corresponding to MIS11, Ma10 is corresponding to MIS 9, Ma11, which divided into three sub layers 11a, 11b, 11c, corresponding to MIS7.5, 7.3, 7.1, respectively Ma12 to MIS5.5, and Ma13 to MIS1, late glacial, or Holocene. The pollen spectra of two cores resemble to each other and show the characteristics of each marine clay layers. The pollen assemblages of Ma9 (MIS 11) dominated by evergreen Quercus and Castanea/Castanopsis/ Lithocarpus pollen, indicate an extreme warm climate, which can correlate to global warming of MIS 11. Sciadopitys pollen also occurred commonly from Ma9. Pollen spectra of Ma10 to Ma12 show similar patterns, particularly Ma10 and 12 (last interglacial) resemble each other. Alnus pollen dominated at the bottom, then deciduous broadleaf tree pollen such as Fagus, deciduous Quercus, Carpinus/Ostrya, and Ulmus/Zelkova increased, Pinus occupied high percentages, and evergreen Quercus pollen characteristically occurred but not so common as Ma9 and Ma13, and Cryptomeria pollen dominated at the top. Pollen spectra of Ma11, which are divided in to three sub layers, show repetition of the sequence mentioned above, although they are not clear because of low resolution. We can find some differences and trends from Ma10 to Ma12. For example, Pseudotsuga/Larix pollen characteristically occurred in Ma11, and Tsuga pollen increased and Fagus pollen decreased from Ma10 to 12, which would reflect a dryer climate caused by the rise of the Rokko Mountains behind the Kobe. Pollen spectra of Ma13 (Holocene) show different pattern from the lower marine clay layers. Evergreen Quercus and Castanea/Castanopsis/Lithocarpus pollen remarkably occurred but not continuous as Ma9, and Celtis/Aphananthe pollen showed the peak before the peak of evergreen Quercus pollen. Furthermore, plenty of charcoal fragments are observed with


pollen, which merely occurred lower marine clay layers, suggesting fire caused by human activities. 1421 The great arc of human dispersal (Plenary talk) Stephen J Oppenheimer School of Anthropology, Oxford University, United Kingdom

During the Late Pleistocene, anatomically modern humans (AMH) dispersed out of Africa across continents. Their routes obeyed the limitations placed on any large terrestrial mammal dependent on daily drinking water, following certain climate-permissive corridors. AMH spread north, with game, across the Sahara to the Levant during the Eemian interglacial (c.125Ka), but failed to continue to Europe, then occupied by Neanderthals. The brief savannah ecosystem in North Africa and the Middle East dried up, and AMH vanished from the Levantine fossil record only to be replaced later by Neanderthals. AMH finally arrived in Europe from south Asia around 45–50,000 years ago, probably as climatic amelioration opened the Fertile Crescent. In contrast to land treks, we can infer AMH had acquired newer adaptive advantages of linear coastal expansion, sustained and driven by marine exploitation, allowing them rapidly to skirt continents, crossing and ascending large rivers en route while utilising estuarine lagoons as staging posts. The added ability to make short but deliberate open water crossings allowed them to cross the mouth of the Red Sea from Eritrea, and subsequently Wallace’s Line to reach the isolated Sahul continent at least 50,000 years ago. The use of non-recombining DNA and the phylo-geographic approach, based on reconstructed gene-trees has been vital in illuminating the topography of their exit route and further travels and the logic of only one successful exit from sub-Saharan Africa - via the Yemen. When did such events take place, and why then? There are repeated concerns expressed over accuracy, precision and consistency of genetic dating. This does not mean it should be discarded for dates reconstructed from other disciplines, since that incestuous approach leads to loss of independence of proxy evidence and circular assertions. Chronometric predictions based on the genetic data should be tested using data from archaeology, palaeo-anthropology and the earth sciences. The latter, often having the best available dating and accuracy for periods earlier than 40 ka, also offer insights for windows of opportunity, based on sea-level and climate fluctuations and even the occasional volcanic date mark. Contentious AMH dates include the definitive exit from Africa, first arrivals in India, China, Central Asia, Indo-China, Sunda, Sahul, and the Americas. For the inter-continental hops, specific topographic questions remain, such as numbers of colonisations and routes. For instance, why are New Guinea and Australia relatively genetically distinct, while South and North America both share the same founding genetic groups? 0735 Timing of activities on the Tokkamachi Fault, central Japan Yoko Ota,1 Mitsuhisa Watanabe2, Yasuhoro Suzuki3, Ikuo Suzuki4, Hiroshi Sawa5, Kaoru Taniguchi6, Daisuke Hirouchi7, Henyu Kim8 1

Yokohama National Univ., Japan Toyo Univ., Japan 3 Nagoya Univ., Japan 4 Niigata Univ., Japan 5 Tsuruoka Colleage of Technology 6 Assoc. for Developement of Earthquake Prediction, Japan 7 Nagoya University of Technology, Japan 8 Earthquake Research Institute , Univ. of Tokyo, Japan 2

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Tokamachi Fault is located on the right bank along the Japan’s longest Shinano River, which flows in the thrust and fold zone, underlain by Plio-Pleistocene Uonuma Formation, following a synclinal axis of Uonuma Formation and flows northward to the Sea of Japan. Various tectonic landforms are present along the Shinano River, but no surface rupture by historical earthquake is recorded and is regarded to be a seismic gap area. We intend to establish paleoearthquake history of the Tokamachi Fault, which has at least three subparallel traces, striking nearly N-S and deforms fluvial terraces along the Shinano River. We excavated four trenches, (1) the Baba site on the west facing a major fault scarp, (2) the Baba N site on the extension of the main scarp, (3) the Shinmiya site on the westernmost fault trace, which has also west facing the scarp, and (4) the Miyakuri site on the range (east) –facing scarp. Reverse faults were found at all these trenches. Very low angle thrusts are found at site 1, where the latest faulting took place between 3100 BP and 3500 BP and the penultimate one occurred after ca. 10,000 BP., but exact timing was not determined. The event at site 2 is after ca. 5000 BP, probably simultaneous with the latest event at site 1. At site 3, the latest activity is estimated to be between 8800 BP and 9400 BP, possibly at the same time with the penultimate faulting at site 1. In contrast, at site 4, high-angle reverse faults are recognized. Here the latest event occurred at between 7400 BP and 9500 BP, and the penultimate event at before the deposition of AT tephra (ca. 27,000 BP) and after ca. 30,000 BP. In summary, the latest faulting at about 3000 years ago is recorded at sites 1 and 2 and the faulting at site 3 at about 8000 – 9000 years ago is also recorded at sites 1 and 4. The activity on the main fault is shorter (ca. 3000- several thousands years) than the subsidiary east facing fault. Some faulting occurred at the same time both on the main and subsidiary faults. Judging from the faulting history, Tokamachi Fault has a high seismic potential, although we cannot determine the fault length, which activated at the same time. 0754 INQUA scale for the recent two earthquakes in Japan and Taiwan Yoko Ota1, Takashi Azuma2, Nina Y Lin3 1

Yokohama National University, Japan Active Fault Research Center, AIST, Japan 3 Institute of Geosciences, National Taiwan Univ., Taiwan 2

We provided INQUA scale mesh map for recent earthquakes in Japan and Taiwan and compared them with seismic intensity map based on the seismogram data. The INQUA scale was proposed from a paleoseismology subcommission at the time of 2003 INQUA Congress, based on seismically-induced ground effects. This scale is useful for evaluation seismic intensity for the areas where no seismograph is installed or no construction for the assessment of seismic intensity. We selected two areas affected by recent great earthquakes. One is the Niigata area of the central Japan, affected by the November 2004 Chuetsu earthquake, and the other is the west-central Taiwan, severely damaged by the September 1999 Chichi earthquake. In both areas, we provided mesh map with grids of ca. 1km square on 1/25,000 topographical map, and evaluated INQUA scale for each mesh based on the size and density of ground effects such as landslide, surface rupture and liquefaction. The Chuetsu earthquake (M=6.8, depth is 13 km) occurred on one of the major thrust and fold belts, underlain by unconsolidated Plio-Pleistocene sediments. Occurrence of various types and sizes of landslides were major effects by the 2004 earthquake, and only very minor surface fault was appeared, although there are many active faults and folds which can produce great earthquakes. INQUA scale intensity VIII is identified on the northern area, close to the epicenter, and many aftershocks concentrated. The 1999 Chichi earthquake (M=7.3, depth

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is 8 km) occurred on the Chelugpu fault, which has repeated activities during the late Quaternary. The amount of maximum vertical offset by the Chichi earthquake is up to 10m. High intensity of X or XI occurred just on the narrow fault zone. Because this fault is reverse fault with uplift of eastern side, landslides, which have also repeated occurrence, appeared on the eastern hanging wall. INQUA scale map is more complicated than PGA or PGA-based intensity map, reflecting local difference of ground condition. Application of this scale for historic earthquake, and some revision of the scale should be concerned. 0918 Coral terraces in the Huon Peninsula, PNG:their morphologies and tectonic deformation Yoko Ota1, John Chappell2, Mari Takahashi3, Norihisa Goto4 1

Yokohama National Univ., Japan RSES, Australian National University, Australia 4 Assoc for Development of Earthquake Prediction, Japan 2

Coral terraces of the Huon Peninsula, have become a type localities for late Quaternary sea level studies, since late 1960’s. However, the distribution of all the terraces and their deformation have not previously been mapped in detail. We present a precise terrace and fault map in order to clarify morphological characteristics, and we discuss tectonic deformation with reference to the Kalasa Fault Zone on northeast Huon Peninsula. Our mapped area covers about 60 km, from the Maseweng River the in southeast to Kwaling River in the northwest. Our mapping and discussion are based on interpretation of airphotos (scales 1/15,000 – 1/120,000) and DEM height readings (90 m grid, SRTM ver.2), in addition to our field observations and published data. The Kalasa Fault Zone, composed of several subparallel traces, strikes NW to SE and defines the boundary between the Cromwell Mountains and the terraced area, which has a maximum width of ca.10km and maximum height of ca. 1000m above sea level. The terraces tilt downwards to the northwest with Upper Quaternary uplift rates from ca. 3.3m/ka to 0.4m/ka. The Kalasa Fault Zone disappears towards the southeast (near the Tewai River) but coral terraces are developed both on the hanging- and foot walls, implying that terrace uplift is not directly related to the activity of Kalasa Fault Zone. Late Quaternary deformation is rather local, causing some vertical displacement of older terraces, and is expressed as an anticlinal ridge of older terraces and short faults that intersect the terraces oblique to the coastline. Major coral terraces I (MIS 1) and VII to XIV (MIS 5e to 13), fringed by prominent barriers on their outer margins, were formed during major eustatic sea level rises, while intervening narrow terraces include benches formed by meter-scale coseismic uplifts at millennial intervals, particularly in high uplift areas. We describe peculiar drainage patterns of dense gullies on the younger terrace risers that originated from coralline spur and groove systems, and barrier-following stream networks; differences of drainage density reflect terrace ages, uplift rates, and bedrock lithological control. Moreover, landslides and debris flows play an important role in dissection of the coral terraces. 0931 PMIP2 climate model simulations and proxy records: towards an integrated reconstruction of the Last Glacial Maximum ocean Bette L Otto-Bliesner, Esther C Brady National Center for Atmospheric Research, United States

It is important to benchmark the sensitivity of oceans to climate change. The Last Glacial Maximum (LGM) is a key past time period to con-

sider this sensitivity because the forcings and boundary conditions are significantly different compared to present and are reasonably wellconstrained allowing climate model applications. New proxies and proxy reconstructions of the LGM ocean have become available in the last few years. For the surface ocean, the international MARGO working group is using a multiproxy approach to produce a new synthesis of sea-surface temperature and sea-ice extent of the glacial ocean. In the deep ocean, 231Pa/230Th has been used to infer rates of deep water advection and pore fluid measurements to determine deep ocean potential temperatures and salinity. The interpretation of these proxy records can be complicated by the complexity of the climate system. It therefore helps if the physical setting can be established using climate models. Models can provide a framework for interpreting ocean core reconstructions and relating them spatially and temporally to one another and to the other parts of the climate system. Two examples from the glacial ocean will be presented. The first considers the glacial Atlantic meridional overturning circulation – the subject of much debate in the scientific literature. An integrated approach of modeling and data supports the interpretation from paleonutrient tracers of a shoaling of North Atlantic Deep Water at LGM, with a strength neither appreciably stronger nor weaker than modern. The second example considers the state of the tropical ocean at LGM, important for understanding climate sensitivity. Tropical cooling estimates based on alkenones and Mg/Ca ratios and census counts of planktonic foraminifera from the MARGO synthesis indicate spatial heterogeneity and proxy differences. We use the PMIP2 LGM simulations to examine the dependence of the cooling to season and depth. Future efforts will involve new capabilities with the development of Earth system models that include predictions, for example, of isotopes, biomass burning, and chemical constituents of the atmosphere. 0143 Himalayan glacial sedimentary environments: a framework for reconstructing and dating the former extent of glaciers in high mountains Lewis A Owen1, Douglas I Benn2 1

University of Cincinnati, United States University of St. Andrews, United Kingdom

2

The Himalaya and Transhimalaya mountains contain the highest concentration of glaciers outside of the Polar Regions, constituting about fifty percent of the total extra-Polar glaciated area. Reconstructing paleoenvironmental change from glacial geologic evidence in the Himalaya and Transhimalaya has been difficult because of the lack of organic material for radiocarbon dating and the problems of correctly identifying the origin of highly dissected landforms. Studies of the contemporary glacial depositional environments, and ancient landforms and sediments in the Hunza valley and K2 region of the Karakoram Mountains, the Lahul and Garhwal Himalaya of northern India, and the Khumbu Himal illustrate the variability in processes, landforms and sediment types. These studies can be used to interpret ancient landforms and sediments for paleoenvironmental reconstructions, and aid in forming strategies for sampling sediments and rocks for the developing techniques of terrestrial cosmogenic radionuclide (TCN) surface exposure and optically stimulated luminescence (OSL) dating. Many Himalayan glaciers have thick covers of supraglacial debris derived from valley sides, and such debris-mantled glaciers exhibit important differences from ‘clean’ glaciers, both in terms of debris transport processes, and the depositional landforms that they produce. Analysis of sediment-landform associations can be used to reconstruct processes of sediment transport and deposition, and the relationship


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between moraines and other landforms and climatic forcing cycles. Such analysis is of fundamental importance in guiding sampling and interpretation in CRN and OSL dating work. Glaciers in many parts of the region have undergone significant retreat in the last century, a trend that is likely to continue in the coming years in response to human induced global warming. Contemporary studies of retreating glaciers, well illustrated in the Khumbu Himal, are now enabling more detailed quantitative models for glacial retreat to be developed. These are aiding in understanding the dynamics of ancient systems and in glacial hazard mitigation.

0825 Holocene and latest Pleistocene alpine glacier fluctuations in the high mountains of East Asia

0145 Defining the timing and extent of Late Quaternary glaciation in the Himalaya

The timing and extent of Holocene and latest Pleistocene alpine glacier fluctuations in the high mountains of East Asia is poorly defined. This is partially due to the logistical and political inaccessibility of the region, and the lack of modern studies of the glacial successions. In recent years, however, renewed interest in the region, especially with the aid of new remote sensing technologies and newly developing dating techniques, such as optically stimulated luminescence and terrestrial cosmogenic nuclide (TCN) surface exposure dating, have provided new insights into the nature of latest Quaternary glacial oscillations. The best studied and preserved glacial successions are present in the Karakoram Mountains of Northern Pakistan, the massifs of Muztag Ata and Kongur Shan in westernmost Tibet, the Greater Himalaya of Northern India, and the valleys on the southern and northern slopes of Mount Everest. These regions, together with other regions throughout the Himalaya and Tibet, provide abundant evidence for significant glacial advances during the Lateglacial Interstadial and the early Holocene. Furthermore, there is evidence for multiple glacial advances throughout the latter part of the Holocene, although these are generally very poorly defined. The best defined Holocene glacier advances are in Muztag Ata and Kongur Shan massifs. Here glacial advances occurred at approximately 16 ka, 13 ka, 10.6 ka, 9.6 ka, 8.0 ka, 6.3 ka, 4.2 ka, 3.5 ka, 1.5 ka and few hundred years before the present. The new studies through East Asia suggest that since the Last Glacial Maximum, the glaciers in East Asia have responded to oscillations in south Asia monsoon that are forced by insolation changes, and climate changes resulting from teleconnections with rapid climate oscillations in the Northern Hemisphere oceans and ice sheets. Continued research on late Holocene glacier advances in northern India using TCNs, dendrochronology and lichenometry will refine the chronologies to aid in identifying the forcing factors of glaciation in East Asia.

Lewis A Owen1, Marc Caffee2, Robert Finkel3, Yeong Bae Seong1, Chaolu Yi4, Jason Dortsch1, Sarah Laxton1 1

University of Cincinnati, United States Purdue University, United States 3 Lawrence Livermore National Laboratory, United States 4 Institute for Tibetan Plateau Research, China 2

The Himalaya and Tibet is the most glaciated region outside of the Poles and they have an important influence on regional and global environmental change. Yet despite the importance of glaciation in High Asia, the dynamics, the nature of Quaternary glaciation in this region is poorly understood. To define the timing and extent of glaciation in this region, we have been systematically examining the glacial and associated geology throughout the region, and dating landforms and sediments using cosmogenic radionuclide (CRN) surface exposure and optically stimulated luminescence dating. To date, we have undertaken detailed studies in mountains of Chitral, Swat, Nanga Parbat, Hunza Valley, K2 area of the Central Karakoram, Lahul, Ladakh, Zanskar, Garhwal, Nanda Devi, Langtang, Khumbu, Northern slopes of Everest, Mustagata-Kongar, Gurla Mandata and Gonga Shan. This has included detailed mapping, together with ~1000 numerical dates on moraines and associated landforms, that define the extent and timing of glaciation. Published CRN dates have recently been reassessed using new production rate data to test synchronuity of glaciation throughout the region and to test the forcing factors. The best chronologies for the eastern region are provided by the valleys to the north and south of Everest, while for the western regions the mountains of the Karakoram and Mustagata-Kongur provide the best chronologies. These studies suggest that the regional patterns and timing of glaciation throughout the region reflect temporal and spatial variability in the south Asian monsoon and, in particular, regional precipitation gradients. As a consequence, old (pre-Last Glacial) moraines and/or tills are more readily preserved in regions of greater aridity, such as central and westernmost Tibet. In contrast, within regions with greater rainfall as a result of the strong influence of the monsoon, such as the southern slopes of the Himalaya and eastern Tibet, the preservation potential of pre-Lateglacial moraine successions is extremely poor because of the associated high erosion rates. Furthermore, glaciation in such regions during the early Holocene insolation maximum was probably more extensive than earlier in the last glacial cycle (and specifically at the global LGM), and thus any evidence of older moraines has been destroyed by subsequent glacial advances. It is therefore likely that glaciation throughout Tibet and the Himalaya is strongly influenced by orography that, in turn, strongly influences climate.

Lewis A Owen1, Yeong Bae Seong1, Sarah Laxton1, Jason Dortch1, Robert Fnkel2, Marc Caffee3, Chaolu Yi4 1

University of Cincinnati, United States Lawrence Livermore National Laboratory, United States 3 University of Purdue, United States 4 Institute for Tibetan Plateau Research, Chinese Academy of Sciences, China 2

0897 A Holocene record of paleostorms and sediment flux from Lake Tutira, New Zealand Mike J Page1, Noel A Trustrum1, Alan R Orpin2, Ursula A Cochran1, Lionel Carter3, Basil Gomez4, Hannah L Brackley1 1

GNS Science, New Zealand National Institute of Water and Atmospheric Research, New Zealand 3 Victoria University of Wellington, New Zealand 4 Indiana State University, United States 2

New Zealand was the last major habitable land area to be settled. Polynesians arrived around 700 –800 years ago, while European settlement and conversion of forest to pasture began only ~150 years ago. This provides a rare opportunity to study climate variability during an extended period in the late Holocene without the complication of human impacts, and to contrast the subsequent dramatic impacts following settlement. A high-resolution record of storm events is preserved in the sediments of Lake Tutira, on the east coast of the North Island. Close coupling of the lake and surrounding landslide-prone steeplands, to-

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gether with the depositional environment in the lake, has resulted in the formation and preservation of layers of sediment representing individual storms. This record is a product of the complex interplay between landscape, climate, plate boundary tectonism, volcanism, human settlement and land-use change. Following Cyclone Bola in 1988, a 6 m-long lake core was obtained, providing a 2250 cal BP record of storm sediment deposits. A recently recovered 27 m-long core extends this record to 7400 cal BP. The sediments exhibit well-defined laminations, comprising minerogenic sediment, interspersed with black organic-rich deposits, slowly accumulating brown silty clays, and tephras. The layers of minerogenic sediment range from 50 mm thick. A number of dating techniques have established that these layers represent storm events. This has now been supported by diatom analysis, using concentration, habitat type, and species richness to indicate the degree of catchment versus in-lake sources of the main sedimentary units. There are ~1000 storm events, and their frequency and magnitude is highly variable, with major clusters that were decades in duration, and usually involving sudden onset and cessation. Major periods of increased storminess occurred around 330 –350, 520 –530, 920 –1050, 1370 –1390, 1830 –2010, 2120 –2140, 3500, 4600 and 6000 cal BP. These variations reflect, in part, variations in El Niño-Southern Oscillation (ENSO) activity, with an overall post4000 year increase in storm frequency. Despite these periods of increased storminess, the sedimentation rate during the European pastoral period has been 420% greater than the pre-human rate. Associated carbon fluxes have been determined for the European period. These records are being compared with marine records in conjunction with NSF-funded MARGINS Source-to-Sink projects in the Waipaoa Sedimentary System, to test the efficacy of sediment deposits on the continental shelf to record terrestrial signals of climate, land use and other environmental change. 0497 Climate forcing of glaciolacustrine sedimentation in Scotland during GS-1. (Project NE/C509158/1, NERC RAPID Climate Change programme: http://www.noc.soton.ac.uk/rapid/rapid. php) Adrian P Palmer, Alison MacLeod, John J Lowe, Jim Rose Department of Geography, Royal Holloway, University of London, United Kingdom

We report investigations of the potential of glaciolacustrine varved sequences to provide precise ages for the timing and duration of climate events in Scotland during Greenland Stadial-1 (GS-1) and thereby establish the degree of synchroneity between climate events in Scotland and Greenland. The study examined laminated sediments sequences that accumulated in lakes temporarily formed in valleys blocked by Loch Lomond Readvance (GS-1) ice. The sediments were analysed using thin section micromorphology (see MacLeod et al.; INQUA Abstract) to establish criteria for the identification and classification of varved sediments. Precise measurement and counting of the annual layers preserved suggests an interval of 519 years is represented. Micromorphological analysis also demonstrates that the summer layers frequently comprise several sub-layers, interpreted as separate flux events. Summer layers vary considerably in the number and thickness of the sub-layers, while both winter and summer layers show considerable structural variation. Previously published records of terrestrial varved sediments have been compared with Greenland ice-core records using measurements of raw varve thickness, which reflect sedimentation rate. Analysis of the internal structure of the summer layers

in the Scottish deposits, however, shows little relationship between varve thickness and internal structure (i.e. number of sub-laminations in the summer layers). We believe that the latter provides a more reliable index of variations in local summer climate conditions; varve thickness reflects localised variations in sediment availability and episodic surge events unrelated to climate forcing. Comparison of the summer layer data (five-point moving average) with the delta 18O variations in the GRIP ice-core record (ss08sea and ss09) for the latter part of GS-1 shows a visual cross-match between both records. The comparison suggests that: (i) the Scottish varves accumulated between 12,119 and 11,506 GRIP years BP; (ii) the GS-1 ice cap on mainland Scotland reached its maximum extent ca. 840 years after the onset of GS-1 in Greenland (11,797 GRIP years BP). Greenland ice and glaciolacustrine sedimentation in Scotland appear to have been responding to a common forcing factor – perhaps decadal migrations of the North Atlantic Polar Front or variations in solar radiation output. Current work within the remit of the RAPID Project aims to replicate these varve sequences, test for compatibility with other varve sequences(see MacLeod et al.; INQUA Abstract), and independently constrain the ages of specific events using tephrostratigraphy (see Pyne-O’Donnell et al.; INQUA Abstract). (1)NERC: Natural Environment Research Council (UK) 0687 The Early to Middle Pleistocene “faunal revolution” Maria R Palombo University “La Sapienza” Rome, Italy

The transition from the Early to Middle Pleistocene (from about 1.2 to 0.6 Ma) marks a fundamental change in the Earth’s climate system and represents a major episode in mammalian fauna reorganisation over the course of the Cenozoic. Since at least 1.3 Ma, discrete bioevents (dispersal of taxa, which also persisted throughout the Middle Pleistocene, and turnover phases) led to a progressive reconstruction of mammalian faunal complexes in Europe that came to an end during the beginning of the Middle Pleistocene. Such a framework of “mixed faunal elements” was regarded by authors either as a “transitional fauna” or a distinct biochron (Protogalerian, Epivillafranchian, Latest or Final Villafranchian). However, the extent and accomplishment of this “mammalian revolution” greatly varied across and between continents. Consequently the question arises: were the climatic and physical changes the only major drivers of this “revolution”? Actually, this is a general question, and over time ecologists and evolutionists have been widely divided as to whether progressive changes in the composition of mammal faunal complexes (fluctuations in biodiversity, biomass, and ecological structure) might be interpreted as a mere response to climate change or as the results of intrinsic biotic factors that exert an important control on faunal renewal. To contribute to the debate, the Eurasian large mammal fossil record has been analysed with the aim of delineating the main biological events affecting the structure of faunal complexes at the Early to Middle Pleistocene transition. The obtained results support the argument that Early to Middle Pleistocene climatic changes were a determining factor especially as regards mammal dispersal, whereas diachroneity in local reconstruction of faunal complexes might also depend on competition/coevolution internal dynamics.


0710 Biochronological frameworks of continental mammalian faunas and Quaternary subdivisions Maria R Palombo University, Italy

Defining and subdividing the Quaternary on the basis of the mammalian fossil record from the continental realm is not a simple task because of the low degree of succession continuity and the scattered palaeontological evidence. Moreover, even if the approaches to the Quaternary are basically interdisciplinary and can combine many different chronological scales, establishing correlations between biochronology, biostratigraphy, chronostratigraphy, climatostratigraphy, and composite regional stratigraphy is often very problematical. As far as biochronology is concerned, the marked geological, environmental and climatic diversity affecting different continental regions makes a correlation based on biological events difficult. Indeed, “biochronological units” represent a time span during which faunas have a degree of taxonomic homogeneity and the corresponding “faunal complexes” have to be regarded as non- overlapping and an “ecologically adjusted group of animals with specific geographic limits and chronological range”. Nevertheless, the stratigraphic order of the highest and lowest occurrences of remains (stratigraphic datum) within a given geographical area does not necessarily reflect the temporal order of their actual first/last appearances (palaeobiological events) in time. This is due to diachroneity in palaeobiological events (i.e. local first and last appearances are strictly linked respectively to dispersal, and the physical and biotic factors causing extinctions) coupled with discontinuity in the continental sedimentary record, the rarity of deposits formed in a regime of virtually continuous sedimentation, the presence of important ecological barriers (that prevent some taxa from dispersing), environmental conditions (that affect the structure of palaeocommunities), and taphonomic and sampling biases. This fact prevents any detailed biochronological framework from having wide geographical significance. Thus, only higher rank biochronological units (Land Mammal Ages, LMAs) - whose separation is based on palaeobiological events which have a wide territorial significance — could be useful for chronological correlations. Nonetheless, the transition between successive LMAs does not always correspond to the boundaries separating marine Series or Stages. For instance, the Villafranchian LMA approximately began with the Middle Pliocene (Piacenzian) and the transition from the early to the middle Villafranchian LMA happened around the Middle/Late Pliocene (Piacenzian/Gelasian) boundary, whereas the transition to the late Villafranchian took place during the latest Pliocene, and those from the Villafranchian to Galerian LMA and from the Galerian to Aurelian LMA respectively predated the beginning of the Middle and Late Pleistocene. A tentative correlation chart for the past 2.6 is presented. 0782 Ecological structure in Quaternary mammalian communities: evidence from the North Mediterranean region Maria R Palombo, Roberto Boldrini, Micaela Novelli University La sapienza Rome, Italy

The Quaternary was characterized by a well-known series of climatic cycles driven by variations in the orbital parameters of the Earth, latitudinal displacements of the vegetation, changes in faunal composition and in the distribution of biomes. During the Plio-Pleistocene, mammals more frequently reacted to climate changes not by evolving and

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producing new species, but by expanding their diffusion area or migrating as the climate changed. Therefore environmental changes facilitated immigration in the North Mediterranean area by new taxa from East and Central Europe, as well as from Africa through the Levantine corridor. Thus the equilibrium of mammalian “palaeocommunities” was upset; a new inter-specific dynamic developed, the ecological structure was modified. Moreover the North Mediterranean territories were and are characterized by differences in physiography as well as in climate. This offers remarkable opportunities to analyse ecological changes in the mammalian palaeocommunities over space and time and to compare their structure (defined as the number of species in different ecological categories: body mass, preferred habitat, trophic habits) with those of modern communities characterising peculiar ecosystems. The aim is not only to analyse dynamic versus stable Quaternary palaeocommunities of the North Mediterranean, but also to test if the ecosystem behaviour might be the net result of all the complex internal system interactions or driven by a limited number of key processes as suggested by Lambert (2006). Results obtained in part suggest little evidence of ecosystem convergence, especially with regard to body mass distribution (that, as has been demonstrated, broadly reflects ecosystem function). Furthermore, the major changes of palaeocommunity structures (fluctuations in biodiversity, biomass, changes in frequency between forest- or woodland-dwellers and more open environment dwellers, etc.) depend on major climate change. More gradual changes depend on intrinsic biotic control (changes in inter- intra-specific competition), as well as on resilience of pre-existing palaeocommunities. 0965 Correlation of fluvial terraces in the Eastern Qilian Shan, Northwest China: implications for climate and tectonic controls Baotian Pan, Hongshan Gao Key Laboratory of Western China’s Environmental Systems, Ministry of Education, Lanzhou University, Lanzhou,Gansu 730000, China, China

The incision and aggradation recorded by fluvial terraces is equally significant in terms of river behavior and for an understanding of the factors affecting landform development during the Quaternary. Fluvial terraces from seven rivers in the eastern Qilian Shan on the actively uplifting Tibetan Pleatau Margin, northwest China, are providing suitable archives for research on regional tectonic activities and paleoclimatic changes. Using a combination of magnetostratigraphy, electron spin resonance (ESR), thermoluminescence (TL), infra-red stimulated luminescence (IRSL), radiocarbon dating of fluvial deposits and loess sequences that overlie fluviatile sediments, our results show that the age of river terraces is 1.24 Ma, 820 –860 ka, 780 ka, 420–440 ka, 230–250 ka, 140 ka, 60 ka and 10 ka, respectively. Based on the ages, stratigraphic and geomorphic patterns on each terrace, we propose that the assemblage of river terraces in the Eastern Qilian Shan was caused by episodic aggradation of fluvial gravel and channel down-cutting, both correlating with orbitally forced climatic fluctuation; i.e. at the 100 ka glacial/interglacial cycle. The terrace sediments have been formed during cold stages (glacial), rivers incised and fluvial terraces were formed during glacial-interglacial transitions. That implies that dramatic climate changes plays a significant role in controlling the formation of terrace sequence in the active orogens. Although climate-driven changes are undoubtedly important in governing aggradation-incision cycles, they cannot provide a self-sustained mechanism for progressive incision. Tectonic uplift has been critical in enabling the incision, without which terraces could not have formed. Assuming that the rate of fluvial incision and that of rock uplift are roughly balanced, the height of each terrace above the modern

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river and its age define a long-term rate of bedrock incision and mountain uplift. On the basis of terrace heights and ages, the valley incision rates of ca. 0.09-0.25 m ka−1 have been identified in the Eastern Qilian Shan, which are similar to previous estimates for uplift in the upper Yellow River and Daxia River in the Linxia Basin at the northeastern margin of the Tibetan Plateau. 0495 Reconstructing Late Holocene climate variability in North East China from varved maar lake sediments Virginia N Panizzo1, Anson W Mackay1, Patrick Rioual2, Guoqiang Chu2, Melanie J Leng3 1

Environmental Change Research Centre, Department of Geography, University College London, London, United Kingdom 2 Institute of Geology and Geophysics, Chinese Academy of Sciences, China 3 NERC Isotope Geosciences Laboratory, Kingsley Dunham Centre, Keyworth, Nottingham, United Kingdom

Climatic variability during the Holocene, principally on centennial and decadal timescales, is increasingly being addressed, especially for the time span covering the past ca. 1200 years. Many palaeoecological studies have focused on regions in the Northern Hemisphere when addressing recent climatic perturbations; however few high resolution records exist from the climate sensitive regions of north east (NE) China. The East Asian Monsoon (EAM) is a major source of precipitation in NE China. Here the cold interior of continental Eurasia and the warm Pacific Ocean create a climatic gradient and in turn it is very important to understand its relationship to the world’s climate systematics. The period of the last 1200 years has been highlighted as a key timeframe for investigating palaeoecological responses to both human and climate impacts. Such examples include if and how the East Asian Monsoon responded to changes in climate over the documented “Medieval Warm Period” (c. AD 900 – 1300), “Little Ice Age” (c. AD 1350 –1850) and recent warming. At present, literature remains contradictory to such environmental changes in NE China over this time-frame due to poor chronological control, low resolution of existing studies and even due to the inexact terminology of these climatic periods. Xiaolongwan Lake is a small, closed, crater lake located in the Long Gang Volcanic Field (LGVF), NE China (42˚18′N; 126˚19′E). It is at an elevation of 655 meters above sea level with a maximum depth of 15 m. Initial analyses of test cores have shown that sediments are seasonally laminated (diatomaceous and minerogenic layers) while charcoal (14C) and tephra horizons are currently being analysed to provide further chronological control. As a result of the site’s remote and hydrologically closed nature, variation in lamination width is argued to be due to variations in dominant climate regimes over the area (i.e. east Asian summer monsoon strength). Diatom flora from a composite core of 143 cm is being analysed to asses the nature of seasonal productivity changes at the site. Quantitative techniques (spectral analysis) will later provide a method of assessing periodicities of climatic changes at the site and their amplitude. 0126 Late Quaternary stratigraphy and development of tidal sand ridges in the eastern Yellow Sea Soo Chul Park1, Bang Hee Lee1, Hyuk Soo Han2 1

Chungnam National University, Korea Korea Seabed Information, Korea

2

The eastern Yellow Sea is characterized by a number of tidal sand ridges which occur as a series of linear sediment bodies in the shelf

(shelf sand ridges) and as a group of individual sand bodies in the nearshore (nearshore sand ridges). The shelf sand ridges are present in water depths of 50–90 m and show large, elongate shapes with a length up to 200 km. In contrast, the nearshore sand ridges are much smaller in size (up to 34 km length) and occur in water depths shallower than about 30 m. Detailed interpretation of seismic and lithologic data, using radiocarbon datings to constrain the ages of the ridges, has shown that the regional sea–level changes played a major role in the existence and development of different morphologic features of these sand ridges.The shelf sand ridges developed mainly during the postglacial transgression (ca. 14,000–9500 BP), possibly during the episodes of stillstand or very slow rise of sea level. The shape of the shelf sand ridges more or less results from an erosional process dominantly acting during the postglacial transgression. The substratum of the shelf sand ridges consists of the regressive or lowstand deltaic mud deposits, probably formed prior to the last glacial maximum (> ca. 17,000 BP). In contrast, the nearshore sand ridges have undergone tidal action during the recent highstand of sea level (ca. < 7000 BP) and show a typical modern geomorphology of erosional sand ridges. The substratum of the nearshore sand ridges consists of remnants of the last interglacial tidal deposits. Large dunes indicate a strong hydrodynamic influence on the entire ridge surface at present. 0045 Changes of tidal flat morphology for the period (14 years) of the construction of the Saemangum tidal dam, west coast of Korea Yong Ahn PARK1, Jin Yong Choi2 1

Seoul National University, Seoul 151-742, Korea, Korea Korea

2

Changes of tidal flat morphology have been monitored during the period of the Saemangum Project along the mid-west coast of Korea from 1992 to 2005. The Saemangum Project is a large scale tideland reclamation project having construction of 33 km tidal sea dike impounding an area of over 40,000 ha. Construction of sea dike began in 1991 and was completed in March 2006. The Saemangum area is one of the typical macro-tidal environment with max. tidal range of up to 6 m in spring period. Tidal flats and its tidal sand bars are the characteristic depositional features. Historically, in fact, several reclamations had already been conducted in the Saemangum area during the last century in order to provide rice fields and salt pans. Comparisons of detailed morphologic maps in the area of the Saemangum Project clearly show net accumulations outside of the tidal dams, that is, indicating a seaward progradation and vertical accretion of tidal flat deposits. During the construction (14 years) of the Saemangum Dam, the tidal flat morphology was changed dramatically. In relation to the study concerned, changes of beach morphology have also been monitored at Byunsan Beach 4 km south of the Saemangum Dam from 1992 to 2005. During the early phase of the dike construction from 1992 to 1997, net deposition of beach deposits occurred rapidly with average accumulation rates over 4 cm/a. The Byunsan Beach, however, showed a erosion-dominated environmental condition with net erosion rates of about 2 cm/a during the second phase of the Saemangum Project from 1997 to 2002. Tidal current flow during the ebb period was dominant as counter-clockwise residual circulation with a net northward currents system along the Byunsan Beach. It is considered that our results will be valuable for a better understanding of coastal sedimentary processes caused by any artificial structure and help for management of coastal area along the west coast of Korea.


0734 Geoarchaeology of the Arabian Gulf Neolithic: dynamic humanenvironment interactions Adrian G Parker1, Gareth W Preston1, Helen H Walkington1, Martin J Hodson2 1

Department of Anthropology and Geography, Oxford Brookes University, Headington, Oxford OX3 0BP, United Kingdom 2 School of Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, United Kingdom

The coastal desert landscape of southeastern Arabia is dominated by extensive linear dunes of the Rub’ al-Khali sand sea. These date to the Late Glacial Maximum (LGM), Younger Dryas and earliest Holocene periods. Geoarchaeological research from the coastal desert region of the Arabian Gulf region shows that the early to mid-Holocene period was characterised by wet conditions derived from Indian Ocean Monsoon rainfall. The landscape developed a cover of savannah grassland with stands of Acacia and Prosopis. It was into this environment that nomadic herder-gatherers migrated from the Near East during the Neolithic from 6500 cal BC. Extensive shell-middens exist along the coastal desert region and provide the most detailed records for Neolithic (6000–3900 cal BC) occupation, exploitation of resources and trade in the gulf region Arabia. The work to date has detailed a rich-assemblage of marine resources (shellfish, crabs, fish and marine mammals) and along with finds of pottery, beads, net sinkers and flint tools represents the presence of a nomadic population. In addition, bone material reveals the herding of goats, sheep and cattle in the surrounding area. A model of transhumance between the mountains (flint and stone tool sources), desert interior (grazing and lakes) and coastal region (marine resources and pottery trade from Mesopotamia) has been suggested for this region. The archaeological record indicates that the Neolithic period came to an abrupt end in eastern Arabia and the Oman peninsula at 3800 cal BC and there is no evidence of human presence in the area for approximately 800 years. This period has been described as the ‘Dark Millennium’ in the lower Arabian Gulf region owing to the lack of known archaeological sites. We suggest that climatic deterioration caused dramatic changes in semi-desert nomadism, subsistence and settlement patterns around 3800 cal BC. The lack of known sites suggests that the population shrank considerably at this time and became concentrated in the few parts of Arabia which offered greater ecological diversity e.g. Indian Ocean coast. The geoarchaeological record shows a marked phase of lake lowering, the onset of dune reactivation and widespread desertification corresponding with the southward retreat of the Indian Ocean Monsoon. 1173 Effects of climate change on late Holocene penguin populations in the Vestfold Hills, East Antarctica Rachael L Parkinson, Andrew McMinn, John A E Gibson Institute of Antarctic and Southern Ocean Studies, University of Tasmania, Australia

Adélie penguins in coastal rookeries are sensitive to sea-ice extent and their abundance is therefore closely related to climate. A better understanding of the historical relationship between penguin population dynamics and climate change in East Antarctica is increasingly important in the face of global warming and increasing human activity in this climatically sensitive region of the globe. In the absence of long term population records, sediments of lakes adjacent to penguin

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rookeries can be used to recover important information about penguin population density and occupation history. In this study, diatom-inferred nutrient concentrations from a lake sediment core from the Vestfold Hills, East Antarctica, were used to reconstruct Adélie penguin population density of a neighbouring rookery in this climatically sensitive region. These results were integrated with regional palaeoclimate data to assess the interrelationships between penguin population density and climate change in the region during the late Holocene. A combined training dataset was used in this study incorporating 149 lakes from five ice-free oases in coastal East Antarctica, including the Vestfold Hills, Larsemann Hills, Bølingen Islands, Rauer Islands and the Windmill Islands. The lake sediment core was taken from a small lake adjacent to a large Adélie penguin rookery. Relationships between contemporary environmental parameters (water chemistry and physical aspects of the lakes) and surface sediment diatom assemblages were explored using Canonical Correspondence Analysis. Phosphate was found to significantly influence the diatom species distributions. A diatom-phosphate transfer function was developed, allowing reconstruction of downcore fluctuations in historical phosphate concentrations. Three distinct zones in the core were identified, illustrating the lake’s evolution on this isostatically rising coastline from marine basin through a transitional marine/lacustrine environment, to its present state as a closed lake basin. The uppermost sediments contain the record of adjacent penguin rookery activity. Diatom-inferred phosphate reconstruction indicates that nutrient input to the lake has oscillated over the last two thousand years. Taken as a proxy for penguin density, this suggests that relative fluctuations in penguin numbers in this rookery have occurred throughout the late Holocene. These fluctuations are due to natural phenomena, as they took place well before human impacts on local and global environments were effected. 0112 Reinterpretation of the development of the classical Baltic Ice Lake Tore Passe Sweden

The conventional picture of the Baltic development is that a glacial lake during the Late Weichselian occupied the Baltic basin. The water level of this lake, the Baltic Ice Lake, is supposed to have risen 25 m above sea level. When the ice margin left the Billingen hill, at the end of the Younger Dryas stadial, the water level again returned to the sea level at a catastrophic drainage. Shore level curves from the southern part of the Baltic show a very rapid regression during the end of the Younger Dryas, which in the classical viewpoint is interpreted by the drainage at the Billingen hill. Results from new extensive investigations performed by the Geological Survey give another explanation of the development. The low area east of the Billingen hill was occupied by a local glacial lake, the Tidan- Vettern Ice Lake and thus not by the Baltic. During the final stage the water level within this local glacial was 25 m above sea level. When the ice margin left the northern tip of the Billingen hill during the early Holocene, the Tidan- Vettern Ice Lake drained and the sea intruded the area. The rapid regression during the end of the Younger Dryas, observed in shore level curves within the Baltic area, is thus not due to the development at the northern tip of the Billingen hill as the deglaciation at this site actually occurred at the beginning of the Holocene.

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0117 The Geological Survey of Sweden - 150 years Tore Passe Sweden

The Geological Survey of Sweden was established 1858 by Axel Erdmann, i.e. before the glacial theory was the public opinion. One year later Otto Torell presented a thesis where he complemented the glacial theory and demonstrated that there had been inland ice over Scandinavia. As head of the Geological Survey Otto Torell employed Gerard de Geer, who provided an explanation of the land uplift by developing Jamieson´s theory of the elasticity of the earth’s crust, put forward a new own theory of the genesis of eskers and created the varve chronology. A shore level curve was published 1928 by Erik Granlund. Are there any older shore level curves in the world? 0106 Paleoenvironmental evolution and prehistoric human environment, in the embayment of Palamari (Skyros Island, Greece) during Middle-Late Holocene Kosmas P Pavlopoulos1, Maria Triantaphyllou2, Panagiotis Karkanas3, Katerina Kouli2, George Syrides4, Kostantinos Vouvalidis4, Nikos Palyvos1, Theodora Tsourou2 1

Harokopio University, Faculty of Geography, Greece Faculty of Geology and Geoenvironment, Dpt. Historical Geology & Paleontology, Greece 3 Ephoreia of Palaeoanthropology-Speleology, Greece 4 Aristotle University of Thessaloniki, Faculty of Sciences, School of Geology, Greece 2

The Palamari bay is located on the northeastern coast of Skyros island (Sporades islands, Aegean Sea). A prehistoric settlement at the northern edge of the bay, is dated between 2800 and 1700 BC (Early Bronze Age II–Middle Bronze Age I). In order to reconstruct the palaeoenvironment and the landscape evolution of the broader area of the Palamari bay, we conducted detailed geomorphological mapping of the coastal alluvial plain, and micropaleontological, palynological, sedimentological, and micromorphological studies of the underlying Late Holocene coastal deposits. Ten (10) samples of organic material were dated using the AMS radiocarbon method, thus providing temporal control of the sedimentary units. Landforms of the coastal alluvial plain, the beach and the seabed of the bay down to the depth of –10 m were mapped at a scale of 1:5000. In addition, twelve detailed beach profiles were mapped across the coastline of the bay. Eight boreholes (the deepest one reaching a depth of 11 m), were drilled and three trenches were excavated, at selected locations. Sedimentary sequences have been studied through visual inspection of the sediments. The stratigraphy of the late Holocene sediments was studied in detail and samples, collected from selected sedimentary layers, were analysed for microfauna and pollen. Four undisturbed and oriented blocks of sediment were collected from one of the trenches, for petrographic and sediment micromorphological studies. Three main sedimentary units were recognized (A, B and C, from oldest to youngest). The ostracod fauna of the lowermost sedimentary unit A, consists predominantly of sand and silty sand with gravel, indicates a shallow freshwater environment. The pollen spectrum reflects an open dry vegetation of Mediterranean type. The overlying unit B, consists predominantly silty sand and clay, characterized by the dominance of brackish water microfauna, indicating a lagoonal depositional

environment, which was periodically supplied with fresh water from the surrounding springs. The pollen spectra identify cultivated land and grazing activities in the vicinity of the lagoon, indicating a strong human presence. The uppermost sedimentary C unit, consists predominantly of silt and sandy silt, corresponds to a backshore environment dominated by aeolian activity and modified by fluvial processes. 0685 Luminescence dating of Middle Pleistocene glaciations, eastern England, UK Steven M Pawley1, Richard M Bailey2, James Rose1 1

Department of Geography, Royal Holloway, University of London, United Kingdom 2 School of Geography, Oxford University Centre for Environment, United Kingdom

During the past 500 ka, lowland regions of the British Isles were affected by several major ice sheet advances. Sedimentary evidence relating to these events occurs widely in eastern England where thick glacigenic sequences accumulated at the margins of these ice sheets and were preserved outside of the Last Glacial Maximum (LGM) ice limit. However, there is a debate over whether the deposits belong to a single glaciation, equated to the Anglian/Elsterian Stage - Marine Isotope Stage (MIS) 12, or represent deposition over a number of separate cold climate stages (MIS 16, 12, 10, and 6). In order to develop an improved chronology for glaciation in this region, we have obtained a large number of optical stimulated luminescence (OSL) dates taken from glacial outwash facies. Samples of coarse-grained quartz sand were measured using the SAR (single aliquot regenerative-dose) protocol. The low radioactive isotope concentrations in sediments of this region enable the traditionally accepted age limit of luminescence dating to be extended into the Middle Pleistocene. The form of the dose response curves, pre-heat plateaux tests, and dose recovery experiments also indicate that equivalent doses can be reliably measured in these samples. Signal analysis methods indicate that age overestimation due to partial bleaching is insignificant and the propensity of adequate solar resetting is further tested from analogous LGM samples. The accuracy of the dating protocol over the Middle Pleistocene timescale is also tested on samples with stratigraphic age control taken from the Thames River terrace stratigraphy. The OSL ages provide evidence that extensive lowland glaciation of the region occurred during MIS 12. This represents the first time that Anglian glacial sequences have been dated directly and the results support existing age estimates on overlying and underlying organic sediments which bracket the glacial deposits between MIS 11 and MIS 13. 0155 Using microtephras to extend regional tephrochronologies: an example from southeast Alaska and implications for hazard assessment Richard J Payne1, Jeff J Blackford1, Johannes van der Plicht2 1

University of Manchester, United Kingdom University of Groningen, The Netherlands

2

Microtephrochronology, the use of microscopic volcanic ash layers to date sediments, has rarely been applied outside Europe but has the potential to improve the tephrochronology in other regions of the world. Here we present the first comprehensive microtephra study in Alaska. Cores were extracted from five peatlands in southeast Alaska, with microtephras located by ashing and microscopy and their glass


geochemistry examined using electron probe microanalysis. Geochemical data from nine tephras were compared between sites and to previous Alaskan tephra studies. One tephra is present in the uppermost 400 mm of all the cores and is believed to represent a previously unidentified eruption of Mt.Churchill, named here as the ‘Lena tephra’. A mid-Holocene tephra in one site is very similar to Aniakchak tephra, and probably represents a previously unidentified Aniakchak eruption, c. 5300 –5030 cal BP. Other tephras are from the late Holocene White River eruption, a mid-Holocene Mt. Churchill eruption and possibly eruptions of Mt. Redoubt and Augustine Volcano, although the evidence for the later two is limited. These results show the potential of microtephras to expand the geographic limits of tephrochronology and demonstrate that Mt. Churchill has been more active in the Holocene than previously appreciated. This finding may necessitate reassessment of volcanic hazards in the region. 0159 Palaeoecological evidence for recent wetland drying in northern Greece Richard J Payne University of Manchester, United Kingdom

The Elatia Mires of Northern Greece are unique ecosystems of high conservation value. Northern Greece has experienced significant climatic change and an increase in aridity over the last c.50 years. The Elatia Mires are climatically marginal and may be sensitive to changing hydroclimate. To investigate the impact of recent climatic change on the mires, a quantitative palaeoecological study was carried out using testate amoebae as sensitive indicators of hydrology. A hydrological transfer function was derived from a sequence of surface samples across four sites. The transfer function has the potential to reconstruct water tables within 2 cm, the best-performing such model yet produced. The palaeocological record was investigated from three nearsurface monoliths extracted from two of the sites. Records were dated using a combination of AMS radiocarbon dates and spheroidal carbonaceous particle profiles. Results from all three profiles show a distinct shift towards a more xerophilic community particularly noted by increases in Euglypha rotunda in the 20th century. Transfer function results show a major lowering of water tables in this period. Although this change cannot be unequivocally attributed to climate change this is the most likely hypothesis. These results suggest the sensitivity of mire ecosystems to the current trend of anthropogenic climate change and provide further evidence for the climatic sensitivity of minerotrophic mires supporting the possibility of obtaining Holocene climate records from these ecosystems. 1193 Numerical methods in the correlation of tephra deposits using geochemical data: the use (or misuse?) of statistics Nicholas JG Pearce1, Charles A Bendall1, John A Westgate2 1

University of Wales, Aberystwyth, United Kingdom Department of Geology, University of Toronto, Canada

2

The most abundant data obtained from tephra deposits is the major element composition of individual glass shards, with anywhere between a few to many tens of analyses being produced from a single deposit. Recently, high spatial resolution, grain specific trace element techniques have added to the amount of data that can be produced from individual tephra deposits, and to handle such data, graphical or statistical approaches are widely used. In North America and New Zealand

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it is common to normalise major element data to an anhydrous basis prior to further analysis, whereas in Europe the raw data is most commonly used. Equally, different conventions are adopted for filtering the data, e.g. by analytical total. The major and trace element data are then used in a variety of ways to correlate or discriminate between individual deposits, with the most typical approach being comparisons of average compositions of the data, either numerically (mean +/- standard deviation) or on bivariate or ternary plots of element concentrations, comparing the “space” occupied by the data from different deposits. With increasing interest in tephrochronology as a tool, a range of statistical methods are now being applied to compare the compositions of different samples, in some cases generating conclusions which contradict the geochemical data. These methods include t-tests of the means, similarity coefficients, statistical distance methods, principal component analysis (PCA) and discriminant function analysis, and logratio methods, including logratio PCA. These approaches to tephra correlation have generated conclusions such as “normalisation should be avoided”, “x-y diagrams are unreliable”, “the more elements used the better” and “trace elements may be of little value”. Here, several graphical and statistical approaches are compared for their ability to discriminate/correlate basic, intermediate and acidic tephra deposits. As an example, the major element composition of the 3 large Yellowstone-sourced tephra deposits (Huckleberry Ridge, Mesa Falls and Lava Creek) cannot be confidently distinguished by any graphical or statistical method thus far tested, but these can be readily separated on the basis of their trace elements, by graphical and statistical means. As a rule, samples with similar major element compositions (evident as coincident fields on plots of normalized data) cannot readily be distinguished by statistical methods, and here trace element data becomes useful. Indeed, some statistical methods produce spurious correlations and discriminations resulting from primary geochemical variation in the glass, or issues associated with the analytical precision of EPMA, factors which are often overlooked. 0817 A novel tree-ring based approach for reconstructing records of long-term snowpack variability in western North America Gregory T Pederson1, Stephen T Gray2, Jacqueline J Shinker2, Daniel B Fagre3, Lisa J Graumlich4 1

U.S. Geological Survey Big Sky Institute Montana State University, United States 2 University of Wyoming, United States 3 U.S. Geological Survey - Northern Rocky Mountain Science Center, United States 4 University of Arizona, United States

Snow drives the majority of ecological and physical processes in the high mountain environments of western North America. Mountain snow also impacts distant lowland regions through runoff and streamflow. Despite the importance of snow, long-term records of spatial and temporal variability in snowpack are sorely lacking. For this project, information preserved in 200+ tree-ring records was used in combination with geospatial analysis techniques and instrumental climatology to first produce regional reconstructions, then gridded maps (cell sizes 10-150 km2), of Snow Water Equivalent (SWE) that span three or more centuries. Our initial work targets key high-mountain headwaters for the Upper Colorado, Upper Yellowstone/Missouri, and Columbia/Saskatchewan Rivers. Preliminary results show marked interannual to multidecadal variability in total SWE. Comparisons with existing proxy records of Pacific Basin climate show coupled ENSO and PDO influences on the total amount of mountain snowpack in these regions.

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However, the strength of the Pacific Basin teleconnection varies within each basin. In the southeastern portion of the Yellowstone/Missouri study area, for example, only the highest elevations show a consistent response to Pacific Basin forcing, while snowpack in lower elevations may show no response, or a weak response of opposite sign. Moreover, the strength and sign of these relationships varies over time. These and other results exemplify why long-term records are essential baseline information for evaluating recent and future changes in mountain snowpack. The overarching goal of this project is to lay the foundation for snowpack reconstructions that encompass high mountain areas in all of western North America. 1375 Grand Canyon (U.S.) terrace records: results of a decade of research into the complexities of dryland responses to climate change Joel L Pederson, Tammy M Rittenour, Ben D DeJong Utah State University, United States

Nearly a decade of mapping, stratigraphic, and geochronologic studies in Grand Canyon, including three graduate-student theses, have resulted in one of the most detailed and best dated tributary and mainstem fluvial terrace records in the world. Combined fieldwork and OSL, Useries, and cosmogenic dating from the head of Grand Canyon to its toe reveal stratigraphic relations, temporal trends, and correlations to climate that are not simple, yet very compelling. Here we present a second generation of new field and geochronology results that build upon our published work. Dryland tributary records spanning the past ~110 ka are dominated by four inset terrace deposits of two distinct types. First are two thick colluvial-alluvial fills that buried catchment topography and thicken upstream towards hillslope sediment sources. These episodes of aggradation and sediment storage date to 110 –85 ka and 50 –30 ka, correlating well to regional climate-cooling trends rather than to pluvial maxima. The other two terrace deposits are distinct in that they thicken downstream from strath to fill terraces towards the center of catchments, being fed via the reworking of the previous fills. Dated to 65–55 ka and 25–7 ka, these correlate to local climate warming and geomorphic disturbance. The spread of geochron data indicates tributary records are likely influenced by catchment size and deposit position within the drainage. One primary theme in our results has been the contrast of tributary records to that of the trunk Colorado River. Over about the same timeframe, the mainstem record has two major exposed fills and one inferred to be below grade, with timing shifted from that of tributaries at 125–90 ka, 75–60 ka, and >20 ka, respectively. Aggradation of the younger two of these seems to correlate to full glacial conditions in headwaters, but the older major fill does not. Our data hint that the age of a deposit shifts depending upon its location along the length of the river through the region. It is somewhat expected that the Colorado River will reveal transience and shifts in its record, because this continental river must integrate its Rocky Mountain headwater-dominated hydrology with its overwhelmingly local Colorado Plateau sediment forcing. These two forcing regions also underwent paleoclimate changes that were distinct in type and timing. All in all, the Grand Canyon record does not bode well for simple models of climate response.

1007 High-resolution snow pit studies of the deposition of cosmogenic 10 Be Joel B Pedro1, Andrew M Smith2, M Curran3, Vin I Morgan3, Krista Simon2, David Fink2, Tas D van Ommen3, Ben Galton-Fenzi1 1

Institute of Antarctic and Southern Ocean Studies, University of Tasmania and Antarctic Climate & Ecosystems CRC, PB 77, Hobart, Australia 2 Australian Nuclear Science and Technology Organisation [ANSTO], PMB 1, Menai, NSW 2234, Australia 3 Australian Government Antarctic Division and Antarctic Cooperative Research Centre, PB 80, Hobart, Tas. 7001, Australia

In November 2005 a snow pit was excavated to a depth of 4 m for 10Be (t½ = 1.5 x 106 years) analysis, close to the summit of Law Dome, East Antarctica. This snow pit augmented a 2 m snow pit dug nearby in December 2001. Both sampling sites were in the vicinity an automated weather station and in each case samples were taken from surface to base in successive 100 mm thick layers using a stainless steel sampling tool. The samples averaged 1.5 kg and were kept frozen until processing for cosmogenic 10Be measurement by accelerator mass spectrometry (AMS) at the ANTARES facility at ANSTO. Annual snow accumulation at the sampling site is high, averaging 640 kg m−2 a−1. The 20 samples from the 2001 snow pit represented approximately one year of snow accumulation. This high resolution record showed a pronounced seasonal signal of 10Be deposition in the late Austral summer – early autumn, with most 10Be ‘wet’, rather than ‘dry’, deposited. d18O measurements on the 40 samples from the 2005 snow pit show that this pit spans close to 3 years of snow deposition. Interpretation of the results has been greatly aided by the instrumental record provided by the nearby weather station (AWS). In addition to meteorological data, the AWS is equipped with a downward pointing ultrasonic radar that provides a continuous record of the height of the snow surface over the sampling period. This permits identification of deposition and removal events that lead to the net accumulation of the snow surface, which can then be associated with specific samples. Additionally, a set of triplicate samples was taken in 2001 using special jigs and clean equipment in precise 25 mm thick layers, with four of these matching the 100 mm thick beryllium sampling layers. These samples have been measured for density, d18O and glacio-chemical species including MSA, Cl, NO3, SO4, Na, Mg and Ca. Here we present preliminary results from the 2005 snow pit, relating these to the 2001 results, and examining implications of this extended record for our earlier findings concerning the transport and deposition of 10Be at Law Dome. 0328 ENSO Dynamics during the last three climatic cycles: climate forcing or feedback? Leopoldo D Pena1, Isabel Cacho1, Patrizia Ferretti2 1

GRC Geociències Marines, Department of Stratigraphy, Paleontology and Marine Geosciences, University of Barcelona, Spain 2 Godwin Laboratory, Department of Earth Sciences, University of Cambridge, United Kingdom

Recent hypotheses consider low latitudes as the source regions for past global rapid climatic changes. In this regard, the Eastern Equatorial Pacific (EEP) is an area with significant potential to trigger global changes due to its active role in the El Niño-Southern Oscillation (ENSO). Here we present results obtained from ODP 1240 (Leg 202, 0˚01.31'N, 86˚ 27.76'W, 2921 mbsl) on paired stable isotopes (d18O,


d13C) and trace elements (Mg/Ca) on planktonic foraminifera for the last 275 ka. Multiple species with different preferential dwelling depths were studied to reconstruct both surface (G. ruber) and thermocline (N. dutertrei) characteristics. These new results provide the longest high resolution records of surface and thermocline layers in the EEP to date. The age model was constructed using 17 AMS radiocarbon dates and graphic correlation of the Sea Surface Temperature (SST) record with Antarctic Vostok deuterium record. Results obtained clearly demonstrate that changes in Deep Thermocline Temperatures (DTT) and N. dutertrei d13C lead SST warming by 1–2.5 ka during glacial Terminations. Moreover, these changes are synchronous within the age model error with major Antarctic Vostok CO2 rises. We have also calculated the local d18O water changes in deep thermocline (d18Odtw) by subtracting the DTT component from the N. dutertrei d18O and global ice volume d18O signal. The results obtained clearly show that thermocline waters oscillated between periods of relatively high salinity and periods of fresher waters which can be interpreted in terms of upwelling strength and would represent long-term changes analogous to those interannual-decadal El Niño-La Niña oscillations. Heaviest d18Odtw anomalies were associated with glacial Terminations, and coexisted with large depletion events in the d13C record consistent with the dominance of strong upwelling conditions in the EEP. Spectral analyses of these records illustrate strong and significant spectral power in the band of both precession and obliquity. These results confirm that seasonal insolation changes driven by the precession cycle are the dominant force in long term ENSO evolution as proposed by some model studies, but these new results also demonstrate that obliquity was critical in modulating the intensity of the precessionchanges. The co-existence of maximum obliquity with low precession during the last three terminations favoured a strong seasonal upwelling cell (super La Niña conditions). We propose that these oceanographic conditions caused the upwelling of supersaturated CO2-rich intermediate waters leading to massive sea-to-air CO2 injections which acted as a trigger of the global deglaciation-warming. 0675 Amino acids in calcite: a tiny time-capsule for the Quaternary Kirsty EH Penkman1, Richard C Preece2, David H Keen3, Darrel Maddy4, Matthew J Collins1 1

University of York, United Kingdom University of Cambridge, United Kingdom 3 University of Birmingham, United Kingdom 4 University of Newcastle-upon-Tyne, United Kingdom 2

Whilst amino acid racemization (AAR) has been applied widely as a dating technique for the Quaternary in Europe, in recent years other geochronological tools have become more routinely used, at the expense of AAR. However, in Africa and Australia, successful results have been achieved using AAR of proteins in ratite eggshell, proposed to act as a closed-system with respect to the entrapped protein. At those sites not lucky enough to have an abundance of large flightless birds, a commonly occurring biomineral with similar closed-system properties would extend the potential of AAR to provide a simple dating tool. In an attempt to isolate a closed system in gastropod shells, the methodology reported here has been refined by (i) using multiple amino acid DL ratios, (ii) cross-checking the AAR values of only Free amino acids (released from degraded proteins) against AAR values of the total amino acid in the mineral, (iii) bleach treating to remove contaminants and the degradable organic matrix. This approach both ensures the analysis of only the original amino acids, and allows the identification of bacterial contamination and post-depositional recrystallization. Yet despite these innovations, beyond MIS 9 the level of resolution in gastropod

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shells becomes limited. However, this work has been recently eclipsed by results obtained from the analysis of the tiny Bithynia opercula, common fossils in Quaternary freshwater deposits. The shells are aragonite, but the humble operculum which closes the gastropod aperture is calcite. Preliminary results with opercula are spectacular: within a single site multiple opercula yield consistent results and the data from multiple sites fall into discrete clusters. As a consequence, the extent of protein degradation in opercula can be used to resolve not only stages but sub-stages within the Quaternary. The analyses of over 600 single opercula from 100 northern European sites are reported, with this coherent calcite intra-crystalline system allowing the development of an AAR chronology to at least 2.5 Ma. The utilisation of these robust biominerals enables increased resolution over the last 0.5 Ma and pushed back the range of this technique in Europe far further than expected. Whilst the limits of dating using solely racemization is reached within the Pliocene in the areas studied, the isolation of an intact closed-system of amino acids from Miocene and Eocene opercula opens up a world of other amino acid degradation reactions, which can be used for dating. 1389 Microfossil records of environmental change, land use and societal collapse at Angkor, Cambodia Dan Penny The University of Sydney, Australia

The mystery surrounding the ‘collapse’ of Angkor, Cambodia’s medieval capital and now one of Asia’s most well-known World Heritage sites, has flourished as a result of the limited and equivocal historical evidence, and the near absolute lack of archaeological evidence – or empirical data of any kind – relating to the demise of the city. Renewed research in archaeology, remote sensing and the earth sciences in Cambodia is beginning to yield crucial evidence regarding the demise of Angkor. The palynology of sediments that accumulate within temple moats and reservoirs offer an opportunity to reconstruct, and radiometrically date, changes in land cover over time. Using this approach it becomes possible to establish an empirical basis for the consideration of Angkor’s diminution after the 15th century CE. For example, periods of land use change have been identified, particularly the abandonment of agricultural land or, in some cases, the continuity of land use long after the supposed abandonment of the city. This approach has also revealed critical information about the redundancy of large reservoirs and their attendant infrastructure, and has contributed to a re-consideration of epigraphic ages for the foundation of Angkor, in 802 CE. This paper will review recent outcomes, present new data from a range of sites, and foreshadow future work in environmental archaeology at Angkor and the region. 0691 Environmental change in the Danish Baltic during the Roman Warm Period inferred from mollusc data Kaj S Petersen1, Peter Rasmussen1, David Ryves2 1

Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350 Copenhagen K, Denmark 2 Department of Geography, Loughborough University, Loughborough, Leicestershire LE11 3TU, United Kingdom

From an ongoing project aiming to explore how Danish Baltic coastal environments have changed over the last 9000 years, we present some

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of the first results concerning environmental changes in the Roman Warm Period (~2000 BP) as shown by changes in molluscan faunas. High resolution analysis of two AMS 14C dated sediment cores from Horsens Fjord (Jutland) and Isefjord (Zealand) located 120 km apart, indicate a contemporaneous change in the mollusc record starting around 2000 cal. BP. At this time mollusc abundance increases at both sites and a suite of taxa indicating higher salinity appear e.g. Ostrea edulis (European flat oyster), Odostomia unidentata, Rissoa violacea, Gari fervensis, Odostomia umbilicaris and Parvicardium scabrum, although in low numbers. These changes in the record testify to a widespread environmental change in the Danish Baltic towards more saline and productive conditions. This interpretation is supported by an independent line of evidence from the archaeological record: large manmade shell middens dated to the centuries around 2000 cal. BP, and predominantly composed of Mytilus edulis (Blue mussel), Cerastoderma edule (Common cockle), Littorina littorea (Common periwinkle), and to a lesser extent Ostrea edulis, are recorded along several Danish and North German fjords. The synchroneity between the inferred changes in the marine environment and the appearance of these Iron Age shell middens strongly suggests a causal connection between the two. The salinity rise might be due to a more frequent inflow of high salinity North Sea water to the Danish Baltic which might have travelled through the Danish straits (Great Belt, Little Belt and Øresund) right into the Baltic Sea proper as diatom and isotopic data from the Gotland Deep also suggest a salinity rise in the central Baltic Sea in the Roman Warm Period. Understanding past changes in North Sea hydrography provides insight into the natural variability of marine ecosystems pre-dating major human impact, and may provide clues about what to expect under future climate scenarios. 0560 Late Quaternary millennial-scale climate variability in eastern Australia from lake sediment, North Stradbroke Island, Queensland Lynda M Petherick, Hamish A McGowan, Patrick T Moss University of Queensland, Australia

A high-resolution, multiproxy record of palaeoclimatic and palaeoenvironmental variability extending to ~37 ka BP has been reconstructed from lake sediment from Native Companion Lagoon (NCL), North Stradbroke Island, Queensland. Aeolian sediment deposits (consisting of both local and far-traveled material) extracted from the lake sediment act as a proxy for aridity in eastern Australia. Variability in aeolian sedimentation in the NCL record appears to have millennial-scale cyclicity through the Late Quaternary, with a period of ~3 ka BP. ICPMS trace element analysis of the aeolian sediment and subsequent provenancing of the far-traveled dust component show variations in dominant dust source areas for NSI, with periods of increased aridity during the late Pleistocene showing increased input into NCL from the Channel Country, Queensland. Through the Holocene, periods of increased aridity in the NCL record correspond with increased dominance of dust source areas in central South Australia, such as Lake Frome. Variations in the dominance of continental dust source areas for NCL indicate variability in the position and intensity of dust transport pathways to North Stradbroke Island, reflecting major changes in atmospheric circulation patterns over Australia. For example, in comparison to periods of decreased aeolian sedimentation, periods of increased aridity indicated in the NCL record show dust input from continental source areas further north. This input from more northern source areas may reflect equator-ward movement and enhancement of the zonal westerly wind belt. Palynological and charcoal analyses from

the NCL sediment indicate drying conditions and increased burning occurring coevally with peaks in aeolian sedimentation, offering further supporting evidence for millennial-scale cyclicity of aridity in eastern Australia through the late Quaternary. 0562 The termination of the Last Glacial Phase in eastern Australia from North Stradbroke Island, Queensland Lynda M Petherick, Patrick T Moss, Hamish A McGowan University of Queensland, Australia

A high-resolution, multiproxy record encompassing the termination of the Last Glacial Phase (LGP), including the Last Glacial Maximum (LGM) has been reconstructed from lake sediment from North Stradbroke Island (NSI), Queensland. The record is based on the sediment (i. e. moisture and organic content) and pollen analysis of lacustrine material. Aeolian sediment flux (consisting of both a local and a far-traveled component) derived from the lake sediment acts as a proxy for aridity in eastern Australia, and indicates that climate leading into the height of the LGM was increasingly unstable. The NSI palaeoenvironmental record (both sediment and pollen) suggests that the height of the LGP was represented by an extended period of climatic and environmental variability, with a cyclic pattern of periods of increasingly arid conditions interrupted by periods of climate amelioration culminating in the height of the LGM at ~19 ka BP. In addition, the sediment record indicates that deglaciation in eastern Australia was not smooth, but was interrupted by three abrupt reversals to near-glacial conditions between 18–14 ka BP. This is supported by the palynological record from the same site, which shows climate switching from cool and dry to warm and humid for the same period. ICP-MS trace element analysis of the aeolian sediment and subsequent provenancing of the far-traveled dust component shows fluctuating input of material to NSI from continental source areas, such as the Channel Country, Queensland, and the Murray-Darling Basin, during the termination of the LGP, which provides further support for increasing instability in eastern Australian climate during this period. 1290 High resolution sample intervals in the loess/paleosol sequence of Stillfried B (Lower Austria) Robert Peticzka, Dieter Riegler, Birgit Terhorst Institute of Geography and Regional Research, University of Vienna, Austria

The reinvestigation of the loess/paloesol sequence in the eastern parts of Lower Austria took place due to the famous key site of the so-called section “Stillfried B” in the field of Quaternary loess research. Although older literature is regarding the paleosol of Stillfried B as Middle Wuermian interstadia, the stratigraphical position of the paleosol is now discussed critically. Our investigations started with a detailed take-up of the geographic position by using tachymetric options. During the field survey standard parameters like carbonate concentration, soil colour according to Munsell and optical verification as well as the measurement of magnetic susceptibility were applied. Undisturbed samples were taken by an arithmetic interval of 10 cm. These samples were analysed using parameters as carbonates, clay content, mineralogical analyses, total cation exchange capacity and aggregate stability. The investigations show that there is a weak pedogenetic horizon which can be compared to the so-called “Stillfried B-paleosol”. Furthermore a second pedogenetic horizon was detected for the first time, but due to the taken sample interval it was not possible to come to an


unambiguous conclusion of the paleopedogenetic situation. Therefore we took a monolithic bloc (195 cm height) of the section including both paleosols and the sample interval was then reduced in the laboratory to 1 cm distance. The result allows us to differentiate between two clearly separated paleosols in the section of Stillfried B. The reduced sample interval lead to new insights. 1039 Century scale land-sea correlation of Indian summer monsoon variability during past six millennia Netajirao R Phadtare Wadia Institute of Himalayan Geology, 33 GMS Road, Dehra Dun, India

The Garhwal (Uttaranchal) Higher Himalaya lies along the northwestern limit of the Indian summer monsoon (ISM) system, and hence it is an important region for ISM studies on both global and regional scales. The continued retreat of Himalayan glaciers throughout the Holocene has resulted in initiation of peat accumulation on lateral moraines, meadows as well as in geomorphic depressions of newly exposed periglacial landmasses. Many pristine peat deposits located in remote alpine meadows and lateral moraines situated above 3500-m altitude in Central Higher Himalaya, therefore, are the excellent archives of Holocene climate and ISM records of the region. One of the best developed peat deposits of Uttaranchal Higher Himalaya representing last 6000-year climate history of the Gangotri area, was discovered in middle of the Dayara meadow (30˚50′10.3″N and 78˚33′27.57″E) situated at 3430-m altitude. The peat profile (1.04-m thick) was continuously sampled at one centimeter interval, constrained with four radiocarbon dates, and studied for multi-proxy climate records (pollen concentration/gm, percent organic matter and magnetic susceptibility of detrital influx). The preliminary data indicate decreased monsoon precipitation implying dry climate during 5900–5600, 5400 –5200, 4700 –3600, 2400 –1300 and 900 –600 cal BP intervals. These dry episodes were separated by relatively improved monsoon strength during intermittent periods. The relationships of these events with contemporary monsoon upwelling records (G. bulloides) from the Arabian Sea, established for the first time, reveals indubitable significance of Himalayan peat deposits for understanding the land-sea correlation of Indian summer monsoon variability during the Holocene period. 0422 Quaternary sedimentation in the Schirmacher Oasis, East Antarctica Binita Phartiyal, Sameer K Bera Birbal Sahni Institute of Palaeobotany, 53-University Road, Lucknow, 226007, India

The interplay of the ocean, atmosphere and the cryosphere in the polar regions makes Antarctica a key in producing ‘rapid’ climatic change. It is probably the best climatic archives of the past & future, with terrestrial sediments, polar ice and marine sediments, covering centennial to millennial years climatic record. As a consequence, information on environmental changes during the recent history of the earth is stored in the deposits found. During the 25th Indian Antarctic Expedition 2005– 2006, mapping of the palaeolakes and the drying lakes of the Schirmacher Oasis (SO) region of East Antarctica was done. This region known for over more than 80 pro-glacial, land locked and epi-shelf lakes. Evidences from the presence of > 1 m thick sedimentary fill in the SO show that the oasis must have been a host of big lake systems

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in the recent past. The present lakes interspersed over the area are the remnants of those huge water bodies which once occupied the oasis. Our observations record the presence of 6 major lakes in the Quaternary times. Several of these lakes have been reduced in size to mere lake lets and ponds. Thus the landlocked lakes of SO are under a threat of drying, possibly due to the combined effect of recession of glaciers feeding them, low melt water, low precipitation and high winds etc. A detailed lithological study of several sections in an east-west transact was made. Many fresh water lakes are still found in SO which are being continuously fed by the continental ice sheet and the ice shelf respectively while very few of the large landlocked lakes are presently existing in this ice free area. These lacustrine sediment fills are a very potential source of information to trace the Quaternary geological history and palaeoclimatic records. Of all the stratigraphic records, those from Antarctica have been amongst the most pivotal adding our understanding of climate change from the southern part of the globe. In the present work we hope to have bring in light that Antarctic palaeo-lacustrine sediment plays an important role in piecing together the history of environmental change in Antarctica and in turn, the key role that Antarctica plays in Earth system science. We are working on generating a multi-proxy (mineral magnetic, palynological, geochemical, sedimentological and chronological) record of the Quaternary climatic changes from these few well preserved Quaternary sections of this 98% ice covered continent. 1018 Multi-millennial simulations of the climate of the late Holocene Steven J Phipps CSIRO Marine and Atmospheric Research, Australia

The CSIRO Mk3L climate system model, a low-resolution coupled atmosphere-sea ice-ocean general circulation model, has been used to conduct multi-millennial simulations of the climate of the late Holocene. As part of Phase 2 of the Paleoclimate Modelling Intercomparison Project, equilibrium simulations have been conducted for pre-industrial conditions, and for the climate of the mid-Holocene. The control climate exhibits a high degree of stability, with the El NiñoSouthern Oscillation being the dominant mode of internal variability. However, the simulated El Niño is weaker, and has a longer return period, than the observed phenomenon. The model is able to simulate the larger-scale features of the climate of the mid-Holocene, with increased summer temperatures at northern mid-latitudes, and cooling in the tropics. However, it is less successful at capturing some of the regional-scale features of the mid-Holocene climate, with the precipitation over northern Africa being deficient. The model simulates a ~13% reduction in the strength of El Niño, a much smaller decrease than that implied by the palaeoclimate record. Transient simulations of the climate of the late Holocene, from 6 ka BP to the present day, have also been conducted. The technique of Lorenz and Lohmann (2004) is employed, in which the rate of change in the Earth’s orbital parameters is accelerated. The model simulates a gradual decrease in summer temperatures at northern mid-latitudes, a gradual warming in the tropics, and a strengthening of El Niño.

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0357 On extending the range of radiocarbon dating Jeffrey S Pigati, Jay Quade, AJ Timothy Jull, Nathaniel A Lifton University of Arizona, United States

Radiocarbon laboratories worldwide routinely provide reliable 14 C dates in the 0 –40 ka range to the geological and archeological communities. However, geochronologists widely recognize that the reliability of 14C dating quickly degrades toward the end of this range and that 14C ages older than ~40 ka are often inaccurate. The primary reason is that the amount of “original” 14C used for age estimation in old samples (>40 ka) is very small (15 m above the modern water table and represent a period of enhanced effective precipitation that spanned most, if not all, of oxygen isotope stage (OIS) 2. Chronologic, isotopic, geochemical, faunal (ostracode and gastropod assemblages), and sedimentological evidence from the Coro Marl collectively suggest that hydrologic conditions, specifically the elevation of the regional ground-water table in the San Pedro Valley, remained relatively constant prior to, during, and after the last glacial maximum. Sedimentological evidence also suggests that the regional water table fell at the end of the late glacial period, approximately 15,500 years ago, before rebounding temporarily during the Younger Dryas Cold Event. We have not found evidence of groundwater highstands in the valley during the Holocene. The timing of these hydrologic changes coincides with large variations in the oxygen isotopic composition of calcite from a nearby speleothem to the west and changes in lake levels at Pluvial Lake Cochise to the east. Thus, not only does our study provide a record of past hydrologic conditions in this part of the American Southwest, it also further validates the concept of ground-water discharge deposits as recorders of past climate change. 0924 Defining the Quaternary Brad Pillans Australian National University, Canberra, Australia

One can only agree with sentiments recently expressed by the eminent stratigrapher Amos Salvador, that a stable, standard geologic time scale is indispensable for clear and precise communication among geologists. Indeed, this is exactly the task of the International Commission on Stratigraphy (ICS), expressed through the most recent iteration of the international Geological Time Scale, GTS2004. However, in GTS2004, both the Quaternary and Tertiary were omitted from the formal time scale hierarchy, with the Quaternary designated as an informal climatostratigraphic unit spanning the last ~2.6 Ma of the Neogene System. These omissions have been hotly debated since 2004 and, consequently, the definition of the Quaternary remains anything but stable in the GTS. If we accept the majority views of INQUA members (polled in 2005), a joint INQUA/ICS Taskforce (convened in 2004), and the most recent ICS vote (Leuven meeting, 2005), that a formally ranked Quaternary should span the last ~2.6 Ma, and we also accept an IUGS ruling (August 2006) that the GTS must retain a strictly hierarchical structure, then this can only be achieved by also lowering the base of the Pleistocene Series to 2.6 Ma (=base Gelasian Stage, currently the uppermost stage of the Pliocene Series). Furthermore, as discussed by Stephen Walsh, if Tertiary and Quaternary are to be included as formal subdivisions of the Cenozoic, then Neogene and Paleogene must be subdivisions of the Tertiary, and the top of the Neogene must correspond with the base of the Quaternary. Given the above criteria, I would recommend that Quaternary and Tertiary be Systems of the Cenozoic Erathem. Neogene and Paleogene would then, necessarily, be ranked as Subsystems of the Tertiary (equivalent rank to the Mississippian and Pennsylvanian subdivisions of the Carboniferous


System). The Quaternary System would then comprise the Pleistocene and Holocene Series, with the base of the Pleistocene redefined at the base of the Gelasian Stage. One final implication of moving the Gelasian Stage to the Pleistocene, would be that other stages would need to be defined for the younger part of the Pleistocene above the Gelasian. Since the Pleistocene is currently subdivided into three Subseries, each of these would need to contain one or more stages. The simplest scenario would be a four-stage subdivision of the Pleistocene, with two stages in the Lower Pleistocene (the Gelasian and one new, younger stage), and one new stage in each of the Middle and Upper Pleistocene Subseries. 1282 Glacial–interglacial cyclicity during the last 500 ky in a new pollen record from northeastern Italy Roberta Pini1, Cesare Ravazzi1, Marta Donegana1, Roberta Banino2, Roberto Avigliano3 1

C.N.R. – Institute for the Dynamics of Environmental Processes (IDPA), Milano, Italy 2 Dip. di Scienze Geologiche e Geotecnologie, Univ. of Milano – Bicocca, Italy 3 Dip. di Georisorse e Territorio, Univ. of Udine, Italy

Pollen analysis was performed on the 262-m long record of Azzano Decimo to reconstruct the main steps of vegetation and environmental changes that occurred during sedimentation. The palynological record is part of a multidisciplinary project including micropaleontology, facies analysis, sand petrography, geochronology. This archive, possibly extending back to MIS 13, yields direct evidence of cyclic foreststeppe successions and of several regressions/transgressions of the Adriatic Sea, related to glacioeustatic oscillations and documented by repeated alternations of environments ranging from continental, paralic to mid/inner shelf. The chronological frame relies on 14C datings (back to 50 ky BP), on the correlation of palynostratigraphical tie points with coeval european pollen sequences and on the comparison of events evidenced in the pollen diagram with detailed marine d18O records. IRSL dating is currently in progress. The Azzano record documents the effects both of the 100 ky frequency orbital forcing and of lower scale climatic events. The pollen record of Azzano Decimo is characterized by forest phases of warm, oceanic and cool temperate climate separated by phases of partial forest withdrawal and spread of steppic communities of dry, continental temperate climate. The succession of forest/steppe alternations was compared with other european pollen records (Follieri et al., 1988; Reille et al., 1998; Drescher-Schneider, 2000; de Beaulieu et al., 2001 and others), with d18O records from the Atlantic Ocean (Bassinot et al., 1994; McManus et al, 1999) and the Mediterranean Sea (Martrat et al., 2004) and with the global record of glacio-eustatic oscillations (Waelbroeck et al., 2002). The beginning of forest spread over steppic communities can be carefully compared with the development of isotopic “Terminations”. In those regions supporting the survival of trees during phases of glacial maximum (like the northeastern sector of Italy, where the study site is located), forest expansion represents the quick reaction of vegetation to the climate warming occurring several thousand years before the phases of maximum flooding. The age of forest development during the last Lateglacial and of speleothem deposition at high altitude in the Alps during the penultimate Termination (Spötl and Mangini, 2006) correlates with the midpoint of the last two glacial Terminations. Differences from South-Iberian, Mediterranean and continental-asiatic records may be related to regional patterns of atmospheric circulation during the terminations.

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1298 Subglacial till is a hybrid Jan A Piotrowski Department of Earth Sciences, University of Aarhus, C.F. Moellers Alle 1120, DK-8000 Aarhus C, Denmark

Recent field and laboratory studies reveal in hitherto unprecedented detail the complexity of subglacial till formation characterised by multiple processes shifting in time and space in glacial cycles. Only in exceptional cases can till generation be attributed to a single process. Instead, typically a till is a hybrid resulting from superposition of signatures derived from accretion by lodgement, melt-out and deformation. Transient bed conditions such as switching between basal coupling and de-coupling, fluctuations of freezing front, and alternating erosion and deposition leading to complex textural and structural imprint can be expected over vast areas of soft beds overridden by Pleistocene ice sheets. The quest to precisely identify and classify a certain subglacial till based on one process of formation which characterised till research over the last two decades seems flawed. The real challenge is to reconstruct till evolution in a glacial cycle with focus on the subglacial bed as a mosaic of frequently shifting and interfingering processes controlled by mechanical and hydrological feedbacks. Pleistocene examples from the European lowland and data from modern glaciers give insight into the transient nature of subglacial processes reflected in till properties and suggest the importance of water pressure fluctuations around the glacier flotation point. Only slight variations of water pressure at the ice-bed interface may result in fundamentally different behaviour of subglacial sediment. Special attention is given to bedded tills whose origin has been debatable. Laboratory experiments indicate that bedded tills have very small preservation potential when subjected to deformation beneath an ice sheet, which suggests that such tills, abundantly found in the geological record are formed by multiple basal de-coupling events by pressurised subglacial meltwater in the vicinity of the glacier flotation point. These data together with generally low drainage capacity of ice sheet substrata suggest glaciological instabilities and frequent surging/streaming events. 0468 Late Holocene palaeoenvironmental evolution and human settlements in the Adige river plain (Italy) Silvia Piovan1, Paolo Mozzi1, Antonella Miola2, Cristina Stefani3 1

Department of Geography - University of Padova, Italy Department of Biology - University of Padova, Italy 3 Department of Geosciences - University of Padova, Italy 2

This multidisciplinary research aims to understand the palaeohydrographical and palaeoecological evolution of the distal part of presentday Adige alluvial plain (north-eastern Italy) and man-environment relations during the Late Holocene. The area is of great archaeological interest for an exceptionally well-preserved roman centuria, which extends for 250 km2 from the city of Rovigo almost to the Lagoon of Venice and important Bronze and Iron Age sites: among them, Roman-Age villa of Ca’ Motte, very close to the decumanus maximus of the centuriation area, situated on the top of a crevasse-splay deposits and Saline site placed on the alluvial ridge of the Philistina Po palaeochannel, characterized by an archaeological stratigraphy with Bronze, Iron and Roman age remains. The investigation takes advantage of microrelief and historical cartographic analyses, remote sensing and boreholes down to the depth of 5–7 m with the Edelman hand auger. In order to quantify the organic

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content of the peat, loss-on-ignition technique has been adopted. Palaeobotanical analyses of the peat layers have been carried out to establish the vegetation assemblage of the swamp environment. The radiocarbon dating of the backswamp peats helped to date the fluvial activity in this area which consists of Late Holocene fine sediments. The classical geomorphological studies have been supported by some petrographical analyses of the drilled sands in order to determine the composition and to compare it with the Adige and Po sediments. As a consequence each sand body has been related to the appropriate fluvial basin. A digital elevation model has been developed, based on a manual interpolation of spot heights with spacing of 0.5 m of the “Carta Tecnica Regionale del Veneto” at scale 1:5000. Landsat-TM and Aster images let the analysis of major landforms while oblique and vertical panchromatic photo-aerial interpretation gave a finer detection of natural morphologies and anthropic structures. Stratigraphical cross-sections of the main alluvial ridge have been carried out, in order to clarify the space-time relations between human settlements and palaeoenvironment since the Bronze Age. A complicated web of palaeochannels incised the alluvial plain through the millennia; its sedimentary history is characterized by periods of aggradation due to the upbuilding of fluvial ridges and crevasse splays alternated with periods when overbank clays and peats accumulated with lower depositional rates. Cross-sections also suggest that the position of the ancient settlements is not casual. In fact, they located in places characterized by high geomorphological conditions and good drainage. 1016 Reconstructing the Angkorian hydrological network: integrating research by solving methodology Samuel T Player University of Sydney, Australia

The ancient city of Angkor, Cambodia, is noted as the largest pre-industrial city in the world and has for decades been steeped in debate concerning the effects of a vast hydrological channel network on its demographic collapse. The failure of the network to effectively manage the distribution of water can theoretically be evidenced by sedimentation, erosion features and pedogenic alterations. Geomorphological analysis is therefore an essential component of the debate. However, in archaeological contexts, geomorphological research is invariably disadvantaged due to the necessary bias towards the archaeological in the selection of site locations. In these settings, as at Angkor, the preservation and/or quality of geomorphic evidence may not be favourable for a confident interpretation but is nevertheless extracted from the site and surrounds. Because of this, basic analytical techniques often fail to yield useful information and inhibit the confident integration of archaeological and geomorphological research. At Angkor, geomorphic interpretation of sections cut through numerous channels has consistently been confounded by basic issues of stratigraphic differentiation. Redoximorphic features consistently obscure the original stratigraphy and; a highly weathered environment and the source of sediments being from hills composed of quartz sandstone conspire to produce compositional homogeneity. In cases such as these it is sometimes prudent to experiment with a range of methods before embarking on a larger project. Results are presented here from a preliminary study where geophysical, physical and chemical analyses are applied to a selection of Angkorian channels for the purposes of stratigraphic differentiation and correlation, palaeoflow velocity estimation,

and estimates of human population density. Electromagnetic induction was tested as a rapid method for mapping channel cross-sections but with limited success. Particle-size analysis and loss-on-ignition when used in combination appeared effective in differentiating channel stratigraphy. Particle size distributions also showed potential for differentiating the relative flow velocities between various channels despite a limited sediment source. Analysis of phosphorus demonstrated significantly higher concentrations at a site proximal to the city centre relative to a more distant location. These preliminary results suggest that successful integration of archaeological and geoscientific research requires that technical aspects are best tackled prior to the main stage of data collection. The relative failures and successes of results presented here suggest that to solve the Angkorian hydrology debate an integrated hierarchy of methods are needed. These include both quantitative, rapid acquisition methods for selecting and interpolating interpretations of detailed point-source studies using traditional approaches. 0746 Neogen deposits of the Kerch strait Alexander A Pokryshkin, Lilia A Esina Southern Branch of Shirshov Institute of Oceanology RAS, Russia

Kerch Strait is situated within a young Epi-Hercynian Scythian plate with Pre-Cretaceous basement and alpine folded region. A border between them stretches along a nearmountain Crimean-Caucasian deep fracture (suture zone). Kerchensko-Tamansky lateral sag is a main structural-tectonic element of the Kerch strait. It was formed in Cenozoic era and was imposed on a Mesozoic trough which existed here earlier. Deep faults play an important part it the tectonics of the region. Kerchensko-Zdanovsky fault above which the Kerch strait was formed can be observed in Neogen structural floor by a number of small transgressions of sub-meridional stretch and that created weakened zones. A total thickness of sedimentary series near the Kerch strait presented by rocks from Jurassic to recent ones is 12 km, 5-6 km of them are composed by Maicopean ball clays. Neogenic deposits prevailing on the Kerch and Taman peninsulas were revealed in the Kerch strait too. They are presented by Middle and Upper Miocene and Pliocene, they are separated from Maicopean deposits by a large regional interval and are characterized by mixed character, variability of the composition and close small inner intervals Middle Miocene is presented by Tarkhan, Chokrak, Carangate and Konksky horizons. Upper Miocene is widely spread in the strait and on shore; it is presented by sarmat clays with sand and limestone small layers and by Meotis deposits composed of clays and pearlweed limestones, which up to the cut are replaced by clays with the limestones layers of a total thickness being 50–250 meters. Pliocenic deposits are almost absent in the strait. Quaternary deposits. Everywhere marine Pliocenic deposits are covered by continental or marine Quaternary deposits (clays, sands, aleurites, shells). Investigations in the Kerch strait afford to say about a wide distribution of Miocenic deposits on the bottom surface of the strait. Along their root Kerchensko-Zdanovsky fault over which the strait was formed looms by a bed of Paleo-Don. Such a research gave a possibility to reveal a number of anticline folds separated by troughs and a series of small tectonic transgressions.


1328 Late Glacial to Mid-Holocene insect records from Aubrac, Massif Central, France (Coleoptera, Diptera Chironomidae) Philippe Ponel1, Emmanuel Gandouin1, Frédéric Guiter1, Valérie Andrieu-Ponel1, Jacques-Louis de Beaulieu2 1

IMEP-CNRS, France Institut Méditerranéen d’Ecologie et de Paléoécologie (IMEP), France

2

The aim of this study is to describe the environmental and climate changes that occurred in the mountains of Aubrac between the last glacial retreat and the Atlantic period, from a coupled analysis of fossil Coleoptera and Diptera Chironomidae. The changes affecting the main ecological categories of Coleoptera lead to divide the sequence into 5 beetle zones: the lowermost zone E is characterized by extremely poor assemblages (periglacial environment), zone D (Oldest Dryas and Late Glacial Interstadial) is marked by regular occurrences of taxa associated with open environments, aquatic taxa including many insects associated with running and highly oxygenated water, and cold adapted taxa with relatively low numbers, zone C (Younger Dryas) is clearly indicated by the occurrence of two important events: a particular abundance of cold adapted taxa and a marked decrease of running water taxa; beetles associated with herbaceous vegetation and open environments are also well represented, zone B (Early Holocene) corresponds to the total disappearance of cold adapted taxa; the transition between zone C and zone B is marked by a dramatic peak of running water taxa, the uppermost zone A (Early/Mid Holocene) is indicated by a total absence of running water taxa which are replaced by standing water or indifferent taxa, a particular abundance of wetland taxa, and of taxa associated with herbaceous vegetation and open environments. Two major ecological and climatic informations can be identified from the Chironomid record: (i) the Late Glacial Interstadial is marked by high percentages of Corynocera ambigua, a typical cold adapted taxa; it shows that relative cold climate conditions prevailed throughout this period, (ii) during the Younger Dryas this taxa is still present, associated with increased percentages of Tanytarsus lugens grp, a cold-oligotrophic water adapted and inhabitant of profundal part of lake. The occurrence of both taxa suggest a marked cooling of the climate and hydrological changes. This preliminary palaeoecological reconstruction needs to be improved in further multi-proxy investigations (pollen, organic matter, plant macroremains, etc.). However some important results can be drawn from this study at this stage: during the LGI cold climatic conditions prevailed in an open landscape, probably because of the altitude of the site; the Younger Dryas is characterised by a drastic cooling marked by the domination of nordic and alpine insects; aquatic Coleoptera suggest major changes in the hydrological regime at the boundary Younger Dryas/Holocene (melting snow and/or precipitation increase). 0997 Quantitative palaeoclimate reconstruction in Australia using fossil beetles: Are climate space limitations intractable? Nick Porch The Australian National University, Australia

OVERVIEW: Quantitative palaeoclimatic reconstructions ultimately depend on two key principles. First, they require a proxy capable of yielding accurate and precise estimates of climatic parameters; usually based on the relationship between modern climatic values and assemblage composition. Second, they require that potential past climate

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spaces are represented in the modern training set; if this is not the case then it is likely that palaeoclimatic reconstructions are inaccurate, regardless of their precision, reflecting the limitations imposed by climate space rather than intrinsic limitations of the methodological approach adopted. In this paper I explore the potential limitations of past climate space configurations in the context of developing a method for reconstructing past climates in Australia. APPROACH: The method for estimating past climatic parameters, using Australian beetle assemblages, is based on 69,194 records from 5900 geocoded localities for more than 7500 species of Australian beetle. For 1150 aquatic, riparian and saprophilic taxa detailed bioclimatic profiles were produced using BIOCLIM; this data forms the basis for developing and testing the coincidence method (overlap of species in the assemblage) using modern data, and for reconstructing past climates. The precision and accuracy of the coincidence method was examined using modern assemblage data derived from the distribution database, using jack-knifed tests; species records for a test site did not contribute to reconstructing the climatic parameters at that site. Results of modern tests indicate the method successfully reconstructs a range of temperature parameters with a high degree of precision and accuracy, especially Temperature of the Warmest and Coldest Quarters and Annual Mean Temperature (linear observed-predicted regressions, respectively, r2 =0.9637, r2 =0.9504, r2 =0.9622, p bogs > soils. The influence of biome type upon charcoal abundance was less clear, perhaps due to a paucity of sites in certain biomes. The implications of these findings for interpretation of charcoal records will be discussed.

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1078 Biomass burning since the LGM: a global synthesis of fire activity based on the analyses of charcoal data Mitchell J Power1, Jenn Marlon2, Natalie Ortiz3 1

University of Edinburgh, United Kingdom University of Oregon, United States 3 University of Bristol, United Kingdom IGBP Paleofire FTI Participants, Initiative sponsered by the International Geosphere Biosphere Program Fast Track Initiative on Fire, Coordinated by QUEST 2

Paleofire reconstructions of global biomass burning indicate that fire regimes have varied on millennial timescales since the last glacial maximum. At these timescales fire activity is controlled by changes in boundary conditions, including variations in global CO2, global ice volume, sea surface temperatures, and the latitudinal and seasonal distribution of insolation. On centennial-to-decadal timescales, climate variability, vegetation type, and human activity are important controls of biomass burning. On the basis of a new global synthesis of charcoal records of biomass burning since the LGM, we present maps of changes in paleofire regimes at 500-year intervals from the LGM to present. In eastern and western North America and western Europe, charcoal records indicate decreased (lower-than-present) biomass burning from 21,000 to 10,000 cal yr BP. Similarly, in southern South America, decreased biomass burning occurs from 21,000 to ~11,000 cal yr BP. In contrast, the tropical latitudes of Central and South America indicate increased (greater than present) biomass burning between 19,000 and 15,000 cal yr BP while charcoal records from Southeast Asia, Indonesia, and New Guinea suggest increased biomass burning from 16,000 to 13,500 cal yr BP. Fire records from southeastern Australia indicate increased biomass burning at 19,000, 17,000, and from ~16,000 to 13,000 cal yr BP. During the Holocene, increased biomass burning occurred at ~9000 cal yr BP in eastern North America, between 6000 and 1000 cal yr BP in western North America, and between 8500 and 6500 cal yr BP in western Europe. Increased biomass burning occurred throughout the Holocene in tropical Central and South America, but was reduced to lower than present levels in southern South America during the last 7000 cal yr BP. Generally, decreased biomass burning is recorded for Australia, Southeast Asia, Indonesia, and New Guinea for most of the Holocene. A brief period of increased biomass burning occurred at ~3500 cal yr BP in western New Guinea and sites throughout Indonesia. The global maps of fire activity indicate both spatial heterogeneity as well as cases of regional coherency. This newly created database allows a first examination of the broad-scale controls that drive global patterns in fire regimes during the Late Quaternary and will play a critical role in validating models that attempt to understand and predict future patterns of global biomass burning. 1157 Biomass burning in tropical ecosystems of South America since the Last Glacial Maximum: a regional paleofire synthesis based on sedimentary charcoal data Mitchell J Power, Francis Mayle University of Edinburgh, United Kingdom IGBP Paleofire FTI Participants, Initiative sponsered by the International Geosphere Biosphere Program Fast Track Initiative on Fire, Coordinated by QUEST

Fire is one of the most important natural disturbances in tropical ecosystems, contributing to global carbon dioxide and methane emissions.

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The role of paleofire activity in tropical South America since the Last Glacial Maximum (LGM) is assessed from a regional synthesis of sedimentary charcoal records. In this research paleofire activity is presented at 500-year time slices for tropical South America as anomalies from present. Across this region, biomass burning was lower-than-present during the LGM, followed by a brief increase between 19,000 and 18,000 cal yr BP. Lower than present biomass burning occurred between 15,000 and 11,500 cal yr BP and may be related to lower than present insolation values. During the Holocene, two distinct periods of greater than present biomass burning occurred in tropical South America between 10,000 and 9000 cal yr BP and again from 6000 cal yr BP to present. These data suggest that biomass burning has varied through time in the Neotropics. Regional coherency in the timing of increased and decreased biomass burning across a variety of site types, investigated with a variety of sampling methodologies, suggest tropical biomass burning is at least partly controlled by large-scale climatic drivers such as orbital forcing. Spatial heterogeneity in the paleofire records suggests biomass (e.g. rainforest versus savannas) and human activity may also be important controls of fire activity. These results offer a useful validation tool for climate modellers attempting to understand past changes in tropical climate variability and the potential of future tropical biomass burning to contribute to global carbon dioxide and methane emissions. 0427 Quaternary plant extinctions: a case study of palm (Arecaceae) lineages from oceanic islands Mat Prebble1, John L Dowe2 1

Department of Archaeology and Natural History, Research School of Pacific and Asian Studies, College of Asia and the Pacific, Australia 2 Australian Centre for Tropical Freshwater Research, James Cook University, Townsville, Australia

Quaternary extinctions are most apparent on islands given that large areas hold more species than small areas and larger populations persist longer than smaller populations. In this sense, islands are predisposed to higher rates of extinction and this is why they are good starting points for understanding the ecological significance of extinction. A number of hypotheses explaining species extinction on islands have been developed from the fossil fauna record. The dominant overkill hypothesis emphasizes extinction of indigenous species as a result of habitat loss following human colonization since the late Pleistocene, but also as a consequence of displacement by introduced and invasive species. Despite the claim of severe reduction of biodiversity coinciding with human colonization of previously uninhabited islands, compared to fauna, relatively few plant extinctions have been recorded. Oceanic islands with historically recorded human impact (e.g. Lord Howe Island) have similar levels of endemism across both flora and fauna. This is not the case for islands with known prehistoric human impacts where on the basis of fossil and extant flora and fauna, faunal endemism usually exceeds floral endemism. Fossil plant records tend to have low taxonomic resolution and it is often not possible to determine their living affinities with precision. Many plant extinctions may be masked by poor taxonomic resolution, as identification of species relies on the poorly differentiated fossil pollen record. In addition, there is a paucity of detailed morphological studies of plant macrofossils. At higher taxonomic levels, recent faunal extinctions are concentrated in certain genera and families. Historic and fossil records of plant extinction appear to show a similar trend, with the palm family, Arecaceae, being well represented. Holocene palaeobotanical records of palm extinction are explored from oceanic islands, including Easter

Island (Paschalococcus disperta) the Hawaiian and Cook Islands (Pritchardia spp.) and the Austral Islands (cf. Pelagodoxa henryana). Localized population declines and extinctions have been recorded from other Pacific islands (New Zealand, Juan Fernandez Islands and Fiji). Unequivocal evidence for endemic species extinction in this family has not been forthcoming. On this basis it is hypothesized that Holocene extinction of endemic palms is rare. Molecular phylogeny and clock estimates of extant Arecoideae subfamily representatives suggest that many species emerged during the Quaternary with one documented example of sympatric speciation on Lord Howe Island (Howea spp.). These data highlight the potential for putative examples to exist on other oceanic islands, including where fossil records indicate possible palm extinction. 0019 Sedimentary deposits from the July 17th 2006 Java tsunami on the West Australian coastline Amy L Prendergast, Nicholas Brown Geoscience Australia, Australia

On July 17th 2006, an Mw = 7.7 earthquake south of Java generated a tsunami that devastated parts of the Javanese coast, killing more than 500 people. The tsunami also affected parts of the Western Australian coast. Within a week of the event, a post tsunami survey was carried out near Steep Point, Western Australia. Tsunami inundation and runup were mapped on the basis of eyewitness accounts, debris lines, vegetation damage and the occurrence of recently deposited fish, starfish, corals and sea urchins well above high-tide mark. Eyewitnesses reported three waves in the tsunami wave train, the second being the largest. A topographic survey using kinematic GPS with accuracies of 0.02 metres in the horizontal and 0.04 metres in the vertical recorded inundation depths of 1–2 m, inundation of up to 200 m inland, and a maximum recorded run-up of 7.9 m AHD (Australian Height Datum). The tsunami caused widespread erosion in the littoral zone, extensive vegetation damage, destroyed several campsites (including transporting a large vehicle ten metres inland) and deposited extensive sediment sheets over coastal dunes. At their seaward edge, these sediments are up to 14 cm thick, tapering landwards over approximately 200 m. The deposits are predominantly composed of moderately well sorted, medium grained silicic sand with some gravel and organic debris. A basal unconformity defines the boundary between tsunami sediments and underlying aeolian dune sand. Buried green vegetation stems with roots traceable to the lower dune unit are observable within the tsunami deposit; however, no roots are present in the tsunami sediments – an indication of their recent mobilisation. Evidence for up to three individual waves is preserved as normally graded sequences mantled by layers of dark grey, organic-rich fine silty sand. Grainsize and microfossil analyses are in progress. Given the strong wind regimes in the area, and the similarity of the underlying dune deposits to the tsunami sediments, it is likely that seasonal erosion will remove all traces of these sediment sheets within years to decades. 1023 Tsunami hazard in south-eastern Australia: integrating tsunami geology, hydrodynamic modelling and the historical record Amy L Prendergast, Michelle Cooper Geoscience Australia, Australia

Along the eastern Australian coastline, where the majority of the Australian population resides, the tsunami hazard derives from several


sources. The Solomons Trench, the New-Hebrides trench off Vanuatu, the Tonga-Kermadec trench north of New Zealand, the Alpine fault in New Zealand and the Puysegur trench south of New Zealand may all have the potential to produce earthquake-generated tsunami capable of reaching Australian shores within hours. Furthermore, the steep continental shelf on the eastern Australian margin is prone to submarine mass failure events capable of generating localised tsunamis. Over 100 potential mass failure scars have been identified on the southeast Australian coast, the largest of which is the Bulli slide near Wollongong. Hydrodynamic modelling suggests that such mass failure events could generate localised tsunami with onshore inundation. Several large waves of unknown source are documented along the Australian coast between Hobart and Newcastle. It has been suggested that these waves recorded on otherwise calm and clear days may be slump-generated tsunami. The most famous such incident occurred on Sydney’s Bondi Beach in 1938 (Black Sunday) when three waves encroached on the beach in quick succession. The backwash was strong enough to drag swimmers out to sea. More than 200 bathers required assistance and five people were killed. In this paper, preliminary results will be presented from an examination of the onshore coastal sedimentary record of mainland south-eastern Australia, focusing on the potential for these sediments to preserve evidence for tsunami inundation. 1114 Understanding the dynamic relationship between the Indian Ocean Monsoon and Westerly climatic systems in Arabia during the Holocene Gareth W Preston1, Adrian G Parker1, Helen Walkington1, Martin J Hodson2 1

Department of Anthropology and Geography, Oxford Brookes University, Headington, Oxford OX3 0BP, United Kingdom 2 School of Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, United Kingdom

South-east Arabia lies at the critical interface between two of the world’s major climatic systems; the Indian Ocean Monsoon (IOM) and the Westerlies. The region is thus highly sensitive to fluctuations in both and is therefore pivotal to our understanding of low latitude climate change during the Holocene. Despite this research potential, terrestrial records are rare and those that are available either lack the sufficient temporal resolution to identify abrupt events or fail to provide a continuous climate record extending into the late Holocene. In particular, few studies have examined the fluctuating interplay between the summer Indian Ocean Monsoon and the winter Westerly cyclonic systems themselves. Consequently, our understanding of climatic change across the Arabian Peninsula during the Holocene remains somewhat ambiguous. Lacustrine sediments examined in this study reveal that dune emplacement continued in south-eastern Arabia until ~9000 BP. In contrast, palaeoclimatic records from elsewhere in Arabia suggest that most of region was under the influence of the IOM at this time. Speleothem records from southern Oman record the northwards migration of the IOM by 10,300 BP and into northern Oman by 9600 BP. Lacustrine sedimentation in south-eastern Arabia did not take place until 8500 BP, thus showing that it took the IOM approximately 1800 years to move between 15˚N and 25˚N. This provides important information on the time lag and northwards migration of the IOM during the early Holocene. Lacustrine conditions persisted throughout study region between 8500–6000 BP, thus supporting palaeoclimatic data from Africa and elsewhere in Arabia that the early Holocene period was one of generally pluvial conditions. An abrupt decrease in lake levels is recorded at 5900 BP, when

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it is proposed the IOM weakened and retreated southward as a result of changes in the earth’s solar radiation receipt. This period marks the onset of long-term aridity throughout the world’s low latitude regions. In Arabia, speleothem records from northern Oman show a significant decline in precipitation, whilst lake deposits in the Rub’ al-Khali terminate. Despite this, lacustrine conditions continued to persist in the study region, suggesting that a precipitation source other than the IOM must have provided the additional rainfall. We propose that a switch to Westerly winter precipitation occurred and furthermore ensured lacustrine conditions persisted into the late Holocene period. The study site thus provides a unique record that demonstrates the highly dynamic relationship between two major climate systems during the Holocene. 0290 Response of aeolian and fluvial dynamics to Quaternary climate change in SE Arabia Frank Preusser, Ingo Blechschmidt, Albert Matter, Dirk Radies Institute of Geological Sciences, Universität Bern, Switzerland

The southern part of the Arabian Peninsula is today just north of the influence of Monsoon induced precipitation. However, from both lacustrine deposits and speleothem data it is known that the region was affected by the Monsoon several times in the past. The strengthening and weakening of the Monsoon caused important changes in the environmental conditions of the region. The aim of our investigation is in particular to identify the impact of past climate change on aeolian and fluvial dynamics and their palaeoclimatic implications. Optical dating indicates that periods of aeolian deposition in the Wahiba Sands, SE Oman, coincide with phases of mid-latitude glaciations, weak Monsoon circulation and low global sea level. The reconstruction of the low altitude wind field as deduced from aeolian bedding shows that the atmospheric circulation pattern during this time was apparently similar to that of the present day. The most striking issue of the circulation today and during glacial times is the position of the InterTropical Convergence Zone (ICTZ) during summer over the southern most part of the Arabian Peninsula, but north of the Wahiba Sands. This area is characterised by generally low wind velocity and the formation of star dunes. The west of the Wahiba Sands is made up of a huge floodplain consisting of debris originating from the Oman Mountains as demonstrated by the flow pattern seen in satellite images and by the petrography of the deposits. However, up to now the aggradation age of the braided plain was not known. New results of optical dating indicate that deposition of the sediment took place during at least three phases at about 340 ka, 220 ka and 130 ka ago, although the latter phase is only indirectly dated. All these phases coincide with increased Monsoon precipitation as identified in the speleothem record that implies a direct connection between fluvial sedimentation and the strengthening of the Monsoon.

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1032 Climatic forcing for Pleistocene megafaunal extinction: evidence from the Darling Downs, southeastern Queensland, Australia Gilbert J Price1, Gregory E Webb2, Scott A Hocknull3, Jian-xin Zhao1, Yue-xing Feng1, Ian H Sobbe4, Bernard N Cooke2 1

Radiogenic Isotope Laboratory, Centre for Microscopy and Microanalysis, University of Queensland, St. Lucia 4072, Queensland, Australia 2 School of Natural Resource Science, Queensland University of Technology, GPO Box 2434, Brisbane 4001, Queensland, Australia 3 Geoscience Department, Queensland Museum, 122 Gerler Road, Hendra 4011, Queensland, Australia 4 M/S 422, Clifton 4361, Queensland, Australia

Several late Pleistocene fossil localities in the Kings Creek catchment, Darling Downs, southeastern Queensland, Australia, were examined in detail to establish an accurate, dated palaeoecological record for the region, and to test human versus climate change megafauna extinction hypotheses. Chronologies were established using a combination of U-series (including U-concentration and U-series age profiling by laser ablation multi-collector inductively coupled plasma mass spectrometry) and accelerator mass spectrometry 14C dating of speleothem, megafauna teeth, shell, and calcrete samples, and optical stimulated luminescence dating of fossil-bearing sediments. Dating confirms that the deposits are late Pleistocene and includes faunal assemblages that bracket human colonisation of Australia (~45–50 ka). A multifaceted palaeoecological investigation involving the identification of specific species ecologies, ecological analogues to modern habitats and communities, and measurements of diversity, revealed significant habitat change between superposed assemblages of site QML796. The basal fossiliferous unit contains taxa that indicate the presence of a mosaic of habitats including riparian vegetation, vine thickets, scrubland, open and closed woodlands, and open grasslands during the late Pleistocene. Those woody and scrubby habitats contracted over the period of deposition so that by the time of deposition of the youngest horizon, the creek sampled a more open type environment. Importantly, sequential faunal horizons show a stepwise decrease in taxonomic diversity that contains the loss of some, but not all, megafauna in the catchment. Dating of such units suggests that those losses occurred over an extended duration (possibly >20 ka) during the period leading up to, and just after, human colonisation of the Australian continent. The apparent loss of some taxa up-section appears to be better correlated with habitat requirements, than with body-size. The palaeoecological and taphonomical data are consistent with a climate change model of megafaunal extinction, but not with a near simultaneous extinction of megafauna as required by the humaninduced blitzkrieg extinction hypothesis. No specific evidence was found to support human involvement in the local extinctions or in forcing the climate change. The results of this study have significant implications regarding the continent-wide extinction of Australian megafauna. 0671 Macrophyte and Charophyte fossils from Southern Italy: an useful proxy to reconstruct the Adriatic coastal environmental changes (Mediterranean Sea) Milena Primavera1, Massimo Caldara2, Girolamo Fiorentino3 1

Dottorato di Ricerca in Geomorfologia e Dinamica Ambientale, Dip. di Geologia e Geofisica, Università degli studi diBari, 70125, Italy 2 Dipartimento di Geologia e Geofisica, Università degli studi di Bari. 70125, Italy 3 Laboratorio di Archeobotanica, Dipartimento di Beni Culturali, Università di Lecce, 73100, Italy

The Late Quaternary climatic oscillations caused important changes in coastal system in the Mediterranean area. Sea level changes mark a series of geomorphological and environmental variations. Macrophyte and Charophyte plant remains from coastal lake cores, are useful tools studying these environments for their specific sensibility to ecological changes (depth, salinity, temperature, energy, susbstrate, pH, etc.). The study sites are two ancient coastal lake systems (Lago Battaglia, now dry; Laghi Alimini) and a wetland area (Ariscianne), along the Adriatic coast of Apulia (Southern Italy). The chronology, provided by AMS radiocarbon date, ascribes the cores to middle and late Holocene. Data collected show a diversification in local vegetation pattern along the successions, outlining transformations in sedimentation basins through time, related to sea-level changes and geomorphological coastal processes accordig to other proxy available for the same cores (i.e. pollen and faunal analysis, magnetic susceptivity, loss on ignition). The relationship between limnic and telmatic species gives also information about both local and regional lake-level fluctuations. 1115 The exploitation of environmental resources during the Neolithic period at Pulo di Molfetta (Italy) by in-site and off-site archaeobotanical investigations Milena Primavera1, Francesca Radina2, Michele Maggiore3, Massimo Caldara3, Girolamo Fiorentino4 1

Dottorato di Ricerca in Geomorfologia e Dinamica Ambientale, Dip. di Geologia e Geofisica, Università degli studi diBari, 70125, Italy 2 Soprintendenza archeolgica della Puglia, Centro Operativo di Bari, Strada Lamberti 70125 Bari, Italy 3 Dipartimento di Geologia e Geofisica, Università degli studi di Bari. 70125, Italy 4 Laboratorio di Archeobotanica, Dipartimento di Beni Culturali, Università di Lecce, 73100, Italy

Archaeobotanical investigations of the early Neolithic settlement of Pulo di Molfetta (Southern Italy) was carried out in order to reconstruct the environmental resources exploited by man during the midHolocene (about 8000 years ago) The site is located on a calcareous plateau which faces off a sinkhole called “Pulo” (deepness 30 m, perimeter 600m) and it is interested by heavy erosion processes. Topographycal and morphological site features led eroded sediments flowing in the natural basin. Our work regards the comparison between archaeobotanical data from archaeological site (in-site) and plant remains from a core drilled in the basin (off-site). The Off-site analysis implements the few data from archaeological site and led to identify changes in vegetal resources and cultivation practices. In particular the abundance of grains and chaff remains (forklets, glumes etc..) suggests that the cereal cultivation and wood exploitation could have influenced the plateau erosion processes. Radiocarbon AMS date provide the correlation between settlement phases vs core layers and the sediment accumulation rates. This integrated study led to: (a) identify different catchment area for wood exploitation, (b) understand land use practices located on the plateau.


1096 Glacial and interglacial eolian dust dispersal patterns across the Chinese Loess Plateau inferred from decomposed loess grain-size records Maarten A Prins1, Mirjam Vriend2 1

Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, The Netherlands 2 Institute for Biodiversity and Ecosystem Dynamics (IBED), Universiteit van Amsterdam, The Netherlands

Previous studies have indicated that a genetically meaningful decomposition (unmixing) of loess grain-size distributions can be accomplished with the end-member modelling algorithm EMMA. The independent decomposition of two series of loess grain-size records from the NE Tibetan Plateau and Loess Plateau spanning the last glacial-interglacial cycle indicates that the two data sets are described by very similar mixing models. The average mixing model presented here is regarded as representative for the vast loess region in northern China, and allows quantification of the contribution of three loess components to the loess grain-size distributions. A genetic interpretation and the paleoclimatic significance of the average mixing model has been provided by comparison of the modelled loess components with modern dust samples in terms of their grain-size distribution and flux rates, and by the distribution patterns of the loess components across the Loess Plateau reconstructed for the last two glacial-interglacial cycles. The sandy and silty loess components represent the coarse dust fraction supplied by saltation and short-term suspension processes over the proximal part of the Loess Plateau during major dust outbreaks in spring and early summer. The low-level winter monsoon (north-westerly wind system) is the likely transporting agent for these dust events. A clayey loess component represents the fine dust component supplied over the entire Loess Plateau by long-term suspension processes during major dust outbreaks and as part of a background supply system. The clayey loess component in the glacial loess deposits is dominantly supplied during major dust outbreaks by the north-westerly winter monsoon, whereas the clayey loess component in the Interglacial paleosols is mainly supplied by non-dust-storm processes, presumably with a significant contribution by the high-level subtropical jet stream (westerly winds). 0300 A terrestrial perspective of Sapropel S1 formation: Palynological land-sea correlation in the Holocene of the Aegean region Jörg Pross1, Ulrich Kotthoff1, Ulrich C Müller1, Odile Peyron2, Gerhard Schmied3, Hartmut Schulz1 1

Institute of Geosciences, University of Frankfurt, Germany Laboratoire de Chrono-Ecologie, Faculté des Sciences et Techniques Besançon, France 3 Geological-Paleontological Institute, University of Hamburg, Germany 2

Sapropel S1 was deposited in the Mediterranean Sea between ~9.5 and ~6 kyr BP. Its formation is ascribed to increased runoff notably through the Nile river, resulting from enhanced monsoonal activity over equatorial Africa. While the link between sapropel S1 formation and African climate is firmly established, the climate dynamics in the northern borderlands of the Mediterranean Sea during sapropel S1 formation are less well understood. We have therefore carried out a high-resolution (~30 to ~150 yr) analysis of terrestrial palynomorphs in a marine core recovered from the Mount Athos Basin (northern Aegean Sea) that comprises the entire Holocene, including the interval of sapropel

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S1 deposition. Particularly high sedimentation rates allow the detailed analysis of the timing between sapropel S1 formation and terrestrial ecosystem change in the northern borderlands of the Aegean Sea (NBAS). They also warrant a good preservation of pollen and spores not only within sapropel S1, but also in sediments pre- and post-dating sapropel deposition. This is in stark contrast to the normal situation in the Eastern Mediterranean Sea where pollen in non-sapropelic sediments is severely oxidized, thus yielding only a fragmentary and/or strongly biased record of terrestrial vegetation change. Our data reveal strong terrestrial vegetation changes in the NBAS associated with the deposition of sapropel S1. The northern borderlands of the Aegean Sea underwent a transition from an open vegetation to oak-dominated woodlands between ~10.4 and ~9.5 kyr BP. Quantitative pollen-based climate reconstructions indicate that reforestation was connected to a ~30% increase in winter precipitation and a ~10% increase in winter temperature. Hence, reforestation was primarily due to increasing winter precipitation, suggesting that moisture availability was the dominant factor controlling vegetation dynamics. Via increased runoff, the higher winter precipitation in the NBAS significantly contributed to the freshwater excess in the Aegean Sea during S1 formation. The well-known interruption of sapropel S1 is reflected by a gentle, yet steady decline of arboreal vegetation starting at 8.5 kyr BP and exhibiting a pronounced drop at 8.2 kyr BP. This drop is connected to a 1.5 ˚C drop in winter temperature. The termination of sapropel S1 is expressed in an arboreal vegetation decline connected to a pronounced (>2 ˚C) reduction in winter temperature, whereas winter precipitation remained nearly constant. This indicates that significantly lower winter temperatures played a leading role in the processes responsible for the resumption of deep-water ventilation in the Aegean Sea. 0319 Environmental change in the high mountain area of Ladakh: Multi-proxy studies on Late Quaternary sediments from the Tso Kar basin Frank Riedel1, Jan Bloemendal2, Bahadur S Kotlia3, Michael Kramer1, Alexandra Oppelt1, Christian Reinhardt1, Pavel Tarasov1, Bernd Wünnemann1 1

Freie Universität Berlin, Institute of Geological Sciences, Germany University of Liverpool, Department of Geography, United Kingdom 3 Kumaun University, Department of Geology, India 2

The Tso Kar basin is located within the valley of salt lakes of the Indian part of Ladakh at about 4600 m a.s.l. The area has been chosen in respect of studying environmental change since the Last Glacial Maximum and particularly during the last 5 ka BP in a region which seems to be reached only by extreme events of the Indian Monsoon but quite regularly by the Westerlies, and which has not significantly been affected by human impact. The main goal is to reconstruct the interplay of both planetary wind systems in respect of temperature and precipitation changes and corresponding effects on the environmental dynamics. The Tso Kar basin is nowadays filled by two interconnected shallow lakes, the smaller Startsabuk Tso which represents a throughflow freshwater lake and the larger Tso Kar proper which represents a hypersaline endorheic lake. Multi-proxy studies on cored sediments and geomorphological investigations of the basin produced the following preliminary results: First AMS dates indicate peat formation and the onset of a lake 5–6 ka after the Last Glacial Maximum, which means a surprisingly early retreat of the glaciers from the basin. The late Pleistocene and Holocene development of the lake basin is preserved in up to 4 m thick lacustrine sediments, which seem to be undisturbed at least in the upper half. The upper half represents the lake

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history from about 9 ka BP on. High palaeo-shorelines and lacustrine sediment outcrops give evidence of a former high lake level which may have occurred during middle Holocene times. Outcrop samples reveal faunal assemblages, such as molluscs and ostracods, related to littoral freshwater or oligosaline lake conditions. The “freshwater phase” within cored sediments seems to correspond with outcrop profiles in terms of ecology and lake environment but is probably highly condensed. Surface samples show the modern distribution of geochemical parameters and of ostracods. Fossil ostracods from cored sediments reflect changes in salinity from freshwater to hypersaline. Trace-element ratios of ostracod valves indicate changes of water properties and can be used quantitatively in respect of the outcropping sediments. Periglacial conditions and the formation of pingos seem to have influenced the basin morphology since the lakes have desiccated considerably during the last century. The reconstruction of the vegetation history with the aid of pollen analysis has been started recently in order to produce an integrated model of the regional environmental change.

which may have been grown without artificial irrigation). Second is a dramatic and presumably irreversible decrease in moisture availability roughly 4000 cal yr. BP. At this time the climate model displays a distinct reduction in precipitation values, and the carbon isotopic composition of the archaeobotanical material shows a clear shift to more positive values. These independent sources of paleoclimatic information, although strongly supporting the previous interpretation of the proxy record in pedogenic carbonate coatings, are restricted roughly to the mid-Holocene. Further research is needed to enhance the chronological frame.

1381 Testing Holocene pedogenic carbonate coatings as a proxy: climate models and archaeobotanical data from the northern Fertile Crescent

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Simone Riehl1, Reid Bryson1, Konstantin Pustovoytov2, Sara Hotchkiss3 1

Center for Climatic Research, University of Wisconsin, United States Institute of Soil Science and Land Evaluation, University of Hohenheim, Germany 3 University of Botany, University of Wisconsin, United States 2

A broad range of archaeological evidence supports an understanding of the northern Fertile Crescent as a region where the most ancient agricultural communities in the world came into being and where large-scale institutional agriculture evolved alongside complex civilizations dominating the economic and cultural development of the Middle East during the Bronze and the Iron Ages. Because of the lack of suitable local paleoclimatic records from the region, the role of environmental factors in agricultural economy remains uncertain. It has been suggested that rates of formation and isotopic composition of pedogenic carbonate coatings on stones can be used to reconstruct the Late Quaternary environmental changes in this particular area of the Near East. Specifically, pedogenic carbonate coatings in southeastern Turkey provided evidence on a maximum of the Holocene moisture availability between ca. 6000 and 4000 cal yr. BP and its minimum over the last 4 ka. However, since this proxy involves potential problems such as diagenetic alteration or admixture of lithogenic carbonate , the existing paleoclimatic scenario based on pedogenic carbonate needs to be tested by independent quantitative data. Here we compare the interpretation of pedogenic carbonate records from with two other sources of paleoclimatic information: modeled Holocene precipitation and temperature changes (Macrophysical Climate Model) and stable carbon isotope composition of ancient plant remains from six mid-Holocene archaeological sites. We also use existing highresolution palynological data from several sites in the Near East to calibrate model output. Our data corroborate two pronounced features of the earlier paleoclimatic interpretation of formation rates and isotopic composition of pedogenic carbonate. First is a period of high moisture availability in the region between 5000 cal yr. BP or earlier and 4000 cal yr. BP, which is suggested both by the climatic model and by relatively negative d13C values of charred plant macroremains (specifically in barley

0793 Precise chronology of the timing of changes in behaviour of the North Atlantic THC and their forcing effects, 16 – 8 ka BP ( Project NE/C509158/1, NERC RAPID Climate Change Programme): http://www.noc.soton.ac.uk/rapid/rapid.php Sean DF Pyne-O’Donnell1, Simon PE Blockley2, Alison MacLeod1, John Lowe1, Mike JC Walker3 Royal Holloway University of London, United Kingdom Oxford University, United Kingdom 3 University of Wales, Lampeter, United Kingdom 2

The RAPID Climate Change Programme is a NERC funded programme aimed at improving our ability to quantify the probability and magnitude of future rapid climate change. It focuses principally (though not exclusively) on the role of the Atlantic Ocean’s Thermohaline Circulation (THC) as a driver of abrupt climate change. Our project within RAPID addresses the LGIT (Late Glacial-Interglacial Transition), a period of short-lived decadal to centennial climatic perturbations of large magnitude which are considered to reflect ‘forcing’ by THC changes. Assessing the degree of synchroneity between THC changes and the resultant effects in the marine, terrestrial and ice realms is a key objective. However, constructing an accurate timescale of sufficiently precise resolution during this period using radiocarbon dating is problematic due to a number of complications such as calibration and marine reservoir offsets. Therefore, to achieve more precise resolutions it is proposed that tephrochronology (volcanic ash isochrones) be used to correlate between sequences. Such ashes also serve to test the accuracy of radiocarbon age models within sequences. Numerous ash layers of Icelandic origin occur throughout the LGIT period, with many being widespread throughout NW Europe and the North Atlantic region. The ongoing detection of new ashes and dating their known distributions augments the tephrostratigraphy of this period. In collaboration with other institutions, a number of terrestrial and marine sequences from Scotland, Norway and the western, northern and eastern North Atlantic have been analysed. Thus far, a number of discrete ash isochrones have been detected which can be correlated with isochrones in published records. Three sequences were found to contain ashes which geochemically correlate with the mid-GS-1 Vedde Ash (12,171±114 NGRIP yr b2k – before AD 2000) and the early GI-1 Borrobol Tephra (ca. 14,400 cal. yr BP) and possibly the Penifiler Tephra (ca. GI-1c). A further sequence was found to contain the early Holocene Saksunarvatn Ash (10,147±89 NGRIP yr b2k) in addition to the Vedde Ash. Newly detected ashes such as the Penifiler and Ashik tephras have yet to be dated (see Pyne-O’Donnell et al., ibid). Ongoing work aims to locate these newly detected ashes in sequences that permit accurate dating (e.g. varved sequences; see MacLeod et al., ibid.). Precise ash isochrones offer significant advantages for the purposes of RAPID. However to realise their full potential a number of methodological difficulties must first be overcome, e.g. stratigraphic precision, reworking, taphonomy, and geochemical identification and alteration.


0795 New distal volcanic ashes in Scotland: problems of geochemical similarity and stratigraphic discrimination (Project NE/ C509158/1, NERC RAPID Climate Change Programme): http:// www.noc.soton.ac.uk/rapid/rapid.php Sean DF Pyne-O’Donnell1, Simon PE Blockley2, Chris SM Turney3, John Lowe1 1

Royal Holloway University of London, United Kingdom Oxford University, United Kingdom 3 University of Wollongong, Australia 2

Three new distal volcanic ashes (‘microtephras’) are reported from a number of lake sites from the Inner Hebrides and Scottish mainland. The stratigraphically deepest and earliest occurs in the middle of Greenland Interstadial 1 (GI-1) and has been named the Penifiler Tephra. It is rhyolitic and possesses a geochemical signature that is very similar to that of the earlier Borrobol Tephra. In at least two of the sequences investigated in this study, basaltic shards were found in association with the Penifiler Tephra, suggesting either a basaltic phase associated with this eruption, or coincident eruptions from a separate basaltic volcanic centre. Such basaltic populations may strengthen correlations with basaltic ashes recently detected in the NGRIP ice-core. The second ash occurs in the early Holocene stratigraphically below the Saksunarvatn Ash and is named the Ashik Tephra. This ash is geochemically bimodal in all the sequences where it occurs, with a rhyolitic population comparable to the later An Druim Tephra, and a basaltic population which is similar to the Saksunarvatn Ash. As the Saksunarvatn Ash source volcano Grimsvötn is exclusively basaltic in nature, it is suggested the two populations derive from the coincident eruptions of different but closely adjacent volcanic centres, with the rhyolitic population deriving from Torfajökull. The third ash occurs stratigraphically above the Saksunarvatn Ash and is provisionally named the Breakish Tephra. It is rhyolitic and possesses a geochemistry comparable to the ca. 2100 BP Glen Garry Tephra which derives from an unknown Icelandic source. The consistent inter-site correlation demonstrated for these new ashes at several sites augments the regional tephrostratigraphic framework, and increases the potential for correlating palaeoenvironmental events during GI-1 and the early Holocene. However, a number of sedimentological, geochemical and taphonomic issues associated with these and other ashes also exist. These issues must be resolved if the technique is to truly deliver its full potential. 0214 Dust storm history inferred from the laminated sediments of Lake Sugan in the dust source areas, China Mingrui Qiang, Fahu Chen Key Laboratory of Western China’s Environmental System, MOE, Lanzhou University, China

To further understand changes in global atmospheric dust loading, it is necessary to establish the long-term history of dust emission and/or dust storms in Chinese dust source areas, which were recognized as dust provenance of the North Pacific and the Greenland sheet over the geologic times. In the hyperarid basins of Arid China the hydrological closed lakes can directly record dust storms. Lake Sugan located in the Qaidam Basin with a surface area of 103 km2, and is mainly fed by groundwater or the rivers derived from groundwater at the fine earth plain to the east of the lake. The strong winds and dust storms prevail there. We collected samples of surface deposits in the Lake Sugan

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catchment, as well as surface lake sediments, eolian materials occulted in the lake ice cover, and airborne sand dust during dust storms for analyses of grain size and elemental compositions. A sediment trap was placed in the lake water for the modern sediments in different seasons. Relationship between the grain-size components and the wind velocities was analyzed. The results show that the coarse fraction of the lake sediments could be transported by the ambient winds and to a lesser extent by river flow in the study area since the grain size decreases from west to east. The decreasing direction is contrary to the direction of river flows. Obvious eolian-impact characteristics were found by SEM on the surface of particles collected in the lake water. The coarse fraction increases at the monitoring site with increases in the intensity and fluctuation wind velocity; in contrast, the fine-grained fraction will decrease with the increases in them. The elements of W, Ti and Al have been enriched by 30%, 13% and 11% relative to the surface ground deposits. Variations in Fe and Sc compositions exhibit an apparent positive correlation not only with intensity of dust storm events but also frequency of the events. The preliminary study on the modern process for dust storms recorded by Lake Sugan suggests that the lake can be an ideal site for us to reconstruct dust storm history in the dust source area. A 2000-year dust storm history was reconstructed using the detrital coarse fraction of sediments suggesting the highly frequent and/or intensive dust storms occurred during the Little Ice Age and the period of 3 –6th century when a stronger winds and colder climate perhaps prevailed. 0212 Loess record of land silicate weathering CO2 consumption and global carbon cycles Xiaoguang Qin, Tungsheng Liu, Zhiqiang Yin, Bo Ning Institute of Geology and Geophysics, Chinese Academy of Sciences, China

Increased interest in the effect of atmospheric CO2 on the past global change has motivated studies of paleo-terrestrial carbon cycles. Chemical weathering of silicate rocks is a major process in the global climate of the Earth by consuming atmospheric CO2 at the surface of the continents over geologic time. This study focuses on evaluating the CO2 consumption of loess chemical weathering by integrating the benchmark mineral method measuring the loss of loess elements and the mineral weathering theory estimating the CO2 consumption of silicate weathering and carbonate dissolution. A 2.5Myr sequence of the CO2 consumption of loess weathering was estimated from the Luochuan loess-paleosol section that has been widely reported in many literatures, for the first time as a proxy of continental carbon pools during Quaternary. The result was compared with marine d18O and d13C records. It was found that the CO2 consumption of silicate weathering fluctuated as paleo-climate changed on glacial-interglacial and longerterm scales. The rapidly change of the silicate weathering CO2 consumption during 0.7~0.8Myr B.P., decreasing gradually from 2.5Myr B.P. to 0.8Myr B.P. and then rapidly increasing after 0.7Myr B.P., was accompanied by the 40kyr – 100kyr cycle transition. The similar secular variations of the continental silicate weathering represented by loess silicate weathering CO2 consumption and ocean carbon pools shown by marine d13C on long-term scales larger than 0.4Myr, implies that the carbon exchange between ocean and land might be a dominating mechanism affecting deep ocean d13C and the continental silicate weathering is indeed a important component of global C cycles.

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0429 Moraine features and their relationship with the geological and glacial sedimentation in inner Tibet Zhuli Qiu, Chaolu Yi Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, PR of China, China

In areas of weak tectonic processes, particular climatic condition plays a main role in glaciations sediment. Different climate has different effects on glaciations landform. So, to some extent, we can inverse ancient climate of a particular area which was seldom influenced by tectonic factors by utilizing features, eg. Morphology, lithologic characters, etc., of the mraines in this area. There are many other causes of moraine landforms, too. One is relief, which contributed to moraine slopes. The other is aspect, which is constrained by the second factor, relief. Therefore, by comparing moraine morphology features in many unfamiliar locations, we can find not only the differences among these moraines, but also those among the causing factors of them. So the ancient circumstances of different locations are clear. Here, after about two months of field work in the west part of Nyainqentanghula Shan and Puruogangri individually, using difference GPS (Global Positioning System) facilities – E650 and Mobile Mappers, our team collected many GPS data, with which we do digital approximation, elevation predication, 3-Dimision points interpolation, surface visualization and surface analyst, such as slope analyst, aspect analyst and scale analyst, etc., by the help of the ANN( Artificial Neuron Net) theory and three main softwares: Arcgis 9.0, Erdas 9.0 and Matlab 7.0. On the base of these analysts, we then gather further information about the shapes of moraines being studied and draw a conclusion that more arid climate, much flatter ground relief, and more north-faced facets of moraines of Glacier 6, west to the Puruogangri ice field, result in much steeper and much less scale lateral moraines than those located on the west slope of the west part of the Nyainqentanghula Shan. 0573 Geomorphic change of Australian tide-dominated estuaries on historical timescales Lynda C Radke1, Anna-Liisa Lahtinen1, Mio Kuhnen2, Brendan P Brooke1, David A Ryan1, Andrew Heap1, Grant Douglas3, Gary Hancock3 1

Geoscience Australia, Australia Department of Agriculture, Fisheries & Forestry, Australia 3 CSIRO Land and Water, Australia 2

Geomorphic habitat area data from ~172 tidally-dominated coastal waterways in Australia were compared on the basis of differences in the degree of modification of the estuaries and their catchments. Systematic changes in some geomorphic habitat areas were found to coincide with diminishing environmental condition status in the National framework (i.e. from near-pristine, through largely unmodified and modified to severely modified). For example, there were apparent increases in the areas of tidal sand banks, intertidal flats and mangroves that were concomitant with increased modification of the estuary/ catchment. The results suggest that many Australian tidally-dominated coastal waterways are infilling at an accelerated rate due to changes in catchment land use and the associated enhanced sediment loads. We then review supporting evidence for the rapid infilling of the Fitzroy Estuary, Queensland, in the form of: (i) the augmentation of mangrovelined tidal sand banks; and (ii) the rapid infilling of billabongs and abandoned channels on the Fitzroy lower floodplain. In the case of

Crescent Lagoon on the Fitzroy floodplain, a Bayesian statistical modelling approach was applied to geochemical constituents (organic and inorganic) in the sediment core (dated to ~120 years BP), enabling the sediment to be apportioned to different sub-catchments. The study found that variability in sediment sources was due in part to the size of flow events in the Fitzroy River. 0604 Holocene channel breakdown and floodplain wetlands: the geomorphology and sedimentology of the Macquarie Marshes, south-eastern Australia Timothy J Ralph, Paul P Hesse, David Yonge Department of Physical Geography, Macquarie University, Australia

The Macquarie Marshes (147°30' E 31°S) occupy the lower reach of the Macquarie River in south-eastern Australia and typify the distinctive Holocene style of many rivers in inland Australia. The river decreases in discharge and capacity downstream before finally breaking down into a complex arrangement of distributary channels and marshes in which the river is lost completely. Ancestral alluvial deposits determine local floodplain base-levels, which, together with intrinsic biophysical processes, influence the distribution of channels and lotic/lentic wetlands. A nested hierarchical pattern of breakdown exists, with spatial scales ranging from the broader alluvial plain (> 100 km2) to individual floodouts and wetlands (< 1 km2). Upstream of the breakdown the single-channel sinuous river has shown little lateral migration since the first surveys in the late 19th century. By contrast, the marshes show great dynamism with channel avulsion in the historical period forming new channels and marshes and leading to complete abandonment of others. Sedimentological data and radiometric results (137Cs, unsupported 210Pb, 14C, OSL dating) from floodplain deposits in the main wetland of the Southern Macquarie Marshes show that overbank sedimentation is greater near the vegetated margin of the primary channel and decreases across the floodplain. Further downstream in the contemporary floodout zone, sediment accretion is greatest where a fine-grained splay and surface distributary channels have formed in the penultimate reach of the marsh channel. These processes have led to the development of a series of progradational marshes with convex-up structures and alluvial ridges adjacent to the main channels. On the lower Macquarie River, the mechanism of channel breakdown appears to be similar to existing models of avulsion, whereby continued in- and near-channel deposition occurs until a trigger event forces the (sub)system over a stability threshold and a secondary channel is formed. In the marshes, vegetation-induced, in-channel and overbank deposition leads to the formation of a broad alluvial ridge, where a gradient advantage develops between the main channel and the lower surrounding floodplain to provide favourable conditions for new channel formation. Channel and marsh abandonment may then occur as an old channel is infilled and flow is rerouted down a new channel which is enlarged via erosion. Since the style of deposition and marsh morphodynamics appear to be characteristic of other floodplain wetlands in the Murray-Darling Basin, this research can provide a conceptual and practical framework for an understanding of other dryland fluvial systems in the context of their late Quaternary evolution.


0879 Synchronized Greenland ice cores reveal climatic surprises in the Late Glacial Sune O Rasmussen, Inger K Seierstad, Katrine K Andersen, Anders Svensson, Matthias Bigler, Dorthe Dahl-Jensen, Sigfus J Johnsen, Jørgen Peder Steffensen Ice and Climate Research, Niels Bohr Institute, Copenhagen, Denmark, Denmark

Greenland ice core profiles provide continuous high resolution information about the glacial climate, and have for decades been used as authoritative templates for correlation with other palaeoclimatic records. The advent of a new stratigraphic ice core time scale, common to the NorthGRIP, GRIP, and GISP2 ice core profiles, raises the question of which features in the Greenland ice core profiles can be used for correlation and synchronization with other palaeoclimatic profiles, and which features must be regarded as more local phenomena. Comparison of the these three key records of the past climate shows that even sites located no more than a few tens of kilometers apart experienced significantly different climatic conditions during parts of the late glacial, indicating that spatial gradients changed abruptly also within relatively stable climatic periods. The presentation will describe the annual layer counting techniques applied for the construction of the Greenland Ice Core Chronology 2005 (GICC05) time scale, which now covers the interval from present day back to about 60 ka b2k (before A.D. 2000). Whereas the Holocene part of the time scale is based on records from both the DYE-3, the GRIP and the NorthGRIP ice cores, the glacial part is solely based on records from the NorthGRIP ice core. Well-resolved glacial profiles from Greenland are available from the NorthGRIP, GRIP, and GISP2 ice cores, but comparison of the records has been hampered by the lack of a common time scale. In order to apply the new time GICC05 scale to the combined records from these three cores, the cores have been synchronized in detail using impurity signals of non-climatic origin. The combined climate records of the three cores can thus be studied on a common time scale, making it possible to identify differences between the records on a decadal scale or better. The presentation will describe the method used for synchronization of the cores and discuss how the new time scale fits with previous Greenland ice core chronologies. Commonalities and differences between the synchronized profiles, especially in the 30 – 8 ka b2k interval, will be identified and discussed. 0681 Palaeoglacier mass balance and the AABR/BR methods– defining modern day values Brice R Rea Geography and Environment, School of Geosciences, University of Aberdeen, UK AB24 3UF., United Kingdom

With the ever increasing use of DEMs in palaeo glacier reconstructions and the availability of freeware spreadsheets for calculation of the AABR (area-altitude-balance-ratio)/BR (balance ratio) these methods are becoming increasingly used in palaeo-glacier reconstruction for deriving quantitative estimates of palaeo-climate. While there are many data detailing contemporary AAR (accumulation area ratio) derived ELAs, there are still only a few studies which have established, from contemporary environments, AABR/BR ratios. Records from the World Glacier Monitoring Service, detailing glacier mass balances and spatial extents, form the basis of this research. From a time series of mass balance data, regressing specific net balance against ELA alti-

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tude, allows the zero net balance ELA to be identified. Once the zero balance ELA is established the glacier hypsometry above and below the ELA is defined. The AABR/BR is calculated using : bnab/bnac = {(zabAac)/(zabAab)}, where, bnab and bnac are the net mass balance gradients in the ablation and accumulation zones respectively, zab and zab are the area-weighted mean altitudes of the accumulation and ablation areas respectively and Aac and Aab are the areas of the accumulation and ablation areas respectively. The AABR/BR is calculated using the right hand side of the equation. This is undertaken for a suite of glaciers representing different global climatic zones and glacier types. This study provides an empirically derived data set characterising AABR/BR ratios to be used in palaeoglacier reconstructions and palaeo-climate quantification. 0698 “Crevasse-Squeeze” ridges – a landform type characteristic of surging Brice R Rea1, David JA Evans2, Eithne M Porter1, David I Twigg3 1

Geography & Environment, School of Geosciences, University of Aberdeen, Aberdeen AB24 3UF, United Kingdom 2 Department of Geography, University of Durham, South Road, Durham DH1 3LE, United Kingdom 3 Department of Civil and Building Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, England, UK, United Kingdom

Surge-type glaciers undergo regular, periodic, rapid pulses where a large mass of ice is transferred from a reservoir in the accumulation zone down through the glacier which may result in a significant advance of the snout. The surge front propagates through the glacier at speeds in excess of 2–3 times the normal glacier velocity, accompanied by high basal water pressures and basal sliding beneath all parts of the affected glacier. The tectonic regime associated with the surge is characterised by an intense zone of compression directly ahead of the surge front within the quiescent ice, and a zone of extension once the surge front has passed. The compression produces folding, thrusting and fracturing at the glacier surface (and at depth) and as this gives way to extension, crevasses widen leaving the glacier surface a jumbled broken mass. This strain regime is unique to surging glaciers and the extreme crevassing and subsequent stagnation makes for a distinctive landsystem, which should allow the identification of surging glacier margins in the Quaternary record. Crevasse-squeeze ridges have been hypothesised as being a diagnostic landform for surging behaviour. This hypothesis is tested by focusing on data collected at the surging margin of Bruarjökull, an outlet of Vatnajökull, Iceland, (the neighbouring glacier to Eyjabakkajökull the “type site” for crevasse-squeeze ridges). Bruarjökull last surged in 1964 and the ice margin has retreated some 2–3 km since then. Numerous crosscutting fractures dissect the snout, some of which have sediment fills. The fills may be one of three types; (1) bedded sands, (2) structureless diamict or (3) very finegrained ash layers. Type (2) features are the focus of interest. Dips of the ridges exposed melting out of the glacier snout are variable, ranging from ~40º to near vertical. Two emplacement mechanisms have been hypothesised: (1) at surge termination when basal water pressures are reduced and the glacier re-couples with the bed, effective pressures at the ice-bed interface increase and the basal diamict is squeezed into the fractured base of the glacier; (2) shearing along thrust faults drags sediment from the bed and emplaces it englacially where it eventually melts out. While hypothesis (1) is likely to be diagnostic of surging behaviour, hypothesis (2) may not necessarily be so. Clast fabric, ice chemistry and structural mapping data are presented which allow these two hypotheses to be tested.

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0644 Recent environmental changes at the end of the world: the diatom-based record of Lago Fagnano, Tierra del Fuego Cristina Recasens1, Daniel Ariztegui1, Nora I Maidana2, Nicolas Waldmann1, Christopher M Moy3, Robert B Dunbar3, James A Austin Jr4, Flavio S Anselmetti5 1

Department of Geology and Paleontology, University of Geneva, Switzerland Dpto. de Biodiversidad y Biología Experimental, Fac. de Cs. Exactas y Naturales, Universidad de Buenos Aires, Argentina 3 Department of Geological and Environmental Sciences, Stanford University, United States 4 Institute for Geophysics, John and Katherine G. Jackson School of Geosciences, University of Texas at Austin, United States 5 Geological Institute, Swiss Federal Institute of Technology ETHZ Zürich, Switzerland 2

The use of diatom stratigraphy in well-dated sedimentary records is an excellent tool to reconstruct past environmental changes. Variations in diatom assemblages blended with geophysical, sedimentological and geochemical datasets allowed us to reconstruct former environmental changes in Lago Fagnano, southern Patagonia. Located at 54°S in Tierra del Fuego, Argentina, this lake occupies a tectonic depression along the Magallanes-Fagnano fault system. Climate in this area is highly influenced by the westerly winds, the Southern Ocean circumpolar flow and the South Pacific gyre, which makes of Tierra del Fuego a key site for paleoclimatic and paleoecological reconstructions in the Southern Hemisphere. Water and surface sediment grab samples were collected in the lake in order to constrain the modern limnology. Taxa identification and counting of diatoms from sediment samples of the modern lake bottom show a highly diverse diatom community, though species from the Discostella genus are visibly dominant. Combining limnological data obtained from the water column with sedimentological and diatom analyses of surface sediment samples allowed to characterize present lake water conditions and its flora. A multi-proxy study of a 160 cm long sediment core was performed in order to characterize the sedimentary record. Sediment density and magnetic susceptibility profiles show relatively uniform values occasionally interrupted by peaks which we are interpreted as turbidites. Rock-eval pyrolysis reveals a relatively uniform distribution of organic and inorganic carbon along the core. Ultra-high resolution X-ray fluorescence micro-profiles show fluctuations at mm scale in major and trace elements. Preliminary results reveal a regularly laminated deposit of alternating light and dark laminae, rich in diatoms and amorphous organic matter, occasionally interrupted by turbidites. Samples collected at estimated decadal frequencies along the core were used for the diatom identification and counting. The different diatom assemblages found in the sedimentary record, well calibrated with the modern limnology, provide valuable paleoecological information. A good interpretation of this dataset is important to develop diatom-based transfer functions, a final goal of this study that will be further applied at different temporal scales. 0927 The reconstruction of a ~850-year palaeomonsoon record from a Christmas Island (Indian Ocean) stalagmite Dale A Redwood1, Russell N Drysdale1, Ian D Goodwin1, Janece McDonald1, John C Hellstrom2, Edward Hodge3, Mick Jeffery4 1

University of Newcastle, Australia University of Melbourne, Australia 3 Australian Nuclear Science and Technology Organisation, Australia 4 Parks Australia North (Christmas island), Australia 2

The monsoon is an important climate system that affects all facets of social, environmental and economic activity in the most heavily populated region on Earth. The monsoon is highly variable, and extremes of drought and flooding occur intermittently. Despite the importance of the monsoon system, our understanding of its highly variable nature and its future behaviour under global warming is scant. Instrumental climate records typically extend no further than the last ~150 years, which is insufficient for characterising the full array of natural and anthropogenic climate variability. Stalagmites from Christmas Island (Indian Ocean) offer a rare opportunity to reconstruct palaeomonsoon activity from within a region that comes under the influence of the Indo-Pacific warm pool (IPWP), a key component in monsoon behaviour. Stable isotope (18O and 13C)and, trace element ratios (Mg/Ca, Sr/Ca and P/Ca) as well as lamination thicknesses are reported for the upper half of stalagmite SC4 from Smith’s Cave, located in the northwest part of Christmas Island. The stalagmite commenced growing around 1150 AD and was active at the time of collection in October 2004. The period reported extends from ~1575 AD to 2004 AD. Micromilling at 50 μm increments for stable isotope analysis coupled with in-situ Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) analysis for trace elements yielded high-resolution, interannual geochemical data, which were used in conjunction with instrumental rainfall records to assess the potential of Christmas Island stalagmites as palaeomonsoon archives. The stalagmite 18O is highly correlated with local instrumental rainfall records, suggesting that 18O is controlled by rainfall amount. Sr/Ca and P/Ca from LAICP-MS are negatively covariant with 13C and Mg/Ca but positively correlated with lamination thickness, here assumed to be a proxy for growth rate. Elevated Mg/Ca and d13C during periods of low growth suggests that prior calcite precipitation and related drip-rate variations are controlling factors. A positive covariance between Sr/Ca, P/Ca and lamination thickness is attributed to selective leaching of Sr and P from the soil zone or variability of biological productivity above the cave during the summer wet season. Results suggest that geochemical properties from Christmas Island stalagmites have excellent potential as high-resolution palaeomonsoon archives. 0251 A Chironomid-Based Transfer Function to Reconstruct the Paleoclimate of Tasmania Andrew BH Rees, Les Cwynar University of New Brunswick, Canada

We are analyzing the chironomid taxa and environmental parameters of 50 Tasmanian lakes in order to determine which among those environmental parameters drive chironomid assemblages. Depending on our results, we intend to build inference models based on parameters that explain significant portions of the variance in chironomid distribution. We have already sampled a set of 50 lakes along an altitudinal gradient with a Mini-Glew corer, measuring a host of environmental variables (e.g. lake depth, pH, temperature, conductivity). We have also processed the upper 1cm of sediment from those lakes for chironomid analysis. After sorting and identifying the majority of chironomid head capsules, preliminary results reveal at least 40 different taxa. A detrended correspondence analysis of a subset of the 50 lakes indicates a gradient length of 2.6, suggesting the option of either linear or unimodal inference models. Furthermore, several of the 40 taxa show a unimodal relationship to elevation (a surrogate of temperature). Once the identification stage is fully complete, we plan on running the appropriate ordinations to quantify relationships between chironomid


assemblages and environmental parameters. As hinted at above, we suspect that temperature will prove to be a significant variable. We intend to apply the inference models to long cores from lakes from a variety of elevations in order to answer fundamental questions about inter-hemispheric climate change during the past 25,000 years. 0866 Pilbara stygofauna – a freshwater heritage in an arid environment: a lesson for the Late Quaternary Jessica M Reeves RMIT University, Australia

The Pilbara region of northern Western Australia, covering ~ 200,000 km2, is hot and dry. Although climatically regarded as semi-arid, with annual evaporation outweighing precipitation 10:1, the Pilbara is located at the tropical fringe. The coastline is the most cyclone-prone region of Australia, with an average of five tropical cyclones per year, associated with the Australian monsoon. The majority of aquifers in the Pilbara yield fresh water, recharged by cyclonic rains; surface waters in comparison, are commonly saline and ephemeral. Attention has recently been drawn to the Pilbara as host to a rich and diverse groundwater fauna – or stygofauna. Twenty-one genera and around 110 species of ostracods alone have been identified, including 72 new species. The majority of these are from distinct freshwater lineages. There is a clear distinction between taxa at the genus level from coastal and lowlying alluvial sites, and upland sites (>300 m altitude). Beyond this, the majority of species are confined within a surface water catchment, or in many cases, a specific aquifer. The distribution of species appears to be controlled primarily by historical events that lead to the formation and the extent of the host aquifer, such as Tertiary aridity, with pre-adaptive colonisation and subsequent speciation. A series of D and 18 O values of groundwater were obtained from the Pilbara, along a transect extending from the coast to 350 km inland. Stable-isotope ratios, in the order of −7.0 ± 3.3 ‰ for 18O and −50 ± 23 ‰ for D, show the characteristically low values of recharge by cyclonic rains, with little evaporative effect. The majority of the inland data lie on a local meteoric water line, D = 7.6 x 18O + 3.8 (r2 = 0.94), with several of the coastal sites plotting on an evaporation line, D = 4.3 x 18O – 16.4 (r2 = 0.98). In addition, the isotopic signatures of the sub-basins show little or no hydraulic connectivity between aquifers. The biotic endemicity and diversity is the bi-product of geographic isolation, and the presence of this biota today in the various aquifers indicates that during extremely dry periods, such as the last glacial maximum, when cyclonic activity must have been significantly reduced or even absent, there must have still been significant rains to refill the aquifers to maintain the necessary gene pools for these organisms. 0868 The Gulf of Carpentaria, northern Australia, through the Late Quaternary: the ostracods’ tale Jessica M Reeves1, Allan R Chivas2, Adriana Garcia2, Patrick De Deckker3 1

RMIT University, Australia University of Wollongong, Australia 3 The Australian National University, Australia 2

Environmental evolution of the Gulf of Carpentaria region, northern Australia, through the last glacial cycle has been determined from a series of six sediment cores. These cores form the focus of a multidisciplinary study to elucidate sea level, climate and environmental

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change in the region. The sedimentary record reveals a series of facies including open shallow marine, marginal marine, estuarine, lacustrine and subaerial exposure, throughout the extent of the basin during this period. The partial or complete closure of the central basin from marine waters is resultant from sea level falling below the height of one or both of the sills that border the Gulf – the Arafura Sill to the west (53 m below present sea level (bpsl)) and Torres Strait to the east (12 m bpsl). The extent and timing of these closures, and restriction of the shallow waterbody within, are intrinsic to local ocean circulation, available latent heat transport and the movement of people and animals between Australia and New Guinea. Ostracod faunal assemblages and variations in the valve morphology, preserved in the sediments of the gulf, record these changes. A 14.8 m core (MD972132) extracted from near the centre of the modern Gulf of Carpentaria, spanning the last 130 ka BP provides the basis of this study. Combined ostracod biofacies and morphological analysis reveals a fluctuating marine environment through Marine Isotope Stage (MIS) 5, terminating in a restricted lagoon around 90 ka BP, followed by an extensive period of subaerial exposure in this region of the gulf. MIS 3 marks a return of marine conditions and an increase in fluvial activity. Lake Carpentaria then appears as a permanent feature, at least to the current 60 m depth contour, from around 40 ka BP, with the freshest water occurring around 16.0 cal ka BP, prior to the most recent marine transgression, at 10.8 cal. ka BP. Stable isotope (18O, 13C) analyses of ostracod valves from this core and trace element analyses (Mg/Ca, Sr/Ca) from previous studies provide further details of the changing hydrology of the lacustrine phase of the basin. The lake may be considered closed through much of this period, balanced between predominantly surface water cover and groundwater control around the margins. At all times when Lake Carpentaria was present, evaporation/precipitation ratios are shown to have been significantly higher than under modern conditions, implying a reduction or absence of the Australian monsoon during these times. 0277 Pluvial Lake Manix, Mojave Desert, USA: Effects of Subbasin Integration on Sedimentary Record Marith C Reheis1, David M Miller1, Charles G Oviatt2 1

U.S. Geological Survey, United States Kansas State University, United States

2

Pluvial Lake Manix, in the Mojave Desert of south-central California, was the terminal basin of the Mojave River until the late Pleistocene when it drained east to form Lake Mojave. Previous studies that focused on outcrops in the central Manix subbasin interpreted multiple glacial-pluvial lacustrine episodes, of which all but the last two (OIS 2 and 4) were represented by deep-lake sediments. Based on sedimentary analysis of a 45-m core from the Manix subbasin and outcrops in the Afton area to the east, we interpret a major subbasin-integration event that incorporated a previously separate valley and significantly impacted sedimentation patterns throughout the greater Manix basin. In addition, at least one of the deep-lake intervals is now thought to represent fluctuating shallow lakes and mudflats. In the Afton subbasin, playa and distal-fan deposits of a closed basin are locally overlain by dramatically deformed lacustrine muds that represent large, reworked but semi-intact blocks of Lake Manix sediment derived from the central Manix subbasin upstream. These muds are overlain by fluvial gravel and sand that represents the initial establishment of stream drainage from the central subbasin, followed by a rapidly upward-fining sequence of sand, silt, and mud that mark the flooding of the newly incorporated subbasin with Lake Manix (Mojave

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River) water. Stratigraphic correlations suggest that this subbasin-integration event occurred just before or shortly after deposition of a distinctive tephra layer within the Manix subbasin; the tephra has not yet been found in the Afton subbasin. The ~7 m of sediment above the tephra had been interpreted as perennial-lake deposits, but new mapping and core analysis suggest that these sediments were deposited in a fluctuating environment of shallow lakes and mudflats. Deposits in the Afton subbasin interpreted as correlative with the 7-m interval consist of perennial-lake muds intercalated with sands that thicken and coarsen shoreward. These relations indicate that lake depth and distance from fluvial inputs were greater in the newly incorporated Afton subbasin than in the correlative Manix subbasin. By this time the Manix area, having been the depocenter of Lake Manix for possibly hundreds of thousands of years, had lost much of its sediment storage capacity; thus, relatively small changes in runoff and lake level could easily cover or expose previously deposited sediment. Sediment patterns in the core suggest that millennial- to centennial-scale cycles of wet and dry periods may be recorded by alternating soils and fluvial, shallow-lake, and mudflat beds. 0688 Micromorphological analysis of the basal processes of an Antarctic Peninsula palaeo-ice stream Benedict T I Reinardy1, Tavi Murray1, Claus-Dieter Hillenbrand2, John Hiemstra1, Rob Larter2, Jeffrey Evans3 1

University of Wales Swansea, United Kingdom British Antarctic Survey, United Kingdom 3 Scott Polar Research Institute, United Kingdom 2

During the Last Glacial period the Antarctic Peninsula Ice Sheet was drained by ice streams flowing through cross-shelf bathymetric troughs to the outermost Larsen shelf. Swath bathymetric data reveal mega-scale glacial lineations (MSGL) on the floor of these troughs (water depths greater than 500 m) indicating fast flow of grounded ice and the pathways of former ice streams. Sediment cores collected from the troughs contain a stiff till overlain by soft till, with the latter interpreted as deformation till. Shear strength data indicate a very sharp boundary between the soft and stiff till. Sub-bottom profiler (TOPAS) data indicate an acoustically transparent layer which is underlain by a sub-bottom reflector and corresponds to the soft till. This transparent layer only partially covers the trough floors and its surface, as well as that of the underlying sub-bottom reflector, varies between rough and smooth. This change in surface roughness suggests that some parts of the ice stream were sliding over the stiff-till bed while other parts were deforming it. We have selected cores for micromorphological analysis in order to sample spatially and temporally the record of basal processes beneath these ice streams. A new micromorphological technique has been developed for quantifying the abundance of characteristic structures. Thin sections were divided into a 1 cm x 1 cm grid and the number of each microstructure within 10 randomly selected cells was counted. The soft and stiff till share similar features such as circular structures, shears, irregular fractures, grain alignments and the development of masepic plasmic fabric. Planar and circular structures observed in close association in both units suggest that internal deformation, i.e., shearing and rotation, occurred at some point during grounded ice flow across the trough bed, and that the stiff till was also subjected to subglacial deformation. The stiff till differs from the soft till by higher numbers of crushed grains and micro-boudins. This finding indicates lower porewater concentrations in the stiff till compared to the overlying soft till. Overall, the results of micromorphological analyses show a dif-

fuse rather than an abrupt transition between the soft and stiff till, and suggest that the soft till is derived from the stiff unit rather than deposited on it. Spatially the distribution of these micro-features in the tills shows a systematic pattern from the inner shelf to the shelf break, and documents changes in basal conditions and the flow regime along the ice stream bed. 0852 Quantifying Environmental Change Associated with Deforestation, Waipaoa Basin, NZ Luke J Reusser, Paul R Bierman University of Vermont, United States

In addition to natural disasters, human land use practices hold the potential to force catastrophic environmental change. Near total conversion of indigenous forest to pasture over the past century in the erosion-prone Waipaoa River Basin, along the tectonically active eastern margin of New Zealand’s North Island, has resulted in some of the most dramatic and widespread erosional features on the planet. Highresolution records of sediment delivery, channel response, and offshore deposition, anchored by well-dated tephra deposits across the region, demonstrate the severity of anthropogenic landscape disturbance. Today, the 2200 km2 Waipaoa River delivers a disproportionately large 15 Mt of sediment to Poverty Bay annually, suggesting a basin-wide average denudation rate of >2 km/My. Recently compiled detailed seismic surveys of sediment accumulation on the continental shelf and slope yield an average rate of sediment delivery from the Waipaoa of ~1 Mt/yr over the Holocene, implying that human induced sediment delivery is elevated by as much as 15 times over background. While these high-resolution data provide a previously unattainable mass flux from the Waipaoa outlet to the sea through time, there is evidence to suggest that they do not portray the full extent of landscape disturbance caused by deforestation. In regions of the Waipaoa Basin most heavily impacted by land clearance, massive gully complexes and extensive shallow landslides shed prodigious amounts of sediment from pastoral hillslopes. Repeat surveys of channel aggradation in one such basin demonstrate that nearly 50% of the sediment eroded from hillslopes is retained in valley bottoms, indicating that river-outlet sediment yields are not wholly representative of current landscape erosion. In an attempt to establish baseline rates of landscape erosion during the late Holocene, we collected ~60 samples of active channel sediment within and around the Waipaoa River Basin for 10Be and 36Cl analysis. 23 of these samples are from prominent tributary basins, and will help determine how quickly various parts of the basin erode, and where most sediment is produced under natural conditions. The remaining samples are from smaller sub-basins characterized by certain erosional processes and/or different vegetation cover classes (gully vs. landslide and/or paddock vs. natural vegetation dominated basins). When coupled with other high-resolution datasets, these cosmogenic basin-scale erosion rates will define better our understanding of the environmental consequences of pervasive deforestation in tectonically active terrain.


0545 Changes in dust composition in the western United States related to human activities over the past ca. 150 years Richard L Reynolds1, Harland Goldstein1, Jess Mordecai2, Katrina A Moser3, Jason C Neff4, Marith C Reheis1, Joseph G Rosenbaum1, James C Yount1 1

U.S. Geological Survey, United States University of Utah, United States 3 University of Western Ontario, Canada 4 University of Colorado, United States 2

An important issue in landscape change deals with the influences of human activities on dust composition and flux, sometimes with farreaching effects on ecosystem dynamics and human health. Chemical, magnetic, and textural studies of eolian dust, deposited in lake sediments and captured in natural subaerial traps, yield information about the impact of human activities on recent and contemporary dust composition compared to dust inputs before settlement in mostly dryland western United States. Lake sediments in the Uinta Mountains (Utah), San Juan Mountains (Colorado), and Yellowstone National Park (Crevice Lake, Montana) provide examples of large shifts in trace-element chemistry within the top 15 cm that include the past ca. 150 years, from Pb-210 dating or varve chronology. In one Uinta lake, about 90 km east of Salt Lake City, many elements increase greatly above nearly constant background values that represent deposition over a few centuries prior to about A.D. 1850: Ag, by 4.0x; As, 4.2x; Cd, 5.3x; Co, 1.6x; Cu, 2.2x; Fe, 2.3x; Mo, 2.5x; Pb, 11.0x; Sb, 4.9x; Sn, 2.8x; W, 1.6x; Te, 5.3x; and Zn, 1.7x. Fly ash from coal combustion occurs in the upper 10 cm where S increases by 2.4x. In the other lakes, similar enrichments are evident over the past ca. 125-150 years for Ag, As, Cd, Cu, Pb, Sb, and Te. Increases in P in the Uinta and San Juan settings (4x and 8x, respectively) may be related to increases in organic matter and P deposition. Changes in dust composition appear to be expressed also in fine-grained sediments on isolated bedrock surfaces that represent natural dust collectors, along a 700-km-long sampling transect from the Mojave Desert to the Colorado Plateau. Sediment trapped in the upper 1–2 cm that likely represents dust deposition during the past century on the basis of its association with mature biologic soil crust and the presence of fly ash, is enriched at most localities in Cd, Pb, P, and Zn relative to deeper sediment. Enrichments in U and V are also found in the central Colorado Plateau, a region of uranium and vanadium mining and processing during the 1950s –1970s. Taken together, these shifts in the chemical composition of lake and upland sediment, supported by analyses of modern dust, reflect compositional changes in local and regional dust since settlement that are most likely related to mining, fossil-fuel combustion (power generation and transportation), agriculture, water diversion, and perhaps waste incineration. 1341 Paleoenvironmental and Archaeological Investigations at Qinghai Lake, Western China David E Rhode1, Haizhou Ma2, David B Madsen3, Jeffrey Brantingham4, Steven L Forman5 1

Desert Research Institute, United States Chinese Academy of Sciences Institute of Salt Lakes, China 3 University of Texas, United States 4 University of California, Los Angeles, United States 5 University of Illinois - Chicago, United States 2

Qinghai Lake, at a present elevation of 3194 m on the northeastern Tibetan Plateau margin, is China’s largest extant closed-basin lake. Its

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position relative to major Asian climate systems makes it sensitive to global-scale climate change, and it has been the subject of numerous investigations primarily involving sediment cores in the lake itself. Exposed shoreline features around the lake basin provide another important lake history record, and these have previously been used to suggest the lake level stood as much as 140 m above its present level, as late as the terminal last glacial maximum. Here we report new chronometric estimates of shoreline features, geomorphic exposures, and archaeological sites to contribute to a shoreline-level history of Qinghai Lake. Our data suggest that Qinghai Lake did not exceed levels greater than 55 m above modern within the past ~90,000 –100,000 years. Maximum highstands of ~ 55 m above modern probably date to ~100,000 yr BP, during Oxygen Isotope Stage (OIS) 5. OIS 3 lake elevations are presently undated and uncertain, but were probably at or below postglacial highs and may have been below modern lake level. The lake probably reached ~3202–3206 m (+8 –12 m above modern) during the early Holocene but stayed below ~3202 m after ~8400 years BP. This shoreline history implies significantly different hydrologic balances in the Qinghai Lake basin before and after ~100,000 BP. We tentatively suggest that the cause of the +55 m highstand may be related to an expanded Asian Monsoon (increasing precipitation) possibly coinciding with declining continental insolation and temperatures (decreasing evaporation) near the end of OIS 5c. 0971 Environmental luminescence: reconstructing terrestrial environmental change using OSL and TL of quartz Edward J Rhodes Research School of Earth Sciences and Research School of Pacific and Asian Studies, Australian National University, ACT0200, Australia

Optically stimulated luminescence (OSL) of quartz now represents an important dating technique with applications to terrestrial and marine environments. The method relies on the removal of trapped charge by daylight exposure during transport immediately prior to deposition. After burial, environmental radiation causes trapping of charge in the lattice, giving rise to the OSL signal observed during subsequent measurement. OSL dating is sometimes limited by incomplete removal of charge prior to deposition owing to insufficient daylight exposure. To overcome this limitation, several methods are used to detect mixed dose distributions resulting from incomplete zeroing. These provide the potential to avoid erroneous age estimates, and in some cases, to isolate a meaningful subset of the data. However, they also provide valuable information regarding environmental conditions at the time of deposition, and can be used to constrain models of sediment entrainment and transport, and post-depositional modification. In the simplest case, the identification of grains which were not zeroed during transport, and retain a significantly higher dose value, indicates that these grains did not have light-exposure for a significant period (e.g. thousands of years) before or during this depositional event. This provides physical limitations to the transport modes, for example grains transported under ice, at night, in highly turbid conditions or as coherent blocks of reworked material. Likewise, the post-depositional introduction of grains from younger horizons with lower dose values can indicate bioturbation processes. Several different OSL parameters are available to assist in reconstructing depositional environments, including dose distributions, determined either using single grain or multigrain aliquots, and De (t) plots, also known as shine plateaux, which can indicate brief partial light exposure. Less bleachable components of the OSL signal have the potential to constrain repeated transport and exposure patterns over periods of up to millions of years. Samples

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from different geological sources or with different environmental histories often have widely varying luminescence sensitivities, that is the luminescence output per unit of applied dose, and this can form the basis of provenancing methods. The sensitivities of both OSL and TL (thermoluminescence) signals change on heating, typically rising by up to several orders of magnitude for temperatures up to ~600 ºC, providing the basis for reconstructing past anthropogenic or wildfire burning events. Luminescence signals record responses to a wide variety of environmental events, and this paper will provide examples from different contexts, and provide an agenda for future developments. 1017 Australasian INTIMATE: Late Quaternary environmental change in central Australia Edward J Rhodes1, Kathryn E Fitzsimmons2, John W Magee2, Patricia C Fanning3, Simon J Holdaway4 1

Research School of Earth Sciences and Research Schol of Pacific and Asian Studies, Australian National University, ACT 0200, Australia 2 Department of Earth and Marine Sciences, Australian National University, ACT 0200, Australia 3 Graduate School of the Environment, Macquarie University, Sydney, NSW 2109, Australia 4 Dept. Anthropology, University of Auckland, Private Bag, Auckland, New Zealand

As part of the Australasian INTIMATE palaeoclimate initiative, we have collated records of terrestrial environmental change in central Australia over the last 30,000 years. Several hundred samples of linear or source bordering dunes have been dated recently at the ANU using OSL, and this dataset includes many ages indicating deposition within this period. Fluvial sediments from ephemeral streams have also been dated, indicating periods of increased run-off. Published papers from other research teams present chronologies from many more dune, lake and fluvial contexts across Australia. Several significant and widespread peaks in activity are observed in the different records, indicating important environmental changes were affecting the continental interior during this period. However, the diverse nature of the physical records, differences in dating methods, and issues in interpreting the climatic meaning of the various contexts means that this is a very complex dataset. A significant peak in several records at around 14 ka suggests that this period is particularly important, and we present more detailed stratigraphic resolution for some locations where this event is observed. We will present a summary of the regional chronological patterns for the different sedimentary environments across central Australia within the last 30,000 years, with a commentary on the data sources, significance and the simplicity or complexity of palaeoclimatic interpretation. We will examine possible palaeoclimatic controls in different regions of the continent, and compare results from the different palaeoenvironmental records. These data allow an interesting comparison with palaeoenvironmental archives from more humid coastal Australia, in particular those based on vegetation and speleothem, besides records from elsewhere in Australasia, Antarctica and other parts of the Southern Hemisphere. 0478 Paleovegetation record of the last climatic cycle from the Tyrrhenian coast of Tuscany (Western Italy) Marianna Ricci Lucchi Dipartimento di Scienze della Terra e Geologico-Ambientali, University of Bologna, Italy

A 105 m-long continuous core (M1-Tirrenia), recording the sedimentary evolution of the Tyrrhenian coast of Tuscany during the last 130 kyr, was studied in detail by means of pollen analysis with the aim to reconstruct the vegetation dynamics in relation to changing climate and environmental conditions.

The high lithological and sedimentological variability of core M1, with facies associations changing from fluvial to alluvial plain, and from coastal plain to shallow-marine, reduces to some extent the continuity of the pollen record and enhances the paleoenvironmental control on pollen distribution. However, the vegetation and climatic record of this core represents remarkable evidence of the continuous presence, even at variable densities, of temperate tree pollen throughout the sequence, thus providing specific indications on the location and nature of cold stage European tree refugia. The succession of forest and open vegetation recorded in the core can be generally compared to what is known for central and southern Europe, but peculiar paleoenvironmental and paleoclimatic features account for a more complex and varied floristic composition. Two main forest periods are recognized: the Last Interglacial (OIS 5e), represented by a 12 m-thick sedimentary succession with a variable and particular pollen content, and the Holocene, recorded by a complete, 51-m thick sedimentary cycle starting at the uncalibrated 14C date of 10,004±50 yr BP. During the major open vegetation period, corresponding to the Last Glacial phase, mixed deciduous Quercus and Pinus forests were densely widespread, and a characteristic pioneershrub vegetation, represented mainly by Ephedra, Hippophae and Juniperus, is also continuously recorded. Moreover, the non-stop occurrence of typically mountain taxa like Abies, Picea and Fagus testifies for favourable, nearby areas of distribution, from which these trees rapidly spread during interstadial or interglacial periods. On the basis of these results, it is clear that the investigated area acted as a privileged glacial refugium for many temperate forest components. High precipitation levels linked to the characteristic paleotopography and the proximity of the sea, are main factors that could have favoured the local presence of refugial populations compared to other sites. 1331 Using speleothems to investigate atmospheric C-14 variation and climate change of the past 45 ka David A Richards1, J Warren Beck2, Dirk L Hoffmann1, Peter L Smart1, Philip J Hopley1, Bruce A Paterson3, Dave P Mattey4 1

School of Geographical Sciences, University of Bristol, United Kingdom NSF AMS Facility, Dept of Physics, University of Arizona,, United States 3 Department of Earth Sciences, University of Bristol, United Kingdom 4 Department of Geology, Royal Holloway, United Kingdom 2

One of the key parameters in the study of past environmental change of the last 50 ka is radiocarbon. Significant centennial- and millennialscale fluctuations in the concentration of atmospheric radiocarbon (Δ14C) have now been observed in many pre-Holocene records. These have been attributed to changes in terrestrial and solar magnetic fields and/or changes in the carbon cycle. However, not all records agree,


leading us to the conclusion that some or all of them have either (1) problems with the calendar age timescale, (2) variable amounts of post-depositional alteration, or (3) complications resulting from indeterminate reservoir or dead carbon effects. Previously, we presented a continuous record of 14C from 45 to 11 ka based on TIMS U, Th and Pa measurements and AMS 14C ages of a stalagmite (GB-89-24-1) from a cave on Grand Bahama (Beck et al., 2001). This record revealed elevated 14C for the duration of growth, particularly so at ~ 44 ka, and a general decline in 14C between 26 and 11 ka from ~ 700 to ~ 100 ‰, which is considered too large to be solely a result of changes in the Earth’s magnetic field intensity. We suggested that this steep decline was also related to redistribution of 14C during a mode of ocean circulation much different to the present day. Here, we focus on efforts to reproduce and explain the millennial and sub-millennial 14C variations observed in the Bahamas speleothem record, using an additional sample from the same cave (GB89-25-3). A robust chronology for these two stalagmites has been obtained using MC-ICPMS U and Th measurements with precisions comparable to AMS 14C analyses for similar sample sizes and comparison between their high-resolution laser-ablation trace-element and stable-isotope axial profiles. We present new data demonstrating reasonable coherence in 14C variation after correction for significantly different values of dead carbon fraction (DCF). A smoothed combined record of d14C variation using constant DCF for each sample agrees well with much of the record from Cariaco Basin (Hughen et al, 2004) after adjustment based on recent ice core chronologies (NGRIP ss09sea, GICC05) and comparison with Hulu speleothem data. However, we still observe a large 14C peak (~ 1000 ‰) at ~ 44 ka that has not been recorded elsewhere and attempt to reconcile this with independent records of geomagnetic intensity, cosmogenic nuclide production and/or current understanding of the reorganisation of ocean circulation during the glacial period. 1334 U-Th ages of multiple-phases of speleothem growth in the Bahamas and sea level change during the past 500 ka David A Richards1, Dirk L Hoffmann1, Peter L Smart1, Charles J Borton2, R Lawrence Edwards2 1

School of Geographical Sciences, University of Bristol, United Kingdom Department of Geology and Geophysics, University of Minnesota, United States 2

U-Th ages of phases of calcite growth in a submerged flowstone and stalagmite sequence from Sagittarius Cave, Grand Bahama serve as important constraints on the timing of sea-level change for the middle and late Pleistocene. We have adopted a combination of both conventional and laser ablation MC-ICPMS using ThermoFinnigan Neptune to achieve high precision and high spatial sampling resolution to determine age estimates and investigate potential diagenetic effects as close as possible to the end of growth phases. Age durations of continuous phases provide maximum constraints on sea-level elevation because calcite deposition could only have occurred when the cave passages were air-filled. Elevation constraints are good because the Bahamas have remained tectonically stable for the period of growth. Growth hiatuses can be attributed to submergence during high sea stands or cessation of drip during periods of aridity, lack of soil cover or fissure blockage. Ages for initiation of growth after two major growth hiatuses in the Sagittarius sequence were likely to have been caused by major high sea-stand events are 302 ± 6 ka, 191 ± 4 ka, and constrain the timing of the marine isotope stage boundaries 9/8, 7/6, respectively (quoted errors 95% CI). Numerous minor hiatuses occur in marine isotope stage 8, indicating that deposition was sensitive to climate or sea level

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change at this time. Initial 234U/238U activities are similar to modern sea water values for early stage 8 growth phase ,while significantly less than this prior to stage 8. This suggests that particularly high sea levels and deposition of new carbonate material occurred during marine isotope stage 9. Comparison of this record is also made with other sealevel data from the Bahamas archipelago and elsewhere. 1295 Reconstruction of a Late Pleistocene paleorelief in Lower Austria Dieter Riegler, Robert Peticzka, Birgit Terhorst Institute of Geography and Regional Research, University of Vienna, Austria

Geomorphodynamic and pedogenetic processes were studied on the summit of Kranawetberg (a paleolithic site) and the northfacing slope towards a dry valley (Langer Grund) on the east boundary of the Austrian loess region “Weinviertel” near the key site “Stillfrieder Komplex” and “Stillfried B”. The paleolithic (Gravettien) site was studied since 1994, therefore several drillings and sections were already analysed. Furthermore, the results of drillings, which were carried out in 2004 were available for the entire slope of the Kranawetberg. The studies show the occurrence of two pedocomplexes, one originating from an interglacial period, the other gives evidence of an interstadial period. Laboratory analyses of grain size distribution and carbonate content were done to confirm the field survey. The samples of the paleolithic excavation were grouped by model-based clustering and integrated in a 3-dimensional model of the summit. A transection of the slope between summit and valley button shows the development of the interacting pedocomplexes. Under the Upper Pleniglacial loess the interstadial pedocomplex is traceable from the summit to the backslope. The underlying interglacial pedocomplex covers parts of the shoulder continuing on the backslope. In the footslope and the valley bottom no paleohorizons were found. The thinning out of the interglacial pedocomplex is the result of denudational processes on the summit. The upper horizons of the interglacial pedocomplex and the interstadial horizons are mixed in the backslope. This situation implies downward movement of material during the interstadial soil formation. A horizon of carbonate leaching and an underlying horizon with enhanced clay content combined with carbonate coatings were found in the drillings of the summit. This fact indicates different stages of interstadial soil formation in the Late Pleistocene of Austria. 1076 Phytoliths: A new chronometer for the Late Quaternary Uwe Rieser1, Christine Prior2, John A Carter3 1

Luminescence Dating Laboratory, School of Geography, Environment and Earth Sciences, Victoria University of Wellington, New Zealand 2 Rafter Radiocarbon Laboratory, Institute of Geological & Nuclear Sciences, Lower Hutt, New Zealand 3 School of Geography, Environment and Earth Sciences, Victoria University of Wellington, New Zealand

Reliable interpretations of environmental change require accurate dating of sedimentary sequences that contain detailed climate records, but often lack datable material. In some locations, ages have been determined by e.g. radiocarbon dating of organic material or luminescence dating of quartz or feldspar. In contrast, phytoliths are present in most Quaternary terrestrial sediments worldwide. Phytoliths are microscopic opaline particles commonly found in soils and sediments. They are produced in many plant cells as the living cell fills with silica, forming

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a solid body. Fragments of the original cellular material are trapped inside the phytolith, effectively protected from post-depositional alteration or contamination. Our research aims to develop both optically stimulated luminescence (OSL) dating of phytoliths and AMS radiocarbon dating of carbon particles occluded within the same phytoliths. As these methods are complementary and independent from each other, paired OSL and AMS dates provide cross-calibration and a check for common problems like re-deposition or anomalous fading. Our ongoing project so far has proved that phytoliths possess a stable OSL component, which can be stimulated either by infrared or green/blue light. They emit light in the blue and UV part of the spectrum, possibly also in other wavelength bands. Laboratory experiments suggest a dating range of at least 100,000 years, with a precision of 5–10%. Comparison of phytolith OSL ages and feldspar OSL ages of the same sediment samples showed agreement within 1sigma errors. However, some problems with phytolith sample preparation and purification remain to be solved, and the optimal OSL measurement protocol has to be found. Radiocarbon dating of organic material occluded in phytoliths only became feasible with the introduction of AMS. Empirically, phytoliths contain between 0.1 and 2% carbon. The small sample size required by AMS, less than one milligram, means that only a few grams of sediment need to be processed to obtain sufficient phytoliths for analysis. Our tests confirm that this trapped organic carbon is suitable for 14C dating and produces expected carbon isotope ratios, but some researchers report inconsistencies in the method. The most probable cause for inaccurate phytolith 14C ages is inadequate sample pretreatment. On the poster we present the current state of our project, including our latest sample preparation procedures and age data. Our AMS ages on phytoliths from sediment samples are now in satisfactory agreement with OSL age control, though further work on preparation methods and independently dated samples remains to be done. 0690 The potential use of Ti-related centres in ESR-dating – an intercomparison of ESR with OSL data from two Pleistocene dunes in SE Australia Sarah Rittner, Koen Beerten, Johanna Lomax, Ulrich Radtke Geographisches Institut der Universität zu Köln, Germany

In recent investigations, the use of Ti-related impurity defects in aeolian quartz has revealed a high potential for ESR dating. Regarding the ESR dating range of quartz – beyond the limits of luminescence dating – a more systematic study would be relevant in view of applying this method in Quaternary research. Accordingly, two dune profiles from a Pleistocene desert environment (Murray Basin, SE Australia) were investigated. Samples from this location meet three methodological requirements: aeolian in origin, age control from optically stimulated luminescence dating (OSL) and high resolution sampling to test internal consistency. The two profiles pose interesting challenges for this methodological study: whereas in one profile the preliminary OSL ages markedly increase with depth, there are indications that the lower half of the other profile is beyond the OSL dating limit. From each profile, nine samples were prepared for the multiple grain technique (aliquot size: 300 mg; grain size: 100–200 microns). The ESR spectra of the Ti centre, with its two relevant subcentres Ti-Li and Ti-H, were analysed to investigate their suitability as potential dating signals. To estimate the palaeodoses for various Ti-related ESR signals, both the multiple aliquot regenerative and additive dose methods were applied. Dose recovery tests (DRT’s) on selected samples were conducted to exclude the case of sensitivity changes for the regenerative method. Bleaching tests were carried out on two samples to analyse whether the

Ti-centres of these quartz samples are fully bleachable. Overall, the outcome of this study is very promising and several tendencies can be observed. Depending on either regenerative or additive dose method, the Ti-related ESR palaeodoses from several samples are in fair up to good agreement with the luminescence data. DRT’s (laboratory dose) show consistent results for several specific absorption lines. At the state of the study, one particular absorption line (presumably the result of overlapping Ti-H and Ti-Li signals) appears to be most suitable for ESR-dating. 0772 The geochronology and dynamics of southeast sector of the Greenland Ice sheet during the Last Glacial Maximum David H Roberts1, Antony J Long1, Christoph Schnabel2, Stewart Freeman2 1

Durham University, United Kingdom NERC Cosmogenic Isotope Analysis Facility Scottish Universities Environmental Research Centre, United Kingdom 2

The southeast sector of the Greenland ice sheet (GIS) is currently experiencing rapid changes in mass balance and ice sheet dynamics at low elevations. However, despite these changes, existing knowledge of short and long term controls on ice sheet dynamics in this region is limited. During the Last Glacial Maximum (LGM), several authors favour a restricted ice sheet confined to troughs, with nunataks, and a limited extent across the continental shelf. Others propose a thicker ice sheet with ice filling the valleys and extending to the shelf break. LGM ice extent over the coastal mountains during the LGM is uncertain although existing models suggest that the culmination of the LGM occurred between 22 – 14 ka BP and ice retreated from the south eastern shelf after c. 13.6 k cal. yr BP to reach the present coast at c. 10 k cal. yr BP. This paper presents the results of a study designed to test these competing LGM ice sheet models based on geomrophological mapping and cosmogenic analyses in a field area located to the east of Angmagssalik. Our work constrains minimum ice thickness during the LGM to 750m and therefore supports a large ice sheet model at LGM in this area. Samples taken from in situ glacially abraded bedrock surfaces in blockfield terrain above a regional trimline yield deglacial ages of c. 11.9 - 10.1 ka BP, indicating warmbased erosion of high level surfaces followed by trimline formation during deglaciation and intense post glacial frost shattering. Ice sheet retreat from the continental shelf and to the southern edge of Sermilik fjord is dated to c. 11.4 to 9.6 ka BP and possibly constrains the timing of the marine based calving retreat of the Helheim ice stream. Dating of the rate of ice retreat inland from this along the Torqulertivit Imiat valley is complicated by overlapping dates, but maximum dates on the outer coast (11.4 Ka BP) and minimum dates up valley (10.1 ka BP) suggest a minimum marginal downwasting rate of c. 7.7m yr driven by rapid surface ablation at this time, which coincides with a period of rapid atmospheric warming observed in the Greenland ice core records.


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0779 Ice marginal dynamics and sediment delivery mechanisms in surging glacier settings: Kuannersuit Glacier, Disko Island, West Greenland

0490 Onshore expression of multiple orbitally driven Late Quaternary marine incursions on the ultra-stable southern South African coast

David H Roberts1, Antony J Long1, Niels T Knudsen2, Jerry M Lloyd1, Jacob C Yde2, Morten Rasch3, Niels Nielsen4

David L Roberts1, Zenobia Jacobs2, Panagiotis Karkanas3, Curtis W Marean4

1

1

2

2

Durham University, United Kingdom University of Aarhus, Denmark 3 Danish Polar Centre, Denmark 4 University of Copenhagen, Denmark

The Kuannersuit glacier surged 11 km between 1995 and 1999. The surge resulted in the formation of an ice cored thrust moraine complex constructed by subglacial and proglacial glaciotectonic processes. Three main thrust phases exist in the marginal zone with phases of compressional folding and thrusting followed by hydrofracture in response to the build up of compressional stresses and the aquicludal nature of submarginal permafrost. Crevasse traces and squeeze ridges vertically cross-cut the margin up ice of the thrust zone. Three types of banded debris-rich basal ice (BDRBI) occur within the thrust complexes: Facies I comprises laterally continuous strata of ice with sorted sediment accumulations, Facies II is laterally discontinuous BDRBI with distinct tectonic structures, whilst Facies III is characterised by brittle deformation and breccia development. Facies I records initial cyclical net adfreezing of subglacial water onto the subsole of the glacier by conductive cooling through the fractured snout. This process may be related to thrusting and the initiation of hydrofractures up the steep, reverse gradient of the thrust complexes, which induced glaciohydraulic supercooling. This facies also supports the existence of a distributive water system submarginally. As marginal compressional stresses built, so Facies I was modified by compressional folding and extensional thrusting to produce the tectonically structured Facies II. Facies III formed through apron entrainment where areas of glacier ice were overrun. Sediment delivery in front of and across the margin occurs through bulldozing, thrusting, hydrofracture, crevasse squeeze and surface meltout. Bulldozing of proglacial sediments during the surge phase forms the outer edge of the thrust moraine complex. Thrust dislocation from subglacial positions entrains debris which, during meltout, delivers subglacial diamicts containing large, sub-rounded to sub-angular, striated clasts to supraglacial locations. The meltout of BDRBI produces variably sorted sediment depending on its production mode (Facies I–III). Crevasse traces produce well sorted fine sediment aggregates that exhibit striated surfaces formed through pressure squeezing, while crevasse-squeeze ridge sediments are often characterised by sub-horizontal stratification indicating settling of sediment from suspension following the pressurised injection of debris laden water. From a palaeoglaciological viewpoint, thrusting and crevasse squeeze ridge development are important for sediment delivery and landform genesis in polythermal, cold based settings such as Kuannersuit, but hydrofracture is also a dominant process responsible for the elevation of sediment into englacial and supraglacial positions, through the formation of BDRBI driven by supercooling and through quiescent phase sedimentation of crevasses.

Council for Geoscience, South Africa School of Earth & Environmental Sciences, University of Wollongong, Australia 3 Ephoreia of Palaeoanthropology-Speleology of southern Greece, Greece 4 Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, United States

Only two eustatic sea level maxima forced by the ~100 ka eccentricity cycle (dominant over the past ~1000 ka) are generally agreed to have attained elevations well above present sea level i.e. MIS 11 and MIS 5. However, consensus concerning the absolute elevation of these maxima remains elusive (MIS 11 in particular). Estimates for MIS 11 range from below present sea level to ~+20m and cannot be explained by variables such as hydro-isostacy and location on the globe. MIS 11 is widely touted as the closest analogue for the present Interglacial (MIS1) and is of special import for predicting global change. Dana Bay and Little Brak River are localities situated ~350 km east of Cape Town on the southern South African coast, an ultra-stable, trailing edge, intraplate tectonic setting. Dana Bay hosts juxtaposed, calcified onshore deposits left by multiple, orbitally driven marine incursions separated by erosional disconformities. The oldest unit comprises a polymict marine gravel reaching ~1.5 m amsl, followed conformably by a ~2 m thick aeolianite. The calcretised upper aeolianite surface was partially truncated by a later bioturbated, shoreface marine calcarenite, with basal large rip-up clasts of calcrete and calcarenite. The calculated true transgressive maximum is ~10.7 m amsl, but the upper surface is gravelly and calcretised suggesting truncation and a minimum elevation only. The saturated OSL signal indicated ages >250– 350 ka, suggesting an MIS 11 age. A younger calcarenite displaying low angle lamination with internal low angle discordances with a corrected elevation of ~7.1 m amsl rests with an erosive contact on the older marine calcarenites and was dated by OSL to MIS 5e. These data suggest two marine incursions higher than present sea level during MIS11, with a transgressive maximum ~3 m higher than MIS 5. This may partly explain the large disparity among estimates for MIS11 maxima. At Little Brak River a regressional gravelly to sandy marine sequence (shoreface to beach) rises landwards from ~10.5 m to ~15.3 m amsl over a distance of ~300 m. The OSL signal was saturated, giving an age of >~230 ka and the molluscan biota suggests a Late Quaternary age. A new series of OSL analyses on these older deposits are being run. If the new dating demonstrates an MIS11 affinity for Little Brak River and Dana Bay, then the different estimates of sea level maxima between the two sites may be due to post- depositional truncation of the latter. 0592 Tsunami risk in southern Africa-a preliminary assessment from evidence of past events David L Roberts Council for Geoscience, South Africa

Southern Africa is far removed from major seismic sources and earthquakes greater than ~M 7.5 are considered unlikely to threaten its coastlines. Nonetheless, the Indian Ocean tsunami of 26 December

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2004 impacted on Mauritius, Madagascar and Mozambique, and was even recorded from the southeastern and southern seaboards of South Africa, with wave heights of up to ~3 m. This emphatically demonstrated that even distant events can impinge on the southern African coastline. Furthermore, large tsunami can be generated by agencies other than seismicity, including bolide impact, volcanicity, submarine slumps and terrestrial landslides/rockfalls. Catastrophic tsunamigenic volcanism is well documented in historical times (e.g. Thera in the Aegean and Krakatau in the Indian Ocean). Flank failure/eruption of the active volcanic islands of Karthala and Reunion represent the most likely sources of potentially tsunamigenic volcanism in the Indian Ocean, whereas Marion Island fills this role in the South Atlantic. A dual risk is posed by submarine slumps along the Indian Ocean and Atlantic coastlines. Sediment cones of major rivers such as the Orange and Tugela as well as a zone of known recent slumping off the southeastern coast represent the most notable threats. Anecdotal evidence exists of tsunami genesis by slumping in an unstable mud delta offshore from the Mzimvubu River mouth. A tsunami wave of ~6 m centring on the west coast town of Dwarskersbos 200 km north of Cape Town on 26th August 1969, was probably also caused by a marine slump. In 1955, a massive rock slab collapsed into Lutuya Bay, Alaska, causing a wave over 500 m in height, the highest ever recorded, amply demonstrating the threat posed by landslides/rockfalls into restricted embayments. An estuary alongside the large town of Knysna on the southern Coast of South Africa was subject to massive prehistoric landslides from the flanking unstable Tertiary/Quaternary dune systems. Steep cliffs comprised of highly fractured Palaeozoic sandstone reach elevations of up to several hundred meters around Cape Town and along the Tsitsikama segment of the southern coast. The cliffs have in the past spawned large rockfalls, notably into the restricted embayment of Hout Bay, Cape Town. These events would have generated large waves which would have been catastrophic if repeated in the modern context of high population densities. These observations highlight the need to quantify the risk posed by tsunami to communities and installations along the southern African coastline. 0538 The timing, source, and flux of Last Glacial loess accumulation in the North American midcontinent Helen M Roberts1, E Arthur Bettis III2, Joseph A Mason3 1

University of Wales, Aberystwyth, United Kingdom University of Iowa, United States 3 University of Wisconsin, United States 2

Terrigenous dust can be both a product and an agent of climate change. Ice core records show increased levels of continental dust during glacial periods compared to interglacials, with exceptional levels of dust being recorded during the last glacial maximum (LGM). The terrestrial deposits of wind blown dust known as loess also support these observations, preserving records of changes in climate and in atmospheric circulation, and documenting the changing sources and flux of dust over time. The greatest thicknesses of Last Glacial loess are preserved in the North American midcontinent, and termed ‘Peoria Loess’. On the basis of thickness alone, these Peoria Loess deposits suggest high dust accumulation rates during the Last Glacial period across a large area of North America. Using optically stimulated luminescence (OSL) dating, we have previously shown that mass accumulation rates (MARs) for non-glacigenic Peoria Loess in western Nebraska are much higher than any other pre-Holocene location worldwide, and that these MARs fluctuate over time. This paper builds upon this earlier

work, extending the area of study across the North American midcontinent along a west-east transect and presenting new data for sites in eastern Nebraska and western Iowa which have both glacigenic and non-glacigenic sources. A combination of optically stimulated luminescence (OSL) dating and geochemistry is employed, providing a powerful tool for the reconstruction of what prove to be dramatic changes in the timing, flux, and source of dust. These loess records may not only serve as passive testimony to the response of dust to climate change, but may also provide evidence to support the active role of dust in forcing climate change. 0543 Advances in luminescence dating of loess Helen M Roberts University of Wales, Aberystwyth, United Kingdom

Loess deposits were the first terrestrial sediments to which luminescence dating was systematically applied, tested, and developed. These deposits provide a direct record of atmospheric circulation, and their temporally extensive nature means that they provide one of the most detailed and significant terrestrial records of climate change found on Earth. However, establishing a reliable absolute chronology is essential if different loess records are to be compared, and teleconnections investigated. The great strength of luminescence dating is that it is applied to the minerogenic component of the sediment itself, enabling the time of sediment deposition to be dated directly. Coupled with this, the current range of the luminescence technique makes it potentially one of the most valuable absolute dating techniques available for the study of loess deposits. Equally, the length of many loess records presents a unique testing ground for the challenge to extend the maximum age range of luminescence techniques. Thus, luminescence dating and loess records complement each other strongly, and the development and testing of luminescence techniques and their application to loess deposits has gone hand-in-hand. Inevitably, because so much pioneering luminescence research has been carried out on loess deposits, this means that some luminescence ages produced during this developmental phase are questionable. However, recent improvements in luminescence dating have brought about increased accuracy and precision, and so confidence in luminescence dating is increasing among the luminescence and the user communities alike. Indeed, luminescence dating is now frequently cited as the method of choice for determining an absolute chronology, particularly for aeolian deposits. Recent developments in luminescence dating of loess, and the subsequent palaeoenvironmental conclusions reached as a result of the successful application of luminescence dating will be discussed. Future research directions and challenges facing luminescence dating will also be considered. 0166 East Mediterranean fire histories since the Last Glacial Maximum from lake sedimentary micro-charcoals Neil Roberts, Rebecca Turner University of Plymouth, United Kingdom

Microscopic charcoal analysis has been used to reconstruct past fire activity over a range of spatial and temporal scales in Europe, the Americas and Australasia. By contrast, and despite the importance of fire in its modern landscape ecology, few systematic attempts have been made in the circum-Mediterranean region to reconstruct longterm fire histories using micro-charcoals or other methods of analysis.


This study has used non-destructive methods of charcoal extraction based on sieving plus heavy-liquid separation (Turner et al in press In: Charcoal from the past: cultural and palaeoenvironmental implications. BAR International Series, Archaeopress, Oxford) along with contiguous core sampling of sedimentary core sequences from a number of East Mediterranean lakes that span the last glacial-interglacial climatic transition. At Eski Acigöl, central Turkey (Roberts et al. Holocene, 2001, 11, 719–734), then a deepwater crater lake, overall microcharcoal concentrations in sediments are low and were dominated by influx from regional-landscape rather than local-scale fire events. This record therefore provides a good proxy for overall fire frequency/intensity across the central Anatolia plateau, whose (hypothetical) modern “natural” vegetation is predominantly open oak-grass-Artemisia parkland. Shallow water sites such as Akgöl typically record much higher overall micro-charcoal abundance as a result of local-scale burning of the marsh surface at times of lowered water table, and thus received episodic local charcoal influx superimposed on background regional airborne sources. These results indicate that site type/catchment area and sampling/analytic methodology can critically influence reconstructed fire histories. We have correlated our charcoal records with existing multi-proxy data from the same cores (stable isotopes and pollen). This shows that climatic variations and biomass availability were the main factors controlling the timing of regional fire activity from the Last Glacial Maximum through to the Early Holocene. The Holocene portion of the Eski Acigöl record contains a significant cyclicity with a periodicity of 1400 to 1500 years which may be linked with external (e.g. solar) forcing. 0050 Palaeoenvironmental change on the Antarctic Peninsula from lake sediments: links to South America Stephen J Roberts1, Dominic A Hodgson2 1

British Antarctic Survey (BAS), High Cross, Madingley Rd, Cambridge, CB3 0ET, United Kingdom 2 CACHE-PEP members, British Antarctic Survey (BAS), High Cross, Madingley Rd, Cambridge, CB3 0ET, United Kingdom

The BAS CACHE-PEP program is examining lake, marine & ice cores from the Antarctic Peninsula & Scotia Arc regions. The aim is to link Antarctic Peninsula & South American palaeoclimatic records across the Polar Front & fill the missing link in the PAGES Americas PEP transect. This poster presents high resolution multi-proxy results from several well-dated AP lacustrine sequences and highlights the potential for future collaborative palaeoclimate projects between South American & Antarctic Peninsula research programs. The Antarctic Peninsula is one of the fastest-warming regions on Earth and a key area for studying the effects of ‘global warming’. Its rate of temperature increase of 3.7±1.6˚C per century is six times the global mean, creating shifts in species distribution, catastrophic disintegration of ice shelves, accelerated discharge of continental glaciers, and the possibility of increased rates of global sea level rise. We are currently investigating several palaeolacustrine records on a N-S transect along the AP to provide relatively long (i.e., post-Last Glacial Maximum-LGM), and widely distributed information about past climate-related change in this region. When reliable chronologies are established, we intend to compare the spatial context of climate change, and leads and lags in climate responses: (1) between maritime and continental climate regimes and (2) across a N-S latitudinal transect from the AP-South America. The lake records presented are currently amongst the most accurately dated archives of Holocene palaeoenvironmental change on the AP. They constrain the timing & deglaciation impacts of the LGM ice sheets as

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they retreated from the continental shelf and further evidence of variable spatial and temporal patterns of ‘warm’ climates during the early and mid-Holocene. 0051 Early Holocene retreat of George VI Ice shelf from clast provenance analysis of lake sediments Stephen J Roberts1, Dominic A Hodgson1, Mike J Bentley2, James A Smith1, Charlotte Bryant3, Ian Millar4 1

British Antarctic Survey (BAS), High Cross, Madingley Rd, Cambridge, CB3 0ET, United Kingdom 2 University of Durham & British Antarctic Survey (BAS), High Cross, Madingley Rd, Cambridge, CB3 0ET, United Kingdom 3 NERC Radiocarbon Laboratory, Scottish Enterprise Technology Park, East Kilbride, Glasgow, G75 OQF, United Kingdom 4 NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham, NG12 5GG, United Kingdom CACHE-PEP project members, British Antarctic Survey (BAS), High Cross, Madingley Rd, Cambridge, CB3 0ET, United Kingdom

The Antarctic Peninsula (AP) is one of the fastest-warming regions on Earth. The rate of temperature increase is six times the global mean, leading to shifts in species distribution, catastrophic disintegration of ice shelves, accelerated discharge of continental glaciers, and the possibility of increased rates of global sea level rise. Lake records from the AP can be used to provide a long-term perspective on these climate-related changes. We tested our interpretation that George VI Ice Shelf (GVIIS) retreated in the early Holocene by examining clasts and sediments from Moutonnée Lake, an epishelf lake currently dammed by GVIIS. Detailed granulometric, geochemical and Sr and Nd isotope data from Moutonnée Lake are compared with geological reference data from two further lakes on Alexander Island (Ablation Lake and Citadel Bastion Lake) and an extensive archive of rocks and isotope geochemical provenance data from the AP region. Underpinning this provenance analysis is the contrast between the plutonic/igneous outcrops in Palmer Land on the western side and the predominantly sedimentary strata of Alexander Island on the eastern side of George VI Sound, and the different depositional patterns expected at Moutonnée Lake during periods of ice shelf presence and absence. Changes in clast distribution and provenance show GVIIS retreated further than its present position only once during the last 10,000 years, starting at c. 9600 calibrated (cal.) yr. B.P. This occurred shortly after the early Holocene climatic optimum recorded in Antarctic ice core records and at the same time as an influx of warmer ocean water onto the AP continental shelf. GVIIS subsequently reformed by c. 7500 cal. yr. B.P., when epishelf lake conditions returned following a climatic downturn recorded in Antarctic ice core records. At Moutonnée Lake there is no evidence that ice-shelf retreat and a return to marine conditions occurred during the well-documented, and prolonged, ‘mid-Holocene warm period’. We suggest that mid-Holocene warming did not lead to retreat of ice shelves in the southern AP. One possible explanation is that, unlike the early Holocene, there is no recorded influx of warm water onto the shelf in the mid-Holocene. Therefore, a combination of oceanic melting of the under-side of the ice shelf and an increase in atmospheric temperature at the surface may be necessary for further retreat of GVIIS beyond present day limits. This study forms part of an ongoing project examining past climate change recorded in lake, marine and ice cores from the AP.

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1285 Geomorphic approaches to the identification of early archaeological sites on the Northern Plains of North America Elizabeth C Robertson University of Saskatchewan, Canada

Archaeological understanding of precontact human activity on the Northern Plains of North America is hampered by the region’s paucity of archaeological sites from the Early Prehistoric and Early Middle Prehistoric Periods. Nonetheless, numerous researchers have attempted to reconstruct lifeways during these periods, with many regarding the limited archaeological data as evidence for culturally determined patterns of population distribution. However, it has been argued that the apparent rarity of early sites does not reflect cultural factors but is actually due to the scarcity of landforms incorporating intact deposits from these periods. If so, research on the archaeological content of such landforms is necessary to determine if early sites are, in fact, rare on the Northern Plains for cultural or geomorphic reasons. With this problem in mind, a subsurface testing program was conducted in the meltwater channels flanking the Cypress Hills of southeastern Alberta, Canada. Previous geomorphic research suggested that these channels have experienced ongoing deposition of sediment from upslope areas since the last glacial retreat, making them an ideal context for the preservation of stratified deposits encompassing the Early Prehistoric and Early Middle Prehistoric Periods. Coring and augering in these channels confirmed that they integrate long sequences of weakly developed buried soils. This pattern suggests that the channels have experienced episodic deposition from upslope locations, with intervening periods of stability during which the newly formed land surfaces experienced soil formation. Chronological data from these deposits indicate that this pattern was established by at least 9500 B.P. Additionally, the subsurface testing program determined that the buried soils frequently yield archaeological material. While it was not possible to definitively identify early cultural material, the ubiquity of archaeological artifacts in the channels suggests that these areas have a long history of human use. Coupled with a geomorphic history that favours stratified burial of such artifacts, this finding suggests that the meltwater channels are an ideal setting for the identification and investigation of stratified sites representing all periods of human occupation on the Northern Plains. Moreover, it indicates that targeted study of landforms with histories of Early to Middle Holocene deposition are a useful and appropriate strategy for building an improved understanding of cultural activity during these poorly understood periods. 1110 The bristlecone pine record covering the 8.2Kyr event Iain Robertson1, Tom Harlan2, Neil Loader1, Cynthia Froyd3, Mary Gagen1 1

Swansea University, United Kingdom Laboratory of Tree-ring Research, United States 3 University of Oxford, United Kingdom 2

The ancient bristlecone pines (Pinus longaeva D.K. Bailey) of the White Mountains of California hold a unique natural archive of information on past climate. The existing absolutely-dated ring-width chronology covers 8700 years and offers an unrivalled annually-resolved record of climatic change. The climatic sensitivity of these trees can be attributed to the fact that they grow at an altitude of ca. 3000–3500m, on poorly-nourished, alkaline soil under arid conditions with a relatively short growing season.

Stable carbon and oxygen isotope values were determined on cellulose isolated from annually-resolved bristlecone pine samples in an attempt to determine the timing and duration of the widely-reported Northern Hemisphere cooling event that occurred approximately 8200 years before present. It has been proposed this rapid climate change event was triggered by a perturbation of the North Atlantic thermohaline circulation, caused by an outburst of meltwater from Lake Agassiz. ‘8.2 Kyr’ event proxy reconstructions to date are primarily in the North Atlantic region but they, and modelling results indicate a wider geographical extent. Defining the magnitude and rate of rapid climate change events at different geographical locations is vital if we are to plan for the effects of future North Atlantic initiated rapid climate change. 1272 More than the sum of their parts: the added value of integrating OSL and terrestrial cosmogenic nuclide dating in surface processes research Ruth AJ Robinson1, Bill M Phillips2, Lewis A Owen3, Joel QG Spencer4, Doug I Benn5 1

University of St. Andrews, United Kingdom University of Idaho, United States 3 University of Cincinnati, United States 4 University of Innsbruck, Austria 5 University of St. Andrews and The University Centre in Svalbard, United Kingdom 2

Two dating techniques, optically stimulated luminescence (OSL) and terrestrial cosmogenic-ray nuclide (TCN) dating, have seen technological development and a concomitant growth in the number and diversity of applications over the past few years. A useful approach to developing sedimentary chronologies in surface processes research involves integrating OSL dating of depositional events with TCN exposure dating of the time since a surface or rock has been exposed. Depending on the environmental setting, these two methods combine to produce similar, but not the same, chronologies and can add support to any dates produced. However, an integrated approach offers more than age duplication. We have combined the TCN depth profile method with OSL dating in the semi-arid Quaternary environments of NW Argentina which allowed us to account for the burial of alluvial surfaces after initial terrace development. Without the OSL burial ages, the TCN surface exposure ages that were determined would have significantly over-estimated the true age. The combined methods permit an internally consistent chronology of the timing of incision and alluviation in a basin and the calculation of storage and denudation rates for a basin that has experienced successive cut and fill sequences due to Late Quaternary tectonics and climate change. A second application involves developing chronologies for the glacial sequences in the semiarid Rongbuk Valley of Tibet. TCN exposure dating of moraine leucogranite boulders was combined with OSL dating of glacial and paraglacial deposits. For every glacial advance, the OSL ages are slightly older than the TCN ages but we which have successfully constrained the age of the glacial limits. Moreover, the ages also provide an indication of the longevity of a glacial limit before the onset of retreat and can constrain the ages of both retreat and readvance. The OSL dates also suggest that a pervasive inter-stadial deposit (~40ka) underlies the ~26ka and younger glacial and paraglacial deposits and provides an environmental reconstruction for an older event than would be impossible with TCN dating alone. Although there are caveats in how


both methods are applied, without the application of two dating methods in these projects, the chronologies would have been either incorrect or much less informative for environmental reconstruction. 1288 Paleoenvironmental Changes Recorded in a Lake Surrounded by Tropical Forest (South Brazilian Amazonia) Renato R Rodrigues1, Renato C Cordeiro1, Bruno J Turcq2, José S Seoane3, Renata O Zocatelli1, Patricia A Roeser1 1

Universidade Federal Fluminense, Brazil IRD-Bondy / Universidade Federal Fluminense, France 3 Universidade Federal do Rio de Janeiro, Brazil 2

Analysis of a core collected in Lago do Saci (Pará, Brazil) showed important changes in the paleoenvironmental history. This study was carried out in the region comprised between the city of Alta Floresta, in the Northern portion of Mato Grosso state, and the São Benedito region, located on the Southern portion of Pará state. This is a plain portion of the Central Crystalline Plateau and is covered by Dense Tropical Forest. Climate type is “Am” (Köppen`s classification), meaning humid with a very intense dry season, between June to August. The base of the sediments has been dated at 28260±270 14C yrs BP. For the core sampled at the margin of the lake (9.118214˚S, 56.265373˚W), six distinct sections were clearly identified. They consist of an upper organic-rich layer and a lower sandy rich layer, separated by four layers that represent transitional phases. The first phase, between 396 and 325 cm, is marked by a high concentration of sand, and is probably associated to a decrease in lake level, low organic matter and water contents (20–30%) and high bulk density (1–1.5g/cm3). The second phase, from 325 to 283cm, represents a transition phase probably associated with the beginning of a rise in the lake level. This phase showed an increase in the water content (30–40%), a decrease in the density (1.5–1g/cm3) and higher concentrations of clay and organic matter in relation to the first phase. At the third phase, between 283 and 240 cm, the density decreased (1-0.5 g/cm3) while water content increased (40–65%). The fourth phase, (240–220 cm), is marked by the deposition of clay, an increase in the density (0.5–1 g/cm3) and a marked decrease in the water content (75–55%). In the fifth phase (220–205 cm) the water content increases again (55–80%) while the density decreases (0.8–0.2 g/cm3). The sixth phase is thick (205-surface) and homogeneous, with the highest concentrations of organic matter, water content (75–85%), and the lowest values of density (0.15–0.5 g/cm3). It

probably corresponds to a rise in lake level, increasing the productivity of the system. Several others analyses (microscopic charcoal, 13C and 15N, metal concentrations, 14C dates, black carbon, chlorophyll) are currently being performed to elucidate the paleoenvironmental changes that have occurred in this region of Amazonia during the last 30,000 yrs. Our results will be compared with other researches done by our group as well as other research groups in the world, and could support models of paleoclimate changes in Amazonia. 1325 The Southern Westerlies during the Last Glacial Maximum in PMIP2 simulations Maisa Rojas1, Patricio I Moreno2 1

Departmnet of geophysics, university of chile, Chile Universidad de Chile, Chile

2

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The Southern Hemisphere westerly winds are an important component of the climate system at hemispheric and global scales. Variations in their intensity and latitudinal position through an ice-age cycle have been proposed as important drivers of global climate change through their influence on deep-ocean circulation and changes in atmospheric CO2. For almost twenty years the discussion on whether the southern westerlies shifted north, south, or whether they focused along a narrow latitudinal band has permeated through the paleoclimate literature. Proxy records from New Zealand, Australia, and the mid-latitude regions of South America have added to the discussion but have not provided a final solution. Here we analyze the behavior of the southern westerlies during the Last Glacial Maximum (LGM) using four coupled ocean-atmosphere simulations carried out by the Paleoclimate Modelling Intercomparison Project Phase 2 (PMIP2). Three out of four models indicate a decrease in the intensity of the westerly flow, both at the near surface and the upper troposphere, with no significant shift in the position of the maximum wind speed associated with the jet streams. Most of the models indicate important regional and seasonal heterogeneities, and a significant contribution of the surface topography in atmospheric circulation patterns. Consistently, all models simulate decreased precipitation over the Southern Hemisphere south of 40S, one of them (HadCM3) simulates a significant increase north of this latitude in the southeast Pacific Ocean. The results presented in this study indicate significant spatial variability in the westerly winds, an aspect not fully acknowledged in previous paleoclimate syntheses and simulations. 1137 Pollen records of alluvial sediments from central western semiarid region of Argentina: Potential and limitations for the reconstruction of vegetation history Leandro D Rojo1, Marta M Paez1, Marcelo A Zárate3 1

Laboratorio de Paleoecología y Palinología, Departamento de Biología, Universidad Nacional de Mar del Plata, Argentina 2 Departamento de Geología, Universidad Nacional de La Pampa, Argentina

Pollen analysis from lacustrine deposits is usually applied to reconstruct Quaternary vegetation history. However, pollen analysis from fluvial deposits has not been investigated as much as pollen from lacustrine ones because of pollen record biases associated to this system dynamics, and therefore there is not an adequate understanding of alluvial pollen analysis. In semiarid regions of central western Argentina, Late Quaternary fluvial and lacustrine deposits are present and provide the opportunity to carry out comparative studies in order to evaluate the potential of alluvial pollen for the reconstruction of vegetation history and past climate. The region is bounded westwards by Andean Ranges and eastwards by Pampean Ranges. It is caracterized by a climate gradient from west to east that goes from arid to semiarid conditions, and by a shrubby Monte and an arboreal Espinal vegetation, respectively. In this region pollen analysis from fluvial and lacustrine deposits were comparatively studied to highlight the potential and limitations of alluvial pollen. Pollen samples at different lithologic units from alluvial terraces at Tunuyán river (33˚28′S, 69˚01′W) in the west and lacustrine deposits at Salina del Bebedero shallow lake (33˚32′S, 66˚39′ W) in the east were collected and analyzed. The results show that alluvial sediments present more sterile samples and pollen abundance fluctuations related to a more episodic and instantaneous accumulation of sediments in these environments. Almost same taxa (Chenopodiaceae-Amaranthaceae, Asteraceae and Poaceae, except Ephedra) dominate the pollen assemblages in both sites, whereas some minor taxa are only present in fluvial system and others in lacustrine deposits. These differences are due to the distinct location of

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deposits along the environmental gradient or alternatively a difference in sediment accumulation. Therefore, alluvial pollen analysis as a tool for the reconstruction of vegetation history must rely not only on fluctuation of dominant pollen taxa but also on the presence/ausence of rare types associations. Based on these results fossil spectra are compared with surface pollen assemblages as modern analogue and an interpretation of past vegetation is presented. 0249 New insights into the formation of a high accumulation pelagic carbonate ridge on the modern Northwest Shelf outer ramp (Australia) Nadege Rollet, John Marshall, John M Kennard, Alix L Post, Graham A Logan, Emmanuelle Grosjean, Alison Hancock, Graham Logan Geoscience Australia, Australia

A survey of the Central Northwest Shelf, Western Australia, was undertaken in June 2006 to identify areas of potential hydrocarbon seepage above the Bedout High basement structure, and which coincides with the location of a seabed pelagic ridge. The concept tested during this study was that leakage and seepage of hydrocarbons could have influenced carbonate depositional trends in the area. In this context, the pelagic ridge was interpreted as a possible chemo-synthetic buildup related to seepage. Multiple datasets (multi-beam swath bathymetry, echo-sounder, side-scan sonar, sub-bottom profile) were acquired over the ridge together with seafloor video footage, and sediment grab and core samples. The northeast trending ridge follows the 200 m isobath, is roughly 300 km long and up to 40 m thick. The ridge has a steep outboard side to the northwest and a smoother inboard side to the southeast. The sediment grabs sampled mostly muddy sand to sandy mud with a high carbonate content (bulk ~90% CaCO3), and consist of benthic (43–45%) and planktonic (25–29%) foraminifera and pteropods (15–19%), plus minor amounts of mollusc and coral fragments. The sand fraction in the gravity cores (up to 5 m in length) is dominated by pelagic foraminifera and pteropods, with lesser amounts of benthic foraminifera, intraclasts, and glauconite. The ridge is comprised of four stratigraphic units mapped on sub-bottom profile data, which penetrate to 110 ms (twt). The general stratigraphic pattern shows asymmetric, landward-building lenses deposited on the top of an erosional surface. This surface is well below the lowstand depth reached during the Last Glacial Maximum (LGM). Aragonite needle-rich micrite has been previously dated from seabed sediments recovered on the outer margin of the ridge. These AMS 14C dates of approximately 19 ka suggest that the aragonite is relict and was precipitated during the LGM. The erosional surface at the base of the ridge outcrops on the northwest side of the ridge, and may suggest that this surface was formed in shallow water during the LGM. The newly acquired sediment samples recovered from the pelagic ridge provide new insights on its composition, age and formation. The absence of shallow gas and thermogenic hydrocarbons suggests that the ridge is not related to hydrocarbon seepage, but that its origin is probably linked with a change in oceanography towards the end of the LGM that has produced a narrow band of high productivity with sediment depositional rates of up to 2 m ka−1. 0056 Are land snails a suitable palaeoindicator for geo-chronological studies? Lea Romaniello1, Saverio Fiore2, Giuseppe Mastronuzzi1 1

Bari University, Italy CNR - Italy, Italy

2

In the reconstruction of the chronological formation of an aeolian dune belt, the radiocarbon method applied to land snail shells is the most diffused. However, radiocarbon analyses on sub-fossil land snail shells often furnish results suggesting that the 14C age anomalies may be due to ingested limestone particles by snails (aging effect). Previous studies indicated other anomalies sources: • Limestone trapped into shell by gastropods • CO2 exchange between gastropods and atmosphere after the Bomb Peak • CO2 adsorbed as the result of different diets.

We collected along the coasts of Southern Italy, at different distances from the shoreline, on different age substrata, living examples of Mediterranean land snails Theba pisana (Muller, 1774) and Cernuella virgata (Da Costa, 1778) that live for no more than two years. The shells were submitted for AMS analysis at CeDaD (Italy). In 10 modern samples, 8 samples gave an average age of 721 ± 40 BP and 2 yielded an apparent modern age. The d13C values for all samples fall within the range expected for plants growing on dunes. Investigation of 13C and 12 C values show that even these modern ages are not real and it is likely that these problems will have affected fossil snails. Two different sections of modern shells collected alive, were observed by SEM to look for limestone inclusions. Although these observations, no evidence was found for the existence of such inclusions. Thus, limestone particles in the shell structure cannot explain the aging effect. To investigate whether CO2 was adsorbed by snails that were living after the Bomb Peak and thus were influenced by it, we obtained a Theba pisana shell, collected whilst alive in the middle of 1800 AD. AMS analysis was performed on this sample by Geochron Laboratories, and it yielded an age of 1770 ± 40 14C yBP and a d13C of −4.4 ‰. This sample appears to be older than its real age and its d13C value is slightly higher than expected. Again, the age is overestimated and not explained by the Bomb Peak. We conclude that the cause of the aging effect in land snails living in Southern Italy is due to the diet. These findings suggest that land snails cannot be considered as useful palaeo-indicators for coastal evolution. Although land snails are good indicators of dune evolution, of climate changes and vegetation type. They could age the sediment until 1145±500 BP. 0324 The earliest Humans in northern Europe – timing, environment and why Britain? Jim Rose1, Ian Candy1, Jonathan Lee2, René Barendregt3, Brian Moorlock2, Richard Hamblin2 1

Royal Holloway, University of London, United Kingdom British Geological Survey, United Kingdom 3 University of Lethbridge, Canada 2

The earliest Humans in northern Europe occupied Britain as early as c.700,000 years ago. There are numerous records in eastern England all of which are associated with deposits of two major rivers that flowed eastward to the Southern North Sea delta. The sites form two groups: channel deposits which include derived human artefacts and thus only provide a minimum age for the presence of humans and floodplain


deposits that indicate the period of occupance. Critical sites associated with habitation include High Lodge, Happisburgh and Pakefield. Determining the age of the human presence has proved difficult but there is a convergence of results. Geomagnetic polarity has shown that all the sites are normally magnetized and therefore younger than 780,000 yrs BP. The association of Mimomys pusillus with the archaeology at Pakefield is considered to support an age of 700,000 for this site. The association of the archaeology with river aggradations which can be tuned to climate forcing suggests that the earliest hominids occupied Britain as early as c. 750,000 years ago. The soil and fauna associated with the archaeology at Pakefield points to the occurrence of a period of mediterranean-style seasonally warm and dry climate. At High Lodge and Happisburgh the evidence points to cool temperate climate conditions, cooler and possibly more continental than the present day. At each of these sites the evidence may only represent a brief instance in the long-term climate changes of the early Middle Pleistocene. However, all sites indicate high bioproductivity with the presence of large mammals, single thread river systems and relatively stable land surfaces. Geodynamically and geomorphologically there is sound reasoning for the presence and survival of human remains at this period of time. Firstly, the British land area was part of the continental land area with the southern North Sea delta extending from the eastern part of East Anglia to the area of Denmark and northern Germany. Secondly the earliest Happisburgh (MIS 16) and Anglian (MIS 12) glaciations crossed the region with exceedingly low basal shear stresses, and so failed to erode the underlying landscape as they did further east in continental Europe. Thus, Middle Pleistocene glaciation of eastern England provided a layer of till that protected the underlying archaeology until the present day. 0325 A processes-based terrestrial Quaternary stratigraphy for cool temperate latitudes Jim Rose1, Jonathan Lee2, Ian Candy1 1

Royal Holloway, University of London, United Kingdom British Geological Survey, United Kingdom

2

Since the last INQUA Congress there has been considerable debate about the terminology and timespan of Quaternary stratigraphy. This presentation seeks to step aside from this debate and consider the value of Quaternary stratigraphy and terminology for increasing our understanding of the ways that terrestrial environments have developed over the last c. 3 million years. This scheme is based on the processes that act on the landscape over any given period of time. In this scheme we propose that the processes operating in any given area are the product of climate modulated by rock type (the resisting agent) and relief (determined by tectonics and antecedent relief-forming factors). Climate can be generalized in terms of the scales and rates of change determined by orbital forcing. Climate change during precession cycles was small and insolation levels forced predominantly chemically and biologically driven processes. Obliquity cycles include patterns of climate change in which physical processes became more effective and high magnitude fluvial and slope processes re-enforced by periglaciation and glaciation in susceptible regions contributed to higher rates of landscape change and higher levels of coarser grained sediment transfer. Eccentricity cycles include climate extremes of longer duration and glaciation and periglaciation as major contributors to landscape change, sediment transfer and sediment mixing. The case is made that these climate-forced processes produce distinctive landform, sediment and soil assemblages which enable mapping and provide a basis for subdivision. In addition, two more subdivisions are proposed: the short

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period at Termination 1 when very rapid, highly variable and short lived climate change produced un-adjusted and fragmentary landforms and sediment bodies; the Holocene during which human activity has had the ability to produce the distinctive products of high energy processes (excavation etc.). This can be recognised by anthropogenic materials and forms. It is proposed that these five episodes be used as a basis subdividing the Quaternary. They are named according to their dominant processes as: Soils and Shallow Marine (precession forced – < 2.6 Ma), Major Rivers (obliquity forced – 2.6 to 0.9 Ma), Glacial/ Interglacial Cycles (eccentricity forced – 0.9 Ma to 15 ka); LGIT 15– 11 ka, and Holocene and Human Activity (11 ka to present). This scheme recognises the materials and forms that characterize the Quaternary, provides a conceptual basis (Earth surface processes) for understanding Quaternary environmental changes; allows prediction of information necessary for human activity, and it is easy to remember! 0326 The case for a mega-tsunami in the Mediterranean around c. 80 ka BP Jim Rose1, Edward J Rhodes2 1

Royal Holloway, University of London, United Kingdom The Australian National University, Australia

2

At a number of localities (Spain, Italy, Greece, Lebanon, Egypt, Tunisia) around the Mediterranean Sea, a massive boulder-bed forms part of the succession of Late Quaternary coastal margin sediments. This boulder-bed contains individual clasts of lithified beach sand or calcrete up to 2 m in diameter, and these clasts are mixed with more of the same material, marine shell fragments and sometimes pre-Quaternary rocks in a badly sorted sediment body, with a thickness in the order of c. 1 m. Most of the larger boulders have a sub-angular edge rounding but some of the smaller clasts are sub rounded and rounded. The boulder-bed can be traced over distances of 100s metres and in places can be seen to be associated with a palaeo-cliff. Where this cliff is less than vertical the boulder-bed may be draped over the cliff surface and thin in a landward direction, with the clasts becoming progressively less angular. The stratigraphic position of the boulder-bed is variable but can be shown to overly deposits of the Last Interglacial (MIS 5e) beach and be buried by aeolian, fluvial and slope deposits associated with cold episodes through MIS 3 and 2. The boulder bed is also distinguished by its position above well developed polygons. These are formed in beach sand and are infilled with carbonate cement. The polygons are uniformly developed, although in cases the upper parts of some is truncated. A number of dating methods have been applied to determine the age of the event which deposited the boulder bed (AAR, OSL and ESR) but a wide scatter of ages has been obtained, possibly due to the derived nature of the material being dated. However the modal age suggests that the event most likely occurred about 80 ka BP. It is proposed. This presentation seeks to explore the origin and significance of the boulder-bed and the polygons. It is proposed that the boulder bed is a mega-tsunami deposit formed when sea-level was substantially below the present level and capable of transporting clasts much larger then the Dec. 26th 2005 Indian Ocean tsunami and that the polygons a desiccation features caused by a massive pre-tsunami drawdown, with calcrete accumulating in the polygonal void after the tsunami event. Discussion of this proposal will be welcomed.

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0494 The Spring Event: results from a new wireless autonomous, multi-sensor subglacial probe Kathryn C Rose, Jane K Hart University of Southampton, United Kingdom

The nature of the subglacial environment is still an area within glaciology that is not yet fully constrained, largely due to the inaccessibility of this zone. The presence of a deforming bed is of particular importance because it denotes specific basal conditions that act to influence, for example, glacier dynamics, sedimentology, ice sheet modelling, and responses to external climate forcing. As a result, ongoing investigation into the nature of the subglacial environment and improvements in the techniques used to monitor this zone are essential. This project has drawn upon the use of networked microsensor technology applying it, for the first time, to a glacial environment. A series of probes have been developed to represent subglacial clasts within the deforming bed. When inserted, via boreholes, at the ice-bed interface they use on board miniaturised sensors to monitor basal conditions, including temperature, pressure and tilt. They act as autonomous wireless units, relaying gathered information relating to the mechanical and physical properties of the bed to the surface via radio transmitters. This allows more realistic, continuous monitoring of the subglacial environment over time scales of at least a year. This data can then be uploaded onto a server, such as the Internet, and accessed by researchers globally. To date, research using these probes has taken place at Briksdalsbreen glacier in southern Norway. Three summer field seasons have been carried out and data has been received from numerous probes, resulting in over two year’s worth of data. In particular, continuous records for pore-water pressure have been obtained. Recent analysis suggests that spring variations in pore-water pressure reflect a seasonal reorganisation in the morphology of the subglacial drainage system, known as the ‘Spring Event’. A transition is evident between a constricted low capacity winter system and a well connected, high capacity summer drainage regime. This evolution is marked by pressure increases, diurnal pressure fluctuations and a sudden increase in glacier motion via sliding. However, this relationship is complicated by temporal and spatial variability, not only in the morphology of the subglacial drainage system, but also in the water inputs into that system. Comparison with other records reflects differences in the timing of the spring event and the nature of the winter drainage system at Briksdalsbreen. The Spring Event reflects the potential for subglacial instability and raises questions about the importance of these early seasonal pressure fluctuations to rates and mechanisms of glacier motion and melt. 0659 Development of proglacial lakes in Eastern Baltic Alar Rosentau1, Jüri Vassiljev2, Tiit Hang1, Volli Kalm1, Leili Saarse2, Avo Miidel2 1

Institute of Geology, University of Tartu, Estonia Institute of Geology, Tallinn University of Technology, Estonia

the east and a proglacial lake in the Gauja basin (Latvia) in the west. Following to the SIS retreat and landuplift the connection between Glacial Lake Peipsi and Privalday Lake was closed, but connection route with the proglacial lake in the Gauja basin was shifted to the northward. About 13.3 cal. kyr BP the Baltic Ice Lake (BIL) was formed in coastal areas of Latvia, Estonia and NW Russia, represented by the highest shoreline in this area. Evidence demonstrates that BIL had the same water level as Glacial Lake Peipsi, because these water bodies were connected via strait in the central Estonia. As this strait compensated for the water level differences between Glacial Lake Peipsi and BIL, the subsequent further merging of proglacial lakes around 12.8 cal. kyr BP in north Estonia did not result in catastrophic drainage, as earlier proposed. The separation of Glacial Lake Peipsi from the BIL is explained by lake drainage through Narva River valley concurrently or slightly before the final drainage event of BIL at 11.6 cal. kyr BP. 1337 Climate dynamics in the polar-front zone; evidence from lake sediments from South Georgia Ninis G Rosqvist1, Sarah Davies2, Steve Moreton3, Melanie Leng4 1

Stockholm university, Sweden University of Wales Aberystwyth, United Kingdom 3 NERC Radiocarbon Laboratory East Kilbride, United Kingdom 4 NIGL British Geological Survey Notthingham, United Kingdom 2

Climate information derived from high-resolution terrestrial archives from the southern polar front zone has the potential to improve climate reconstructions because significant atmospheric and oceanic climate boundaries determine the climate of this region. Here we present results from a multi-proxy study of lake sediments obtained from South Georgia, located south of the Antarctic convergence at 54˚E, 36˚W. The lakes are strategically located on the north-east coast of South Georgia, on the Barff Peninsula, Cumberland East Bay, and on the Tonsberg Peninsula, Stromness Bay. Basal dates show that the deglaciation had commenced by 18500 calendar years BP and that the glaciers had retreated well within the fjords by 12000 calendar years BP. Results from analysis of trace elements (XRF) reveal that a major increase in certain trace elements occurred as the lake was exposed due to ice retreat from the Barff Peninsula site. The XRF results also show that the input of glacigenic minerogenic particles almost completely ceased around 8000 at this site. An increase in organic content and changes in carbon and nitrogen isotopes show that conditions for lake productivity improved at this time both at the Barff and Tonsberg sites. Simultaneously the composition of oxygen isotopes in diatom silica became enriched indicating warmer lake waters. 1339 Climate variability over the last 1000 years in Northern Scandinavia: inferences from lake sediment oxygen isotopes in biogenic silica and authigenic carbonates

2

GIS-based palaeogeographic reconstruction of the development of the large proglacial lakes in eastern Baltic during the deglaciation of Scandinavian Ice Sheet (SIS) is presented. Late glacial shoreline database and modern digital terrain model were used for palaeoreconstructions. Timing of the proglacial lakes were derived from the ages of the ice marginal positions and varvochronology. The study reveals that about 14.7 cal. kyr BP Glacial Lake Peipsi was formed in eastern Baltic. This lake shared strait-like connections with Privalday Lake (NW Russia) in

Ninis G Rosqvist1, Melanie Leng2, Christina Jonsson1 1

Stockholm university, Sweden NIGL British Geological Survey, Nottingham, United Kingdom

2

Climate in Scandinavia is to a large extent dictated by the atmospheric circulation over the North Atlantic, which in turn is governed by ocean circulation dynamics. This area is therefore key for reconstructions of past climate variability with the aim of identifying and separating forcing factors. Here we present the first high resolution lake sediment


records of climate variation based on the oxygen and isotope composition of biogenic silica and authigenic carbonate for northern Scandinavia. Modern lake-water isotope data indicate that controls on its oxygen and hydrogen composition are unlikely to be evaporation or temperature, and its variations must therefore reflect changes in, or at the source of precipitation. Because substantial and persistent changes of the isotopic composition of the precipitation are required to change the mean annual isotope composition of lake surface water, we argue that the recorded changes were significant and that the recurrence of such changes would greatly affect future regional climate conditions in the North Atlantic.

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the ocean stratigraphy (Cromerian complex of the continental stratigraphy), but the interpretation remains still open. In any case, the pollen data highlight the sensitivity of the Piànico-Sèllere Basin sedimentation in recording minor climatic fluctuations and related abrupt environmental changes. 0981 Stratigraphy and geochronology of Late Pleistocene valley fill deposits in the Hope Valley, Southern Alps, New Zealand Henrik Rother1, James Shulmeister2, Uwe Rieser3 1

1294 The palaeobotanical record (pollen and plant macrofossils) of the Piànico-Sèllere Middle Pleistocene lacustrine succession (North Italy) Sabina Rossi1, Jacques-Louis de Beaulieu2, Edoardo Martinetto3, Cesare Ravazzi4, Maurice Reille2, Elena Vassio5 1

Dip Scienze Chimiche e Ambientali, University of Insubria, Como, Italy IMEP UMR 6116 CNRS, Europole Méditerranéen de 3l’Arbois, Aix-enProvence, France 3 University of Torino, Italy 4 C.N.R. - IDPA, Milano, Italy 5 Dip Scienze della Terra, University of Torino, Italy 2

Close to the Iseo lake, the Piànico-Sèllere palaeolake (Lombardy), deeply cut by the Borlezza river, is known since the 19 th century for its rich plant macrofossil assemblages. Their study led to general consensus on a “Riss-Würm” age for this formation (e.g. Lona and Venzo, 1957). The need of new evidences has been the starting point for an international interdisciplinary research project by the Piànico-Sèllere Working Group (PSWG) including sedimentology, varves analysis, palaeomagnetism, tephrochronology and geochronology beside palaeobotany. The dating of two tephra layers provides contradictory ages (ca 400 ka or ca 800 ka) which exclude an attribution to the last interglacial. The pollen analysis of several outcrops, correlated thanks to the counting of annual laminations and the identification of marker layers, led to the identification of three major temperate periods (namely “Piànico-Sèllere Interglacial, Clusone I interstadial, Clusone II interstadial) alternating with stadial phases. The forest dynamics during the temperate phases are marked by the abundance of Quercetum elements, Carpinus and Abies. Pinus, Picea and steppe elements expand during stadial episodes. This succession illustrates an “Interglacial complex” and may be compared with similar events documented by most of the Middle and Upper Pleistocene Marine Isotopic Stages. However, correlation based on the pollen content with other continental “key-sites” is not easy, as different geographic regions can have distinct vegetation dynamics and presence/absence of certain species. As the Piànico fossil flora does not display taxa typical for the Early Pleistocene(e.g. Carya, Liquidambar, Eucommia), except occasional grains of Carya, Pterocarya and Tsuga, an attribution to an Early Pleistocene interglacial can be excluded, as confirmed by other Italian sites. Even though the pollen content (Carpinus, Abies, Buxus abundance; Fagus absence) and the general structure (a long interglacial followed by two interstadials) could be similar to those of the Eemian (=“RissWürm” auct.), the Piànico-Sèllere interglacial has a different dynamic (all the species spread simultaneously; exotic taxa among macrofossils; cold event in the middle of the Interglacial). All the data, and the macrofloral record identifying a good number of locally extinct taxa, concur with a Middle Pleistocene attribution. The length and the structure of the interglacial could bring to a correlation with the MIS 19 of

Institute for Environmental Research, Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, Australia 2 Department of Geological Sciences, University of Canterbury, Christchurch, New Zealand 3 Luminescence Dating Laboratory, Victoria University of Wellington, New Zealand

Here we present sedimentological descriptions and infrared stimulated luminescence (IRSL) ages from depositional valley fill exposed in the Hope Valley of the Southern Alps, New Zealand. The investigated valley reach is characterized by a thick fill sequence of paired and unpaired alluvial terraces that extend to more than 450 m above modern river level. The most extensive fill remnant is a roughly 12 km long continuous terrace surface located ~160 m above the modern river. The terrace is connected to a latero-terminal moraine complex and it has widely been suggested that the terrace and its aggradational sediment column formed during the Last Glacial maximum (LGM). Our study sites were selected based on suitability for IRSL dating and the desire to log the vertical span of the fill stratigraphy at several locations in the valley. Results show that fill deposits in the Hope Valley are sedimentologically and structurally diverse comprising deformed and undeformed morainic, (glacio-) fluvial, (glacio-) lacustrine, till, debris flow, fan and aeolian deposits. The overall sedimentological arrangement indicates a range from glacial to proglacial to paraglacial deposition in the general context of a retreating / stagnating valley glacier system. Numerical age control for five of the investigated sections was obtained by IRSL dating on fine grained silt and sand deposits. Results demonstrate that a volumetrically significant portion of the fill sequence in the valley pre-dates the LGM and instead represents deposition during OIS 5 and OIS 3. LGM deposits are volumetrically small and occur only as a thin cap over OIS 5/3 deposits. At one site in the valley a thick sequence of OIS 6 glacial deposits was found. The overall results allow a detailed reconstruction of repeated phases of large scale valley infilling and re-exhumation over the last two glacial cycles. 1043 A conceptual model for New Zealand glaciation and 10Be exposure ages from moraine sequences in the central Southern Alps, New Zealand Henrik Rother1, James Shulmeister2, David Fink1 1

Institute for Environmental Research, Australian Nuclear Science and Technology Organisation (ANSTO), Australia 2 Department of Geological Sciences, University of Canterbury, Christchurch, New Zealand

The response of Southern Hemisphere glaciers to Quaternary climate forcing has become a prime research focus in the debate on the dynamics of global climate systems. Present models addressing this issue suggest that the timing and extent of past glaciations in New Zealand

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were forced through Milankovitch style cooling transmitted from the Northern Hemisphere (NH) either via oceanic or atmospheric pathways. We suggest an alternative approach. Our model is based on the observation that extensive Quaternary glaciation under the perhumid conditions of the Southern Alps can be generated with very moderate cooling of the order of 2–4 ˚C. At such cooling several meters of precipitation would convert from rainfall to snowfall thereby quickly driving drastic increases in ice accumulation. The required climatic conditions could be caused by changes in synoptic climatology alone, specifically via enhanced regional flow of moist westerly air masses over New Zealand, which would lower temperatures while maintaining very high precipitation totals. This implies that Northern Hemisphere climate forcing may not have been the exclusive driver of glaciations in New Zealand. We suggest that synoptic style climate variations are more consistent with the available field evidence and provide a better explanation for at least some Late Quaternary glacial events, in particular during the Last-Glacial-Interglacial-Transition (e.g. Younger Dryas and/or Antarctic Cold Reversal). If our conceptual model is appropriate, the timing and extent of sub-orbital glacial chronologies in NZ should differ from glacial chronologies in the NH. To address this question we collected a series of rock samples from moraine sequences in the Hope-Waiau valley system of the central Southern Alps for 10Be exposure age dating (SED) of past ice advances. All samples were prepared and measured at the ANTARES accelerator facility of the Australian Nuclear Science and Technology Organisation (ANSTO) in Sydney. Preliminary results from the Hope-Waiau system provide age control for the last glacial retreat and indicate that recession from LGM positions commenced close to 20–19 ka similar to other New Zealand glaciers (e.g. Cobb Valley, Shulmeister et al. 2005) but somewhat earlier than in the NH. The recession was interrupted by short lived ice re-advances at ~18 ka (Glynn Wye moraine) and during the LGIT at ~13 ka (Lewis Pass moraine). It is planned to expand the exposure age dating campaign into other glacial valleys of New Zealand and use other paleo-environmental archives to further test our conceptual model. 1058 Atmospheric circulation changes evidenced by cyclic dust deposition in the US Great plains (Nebraska, USA).during Upper Pleistocene Denis-Didier Rousseau1, Pierre Antoine2, Stephane Kunesch2, Julien Rossignol1, Andreas Lang3, Susan Packman3, Christine Hatte4 1

Institut des Sciences de l’Evolution, CNRS-Université Montpellier II, case 61, pl. E. Bataillon, 34095 Montpellier cedex 05, Fr, France 2 Laboratoire de Géographie physique, UMR CNRS 8591, 1, Place Aristide Briand, 92 195 Meudon cedex, France, France 3 Department of Geography, University of Liverpool, Liverpool L69 7ZT, U.K., United Kingdom 4 Laboratoire des Sciences du Climat et de l’Environnement, UMR CEA-CNRS 1572, Domaine du CNRS, bat 12, F-91198 Gif-sur-Yvette, F, France

The Peoria Loess unit is a well-defined stratigraphical unit in the Upper Pleistocene of the North American Quaternary. Deposited between 30–25 ka and about 12 ka ago. It has been indicated that this unit shows the highest ever-worldwide depositional rate for eolian deposits, as its thickness varies, near the source area, between 19 m and 46 m, extreme values that are not even recorded in the Chinese sequences. The results of our present investigation indicate that this particular unit is not homogenous. Its shows different subunits where lithological variation can be observed through the occurrence of embryonic gley horizons alternating with laminated loess. Furthermore the analysis of the grain

size shows cycles corresponding to variations in the eolian dynamics responsible of the dust transport and deposition. A grain size index interpreted as characterizing the eolian dynamics (higher values corresponding to stronger wind conditions) shows higher values than those observed in Europe. A comparison of this index is proposed with the Greenland dust and d18O records. It shows that the main climatic history, as corresponding to events occurring mainly in North Atlantic domain, is recorded in the Peoria Loess deposits. However, the variation in the magnitude of the eolian events indicates a different behavior than in European loess sequences. The strong North Atlantic coolings as expressed by the Heinrich events, recorded in Europe by the coarser deposits, are not discriminated in the sequence by coarser material in the studied sequence, and so better follow observations obtained off California for the north East Pacific domain. 1234 Record of the Dansgaard-Oechger events in European eolian deposits Denis-Didier Rousseau1, Pierre Antoine2, Christine Hatte3, Andreas Lang4, Ludwig Zoeller5, Markus Fuchs5, Natalia Gerasimenko6, Slobodan Markovic7 1

Institut des Sciences de l’Evolution, CNRS-Université Montpellier II, case 61, pl. E. Bataillon, 34095 Montpellier cedex 05, Fr, France 2 Laboratoire de Géographie physique, UMR CNRS 8591, 1, Place Aristide Briand, 92 195 Meudon cedex, France, France 3 Laboratoire des Sciences du Climat et de l’Environnement,, UMR 1572 CEA/ CNRS, Avenue de la Terrasse, 91198 Gif sur Yvette Cedex, France 4 Department of Geography, University of Liverpool, Liverpool L69 7ZT, U.K., United Kingdom 5 Universität Bayreuth, Lehrstuhl für Geomorphologie, Universitätsstr. 30, D95440 Bayreuth, Germany, Germany 6 Geomorphology Department, National Taras Shevchenko University of Kyiv, Glushkova 2, Kyiv, GSP 8600, Ukraine, Ukraine 7 Quaternary Research Center, Trg Dositeja Obradovica 3, 21000 Novi Sad, Serbia., Yugoslavia

Loess deposits are covering a wide part of Northern Europe, an area expanding from the coasts of Brittany to the Russian plain. Since ten years or so, efforts have been concentrated in selecting European loess sequences along a main W-E transect at roughly 49°N of latitude, from Northern France to Ukraine. First it has been demonstrated that the main eolian deposition over Europe occurred during the time interval comprised between 38 and 15 kyrs. Second, the high-resolution study of the sequences indicates the alternation of well-developed soils, embryonic or tundra gley paleosols and loess deposits. The succession of these different units show a particular pattern which is correlated with the DO sequence including Greenland IS 8 to 2, even if other shorter intervals, not labeled as DO events, are expressed in the eolian deposits. This correlation is supported by (i) OSL and AMS dates on the organic matter preserved in the loess units, (ii) mollusk assemblages variations, (iii) d13C on organic matter preserved in the loess, and (iv) grain size analysis. We present here the last results of our investigation showing that the DO events preserved in the European loess sequences correspond to interval of low eolian regime, showing higher moisture than during the deposition of the dust. The duration of the DO events also influence the nature of the associated units (paleosol, tundra gleys or embryonic soils, loess) whereas the Heinrich events in between DO events are intervals of dry and windy conditions expressed by coarser material.


1242 Inverse modeling of biomes and 13C to reconstruct the Grande Pile Eemian record: Characterization of an instable climate interval Denis-Didier Rousseau1, Christine Hatte2, Joel Guiot3, Patrick Schevin1, Danielle Duzer1, George Kukla4 1

Institut des Sciences de l’Evolution, CNRS-Université Montpellier II, case 61, pl. E. Bataillon, 34095 Montpellier cedex 05, Fr, France 2 Laboratoire des Sciences du Climat et de l’Environnement,, UMR 1572 CEA/CNRS, France 3 CEREGE, UMR 6635 CNRS/Université P. Cézanne, Europôle Méditerranéen de l’Arbois, BP 80-13545 Aix-en-Provence, cedex 04, France, France 4 Lamont-Doherty Earth Observatory of Columbia University, Palisades, N.Y. 10964, USA, United States

A new method to reconstruct past climatic conditions from pollen and isotopic data is applied to new counts from a new core, GP21, in the Grande Pile area. The climatic conditions reconstructed concerns the 130 to 100 kyr interval, which includes the Eemian lato sensu. To do so, we applied the Biome4 vegetation model in inverse mode to both pollen counts and d13C values. The method considers the d13C, measured in parallel to the pollen samples, as another constraint for the model. First the biomes and the d13C simulated by the model are compared with the biome allocation, yielded after the biomisation of the pollen data, and the measured d13C considered after a determined degradation effect on the preserved organic matter d13C. This procedure allowed us the reconstruction of the mean annual temperature and precipitation and of the warmest and coldest months mean temperatures. We show that during the Eemian itself, the precipitation indicates similar values to the modern ones with no particular variation, contrary to the cold stadials and the penultimate glaciation characterized by very low values. Conversely the temperature estimates indicate different pattern. Indeed several oscillations are identified during the studied interval. The peak interglacial values are reached early at about 125– 124 kyr, but two other warm intervals are identified afterwards. The variations of the temperature estimates seem related to sea surface oscillations occurring in the North Atlantic region and support the reconstruction of Northern Hemisphere ice-sheets building timing. Furthermore seasonality variations are also identified through the comparison of the warmest and coldest month temperatures, which indicate a different pattern during the studied interval. 0489 The QUAVIDA synergy: Quaternary fire, vegetation and climate change in Australasia Cassandra Rowe1, Rebecca Fraser2, Sandy Harrison1, John Dodson3

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future climate changes. QUAVIDA will do this by using state-of-theart earth system models in hypothesis-testing mode, running simulations for specific times in the past but with different model components operative and using different scenarios of external and internal forcing. In order to evaluate and interpret these simulations, comprehensive data sets describing palaeoenvironmental conditions at key times in the past will be required. Thus, the first major focus of activity within QUAVIDA has been the creation of a comprehensive database of palaeoenvironmental information from Australasia, covering the last 70,000 years. The database contains radiometrically-dated pollen, phytolith, plant macrofossil, stickrat midden, carbon isotope and charcoal records. Interrogation of this database will yield benchmark reconstructions of vegetation patterns and fire regimes for the evaluation of the model simulations. Using more than one source of palaeoenvironmental information allows differences in the temporal and spatial scale of different kinds of observations to be taken into account in making reconstructions. It also allows for the fact that different sources record different aspects of climate and/or environmental changes. This presentation will introduce QUAVIDA, the methods and preliminary results of the palaeo-data synthesis, and discuss the project’s contribution to the international earth-modelling community. 1121 The Australasian Pollen and Spore Atlas: A new online relational database Cassandra Rowe, Simon G Haberle, Geoffrey S Hope, Stuart Hungerford, Markus Buchhorn Australian National University, Australia

The Australasian Pollen and Spore Atlas enables online accessibility to the largest collection of pollen and spores information in the Australasian region that is currently located at the Australian National University. This is a searchable database that is accessible over the web and suitable for professional as well as the technical novice involved in pollen and spore identification. Novel approaches to the federation of other smaller existing pollen and spores databases will result in an ever expanding and freely available resource. The information made available will increase research capacity across the region through a reduction in duplication and enhanced accessibility to key knowledge available in the Australasian Pollen and Spore Atlas. Key features of the database are illustrated on the poster and an online demonstration will be available during the conference. 1415 Late Holocene ecosystem variability and anthropogenic activities in the Savanna biome of Southern Kenya

1

University of Bristol, United Kingdom University of Wales, United Kingdom 3 Australian Nuclear Science and Technology Organisation, Australia 2

Mathai S Rucina1, Marchant R Alstair2, Laura Downton2, Mwihaki V Muiruri1, Hooghiemstra Henry3 1

QUAVIDA is a new project which aims to understand the interactions among vegetation structure and function, climate and fire regimes during the Late Quaternary. The project targets Australasia as a critical area in the development of a global picture of environmental change. Australasia has experienced major wet/dry, temperature and atmospheric CO2 fluctuations in the past; human arrival and occupation have also had a substantial environmental influence. Much of the vegetation within the region is fire-prone (and fire-adapted), with fire management long and widely practised. We need to understand the natural climate variability, disentangle the role of humans in past changes and investigate how plant types, vegetation and fire regimes will respond to

National Museums of Kenya, Kenya University of York, United Kingdom 3 University of Amsterdam, The Netherlands 2

Palaeoecological records from dry environs are relatively rare due to poor accumulation of sediments. Pollen and charcoal analysis are presented from Namelok Swamp southern Kenya to reveal anthropogenic activities and climate variability over the last 2250 yr BP. One of the main changes is a shift to open woodland dominated by Acacia and grasses that appears to be a result of increased fire intensity in the savanna biome. This transition may be linked to desire for new pasture and to control animal diseases. An increase in Poaceae reflects a period

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of disturbance and increased land cover change due intensive clearance; this is also associted with a decrease in arboreal taxa such as Syzygium; such an increase may be linked to pastoralists exploiting savanna and using the species in iron smelting. Alternatively the climate could have been drier reducing suitability for growth of the taxon. However, the species showed some increases, possibly as a result of a wetter climate; a similar trend is recorded by the increase of Cissampelos. The low percentages of Anthocleista, Celtis and Podocarpus are indicators of reduced precipitation in the environs and variability in climate. The rise in Amaranthaceae/Chenopodiaceae and Asteraceae reflects disturbance possibly linked to cultivation in the savanna as agriculture expanded into the wetland areas.

record (190–257 cm) and more-less comparable scores for the steppe and taiga biomes at 40–170-cm depth. This pattern suggests greater than present forestation of the landscape in the middle Holocene associated with a warmer and wetter climate. The small organic remains submitted for the AMS dating will help to establish accurate age-depth model for the studied record in the near future. 1109 Reconstruction of palaeogeography of Pleistocene Interglacials according carbonates content Eugenija Rudnickaite Department of Geology and Mineralogy of Vilnius University, Lithuania

0110 Vegetation and climate of Northwest Mongolia (Hoton-Nur lake) during Late Glacial and Holocene reconstructed from pollen data Natalia A Rudaya1, Pavel E Tarasov2, Andrei A Andreev3, Ivan A Kalugin4, Andrei V Daryin4, Narantsetseg Tserendash5 1

Institute of Archaeology and Ethnography SB RAS, Ak. Lavrentieva 17, Novosibirsk, 630090, Russia, Russia 2 Free University of Berlin, Institute of Geological Sciences, Palaeontology Department, Malteserstr. 74-100, Building D, Berlin, Germany 3 Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A43, 14473 Potsdam, Germany, Germany 4 Trofimuk United Institute of Geology, Geophysics and Mineralogy SB RAS, Ak. Koptyuga 3, Novosibirsk, 630090, Russia, Russia 5 Institute of Geology and Mineral Resources of MAS, 210351 Enkhtaivnii orgon choloo 63 Bayanzurkh duureg, Ulaanbaatar, Mongolia, Mongolia

Hoton-Nur Lake is located in the northern part of the Mongolian Altai at 2083m a.s.l. Sharp continental climate which prevails in Northwest Mongolia is characterized by small amount of precipitation, permanent winds, large amplitudes of seasonal and day temperatures. Modern vegetation of area is represented by high-mountain dry steppes. In the northern part of lake cold-tolerant grass and forb steppes are widespread in combination with cryophyte Kobresia- and sedge-meadows. Siberian larch is a dominants tree species forests and small patches of larch forests with Picea obovata grow at the mountain slopes southwest of the lake and in the river valleys. The mountain tundra occurs above 3000m. A 257cm core was taken from a 35-m depth in the central part of the lake. A total of 122 pollen samples were analyzed with a time-resolution of ca 25–100 years. Results of pollen analysis are displayed in the pollen diagram. The lower part of the sediment core has a very low pollen concentration and is characterized by high contents of herbaceous pollen (Chenopodiaceae, Artemisia and Cyperaceae). That allows reconstruction of the widely spread late Pleistocene high-mountain dry steppe and Kobresia-meadows. Contents of arboreal pollen and especially pollen of Picea obovata increase in the middle part of core. The share of arid herbs and semi-shrubs decreases. In the upper (Holocene) part of the core pollen spectra are characterized by high contents of arboreal pollen produced by Picea obovata, Pinus sibirica, P. sylvestris, Larix sibirica and Abies sibirica. Pollen of shrubs is rare and mainly consists of Betula rotundifolia. Non-arboreal vegetation is represented by Artemisia, Chenopodiaceae, Poaceae, Cyperaceae species. The role of spore-bearing plants in the analyzed spectra is insignificant. Significant decrease in the content of coniferous pollen and increase in herbaceous pollen in the spectra of the upper 30-cm part of the core reflect vegetation and climate conditions similar to modern. A biome reconstruction method was applied for the vegetation reconstruction following Tarasov et al. (1998). The reconstruction reveals high scores for the cool steppe biome in the lower part of the

For reconstructions of palaeoclimatic conditions and palaeosedimentary environments content of carbonates in the sediments was studied. The stratotype outcrops and drill cores samples of various interglacial sediments were investigated in Lithuania. The carbonates analysis of sediments done according V.N.Shczierbina (1958) method improved by us (Rudnickaite, 1980). Not only calcite but also dolomite could be determined using this method. Total carbonates content determined by method used here usually is higher than determined by other techniques like Kozlovskis or titration etc. The carbonates content of interglacial sediments was determined for bulk sample. The latter circumstance should be considered for palaeoreconstructions. Moreover, more precise conclusions about climatic conditions of sedimentary environment could be made, when calcite and dolomite quantities are known. The carbonate content was compared to spore and pollen data. The direct relationship was noticed between the variation of total carbonate content and interglacial vegetation development sequence, caused by climate. Maximal carbonate content in the various interglacial sediments coincides with the climatic optimum phases of vegetation. The decrease carbonate content related to the decrease of climate temperature reflected in composition of vegetation. Applying carbonate content data is important to consider overall basin regime and sedimentary environments. The carbonates content could be at some extent elevated by allochthonous detrital part of sediments. During the initial stages of glacial retreat and advance the coarser allochthonous material is deposited. Therefore, the interpretation of carbonate content data should be complex. Otherwise it could be misleading. The origin of carbonates of various interglacials was quit different in many aspects, because the climatic conditions, vegetation and fauna evolution were different in Lithuania. The carbonates in Pleistocene Interglacial lacustrine deposits reflect the geochemical evolution of the landscape. The vertical variation of carbonates of interglacial lacustrine deposits is notable not only in the sediments of the same age but also in the sections of different age. The comparison of calcite and dolomite curves enables to make more precise palaeogeographical interpretations. The carbonates content determination is recommended for lacustrine deposits. It is advisable to do it prior to making time-consuming pollen analysis. The combination of the mentioned techniques along with others would make the interpretations of palaeogeographical conditions of the Pleistocene Interglacials easier and more precise. The carbonates composition, quantity and the character of variation curves reflect sedimentary environments and past climate. The mentioned data enables to reveal general features of the sedimentary basin position in respect of glacier margin.


1005 The benefits of a multi-proxy approach to understanding charcoal presence and distribution across a 50,000 year record: Lynch’s Crater, northeast Queensland, Australia Susan Rule School of Geography and Environmental Science, Monash University, Australia

Charcoal provides a measure of disturbance of the vegetation by fire that can be natural or anthropogenic in origin. Fire and sclerophyll vegetation are dominant features of the Australia landscape and in combination are seen as a major factor in maintaining vegetation composition. However, it has been proposed that Australian Aborigines and their use of fire have been seen as the catalyst for the dominance of sclerophyll vegetation from the Late Quaternary to the present-day within more humid areas. Lynch’s Crater has been influential in this proposal with marked changes in the charcoal record corresponding to vegetation change from rainforest to sclerophyll vegetation. With the retrieval of a new core from Lynch’s Crater a major aim is to assess the nature and extent of human influence on the landscape relative to that of climate variability. This multi-proxy study, including pollen,non pollen palynmorphs, microscopic and macroscopic charcoal and macrofossils, spanning 50,000 years with an average sampling resolution of 63 years will allow assessment of the significance of variation that is uncertain in lesser resolved sequences and the use of macroscopic charcoal and macrofossil analyses in addition to pollen will allow refinement of taxon identification for many local taxa and more certain reconstruction of existing plant communities and environmental conditions especially the role of fire. One way to investigate the relationships between charcoal and fire and ultimately vegetation distribution is to see whether charcoal morphology can be used as an indicator of vegetation type. A modified version of Umbanhowar and McGrath’s experiment (2001), where a 2:1 ratio was used to separate cyperaceae/ poaceae taxa (elongated charcoal) from woody (blocky charcoal) taxa, was used on the macroscopic charcoal component. Preliminary results suggest a change of dominant fuel type does occur, with the base of the record dominated by elongated type charcoal and the Holocene section dominated by blocky type charcoal. However other components of the study, pollen, macrofossils and non pollen palynmorphs, have allowed for a greater degree of certainty regarding the extent and degree of biomass burning within the swamp environment. 0977 A high resolution record covering the last 50,000 years from Lynch’s Crater, northeast Queensland, Australia Susan Rule1, Peter Kershaw1, Simon Haberle2, Chris Turney3 1

School of Geography and Environmental Science, Monash University, Victoria., Australia 2 Research School of Pacific and Asian Studies Australian National University, Canberra., Australia 3 GeoQuEST Research Centre, School of Earth and Environmental Sciences, University of Wollongong, NSW., Australia

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components of the record and peat humification data indicate sub-orbital and orbital frequencies linked to long-term changes in ENSO in the tropical Pacific Ocean as well as suggesting strong inter-hemispheric ENSO connections. A new 50,000 year record at contiguous 2 cm intervals through some 8 m of sediment is designed to test and temporally refine this connection. This multi-proxy study, including pollen, microscopic and macroscopic charcoal and macrofossils, has produced just over 400 samples for each proxy with 30 radiocarbon dates that demonstrate a fairly constant rate of sedimentation. An average sampling resolution of 63 years allows investigation on a centennial timescale which is within the time-frame of present-day noted changes and within the turnover rate for some of the indicator species, rainforest (angiosperm/gymnosperm) canopy species, within the record. Preliminary results confirm vegetation change and biomass burning around 45,000 yrs BP with Araucariaceae showing the most substantial decline. Sclerophyll components dominate thereon until the Holocene, although rainforest components are present throughout though in low numbers. The presence of only microscopic charcoal through the latter part of this period may suggest a regional signal for the burning; this is also indicated by the low aquatic/swamp pollen concentration which suggests there may have been insufficient fuel on the swamp to carry a substantial fire. Within the Holocene, the high resolution record reveals a previously undetected abrupt reversal in rainforest expansion between approximately 7775 cal yrs BP and 7,000 cal. yrs BP with expansion of the sclerophyll component mirrored in the microscopic charcoal curve. 0111 Speciation timing and the origin of Neotropical biodiversity Valentí Rull Autonomous University of Barcelona, Spain

The tempo and mode of origin of extant neotropical species has been largely debated. One hypothesis (Q) is that they emerged primarily during the Quaternary (the last ~2 my), favored by the alternating glacial/interglacial climates. An opposite view (T hypothesis) proposes an older Tertiary origin linked primarily to paleogeographic changes. A thorough review of the available literature on DNA molecular dating shows that the Q-T debate no longer makes sense. The >1400 neotropical species dated so far appeared in a continual fashion since the Early Miocene (~24 my BP) to the Quaternary, thought speciation rates maximized during the Plio-Pleistocene (the last ~5 my), coinciding with a global climatic cooling. Paleogeographic mechanisms of speciation are relatively well known, but diversification processes linked to climate are still poorly understood. 0776 Changes in terrestrial carbon storage during the Little Ice Age and their influence on atmospheric CO2 concentrations: results from a dynamic global vegetation model Mats Rundgren1, Benjamin Smith1, Svante Björck1, Martin T Sykes1, Eduardo Zorita2, Eduardo Zorita2 1

Lynch’s Crater has provided a long and continuous pollen record through the last two glacial cycles from lake and swamp sediments and indicated changes in vegetation and biomass burning, around 45,000 yrs BP that are suggestive of initial impact of people on the landscape. Recent research has shown that through this period, demonstrated from intensive radiocarbon dating, peat accumulation was constant and sensitive to climatic variations. Spectral analysis on pollen and charcoal

GeoBiosphere Science Centre, Lund University, Sweden GKSS Research Centre, Geesthacht, Germany

2

Ice core records indicate that atmospheric CO2 concentrations were reduced by approximately 6 ppmv between c. 1600 and 1750 A.D. Because it is coincident with the Little Ice Age (LIA), this CO2 oscillation has been proposed to reflect a climatic response of the global carbon cycle. A combination of oceanic and terrestrial responses

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during the LIA is indicated by some climate-model experiments, while inverse modelling of CO2 and d13C records from ice cores suggest that low CO2 concentrations were primarily an effect of increased terrestrial carbon storage. Because it incorporates effects of changes in solar irradiance, CO2 concentration, temperature and precipitation on the carbon-storage capacity of vegetation and soil, we applied the dynamic global vegetation model LPJ-DGVM to estimate the impact of terrestrial biospheric processes on the CO2 evolution during the LIA. Output data for temperature, precipitation and surface radiation from a simulation with the global climate model ECHO-G forced by solar, greenhouse and volcanic forcing over the period 1550-1990 A.D. were used as input to LPJ. The CO2 concentrations assumed by LPJ were identical to those forcing the ECHO-G simulation. In addition to an experiment with variability of all four variables switched “on”, we performed factorial experiments with only temperature, precipitation, radiation or CO2 concentrations changing. Minimum global temperature and precipitation values are predicted for the Late Maunder Minimum (LMM; c. 1675–1715 A.D.) by ECHO-G. This is a particularly cold interval of the LIA characterized by low sunspot numbers, which illustrates the climatic influence of solar variability. Our LPJ results indicate that a climatic event like the LMM causes marked regional changes in vegetation and soil carbon stocks without having any substantial influence on global terrestrial carbon storage (+0.6 Gt). Carbon is redistributed within the terrestrial biosphere from high to low and mid latitudes, and soil processes are globally as important as vegetation processes in driving the changes in terrestrial carbon storage. The mechanisms of response of carbon storage to the climate perturbation were complex and varied regionally, with changes in carbon storage being effected primarily through temperature changes in boreal, polar and moist tropical climates, and through the water cycle in dry temperate and tropical climates. Both lower temperatures and lower precipitation were important in determining soil carbon storage globally. Based on our results, climatic responses by the terrestrial biosphere may explain only a minor part of the atmospheric CO2 decrease at the time of the LIA. 0550 Comparing Long Glacial Records from North and South America Nat W Rutter1, Jorge Rabassa2, Rene Barendregt3 1

Dept. Earth & Atmospheric Sciences, U. of Alberta, Edmonton, AB, Canada CADIC-CONICET, Ushuaia, C.C. 92, 9410 Ushuaia, Argentina 3 Dept. Geography, U. of Lethbridge, Lethbridge, ABN, Canada 2

The objective of this presentation is to compare, correlate, and estimate ages of glaciations between North and South America during the Quaternary period. These are then compared against the well-known Chinese loess/paleosol sequences and oxygen isotope deep sea records (DSDP-607) that record over 37 major cold-warm cycles over at least the past 2.5 Ma. The chronology of the loess/paleosol and deep sea records are constructed by various radiometric dating methods, paleomagnetic polarities and orbital time scales. The loess/paleosol and deep sea records are correlative over the last 1.6 Ma, and demonstrate that major climatic cycles were at least hemispheric in extent. Earlier correlations between these records are questionable. Although late glacial continental and Cordilleran events are well dated, age estimates and extent of glaciations for earlier events are speculative. What data there is, are based upon paleomagnetic polarities and fragmented and scattered glacial deposits, mostly till. Four major glacial events have been recognized in the Northern Cordillera and the southern Continental Plains areas. The oldest indicated glaciations in the Gauss chron, then two in the lower and upper Matuyama and two in the late Brunhes

chrons. In South America, the glacial record is much more complete, mostly found in the Andian/Patagonian areas of Argentina. This is due to the extensive datable volcanics interbedded with glacial deposits (mostly till). Over 15 glaciations have been resolved through radiometric dating (potassium/argon and argon/argon) and paleomagnetic polarities that are distributed in several intervals throughout the Quaternary. Because of the poor resolutions, comparing the timing of North American and South American glaciations is questionable. Only the late Brunhes glaciations can be correlated with any confidence. This demonstrates, however, that severe climatic conditions prevailed during these periods in both North and South America. When comparing the loess/paleosol sequences-deep sea oxygen isotope data with the glacial data, we can only correlate the glacial records of North and South America with Marine Isotope Stages 2 and either 6 or 8. Earlier glacial dates in both North and South America are at such a low resolution that we can only say that certain glaciations fall within an interval of several isotope stages. Much more work is necessary before we can confidently equate North and South American glaciations. 0278 Rotting in an Andosol in a montane swamp at Esuani, Papua New Guinea Bryan P Ruxton, Colin F Pain University of Canberra, Australia

Propanoates are over half way between kerogen and methane but still require an activation energy of 10 kcal/mol to go further. In swamps hydroxy hexyl members with fruity odours are derived by rotting of some plant materials. These chemicals are found in an Andosol on the upper slopes of Mount Victoria in Papua New Guinea. They formed in a poorly drained backswamp, now dissected to a terrace, at 2800 m above sea level. Depending on temperature, former anaerobic conditions may have allowed fermentation to take place. This was followed by mouldering on landscape dissection. The volcanic ash soil is believed to have been derived by Plinean eruptions from Mount Lamington Volcano 65 km to east in Holocene time. The present soil profile is a Hydrandept with a thick black A horizon over a bleached, pallid C horizon. The latter has rare organic carbon which has been analysed by gas chromatography. Fatty acids and propanoate esters dominate this fraction. Some benzene dicarboxylic acids along with octane and phthalates also occur. Some of the phthalates may be due to plastic contamination from sample tube lids. 0565 Late Quaternary production and accumulation of sediment on a storm influenced cool-water carbonate inner shelf David A Ryan, Brendan P Brooke, Michelle I Spooner Geoscience Australia, Australia

Cool water carbonate environments may be responsible for up to one third of the carbonate sediment produced on continental shelves, and are useful modern analogues for many geologically ancient deposits. The extensive southern margin of the Australian continent is recognised as the world’s largest modern example of a high energy, cool water carbonate depositional realm. A number of studies have suggested that Quaternary sediment production is largely influenced by oceanography, and that wave abrasion strongly limits sediment accumulation. Therefore, the outer-shelf, below the storm wave base, is thought to be the focus of sediment accumulation. The inner shelf is considered a zone of active sediment production due to the prolifera-


tion of carbonate secreting organisms, although few studies have investigated sediment production and accumulation in this energetic and dynamic environment. The relatively undocumented western margin of the Great Australian Bight (GAB) provides a useful study area to investigate the importance of inner shelves as carbonate ‘factories’. We collected surficial sediments, cores, video, shallow seismics, and multibeam sonar data on the inner shelf of the Recherche Archipelago, part of the western GAB, in order to better refine our understanding of inner shelf sedimentary dynamics during the Holocene transgression and highstand. The present seabed of this inner shelf features extensive areas of exposed flat-lying limestone that sits on the granite basement. The Pleistocene erosional surface is overlain by a coarse pecten and rhodolith dominated gravel lag. However, a 2–5 m thick veneer of Holocene sediment was mapped throughout much of the study area, particularly in association with basement topographic irregularities. Holocene sediments comprise cross-bedded gravelly carbonate sands dominated by fragments of calcareous algae (rhodoliths) and bryozoans, whereas a terrigenous-dominated beach dune and littoral deposit occurs inshore. Seismic evidence, and the presence of preserved palaeo-shoreline features suggests that slow but episodic aggradation of marine sediment has occurred over successive sea level cycles, despite erosion during lowstands. This accumulation is partly attributable to the sheltering effect of granite topographic highs, and subaerial cementation of the carbonate sediments. 1209 Vegetation dynamics and lake level change during the last 1000 years recorded in Lake Emakat, northern Tanzania Maria Ryner1, Karin Holmgren1, David Taylor2, Helena Öberg1 1

Department of Physical Geography and Quaternary Geology, Sweden Department of Geography, Trinity College, Ireland

2

The last millennium of environmental history of eastern Africa is a period when human impact commonly becomes visible in palaeoclimatological archives and most perceivable in vegetation proxies. We present a palaeoenvironmental reconstruction covering the last ~1000 years based on lake surface sediment cores from Lake Emakat located in Empakaai Crater in the highlands of northern Tanzania. Analyses of pollen and charcoal and dated fossil tree stumps, located in the lake and on the shore, reveal vegetation change related to both climate variability and human impact. The forested catchment of Lake Emakat, limited by the intact caldera walls, and surrounding plains are subjected to frequent burning with an increase in fire c. AD 1300 coinciding with the expansion of the Tatog people in the region, followed by a general trend towards an open wooded landscape in the 19th century associated with continuing human use of the caldera. The catchment pollen indicates slightly cooler and possibly drier conditions in the 14th century. The near shore vegetation, however, indicate recurrent lake level lowering c AD 900–1100, 1600–1800 and late 19th century representing drier conditions. The inferred drier periods in Lake Emakat are general in agreement with other palaeoenvironmental records in eastern Africa taking into account the difficulty with precise timing of events.

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1124 Late Quaternary environmental changes from diatom record of the Pyeongtaek Wetland in Korea Eunyoung Ryu1, Seong-Joo Lee1, Dong-Yoon Yang2, Ju-Yong Kim2, Bong-Jin Lee1 1

Department of Geology, Kyungpook National University, Korea Geological and Environmental Hazards Division, Korea Institute of Geoscience and Mineral Resources, Korea 2

Lacustrine fossil diatom records provide long time series of data on limnological and climatic conditions. These data are useful for establishing nature patterns of climate variability. Lake level fluctuations may reflect changes in moisture balance. Sediment samples from a continuous 3.1m profile in the Pyeongtaek Wetland in western coast of Korea were investigated in order to reconstruct the paleoenvironmental changes. To achieve this, we analyzed the sedimentological composition and diatom assemblages. Diatom record from Pyeongtaek Wetland on the western coast of Korea, reveals a series of well-defined changes in lake level and paleoenvironmental conditions during the Late Quaternary. From 21000 to 7000 yr BP, diatoms are not found. Diatom record begins at about 7000 yr BP and diatom assemblage composition showed changes around 5800, 5000 and 4500 yr BP. The dominant taxa are Aulacoseira distance, A. granulata, Cyclotella meneghiniana, Cymbella turmida, Eunotia pectinalis, E. praerupta, Fragilaria brevistriata, F. construens, and Navicula lanceolata together with abundant sponge spicules. Possible relationships between relative water levels and salinity clearly emerge from these assemblages. The dominated by Aulacoseira species and sponge spicules mean standing still water and lowering lake level. Through the Holocene, diatom assemblage underwent several changes linked to fluctuating limnological conditions. As slightly higher salinity was observed in the diatom record and especially presence of marine species of Diploneis smithii, the basin is thought to have experienced by slightly marine influence such as tidal one. Age-controlled diatom assemblages together with the sedimentological analysis indicate that the depositional environments have changed from lake to freshwater wetlands during the Holocene, which were resulted from lake level change and due to onset of aridity. Lake level changes reported from other sites in western Korea support the finding that reconstructed lacustrine processes directly linked to climate. In addition, the wetland seems to have exposed to the air several times as indicated by layers of silt and mud that did not produce diatoms. 0750 Mid-Holocene changes in Mediterranean Europe Laura Sadori, Marco Giardini Università di Roma, Italy

The purpose of this contribution is to discriminate climate forcing and human influence in the Mediterranean basin, using available independent data from several sites. Disentangling climatic and human impact is an everlasting minefield, in a matter where there is no easy solution. Potentially the best way to detect the cause of landscape change comes from combining continuous lacustrine records obtained as close as possible to prehistoric and historic sites. A complex pattern of climatic change prevailed across the Mediterranean regions throughout the Holocene. The vegetation history of the present interglacial period is characterized by a dynamic process in which all the pollen taxa found in the region have been there since the

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end of the last glacial. Most edible plants (potentially indicators of human activities) such as cereals, pulses and fruit trees are native to Mediterranean regions and are found during the whole Holocene and even before in the pollen diagrams. A good tool for disentangling climate change and human impact is the combined interpretation of pollen percentage and concentration data of which the latter may be considered as an estimate of the biomass amount. Dramatic and rapid tree pollen concentration drops found during forest phases of previous interglacials (when the human impact can be ruled out) in several sites of the region were interpreted as vegetation responses to climate changes. Holocene pollen concentrations changes cannot be univocally ascribed to humans. The possibility of human induced fires conditioning the vegetation has been checked using micro-charcoals as indicators of forest fires or human presence. Other independent lacustrine proxies to keep into account are found in lake levels and isotope records. Many southern European records show substantial differences between early and late Holocene vegetation, suggesting a general evolution from wetter to drier climatic conditions with clearly arid phases singled out in south-western Europe and in the central Mediterranean by independent methods. This trend began around 8 kyr BP (cal. age) and culminated around 6–5 kyr BP. In contrast to this, south-eastern Europe and Atlantic Hiberian peninsula apparently experienced increased humidity from c. 9 to 7 kyr BP. Around 6 kyr BP, strong changes in woodland range, density, and composition occurred, and typical Mediterranean vegetation spread throughout the basin. Anthropogenic effects cannot be excluded, even if there is no doubt that major synchronous changes in vegetation throughout the whole Mediterranean region, could not have been caused by humans alone. 0773 The Lateglacial and Postglacial record of environmental history at Lago di Mezzano, a maar lake of central Italy Laura Sadori Università di Roma, Italy

Lago di Mezzano (Central Italy, 42˚37′N, 11˚56′E, 452 m a.s.l.) is an extant maar lake lying inside the caldera of the extinct Latera volcano, located 100 km NW of Rome. In the Mediterranean basin, in regions where man has been present since the Palaeolithic age, and whose impact on the environment increased through the millennia, the difficulty exists of singling out the changes induced by human populations on vegetation. As Mediterranean Italy is a sensitive region from a climatic perspective and as many prehistoric sites are found in the surroundings and in the lake itself, a multi-disciplinary approach in the study of its sediments turned out a precious tool to disentangle human impact from natural trends. Three parallel cores were taken from the center of the lake, each with a minimum length of 28 m using a piston corer by the GFZ team of Potsdam. Pollen and microcharcoals data have been integrated by magnetic susceptibility measurements, geochemical proxies, and a geomorphologic survey. The multidisciplinary approach has been used to define the nature of the landscape changes since the end of the last glacial, the top 14 m of the core. The chronology is based on AMS radiocarbon dates, tephra layers characterizations, varve thickness measurements, and interpolated sedimentation rates. The sediments record the Lateglacial period, indeed rarely found in the Mediterranean, with a high temporal resolution. Both interstadial (Bølling/Allerød) and stadial (Younger Dryas) periods are clear in pollen and microcharcoal, in lithology, loss of ignition, organic and inorganic carbon, and biogenic opal. The Holocene reforestation, matching changes in the nature of the sediment, is a bit more precocious, fast,

and effective than at other sites. Real forest conditions with deciduous oaks dominant and high beech values are found from 10000 to 7500 years BP, when a drop of arboreal concentration and a temporary decrease of arboreal percentages match a peak of inorganic carbon. The cultivated and sinanthropic taxa are of scarce help in determining the periods of human presence and impact. All cultivated plants, except Juglans, are found spontaneous since the start of the Holocene. It is not possible to ascertain if some traces visible in the diagrams since the Copper age can be ascribed to human action. The human presence became of impact at Lago di Mezzano since the Bronze age, when pollen of cultivated, ruderal, and weed plants, microcharcoals and other sedimented limnological clues. 0857 Glacial Fluctuations of the Seno Última Esperanza piedmont lobe during the Last Glacial-Interglacial Transition, SW Patagonia, Chile Esteban A Sagredo1, Patricio I Moreno1, Rodrigo P Villa2, Michael R Kaplan3 1

Institute of Ecology and Biodiversity, Dept. of Ecological Sciences, University of Chile, Chile 2 Centro de Estudios del Cuaternario (CEQUA), Punta Arenas, Chile 3 Lamont-Doherty Earth Observatory of Columbia University, United States

Outlet glaciers from the Patagonian Ice Sheet coalesced and formed the Seno Última Esperanza piedmont lobe in the Chilean sector of SW Patagonia (51˚25′–52˚25′S) during the Last Glacial Maximum (LGM). Ongoing studies in this region are aimed at resolving the regional timing and structure of the LGM and the Last Glacial-Interglacial Transition to improve our understanding of the interhemispheric phasing of climate signals, and the causes and mechanisms underlying glacial terminations. Geomorphic and stratigraphic evidence indicate a series of stages since the final LGM advance, which include: (i) deposition of prominent moraine complexes and outwash plains, subsequent (ii) deposition of moraine complexes and emplacement of kame terraces at intermediate positions, and erosion along ice-dammed proglacial lake shores, (iii) development of ice-dammed proglacial lakes at lower elevations accompanying ice recession, and (iv) a possible glacial readvance within the proglacial lake environment and enhanced deposition of Ice Rafted Detritus (IRD). Our chronology indicates that the glaciers abandoned the LGM position shortly before 14,520±140 14 C yr BP (17.5 cal kyr BP), as the tributary ice lobes thinned and experienced moderate recession, exposing terminal areas formerly covered by ice above 250 masl. A stabilization phase ensued with deposition of moraines and kame complexes, contemporaneous with small ice dammed lakes, perched deltas, and the formation of lake terraces (~135–145 masl) on the glacial deposits. A large proglacial lake developed as the glaciers abandoned this intermediate position. Minimum ages for the abandonment of the intermediate position come from: (i) the Eberhard site (70 masl), which indicate that this area was ice free and flooded by the proglacial lake by 13,745±50 14C yr BP (16.4 cal kyr BP), and by (ii) basal radiocarbon dates from a lake within the intermediate moraine complex of the Lago Pinto tributary lobe, which show abandonment of this position at 13,670±50 14C yr BP (16.3 kyr BP). Ice recession led to a lowering of the proglacial lake, exposing the Dumestre site (~80 masl) by 12,895±45 14C yr BP (15.2 cal kyr BP), but the lake level still persisted below ~70 masl. Increased IRD deposition between 12,500±60 and 10,695±40 14C yr BP (14.6–12.8 cal kyr BP), coupled with stratigraphic evidence for a glacial readvance indicate renewed glacial activity of the Última Esperanza lobe during the Antarctic Cold Reversal. The proglacial lake drained toward the Pacific Ocean after 12.8 cal kyr BP, driven by ice recession or deepening of spillways in the Andean region.


1088 Evolution of coastal depositional systems in response to rapid and slow sea-level rises during the last deglaciation: examples from Asian rivers Yoshiki Saito Geological Survey of Japan, AIST, Japan

Sea-level changes control the accommodation space in coastal depositional systems and affect their stacking. In an estuary system, the depositional system migrates landward because the accommodation space created by the sea-level rise is not filled completely by sediments supplied by the river. Sea-level rise induces river channel instability and flooding, resulting in thick sediment accumulation in fluvial and coastal plains. On the other hand, in regressive systems under falling or stable sea levels, sediments supplied by rivers are transported to the sea, bypassing fluvial and coastal plains because of their limited accommodation space, resulting in the lateral accretion of deltaic systems (progradation). The main difference between estuarine and deltaic systems is depocenter location; in an estuary system, the depocenter is on the fluvial to coastal plains, including the intertidal zone, whereas in a delta system, it is in coastal to offshore areas. Once delta initiation has occurred, sediments accumulate widely in subaerial to subaqueous areas, resulting in both aggradation and progradation as the sea level rises. The Ganges-Brahmaputra and Mahakam (Borneo Is) deltas are examples of broad deltas of this type.

Sea-level rise after the Last Glacial Maximum is characterized by a series of rapid rises in response to meltwater pulses followed by a slow rise. These millennial-scale sea-level changes have affected coastal depositional systems and are recorded in the sediment facies and stacking. The transgressive succession in incised valleys in Asian large rivers consists of a series of backstepping aggradational estuarine deposits. The rapid retreat (backstepping) is correlated with a rapid sea-level rise: e.g., incised valley fills of the Changjiang (Yangtze), Huanghe (Yellow River), Red River (Song Hong), and Mekong River. Three backsteppings recognized in these incised-valley fills might be correlated with MWP-1a, 1b and 8-9 ka event. The delta initiation of these rivers occurred just after the last event, followed by aggradational delta development during the last phase of sea-level rise. 0273 Ages of the upstream Paraná River Quaternary deposits in Brazil Alethéa E M Sallun, Kenitiro Suguio Instituto Geológico (IG/SMA-SP), Instituto de Geociências (IGc/USP), alethe [email protected], Brazil

La Plata river hydrographic basin is the second biggest one of the planet and is formed by three most important rivers: Paraná, Paraguay and Uruguay. The upstream Paraná river in Brazil represents the second major drainage system in South America. Sedimentary deposits correlatable in time with phases of Quaternary geological evolution, which marked conspicuously the present landscape in the area, were studied aiming the decipheration of the upstream Paraná river geological history. These deposits are of alluvial and colluvial origins, and are superimposed on sedimentary and igneous (basalts) Mesozoic rocks. Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) datings indicated their Pleistocene ages. As the colluvial depos-

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its exhibit increasing ages with depths, they certainly represent vertical accretionary deposits. Therefore, these ages were grouped as an attempt to recognize the different colluviation phases related to most important colluvial generations. It was also shown that these deposits are scattered in different geomorphological compartments of this hydrographic basin. The late Mesozoic sedimentation was followed by a long depositional hiatus (nondepositional phase), and these colluvial deposits represent one of the most impressive weathering event of the Late Quaternary in Brazil. The data obtained from the upstream Paraná river deposits show that this hydrographic basin began its activities at least about 1 My ago, and the associated landscape was continuously fashioned throughout successive constructive (fluvial terraces) and destructive (erosional surfaces) phases. This Quaternary deposition was possibly propitiated by paleoclimatic and/or neotectonic events, which changed the drainage baselevels with consequent relief transformations. Possibly the most important colluviations were related to drastic global palaeoclimatic changes during the Pleistocene, when occurred glacial and interglacial episodes of the northern hemisphere. The obtained data must improve the upstream Paraná river evolutionay history, still only a few known in terms of Quaternary geology viewpoint, as well supply data to fight against the problems of accelerated erosional susceptibility. 0208 Soil and geomorphic evidence for a complex origin of the Nahanni karst landscape, Northwest Territories, Canada Paul T Sanborn1, Scott Smith2, David Huntley3 1

University of Northern British Columbia, Canada Agriculture and Agri-Food Canada, Canada 3 Geological Survey of Canada, Canada 2

The subarctic Nahanni karst region of the southern Mackenzie Mountains (Northwest Territories, Canada) contains an assemblage of landforms that is globally unique at latitude 61-62ºN. New soil and geomorphic evidence indicates that this landscape reflects a complex interplay of Quaternary glacial, karst, and aeolian processes. Of particular interest is a 15 km long × 1-3 km wide belt containing a labyrinth of vertical-walled canyons, limestone towers, poljes, and numerous dolines, occupying a saddle between the Nahanni and Ram Plateaus that separates the South Nahanni watershed from the Sundog Basin to the north. On level to gently sloping bedrock-controlled surfaces at 800–900 m elevation within this belt, soils have formed on a discontinuous (< 50 cm thick) veneer of silty sediments overlying limestone and isolated remnants of shale. These weakly-developed soils often consist only of humus-rich A horizons resting directly on bedrock. At similar elevations on the northwestern edge of this belt, and on prominent terraces to the north on the flank of the Ram Plateau, soils have formed on non- or weakly calcareous glaciofluvial deposits containing a high proportion of locally-derived shale clasts. These materials are overlain by a veneer (15–35 cm thick) of stone-free silty sediments containing the most strongly-expressed portions of the yellowish brown B horizons. Similar silty materials occur in higher elevation (> 1100 m) lithic alpine soils on the eastern Nahanni Plateau, and this ubiquitous distribution suggests an aeolian origin. Except where permafrost is present in sheltered depressions or on north aspects, all soils examined in the Nahanni karst region would be classified as Brunisolic in the Canadian classification system (Inceptisols in Soil Taxonomy). This limited degree of pedogenic development is comparable to that of soils formed on Late Quaternary glacial deposits in the southern and central portions of the adjacent Yukon Territory. Extensive glaciolacustrine deposits in the South Nahanni River valley and

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the inferred retreat pattern of the Wisconsinan Laurentide ice suggest that significant eastward and/or northward meltwater drainage occurred through the Nahanni-Ram Plateau saddle. The canyons in the Nahanni labyrinth karst show a striking resemblance to those of channeled scablands attributed to catastrophic meltwater floods in eastern Washington (U.S.A.) and southern Yukon. The youthfulness of soils in and adjacent to the Nahanni-Ram Plateau saddle is consistent with modification of a karst landscape by meltwater during late Quaternary deglaciation, followed by a regional overlay of silty aeolian deposits derived from exposed glaciolacustrine sediments.

have been affected, as Greenland temperatures, by precession. The attenuation of the precession impact at latitudes higher than 40°N is likely due to glacial ice sheet extent. In contrast, during the last interglacial, the precession imprint on Atlantic and Mediterranean forests and Greenland temperatures is visible at any given latitude.

0625 Contrasting impacts of Dansgaard-Oeschger oscillations over a western European latitudinal transect (36°N–45°N)

Calogero M Santoro1, Claudio Latorre2, Carolina Salas3

Maria Fernanda Sanchez Goñi1, Amaelle Landais2, Filipa Naughton1, William Fletcher1, Stéphanie Desprat3, Elsa Cortijo4, Edouard Bard5, Frauke Rostek5 1

EPHE, UMR-CNRS 5805 EPOC, Université Bordeaux 1, Avenue des Facultés, 33405 Talence, France 2 Laboratoire des Sciences du Climat et de l’Environnement IPSL CEA CNRS UMR 1572, Bât. 712 / Orme des merisiers 91191 Gif-sur-Yv, France 3 Woods Hole Oceanographic Institution, Woods Hole, M.A. 02543, United States 4 Laboratoire des Sciences du Climat et de l’Environnement (LSCE-Vallée), Bât. 12, avenue de la Terrasse, F-91198 Gif-sur-Yvette, France 5 Collège de France CEREGE, UMR-6635, Le Trocadéro, Europole de l’Arbois BP80 13545 Aix-en-Provence cdx 4, France, France

Terrestrial and marine proxies (pollen, planktic and benthic oxygen isotopes, alkenone- and foraminifer-derived sea surface temperatures, ice rafted debris) from IMAGES deep-sea cores MD95–2042 (37°N, 10°W) and MD95-2043 (36°N, 2°W) have shown that southern Iberian and offshore environments were strongly affected by Dangaard-Oeschger (D–O) oscillations and Heinrich events. Cold sea surface temperatures (SST) were contemporaneous with the expansion of semi-desert indicating a cold, dry climate in this region. In turn, D–O interstadials were synchronous with the expansion of Mediterranean forest. A similar multiproxy study conducted further north in the Atlantic region on cores MD99-2331 and MD04-2845 retrieved in the Galician margin (42°N, 9°W) and in the Bay of Biscay (45°N, 5°W), respectively, reveals that the alternation between D–O stadials and interstadials was synchronous with changes between deciduous Quercus-Betula-Pinus-open forest and steppic formations. In northwestern Iberia, heathlands and grasses dominated the herbaceous vegetation during cold D–O episodes while Artemisia, sedges and Calluna expanded in western France. The four sequences reveal the imprint of all the D–O oscillations in western Europe and offshore. However, the amplitude of Atlantic and Mediterranean forest expansions differs for any given D–O warming. For example, during D–O 12 (relatively high temperatures in Greenland) the expansion of Atlantic forest in NW Iberia and France is stronger than that of the Mediterranean forest. During D–O 8, Mediterranean forest displays a maximum while the response of the Atlantic forests is muted. The comparison of the four records with the precession index indicates that minima in precession (particularly warm summers) correspond with the largest expansions of Mediterranean forest during D–O warming. As the precession minima seem also to produce the highest precipitation episodes in the eastern Mediterranean, as revealed by the Soreq cave isotopic record, we suggest that the strongest expansions of the Mediterranean forest during D–O 24, 21, 17, 8 and 1 depend not only on the warmest summer temperatures but also on precipitation maxima. Precession has therefore a strong imprint in the expansion and contraction of the Mediterranean forest contrasting with the forest cover evolution of the European Atlantic region which seems not to

0945 Early Peopling and Paleoenvironments during the Pleistocene/ Holocene Transition in northernmost Chile (17–21˚S)

1

Universidad Tarapacá Arica, IAI, CIHDE, Chile CASEB/Depto. Ecologia, P. Universidad Catolica de Chile and Institute of Ecology & Biodiversity, Casilla 653, Santiago, Chile 3 Universidad Tarapacá Arica, Departamento Antropogía, Chile 2

The early peopling of the Americas at the end of the Pleistocene (~13,000–10,000 calibrated 14C years before present or yrs BP) has been the subject of considerable debate over the last several decades. Part of the problem resides in the very limited amount of known and accepted sites for South America, despite a number of systematic surveys by many international and regional researchers since the 1940’s. Aside from the well-known pre-Clovis Monte Verde site, there are extremely few “Paleoindian” archaeological sites in Chile, mostly located either in the southern or central regions of the country. These sites are also completely absent from high altitude (>3500 m) environments. Recently, new records of past climate and vegetation change from northern Chile indicate that the hyperarid environments of the Andean Precordillera and adjacent Atacama Desert (2000 – 3000 m) were considerably wetter and more productive at precisely the time when most of the early Americans came through the region. This extensive eco-zone has been mostly unexplored in terms of its archaeological potential. Here, we present our first findings from this hyperarid region of northernmost Chile (17–21˚S). We use a multidisciplinary predictive model that incorporates data from: (1) local and regional paleoclimate (midden records), (2) geomorphology and stratigraphy (past wetlands and springs), and (3) archaeological prospecting. This strategy has enabled us to develop a relatively precise method for predicting the location and associated cultural patterns of past possible habitats suitable for human societies at the Pleistocene-Holocene transition. 1435 Reconstruction of monsoonal rainfall from pedogenic carbonate of the Late Quaternary Ganga and Yamuna alluvial plain by stable isotope tracers: Implication to climate forcing on vegetation Prasanta Sanyal1, S Agrawal1, A Sarkar1, S Sinha2, Sampat K Tandon3, Martin R Gibling4 1

Indian Institute of Technology Kharagpur, India Indian Institute of Technology Kanpur, India 3 University of Delhi, India 4 Dalhousie University, Canada 2

Indian Monsoon is an important component of the climate system of the Tropical region. A seasonally reversing wind system with moist oceanic air from south-west during summer and cold, dry continental air from north-east during winter characterizes the monsoonal climate. This system is responsible for heavy rains during June to September in the Indian subcontinent. Monsoon variations in terms of wind strength


or upwelling reflected in the geochemical and biological changes in ocean are well recorded for the Late Quaternary period. Variations in the monsoonal intensity in ocean should also be reflected over the Indian subcontinent in terms of variation of rainfall amount. However, limited information is available about monsoonal rainfall variation from continental archives. Sediments in the Ganga and Yamuna alluvial plains, supplied by monsoon fed rivers, can provide excellent opportunity to reconstruct past rainfall. Our preliminary results from oxygen isotope ratio of pedogenic carbonate from the Ganga and Yamuna basins showed that monsoonal intensity has varied with time for last 100 ka. In addition, carbon isotope ratio of same pedogenic carbonate showed that vegetation was characterized by mixed C3-C4 vegetation. The abundance of C3-C4 vegetation has also varied with time although no one to one correlation has been found between monsoon variations and vegetational abundance change. 0655 TOPO-Europe – a challenge for other continents combining lithospheric activities with surface processes Sierd Sapl Cloetingh1, Jörg F W Negendank2 1

Vrije Universiteit Amsterdam - Faculteit der Aard- en Levenswetenschappen, The Netherlands 2 c/o: GeoForschungsZentrum Potsdam, Secretary General of ILP - International Lithosphere Program, Germany

Continental topography is at the interface of processes taking place at depth in the Earth, at Earth’s surface, and in the atmosphere. During the last 20 Ma plate-tectonic and other geodynamic processes in the Earth’s interior have caused many changes in the Earth’s surface topography. The lithosphere responds to forces exerted by these processes, creating mountain belts (e.g. the Alps), elongated rift zones (e.g. the Rhine rift system) and large sedimentary basins (e.g. the North Sea and Pannonian Basins). Improved knowledge of the Earth’s mantle and its coupling to the lithosphere and its surface is key to understanding the enormous forces that generate these features. The impact of SolidEarth processes on surface topography at plate boundaries has been known for several decades, but their significance for intraplate domains, and particularly coastal regions, has only recently been appreciated. The present state and behaviour of the shallow Earth system is a consequence of processes operating on a wide range of time and spatial scales. Time-varying phenomena include (i) long-term tectonic controls on subsidence, uplift and river systems, (ii) residual isostatic effects of the ice ages on crustal movements, (iii) natural climate and environmental changes over the last millennia and up to the present, and (iv) the powerful short-term anthropogenic impact of the last century. Spatial phenomena include huge mantle convection cells, mantle plumes and major variations in the structure of deep Solid-Earth interfaces, ocean currents, major rivers and streams. To trace, quantify and forecast topography evolution in response to Solid-Earth processes and movements of surface waters, it is essential that researchers proficient in a wide range of sub-disciplines interact and collaborate. TOPO-EUROPE endeavours to link the results of geomorphologic, geological, geophysical, geodetic, remote sensing and geotechnologic investigations. Such an integrated, multidisciplinary approach has yet to be achieved on a truly European scale. A consortium of national research centres, geoscience institutes of universities and national geoscience surveys, each with proven strengths and capabilities in distinct scientific fields, will join forces to implement research strategies that lead to an improved understanding of Europe’s dynamic topography and enhanced forecasting capabilities. The goal is to simulate the recent past by “inverting” geological data and forecasting the future by

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connecting the past, present and future evolution of the system. TOPOEurope is a Task-Force of ILP (International Lithosphere Program) and now financed as a EUROCORES-project (ESF) 0123 PONTO-MEOTIC EUSTATIC AND SOME PROBLEMS OF STONE AGE NORTHERN BLACK SEA COAST (about 32–6 ky BP) Igor Viktorovich Sapozhnikov Archaeological Institute of National Academy of Sciences, Odessa branch., Ukraine

Positive result of W.Pittman and W.Ryan idea’s about “Noah’s Flood” became activization of scientists of different specialities, including archeologists. The majority of the last is not considered postglacial transgressions of Black sea as catastrophic. In archeology already more than 100 years exist the hypotheses caused by global climatic changes and accordingly by transgressions and (or) regresses of seas. One of them shows that during phases of approach of a glacier ancient peoples moved to the South in Black sea coasts that led to increasing of population density (G.F. Osborn, V. Chmelevsky, etc.). Also exists “antithesis” of this concept. According to it, raised concentration of mesolithic and neolithic sites are connect with regresses, and absence or small number of them – with transgressions of Black sea (V. Dergachev). There is a point of view, that in a result of postglacial transgressions in the South of the East Europe the huge water pool was created (Aralo-Caspian and Black sea), which interfered with migration of population from the South to the North (H. Obermayer, A. Chepalyga, etc.). One of the most original is the idea about migration of mesolithic Grebeniky culture from Greece to the Northern Black Sea coast directly under influence of transgression (flood) about 7.5 kyr BP (L. Zaliznyak). D.W.Anthony has already proved, that low density of population of a coastal zone of Northern Black Sea coast in mesolithic and neolithic times does not confirm the idea about direct interrelation of early holocene transgressions on the demography of the ancient population. “Grebenyaki migration” basically contradicts to archeological evidence, and in specified time fixed not transgression but regression. Besides the cartography of sites and the analysis of archeological data do not confirm the point of view that the Manych-Kerchensky passage during its existence could be a serious obstacle for cultural contacts and movement of the populations. So, now the interrelation of eustatic of the ancient Ponto-Meotic sea with cultural-historical processes in the Stone Age in the given region is not filled yet by concrete facts. Moreover, for upper paleolithic and mesolithic times in Northern Black Sea coast we don’t know facts of use of biological resources of sea by ancient people. As to V.Dergachev’s idea – a small numbers of known neolithitic sites can be explained in that the majority of them has been flooded as a result of later transgressions. 0861 14 C plateaus and global stratigraphic correlation of ocean and climate records of early deglacial times Michael Sarnthein1, Pieter M Grootes2, James P Kennett3 1

Institut für Geowissenschaften, University of Kiel, D 24098 Kiel, Germany Leibniz Laboratory, University of Kiel, D 24098 Kiel, Germany 3 Dept. of Earth Sciences, Univ. of California, Santa Barbara CA 93106, United States 2

The concept of the „Global ocean Conveyor Belt“ is largely based on modern 14C ventilation ages of ocean deepwater (Broecker et al., 1984;

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Schlosser et al., 2001). Per analogy, recent “14C plateau“-based evidence of past 14C ventilation ages from four key sites in the northern North Pacific and North Atlantic (Icelandic Sea) now provide unique new insights into the fate of deglacial ocean Meridional Overturning Circulation (MOC) and climatic change between 23 and 13 cal. ka, twice indicating opposite trends of change in deepwater formation during Heinrich 1 (H1) stadial. Starting 17 cal. ka intermediate-water ventilation ages in the Icelandic Sea, the source region of modern and LGM MOC, abruptly increased from 440 to >2000 yr, reflecting a brief northward reversal of the Denmark Strait Overflow, that is the start of estuarine circulation in the Nordic Seas. This scenario terminated with the onset of the Bølling-Allerød (14.7 cal. ka), when Atlantic MOC turned back to its “normal” state. In contrast, coeval North Pacific deep- and intermediate-water ventilation ages all over decreased from ~3800 to 1150/2200 yr, suggesting a North Pacific site of deepwater formation. Both events imply two major flushings of the deep ocean and short-term reorganiza-tion of oceanic heat transport to northern high latitudes. In the subarctic North Pacific, this transport dominated regional millennial-scale SST and climate change. In the far western North Pacific, East Asian monsoon and climatic change were dominated by atmo-spheric circulation patterns and thus ran in phase with North Atlantic climate. For the northeast Pacific 14C plateau-based correlations of the climate record remain unsolved because of a crucial stratigraphic gap during the early deglacial interval in ODP Site 893. We are currently attempting to produce a sequence of 14C ages over this gap using another IMAGES long-core sequence from the Santa Barbara Basin. 1249 Fire and human impacts on vegetation changes during the Holocene in the Kyoto basin, Japan Naoko Sasaki1, Hikaru Takahara2, Goh Kishimoto3 1

Research Institute for Humanity and Nature, Japan Kyoto Prefectural University, Japan 3 Forestry Agency of Japan, Japan 2

Japanese forests have been heavily impacted by human activities. Present landscape around Kyoto, the ancient capital of Japan, is mostly characterized by secondary forests. This cultural landscape, so-called “satoyama”, is believed to be the result of long and continuous human activity, including the collection of fuel wood and litter for fertilization, and slash-and-burn agriculture. By the pollen and charcoal analysis of a sediment core obtained from Mizoroga-ike mire, we have clarified the vegetation and fire history during the Holocene in the Kyoto basin. Mizoroga-ike is small mire located on the outskirts of Kyoto city, Japan. It lies at an elevation of 75-m in the warm-temperate zone. The present vegetation is secondary forest composed of deciduous oaks (Quercus subgenus Lepidobalanus spp.) and red pine (Pinus densiflora), and plantation of Japanese cypress (Chamaecyparis obtusa). We obtained 10-m core from Mizoroga-ike and the chronology of the core was established based on eight AMS radiocarbon dates of plant macrofossils and two tephra layers. A pollen record from the mire suggests that during the early Holocene, deciduous forest dominated by oaks and hornbeams developed. During the middle Holocene, the site was surrounded by evergreen broad-leaved forests. Pine increased since ca. 1400 yr B.P., reflecting a regional increase of the taxon because of human impacts. The forests surrounding the mire were replaced by secondary forests, dominated by deciduous oaks and red pine, at ca. 950 yr B.P. Pine increased continuously, and become dominant in the landscape at ca. 200 yr B.P. Charcoal abundance increased conspicuously between ca. 12000 yr B.P. and 11000 yr B.P.,

and ca. 9000 yr B.P. and 7000 yr B.P. In the late Holocene, charcoal fragments occurred with buckwheat pollen suggesting human activity, but amount of charcoal fragments is less than that of early Holocene. In this region, forest fires occurred frequently in the early Holocene (Inoue et al. 2001, 2005). The causes of the frequent fires in the early Holocene are still unclear, but the drier climate must have been partially responsible for the frequent fires either by anthropogenic or natural causes. 0425 Luminescence and Electron Spin Resonance studies on natural Gypsum (CaSO4.2H2O) and its applications to geochronometry M D Sastry1, Y C Nagar2, K P Mishra3, M N Deo3, G Kocurek4, S K Wadhawan5, N Juyal6, A K Singhvi6 1

Physical Research Laboratory, Ahmedabad 380009, India India 3 Bhabha Atomic Research Institute, Mumbai, India 4 Geological Sciences, University of Texas at Austin, United States 5 Geological Survey of India-WR, Gandhinagar, Gujarat, India 6 Physical Research Laboratory, Ahmedabad 380009, India 2

Gypsum is an important mineral for Dry land Paleoclimatology. It represents the periods of extended aridity. A successful feasibility study for its chronometry using Electron Spin Resonance (ESR) using samples from White Sands USA and the Thar desert in India, is presented. The study comprised sample characterization using Fourier Transform Infrared Spectroscopy, X-ray diffraction, Differential Thermal Analysis (DTA) / thermogravimetry (TG) and age estimation using Luminescence (L) and ESR. DTA/TG indicated loss of water in two steps at 90–150C and at 190C. This restricts the use of luminescence methods as these involve heating/preheating. Five ESR centers, G1, G2, G4, C and LS were observed. Centre LS (O3-) was photo-bleachable. The radiation response of SO4- centre was linear to >1000 Gy and the minimum measurable ages was ~500 years. Concordance of ESR ages with independent optical ages of quartz from the same sediment layers, suggest that the mean life of the SO4- signal is >100 ka. This is a minimum estimate given that the SO4- resides in a CaSO4 host matrix. This comparison also implies that the alpha efficiency of this signal should be ~0.25. ESR analysis of White Sands and the Thar Desert, provided stratigraphically reasonable ages in the range 7 ka -500a and from 13ka- 1ka, respectively. Two anomalous ages corresponded to samples whose micro-morphological analysis suggested multi-stage gypsum growth. The White Sands gypsum gave a clear gypsum ESR spectrum and the ESR spectrum of the Thar Desert gyspum was masked by Mn2+ signal. FT-IR evidence of hannebachite (CaSO3.½H2O) in the Thar samples, suggested that, (i) White Sands formed by direct calcium-sulphate precipitation and, (ii) the Thar samples formed through bacterial reduction of sulfur (BSR) under a reducing environment. As the Thar Desert samples contained hannebachite in a significant proportion, it can reasonably be assumed that the SO3 - center most likely resides in the sulphite rich region. Thus, analogous to SO4-in sulphate and it can possibly be used for dating the samples that contain hannebachite. Detection of SO4-and LS (O3-) signals suggested that both the formation event and the later date transport event of gypsum are dateable. For white sands, it implied that the formation and transportation were only a few centuries apart. Results and application of ESR and L to White Sands and Thar Desert will be presented.


0835 Late Holocene Hydroclimatic Variability, Northwestern Great Plains, Canada and USA David J Sauchyn1, Jonathan Barichivich2 1

Prairie Adaptation Research Collaborative, Canada Chile

2

The impacts of drought have punctuated the short European history of the northern plains of the western interior of Canada and the USA. The corresponding short instrumental records of climate and surface water supplies limit our understanding of the frequency and cause of drought in this region. In the Tree-Ring Lab at the University of Regina (www. parc.ca/urtreelab), we have developed a network of robust moisturesensitive tree-ring chronologies extending from the island forests of eastern Montana and across southern and western Alberta. Most of the sampling sites are dry (i.e. open-canopy forests on ridge crests, southand west-facing slopes, rapidly drained soils) where available soil moisture is the main control of tree growth. Therefore these tree-ring data are proxies of summer and annual precipitation, soil moisture and runoff. The tree rings are an especially good proxy of drought. We examined the spatiotemporal variability of tree growth using principal component (PC) and wavelet analysis. Correlations between the two leading PCs and global SSTs and SLP reveal responses of tree growth to ENSO, PDO and AMO. Periodic signals in the tree-ring records were identified and compared with those characterizing to ENSO, PDO and AMO forcings. This comparative wavelet analysis indicates that moisture variability at interannual (2–7 yr) and decadal to interdecadal (~15–25 yr) timescales, throughout the range of the network, is strongly linked to sea surface temperatures in the Pacific Ocean (i.e. ENSO and PDO), while multidecadal variability (~30-70 yr) is mainly related to conditions in the Atlantic Ocean (AMO). These hydroclimate forcings and their interactions modulate to a great extent the moisture variability in this region at different temporal and spatial scales. The low frequency cycling of hydroclimate will underlie the trends imposed by global warming. 0297 Albeluvisol development with time in loamy marine sediments of SW-Norway Daniela Sauer1, Isabelle Schülli-Maurer1, Ragnhild Sperstad2, Rolf Sørensen3, Karl Stahr1 1

Institute of Soil Science and Land Evaluation, Hohenheim University, Germany 2 Norwegian Institute of Forest and Landscape, Norway 3 Norwegian University of Life Sciences, Norway

The coastal areas of Scandinavia provide suitable conditions for studying soil development with time, due to glacio-isostatic uplift. Our study area is located along both sides of the Oslofjord (Vestfold and Østfold). The climate in this area is rather mild although it is located between 59˚ and 59˚ 40′ latitude. The mean annual temperature ranges from 5.4 to 6. 0˚C. Precipitation is 975–1094 mm year−1 in Vestfold and 751–829 mm year−1 in Østfold. Due to the steadiness of the uplift, no separate terraces were formed in the study area, but soils continuously get older from the coast inland. We established two soil chronosequences comprising six pedons each, one in Vestfold (1650– 9000 years) and one in Østfold (3000–11050 years). The ages were estimated by use of several sea level curves established for various locations in the area, based on calibrated radiocarbon datings. The parent material is loamy marine sediment. The geological basement below

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the sediment consists of basic magmatite (monzonite, latite) in Vestfold and predominantly acid magmatite (granite) in Østfold. Higher precipitation in Vestfold leads to earlier beginning of clay illuviation. Clay coatings are perceptible in Vestfold already in the 1650 years old soil. In Østfold they become visible for the first time in the 3500 years old soil. The E horizon becomes lighter with age, but its thickness stays constantly around 40 cm in both areas. The development of the characteristic albeluvic tonguing starts after 4000 to 5000 years. The tongues initially develop mainly along intersections of cracks. Due to ongoing leaching they increase in length and width, progressively consuming the prisms in between the cracks in the upper part of the Bt horizon. Base saturation in the upper 25 cm exhibits a decrease with time which can be best described by an exponential model, while pH (water) stays constantly at pH 4.4 ± 0.4 in all soils covering a range of 1650 to 11050 years in age. These findings indicate that the soil pH is buffered by protonation of surface charges occupied by exchangeable base cations over a time span of more than 9000 years. The Fed/Fet ratio shows an increase with time which can be described by both, a linear or potential model, reflecting progressive iron release from mineral weathering. The Feo/Fed ratio shows a linear decrease indicating increasing degree of iron oxide crystallization. 0305 Recent environmental changes on subantarctic Macquarie Island Krystyna M Saunders, Andrew McMinn, Anthony J Cowles University of Tasmania, Australia

World Heritage listed subantarctic Macquarie Island is a unique and important environment. Human activities over the last 100+ years have had dramatic impacts on the vegetation and local seal and penguin populations as a result of commercial exploitation. Another human impact is the introduction of feral animals, particularly rabbits. We use a palaeoecological approach to investigate environment changes that have occurred since human activities began on Macquarie Island. Two cores (one from a coastal lake and the other from an inland lake) were obtained and analysed for diatoms, particle size, total carbon, nitrogen and sulphur contents, and dated using 210Pb and 14C. Initial dating results indicate the coastal lake core spans the past 110 years, whereas the inland lake core spans over 250 years. Diatom assemblages from the coastal lake are dominated by Fragilaria species, with little change in community structure. Particle size, total carbon, nitrogen and sulphur contents results indicate that little change has occurred in either core. We are developing diatom-based transfer functions for inferring past environmental conditions to determine changes in these sediment cores and recent environmental changes on Macquarie Island, and to investigate the impact of human activities and climatic changes. This is potentially valuable information for future conservation and management of Macquarie Island and understanding the potentially devastating impacts of unplanned introductions by humans.

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0751 Vegetation and Climate Development in the Southern Patagonian Steppe (Argentina) During the Younger Quaternary: Cores from the Laguna Potrok Aike Maar Frank Schaebitz1, Michael Wille1, Marta Paez2, Flavia Quintana2, Nora Maidana3, Andreas Luecke4, Christoph Mayr5, Bernd Zolitschka6 1

Seminar for Geography and Education, University of Cologne, Gronewaldstr. 2, D-50931 Cologne, Germany, Germany 2 Laboratorio de Paleoecología y Palinología, Universidad de Mar del Plata. Funes 3250, 7600 Mar del Plata, Buenos Aires, Argenti, Argentina 3 Dept. for Biodiversity and Experimental Biology, University of Buenos Aires CONICET, Ciudad Universitaria, C1428EHA. Buenos A, Argentina 4 Institute of Chemistry and Dynamics of the Geosphere, ICG V: Sedimentary Systems, Research Center Jülich, D-52425 Jülich, Germa, Germany 5 GeoBio-CenterLMU, Ludwig-Maximilian-University, Richard-Wagner-Str. 10, D-80333 Munich, Germany, Germany 6 Geomorphology and Polar Research (GEOPOLAR), Institute of Geography, University of Bremen, Celsiusstr. FVG-M, D-28359 Bremen, G, Germany

Multi-proxy studies of sediment cores from the 100 m deep maar lake, Laguna Potrok Aike (52°S, 70°W), situated more than 80 km away from the Andean Forest in the dry Steppe of south-eastern Patagonia provide information about the vegetation development and the climate history during the Late Quaternary. One sediment core from a subaquatic lake level terrace 35 m below the present day lake level exhibits an unconformity and in its oldest parts, reaches back to oxygen isotope stage 3 (53 ka). Another core, from the centre of the maar measuring 19 m in length, offers the possibility to reconstruct the environmental conditions over the last 16,000 cal BP continuously. The combined interpretation of sedimentary, isotopic and biological proxies indicates that variations in moisture availability and lake level fluctuations occurred on centennial to millennial timescales. Pollen data suggest that glacial conditions are represented by a cold and humid steppe vegetation surrounding the lake. Only low amounts of Nothofagus pollen were brought to Laguna Potrok Aike by westerly winds during these cold periods, indicating that isolated stands of Nothofagus trees were present in sheltered positions at the foothills of the Andes during OIS 3. The amount of Nothofagus pollen increased during the Late-Glacial, (14–11.6 ka cal BP), mainly due to rising temperatures. Nothofagus pollen are reaching highest values but also exhibit a high variability during the Holocene, during which Steppe taxa dominate. In combination with other sediment proxies and in accordance with modern meteorological data, we suggest that the fluctuations of Andean pollen taxa during the Holocene are related to variations in the strength and/or position of the Southern Hemisphere Westerlies. Human impact due to sheep breeders in the 19th century is clearly visible in the records, evinced by the appearance of unusually high amounts of Rumex pollen. 0608 East Asian Monsoon records from Lake Sihailongwan (Northeastern China) – hydrology and dust flux Georg Schettler1, Jens Mingram1, Qian Liu2, Martina Stebich3, Rolf L Romer1, Guoqiang Chu2, Jintai Han2 1

GeoForschungsZentrum Potsdam, Telegrafenberg, D-14473 Potsdam, Germany 2 Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029 Beijing, China 3 Forschungsstation für Quartärpaläontologie Weimar, Senckenberg Forschungsinstitut und Naturmuseum, D-99423 Weimar, Germany

Lacustrine records of the Cenocoic Long Gang volcanic field enable to reconstruct influx of dust from remote source areas (Inner Asia) in close relation to local changes of summer monsoon strength. Lake Sihailongwan (42˚17′N, 126˚36′) provides a nearly continuously varved sediment record optimal for palaeoclimatic studies. Primary production of Sihailongwan is strongly externally forced by inflow of nutrient-rich groundwater which is largely fed by summer monsoon rainfall. Summer monsoon strength is qualitatively reconstructed on the base of net accumulation rates for biogenic silica. Sihailongwan sediments document Lateglacial climate change to wetter and warmer summer conditions. Climatic amelioration finds response by strong rise in pollen concentration and gradual occupation of thermophile broadleaf taxa (c. 14,300; ages are given in varve yrs BP if not otherwise stated). Around 13,600 broadleaved forests with Ulmus and Fraxinus as major components rapidly spread. Summer monsoon strengthening relapsed during a Younger Dryas like event. Re-appearance of Picea and Larix coupled with Ulmus and Fraxinus decline characterises vegetation change during 1000 yr lasting climatic deterioration.

Between 11500 and 9500 groundwater inflow reached the high level of the Lateglacial before the Younger Dryas. Overall drier conditions prevailed between 9500 and 8000. Summer monsoon rainfall reached a maximum around 7900 and gradually decreased onto minima around 6400 and 4900. Re-increase of summer monsoon rainfall after 4500 was interrupted by a dry interval (4100 - 3600) followed by a long-lasting wet episode until 2250. After temporary re-increase of the summer monsoon strength around AD 200, summer monsoon rainfall reached a minimum around AD 400. Summer monsoon rainfall gradually increased afterwards until AD 800, shows a declining trend until AD 1400, and re-strengthening after AD 1700. Dust input was overall higher during Lateglacial and early Holocene. During a dry period between 10000 and 8000 aeolian influx gradually declined. Dust deposition does not show systematic increase in the inferred Holocene dry periods, instead, bSiO2 and Al2O3 flux rates are positively correlated reflecting more efficient dust removal by wet-deposition for higher precipitation frequency. At the beginning (4100) and the end (3600) of a dry climatic episode, aeolian inputs remarkably peaked. Dust deposition shows increase since about AD 800. The latter probably reflects disturbance of natural vegetation cover by overgrazing and agriculture in remote source areas of the dust. First results, regarding the Pb, Sr and Nd isotope composition of the siliciclastic influx, document changes in the provenience of the dust over time. 1261 Timing of the Younger Dryas glaciation in the Swiss Alps Inga Schindelwig, Sven Lukas, Naki Akcar, Christian Schlüchter Institute of Geological Sciences, University of Bern, Switzerland

The last recurrence to cold climate conditions prior to the onset of the Holocene is the Younger Dryas cooling event (YD, c. 12,700–11,500 cal yr BP), which has been described in various locations in Europe and throughout the world. The end of the YD shows a strong temperature increase and marks the transition from lateglacial to postglacial times. There are many different sites in Switzerland where the YD has been recorded, but only four sites glaciated during the Younger Dryas have so far been dated directly by surface exposure dating (SED). We


aim at increasing the number of dated YD localities in order to (a) advance our understanding of extent and timing of glaciation and (b) reconstruct palaeoclimatic conditions at different sites during this period. To this effect, we have initially chosen a number of areas that satisfy different criteria and regional climatic settings within the Swiss Alps. These areas are the valleys Val Torta, Val Cristallina and Belalp. At the three sites presented here, as in various valleys of the Swiss Alps, these comprise several consecutive moraines (sometimes up to 6 ridges). The moraines are frequently several 100’s of metres in length and 10’s of metres in height, continuous, prominent features and have previously been associated with YD glaciation on morphological grounds alone. We will here present the first results of SED of samples taken from boulders situated on moraine crestlines. We will compare our results to previous findings and link this with palaeoclimatic proxy data across the Swiss Alps in order to constrain glacier response to climate change during YD. 0642 Holocene Alpine Glacier Fluctuations Christian Schlüchter, Ulrich E Jörin Institute of Geological Sciences, University of Bern, Switzerland

The most recent glacier advance phase in the Alps during the eighties of the last century is characterised by distinct erosive behaviour in the frontal part of the glacier lobes: an important in-depth component associated with this ice expansion caused erosion and reworking of preadvance sediments. Organic components associated with these older sediments were not only overridden by the transgressive glacier but also partially eroded and brought up to the glacier front by basal shearing and by high-energy meltwater outbursts. The organic clasts were found either embedded in basal till or imbricated on the flood terraces along the meltwater streams. These organic clasts are either discs of various size of compressed peat or mechanically deformed wood-chips of flake to half-tree size. Some rare specimens are covered with patches of the original bark. The origin of the organic components is the basin complex with its sediments covered by glaciers during the Little Ice Age. A large number of organic specimens have been radiocarbon dated. These dates obtained cluster in defined time windows over the last 10,000 years. The interpretation is that time slices represented by the dated organics correspond to phases of glacier recessions and time slices without organic representation are glacier transgressions into the basins under consideration. The reference geometry of the ice is the glacier front of the late nineties of the last century. The accumulated time of ice regression over the last 10,000 years is more than 50%. There is also a distinct change in glacier dynamics between the first and second half of the Holocene. At Roman time, e.g., the glacier fronts were in the order of 300 m higher than during the late nineties. The main conclusion is that Holocene glacier variations were substantial and recessions and trangressions happened within short time periods and their amplitudes can be quantified with acceptable confidence.

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0684 Cold-based ice limits the potential of cosmogenic nuclide dating in Antarctica Stefan Strasky1, Luigia Di Nicola2, Carlo Baroni3, Maria C Salvatore4, Heinrich Baur1, Peter W Kubik5, Rainer Wieler1, Christian Schlüchter6 1

Isotope Geochemistry and Mineral Resources, ETH Zürich, Switzerland Scienze della Terra, Università di Siena, Italy 3 Scienze della Terra, Università di Pisa, Italy 4 Scienze della Terra, Università La Sapienza, Italy 5 Paul Scherrer-Institute, c/o Particle Physics, ETH Zürich, Switzerland 6 Geological Sciences, University of Bern, Switzerland 2

Glacial geological and geomorphological surveys of the coastal mountains of Terra Nova Bay, northern Victoria Land, Antarctica, showed evidence of at least three glacial events that occurred before the Last Glacial Maximum (LGM). About 100 km from the coast, on a nunatak at the boarder of the East Antractic Ice Sheet (EAIS), still two pre-LGM events could be distinguished. Surface exposure dating with in situ produced cosmogenic nuclides (10Be and 21Ne) of both areas reveals more glacial events than previously observed and different histories of landscape evolution. The glacial deposits on the nunatak are directly related to EAIS fluctuations and show continuous exposure and low erosion rates for the oldest surfaces (929 ± 29; 678 ± 30 kyr), and burial periods of 330 and 530 kyr for two younger ones (284 ± 17; 83 ± 14 kyr). In the coastal area the landscape was much more affected by burial beneath snowdrifts or cold-based ice from local or outlet glaciers. All samples from this area have a complex exposure history; they were probably repeatedly exposed and buried. The burial period becomes increasingly important with lower elevations, ranging from 760 kyr at 910 m asl to about 2 Myr at 470 m asl. Calculations of the minimum total sample history (21Ne exposure age + burial age) show that seven out of ten erratic boulders yield a total history of about 2.15 Myr. Although, these calculations are based on over simplified assumptions (no erosion, continuous exposure followed by only one burial period) they are in agreement with surface exposure ages from rounded mountain tops (2.23 ± 0.086 Myr to 2.56 ± 0.230 Myr), which are evidence of the oldest glaciation in the coastal area. This finding suggests that a major (wet based?) glacial advance occurred in the Terra Nova Bay area ~2.5 Myr ago, eroding enough material to wipe out any inherited cosmogenic nuclides. All subsequent (cold-based) glacial events had insignificant subglacial erosion, hence didn’t modify the pre-existing Pliocene landscape and make it hard to develop an absolutely dated glacial chronology. To gain more information about the exact timing of pre-LGM glaciations it is therefore important to focus on the nunataks adjacent to the EAIS, where burial is less significant. A combined cosmogenic nuclide analysis is a prerequisite for any meaningful surface exposure dating in Antarctica. 1065 Evidence for a Late Glacial event in the Kanding area, eastern Tibet Stefan Strasky1, Angela Graf2, Christian Schlüchter2, Zhizhong Zhao3, Susan Ivy-Ochs4, Peter W Kubik4, Heinrich Baur1, Rainer Wieler1 1

Isotope Geochemistry and Mineral Resources, ETH Zürich, Switzerland Geological Sciences, University of Bern, Switzerland 3 Geomechanics, Chinese Ministry of Land and Resources, China 4 Paul Scherrer-Institute, c/o Particle Physics, ETH Zürich, Switzerland 2

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The correlation of Tibetan glacial systems to the rest of the world is still a major issue in paleoclimatology. Due to its extreme continental environment – far away from the climatic key area of the North Atlantic – Tibet may host a unique glacial history. With surface exposure dating with in situ produced cosmogenic nuclides (10Be and 21Ne) we try to establish an absolutely dated regional glacial chronology for a valley system at the eastern margin of the Tibetan Plateau. The study area is located near Kanding, in the Daxue Mountains, to the north of Mt Gongga. Previous studies in the upper part of the valley showed evidence for a Younger Dryas glacial advance at around 11.6 kyr. This suggests a synchronous behaviour of Tibetan glaciers to short term global climate fluctuations. To verify these findings, we sampled five erratic boulders in the lower part of the valley, where a local glacier from a tributary valley entered the main valley. All samples derive from glacial deposits from this tributary valley. The minimum 10Be ages range from 12.0 ± 0.5 kyr to 14.3 ± 0.6 kyr. Cosmogenic noble gas analyses confirm the radionuclide data; minimum 21Ne ages are 12.9 ± 2 kyr to 15.5 ± 3 kyr, ruling out any pre-exposure of the samples. This result indicates a clear evidence of an early Late Glacial event in the Kanding area. Furthermore, it supports the idea that also Tibetan glacial systems – at least locally – react very sensitive to abrupt climate changes such as the Heinrich Events or the Younger Dryas cold reversal. 1168 The vegetation history of High Asia as a mirror of Late Quaternary climate change and human influence Frank Schluetz1, Frank Lehmkuhl2, Georg Miehe3, Knut Kaiser3, Jianquan Liu4 1

Department of Palynology and Climate Dynamics, Albrecht-von-Haller Institute of Plant Science, University of Göttingen, D-37073, Germany 2 Department of Geography, RWTH Aachen University, D-52056 Aachen, Germany, Germany 3 Faculty of Geography, University of Marburg, Deutschhausstr. 10, D-35032 Marburg, Germany, Germany 4 Laboratory of Qinghai-Tibetan Plateau Ecological Adaptation, Northwest Plateau Institute of Biology, Chinese Academy of Science, China

In recent years we have used a variety of terrestrial archives from High Asia (e.g., Tibetan Plateau, Altai Mountains) for palynological research on vegetation history, climate change and human influence during the Late Quaternary. Based on these data, we here present some insights into the dependency of vegetation on climate conditions and nomadic land use. We documented the history of grazing using peat and topsoil profiles from grazed areas, having sufficient amounts of pollen of insect pollinated grazing indicators, not or seldom, which are detected in lake sediments. Identification of forested areas required an adjusted sampling strategy. Due to the low pollen dispersal of juniper trees, profiles from the direct vicinity of potential forest locations were acquired. Pollen and charcoal from buried paleosols permitted spatial extrapolation of results from pollen profiles. Pollen spectra of surface samples were found to be influenced by the recent pronounced increases in grazing intensity. Starting with the genesis of the Kobresia-mats after the LGM we followed their history up into the present; today, Kobresia-pastures are the dominant vegetation type in eastern Tibet, covering an area of about 400,000 km2. We demonstrate that nomadic use influenced their development possibly as early as 8500 years ago concomitant with the early domestication of yaks. Since then, structure and species composition of the mats has been shaped by grazing. With increasing grazing pressure due to climate cooling (lower biomass production) and growing herds, dense golf course-like mats of Kobresia

pygmaea developed and inhibited the re-establishment of forests lost to climate change or human destruction. The nomads directly induced the depauperate state of forests in Tibet by transforming wooded areas into grazing grounds by fire. They furthermore indirectly contributed to forest decline by promoting the spread of dense Kobresia turfs. More recently, locally intense grazing led to the degradation of Kobresia mats and creation of patches of bare mineral soil, which has allowed the establishment of forests in special situations. Climatic data show vast regions of Kobresia-mats located in areas climatically suited for forest. These areas can thus not be considered to be alpine. Strictly speaking, they are not examples of High Asian natural wilderness (mats) but rather part of a cultural landscape shaped by nomads (pastures). 0742 A high resolution stable isotope record obtained from a Holocene speleothem from Grotta di Ernesto, Italy Denis Scholz1, Silvia Frisia2, Christoph Spötl3, Augusto Mangini1, Andrea Borsato4, Jens Fohlmeister1 1

Heidelberger Akademie der Wissenschaften, Germany Museo Tridentino di Scienze Naturali, Italy 3 Institut für Geologie und Paläontologie der Universität Innsbruck, Austria 4 Heidelberger Akademie der Wissenschaften, Italy 2

Eight TIMS U-series ages as well as high-resolution stable isotope profiles on stalagmite ER76 from Grotta di Ernesto, Italy, have been determined. Due to its low 238U (20–40 ng/g) content, which is typical for stalagmites from Grotta di Ernesto, U-series dating of ER76 is rather difficult. Nevertheless, we were able to determine a 230Th/U-age of 2.27 ± 0.08 kyr in the youngest part, at 30 mm distance from top (dft). Overall, eleven U-series ages, eight measured in Heidelberg and three from a previous study, were used to construct the final age-depth relationship. The age model and its uncertainty was estimated using a mixed-effect regression model. ER76 was actively growing when it was collected, and it was shown that ER76 exhibits annual laminae in the period between 1650 and 1995 AD (i.e. the upper 20 mm of the stalagmite). The thickness of these annual laminae lies between 0.02 and 0.1 mm. In combination with the new age model obtained by U-series dating this shows that there must be a substantial hiatus between 2.5 and 0.5 kyr in ER76. In the older part (i.e. between 60 and 370 mm dft), ER76 exhibits a rather constant growth rate of approximately 0.05 mm/yr between 8 and 2.5 kyr. ER76 has also been studied by lamina counting, and the good agreement of the number of lamina with the age model reveals that the lamina have yearly resolution. Oxygen and carbon stable isotope profiles were measured at the University of Innsbruck at a resolution of 0.1 mm between 0 and 8 mm dft and 0.25 mm below 8 mm dft. An earlier study revealed that ER76 recorded several Holocene warm/dry and cold/wet phases, respectively. Because the resolution in that study was approximately 2 mm, the new profiles have a ten times higher resolution which should enable to detect even rapid climate events and to perform frequency analysis. 0180 Tales and Facts: Beowulf and Lejre Niels Schroeder Roskilde University, Denmark


The classical site for the Beowulf poem (Lejre-Denmark) – has been re-examined. A geological mapping of the area and geochemical/ palynological analysis of a core from Lake Kornerup indicates, together with new archaeological discoveries that it is possible to compare the story of the poem with the history of the terrain in the Lejre area. Lejre is situated in the centre of Zealand, where the iron age road from NE Zealand to SW Zealand crossed the roads connecting the ship landing sites at the Fjords and the Sound, the location dictated by the wetland and river system, that is areas avoided by the roads. So the Lejre headquarters of the local king is located at the strategic crossing of the roads and river. The main river at Lejre has been relocated from its original course close to the village, to a new more easterly course, towards Lake Kornerup. Pollen and chemical analyses of core samples from Lake Kornerup shows a distinct change in the water quality of the lake, as a result of the river inflow. In times gone by, we had expected that this relocation happened around 1300 AD in connection with construction of watermills. Now new AMS14C datings of samples from Lake Kornerup clearly show that the relocation took place between 700 and 900 AD. As watermills were not known in Denmark at this time, it is tempting to compare the poem with the new archaeological discoveries. It seems that at the same time as the course of the river shifted, the great Hall (Heorot) of Beowulf’s time was abandoned – or had been demolished and moved 600 metres towards SSE.

The search for genuine history in Beowulf’s poem is of course impossible. Neither the monster Grendel nor his mother are something near human beings. They are problems. But if the main problem was enemies coming silently up the river to attack the King’s men, it should be wise to shift the course of the river and at the same time to move the great Hall to the new strategic crossing of the roads and river. 0197 Climate Change and Human Occupation in Denmark and Syria Niels Schroeder, Gitte Jensen, Magnus Limborg, Jend Siggaard Roskilde University, Denmark

Classical sites for studies of human occupation and climatic changes in Denmark and Syria – have been re-examined. A detailed geological/ geophysical mapping of selected sites and geochemical/palynological analysis of cores/profiles confirms that climate change has been the decisive factor behind the main changes in human activities in the areas. It also confirms that the climatic histories of the sites are closely correlated - with strong ties to global causes of climate change. The NAO (North Atlantic Oscillation) caused contrasting rainfall conditions in Denmark and Levant. Over a period of one hundred years, an observation based climatic overview shows an inverted correlation in precipitation trends in Denmark and the Levant. For the Holocene, it can be concluded that the Blytt-Sernander model fits well with both the climatic proxies from the Nordic countries and the rainfall history of the Levant. The changes in human occupation in the Levant and in Denmark both seems to correlate with the proxies of climate change esp. the change from Atlantic to Subboreal around 4000 BC, the change from Subboreal to Subatlantic around 500 BC and the change around 650 and 1400 AD (the start and end of the medieval warm period) are marked in as well the climate record as in pollen and archaeological records (monsoon shifts and NAO seems main responsible agents). We have re-examined the Yarbrud site in Syria (OSL dating and pollen analysis) and it seems possible to correlate the 25 cultural layers here,

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from 10 to 110,000 BC, with the 25 Dansgaard/Oescher events of NORTHGRIP. 0678 The discrepancy between the method of Cosmogenic Nuclide Exposure Dating on moraines and morphodynamics, weathering, glacierdynamics, erosion and global climate Nils Schröder University of Göttingen, Intstitute of Geography, Department of Geography and High Mountain Geomorphology, Germany

To get correct results of Cosmogenic Nuclide Exposure Dating on moraines makes it necessary that bedding conditions of the sampled boulders did not change since deposition and that all kinds of mechanical and chemical weathering on these boulders are interrupted or slowed down and constant respectively since deposition. The absence of geomorphologic processes are especially in mountain areas in contradiction to all accepted results of geomorphologic research of the past. There are several sources of error that adulterate the results of dating to longer and shorter time of exposition. The former exposition of sampled boulders can not be reconstructed in any kind due to the lacking knowledge about the combination of altitude and exposition before transport, during transport, rearrangement in the meantime, surface erosion during transport and after deposition and temporary shielding. The combination of these possible errors differs for each side of the sampled boulder so that it obviates any result of a comparison. The surface weathering and erosion of the boulders adulterates also the possibility of comparing the relation between unstable and stable isotopes. Examples for weathering and erosion of boulders will be presented. The mechanisms of glacial transport and deposition reduce the possibility of finding boulders on moraine-crests that have not been exposed before and especially in terminal moraines are often dumped together materials of older moraine stages, mudflows and gravels. Another unknown fact is the surface development of the moraines after glacier retreat that can not be precisely reconstructed. The often suggested fast slope flattening is implausible especially for the steep inner slope that is often undercut by melting water for longer times after glacier retreat. Slope flattening dislocates the moraine crest downwards the outer slope of the moraine and surface erosion excavates boulders that were covered before. The accepted surface erosion- and weathering rates for different climates make clear that neither moraines nor boulders can have the identical surface as several thousand years before. The sampling on the flat surface of the boulders is in the contrast to the aim of dating the freshest parts of a boulder which are the rounded edges by glacial transport. Another inaccuracy is caused by the unbalanced amount of particles from the upper centimetres of a rock surface that a sample contains. One can assume that all these uncertainties make clear why the results of Cosmogenic Nuclide Exposure Dating on moraines differ from climatologic and geomorphologic observations. 0135 Young Quaternary Lake-Level Changes in Nam Co Basin, Southeastern Tibetan Plateau, China Brigitta Schuett1, Jonas Berking1, Manfred Frechen2, Chaolu Yi3 1

Freie Universität Berlin, Department of Earth Sciences, Physical Geography, Germany 2 Leibniz Institute for Applied Geosciences (GGA-Institut), Section S3: Geochronology and Isotope Hydrology, Hannover, Germany 3 Institute of Tibetan Plateau Research, CAS, Beijing, China

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The endorheic Nam Co Lake, southeastern Tibetan Plateau, was selected to investigate the interrelation between post-glacial glacier decay and lake level fluctuations. The intersection zone of littoral, glacial and fluvial processes in the south of Nam Co was investigated geomorphologically. Data show that during the Last Glacial Maximum fluvial deposits fed by melt water poured from the mountains and accumulated in the foreland. During the transition between MIS 1 and MIS2 glacier decay caused changes in water balance and created an increase of the lake level which is presently shown by a marked cliff line to be detected all around Nam Co with its base approx. 29 m above the present lake level. Through this affected runoff dynamics caused channel incision into the basal fan deposits. During the Holocene decreasing lake level is traced by beach ridges while at the channel’s embouchure to the wave-cut platform new fans are deposited. LGM ice cap estimations for the tributary Nyainqentanghla Range explains about 50 % of the post-glacial volume growth compared to a LGM lake level low appropriate to the present lake level, not including a even lower lake level. In consequence, the remaining 50 % of post-glacial lake volume growth correspond to increased inflow from the western and northern tributaries as regulated by temporary increased precipitation or decreased evaporation. As Nam Co is an endorheic lake post-glacial water loss has to be primarily explained by evaporation and moisture conditions, and thus, leads to the Southeast Asian Monsoon as a major river of local post-glacial water balance. 0136 Archeological Findings in the Upper and Middle Orchon Valley and their Geographical Setup Brigitta Schuett1, Wolfgang Schwanghart1, Jan Bemmann2, Ernst Pohl2 1

Freie Universitaet Berlin, Department of Earth Sciences, Physical Geography, Germany 2 Rheinische Friedrich-Wilhelms-Universität Bonn, Institut für Kunstgeschichte und Archäologie, Germany

The Upper and Middle Orchon Valley are an important corridor in the transition zone between the southern Changai Mountains and the central Mongolian Steppe. Its environmentally favorable and strategic position made it from the beginning of settlement in this area the major axis of migration. A climax phase of human activities in this area represents the late Medieval, when Dschingis Khan chose the fan deposits of the Upper Orchon Valley at its mouth into the central Mongolian Steppe as location for his capital Karakorum (Qara Qorum). The location of Karakorum is chosen advisedly as here favorable climatic conditions in the lee of the Changai Moutains offer protection from the severe summer storms. Its situation on top of the Orchon River’s fan deposits with their coarse gravels covered by eolian fines guarantees dry sunsurface conditions while at the same time the adjoining river course of the Orchon provides fresh water and evacuation of disposed waste water. Finally, the location of Karakorum is positioned like a keystone between the Changai Mountains in the south and the central Mongolian Steppe in the north at the major migration line, allowing the continuous control of each kind of movements. Karakorum, being one of the most impressive and extended historical monuments in the Upper and Middle Orchon Valley, is not the only archeological site of interest in this area, yet. A multiply of archeological findings, including tombs, defense constructions, sacred sites such as the Turkic memorial complex of Khoshöö Tsaidam, towns and palaces and temples document that the Upper and Middle Orchon Valley in the past was a preferred settlement location, settled since many

thousand years. Locations of each of these kinds of findings show typical characters, reflecting the needs and the environmental conditions during its construction and use. A first survey of sites in the Middle and Upper Orchon Valley and the analysis of the landscape characteristics of their location provide a preliminary insight into these temporally, due to environmental conditions and political and technical needs, changing conditions. 0230 Geomorphometric Analysis of landscape units in the Nam Co Basin, Tibetan Plateau, China Brigitta Schuett1, Jonas Berking1, Andre Keil1, Chaolu Yi2 1

Freie Universität Berlin, Fachbereich Geowissenschaften, Physische Geographie, Germany 2 Institute of Tibetan Plateau Research, Chinese Academy of Sciences, China

In central Tibet, at about 30°N and 90°E in 4722m asl the lake Nam Co builds the largest and highest lake system and drainage basin on the central Tibetan Plateau . Continuous sedimentation with high temporal resolution makes sediments from lake systems ideal archives of environmental signals, predominantly driven by climate and human activities. However, lake sediments are the last member in the sequence of the sediment cascade of a catchment: such as fans, terraces, colluvial deposits and lake sediments. Research of the geomorphologic environment therefore holds various information about landscape evolution and the present character. Here we tried to identify landscape characteristics by terrain analysis of the Nam Co drainage basin. Classification showed strong N-S-contrasts in the study site, highlighting glacial affected areas in the mountainous south and unglaciated areas in the hilly north. Next to this, more detailed terrain analysis allows to distinguish eight different geomorphologic units grouped as follows. • In the south of Nam Co last in LGM valley glaciers and glacial shaped areas are predominant. • In the north and west of Nam Co glacial morphodynamics are lacking. Relief can be characterized as a hilly landscape highly influenced by tectonics and with extended fluvial deposits which along the littoral zone interfinger with lacustrine deposits. • Also in the east of Nam Co glacial deposits are lacking. Aeolian deposits cover wide areas forming extended primary dune fields in the late Quaternary littoral zone and covering the basal parts of the slopes with sand-sheets, most recently dissected by first and second order channels. Each landscape unit is characterized by its morphometry. Data base for the morphometric analysis are corrected SRTM data with 90m*90m horizontal resolution and a vertical reliability of approx. ± 4 m (2 ). In our ongoing work we are looking forward to couple morphometric terrain analysis with our results of Holocene landscape evolution and approximations of lake-level changes. The project is part of the DFG bundle project: “ The Tibetan Plateau: Geodynamics and Evolution” – “Lake System Response of Nam Co Area, Central Tibet, to Late Quaternary Monsoon dynamics” – in joint cooperation with CAS and ITP.


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0631 Fluvio-lacustrine Holocene sedimentation dynamics of Nam Co, Tibetan Plateau, China

and landscape in these highly diverse regions. Located in the triangle of the westerlies and the Indian and Asian Monsoon these areas and their societies sensitively reacted to changes in atmospheric circulation patterns.

Brigitta Schuett1, Manfred Frechen2, Antje Schwalb3, Claudia Wrozyna3, Caolu Yi4

Ugii Nuur (102˚46′E, 47˚45′N, 1330 m a.s.l.) is a freshwater lake located in the steppe area of Mongolia. Its vicinity to the former capital Qara Qorum and the repeatedly settled Orkhon Valley make the basin a valuable site to study climate, landscape and societal evolution. Although the Ugii Nuur basin is not located in the direct influence of the Asian Summer Monsoon we hypothesize that Holocene changes in the monsoonal regime caused alterations in the influence of the westerlies in this region. Paleoenvironments in the Ugii Nuur basin were investigated by analyzing bulk parameters and mineralogical and geochemical indicators of lacustrine and terrestrial sediments, and by surveying landforms by Differential GPS and vertical electrical soundings. The findings show evidence for climate anomalies during the early and middle Holocene in this region and provide a valuable basis for further investigations integrating approaches from environmental sciences and archeologists.

1

Freie Universität Berlin, Fachbereich Geowissenschaften, Physische Geographie, Germany 2 Leibniz Institute for Applied Geosciences (GGA-Institut), Section S3: Geochronology and Isotope Hydrology, Germany 3 Institut für Umweltgeologie, Technische Universität Braunschweig, Germany 5 CAS Institute of Tibetan Plateau Research, Beijing, China

In the northwest of Lake Nam Co, southern Tibetan Plateau, at the mouth of one of its major tributaries draining from the northwest, riverbank erosion created a ca. 10m high outcrop. The sediment sequence mainly consisting of silty clays and clayey silts was recorded in detail and sampled every 10 cm. 14-C dating shows that the sediments were deposited continuously during the Holocene, with decreasing ages from bottom to top from about 8 ka BP in 8m depth to 2 ka BP in 2.3 m depth below surface.

The uppermost four meters of the outcrop show 1–2 cm thick alternating layers of light-grey silty clay and 0.5 cm thick layers of aquatic plants. This section of the outcrop is also characterized by abundant roots of aquatic plants. Below 3.8 m depth these roots and also layers of aquatic plants are missing. Ostracode valves occur all over the outcrop, changing species association in approx. 4m depth. Below 5 m depth, visible plant remains were lacking. Sediments below 5m depth show alternating dark grey and light grey laminae about 1–3 mm thick; the total thickness of this laminated layer cannot be assessed because at 10 m depth below surface the present channel was reached. Basal sediments were frozen during sampling (August 2005), which points to the occurrence of a local ice lense. The mineralogical composition of the sediments emphasize the distinct change in facies in approx. 4 m depth: whereas the sediments below 4 m are mainly composed of calcite and detrital dolomite (> 60 vol.-%), the uppermost 4 m are characterized by high quartz and feldspar contents reaching values of up to 90 vol.-%. Sediment texture and fossil content suggest that sediments outcropping in northwestern Nam Co are of fluvio-lacustrine origin and were deposited in a delta environment of Nam Co. The sandy character and relatively low numbers of ostracode valves in the topmost sediments indicate increased fluvial influence, possibly due to a temporarily increased flood frequency while lake level was low. Sediments below 4m can be clearly identified as lacustrine deposits. Homogenous sediments indicate strong wave motion, while finely laminated laminae below 9m depth may represent warves deposited in a proglacial lake. 0787 Holocene climate dynamics in central Mongolia inferred from sediments of Lake Ugii Nuur Wolfgang Schwanghart, Brigitta Schütt Freie Universität Berlin, Germany

Monsoon Asia and Central Asia have been a focus of paleoenvironmental research in order to gain insight into the evolution of climate

0790 Large scale meteorological factors of dust mobilization in the Bodélé Depression, Chad Wolfgang Schwanghart, Brigitta Schütt Freie Universität Berlin, Germany

Mineral dust in the atmosphere is mainly controlled by eolian morphodynamics mobilizing particles that can be held in suspension by the wind, fostered by local turbulences. The Earth’s major dust source is the Bodélé Depression (17°N, 18°E) in the south of the Tibesti Mountains. Here, sandstorms generate dust particles transported as far as the Caribbean Sea and the Amazonas Basin. During the dry winter months the NE-Passat carries dust originating from the Bodélé Depression close to the surface as far as the Guinean Coast. These 3–4 days lasting weather extremes are referred to as Harmattan dust events. They cause severe weather conditions due to heat absorbtion and visibility reduction and, hence, occasion high economical losses and put the population’s health at risk. In this study we examined the mesoscale meteorological settings causing the dust generating winds in the Bodélé Depression. Atmospheric dust concentrations were characterized by the Aerosol Index of the Total Ozone Mapping Spectrometer (TOMS-AI) on Nimbus satellite from 1981 to 1990. This daily data was correlated to the meteorological variables quantified by intrinsic data from the NCEP/NCAR-Reanalysis Programme. It has been found that dust mobilization during the Harmattan Season is highly dependent on air pressure variability in the Mediterranean area. High pressure to the north of the Bodélé causes an intensification of the near surface NE-Passat leading to an increased entrainment of dust in the Bodélé Depression. Hence, the occurence of Harmattan dust events can at least partly be explained, an information valuable in the prediction of these severe weather conditions.

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0804 Archeological findings in the Upper and Middle Orchon Valley and their geographical setup Wolfgang Schwanghart1, Brigitta Schütt1, Ernst Pohl2, Jan Bemmann2 1

Freie Universität Berlin, Germany Friedrich-Wilhelms-Universität Bonn, Germany

2

The Upper and Middle Orchon Valley are an important corridor in the transition zone between the southern Changai Mountains and the central Mongolian Steppe. Its environmentally favorable and strategic position made it from the beginning of settlement in this area the major axis of migration. A multiply of archeological findings, including tombs, defense constructions, sacred sites such as the Turkic memorial complex of Khoshöö Tsaidam, towns and palaces and temples document that the Upper and Middle Orchon Valley in the past was a preferred settlement location. Locations of each of these kinds of findings show typical characters, reflecting the needs and the environmental conditions during its construction and use. A first survey of sites in the Middle and Upper Orchon Valley and the analysis of the landscape characteristics of their location provide a preliminary insight into these temporally, due to environmental conditions and political and technical needs, changing conditions. 0842 Short term redeposition rates versus long term deposition rates in a mangrove forest, Can Gio, Saigon River mouth, Southern Vietnam Klaus Schwarzer1, Patrycja Czerniak2, Coastal and Shelf Geolog3 1

University Kiel, Institute of Geosciences, Sedimentology, Coastal and Shelf Geology, Olshausenstrasse 40, 24118 Kiel, Germany 2 University Kiel, Institute of Geosciences, Sedimentology, Olshausenstrasse 40, 24118 Kiel, Poland 3 Thuyen Le Xuan, Vietnam

Mangroves have their widest extent along tropical muddy coasts in lowland deltas where sediment delivery allows a progression of the coastline. In the presence of mangroves usually less erosion occurs whilst expansion takes place at particular coastal types with mangrove existence, i.e. at river mouths and in sheltered areas. Along those coastlines a “healthy” mangrove belt has a width of at least 300 m – 500 m. These coastlines have a natural variability of erosion and accumulation and are adapted to natural periodic disturbances. In deltaic areas they can even keep pace with a sea level rise up to 4.5 mm/year and are growing due to an increase in tidal flooding. As sea level rises and water flow alters the distribution of salt- and freshwater in mangrove areas will change. The mangrove ecosystem will respond by changing in productivity, aerial extent and species diversity. However, forest structure and productivity may be disrupted temporarily by natural catastrophic storm floods and/or anthropogenic influences. Nowadays these unique areas undergo a rapid and accelerated alteration due to the consequences of climate change, resulting in eustatic sea level rise, change of global temperature and precipitation patterns, changes in storm frequency and intensity, changes in the prevailing ocean wave heights and direction and changes in the tidal regime. In Can Gio mangrove reserve and in the Saigon River mouth we took several up to 4 m long sediment cores, which allow analyzing a continuous mangrove sediment profile of more than 7 m. Grain size- and clay mineral analyses, detailed analysis of microfossils and age control by AMS C-14 dating for the deeper areas and Pb-210 dating for the upper parts

allows to reconstruct the environmental development of this area for the last 800 years. An average growing rate of 4.5 mm/year was estimated at least for the upper 0.5 m. By detailed redeposition measurements during a 2 years period along 3 tidal creeks at 54 positions in different types of mangrove forest it turned out that erosion and redeposition have a strong seasonal signal. During the wet season with strong monsoonal rainfall erosion and redeposition in the forest can reach values up to 10 cm in 2 weeks. While during the dry season the tidal regime controls the sedimentation processes it is the rainfall during the wet season which dominates the erosion and deposition. 0291 Alpine fluvial evironment and land-use changes: The Bernese Alps during the Late Holocene Lothar Schulte1, Heinz Veit2, Ramon Julià3, Francesc Burjachs4 1

Department of Physical and Regional Geography, University of Barcelona, Spain 2 Institute of Geography, University of Bern, Switzerland 3 Institute of Earth Science “Jaume Almera”, CSIC, Barcelona, Spain 4 ICREA at the Department of Prehistory, University Rovira i Virgili, Tarragona, Spain

In high mountain ranges gently sloping surfaces appropriate for settlement are scarce, and they are commonly related to distal parts of alluvial fans that are prone to geomorphic hazards as the 2005 flood in the Bernese Alps showed. The understanding of Holocene alpine fluvial processes influenced by human-environmental interactions is crucial for spatial planning. To address the influence of external factors, such as climatic variability and land use, on aggradation and floods, we focused our research on the Late Holocene sedimentary and geomorphologic history of the Lütschine fan delta. Our multiproxy approach includes morphological mapping, sedimentology, geochemistry, palynology, historical maps, building inventories and 14C-dating techniques and provides valuable data for the reconstruction of paleofloods, wetland environments, and anthropogenic impact. The sedimentological findings of the Lütschine fan delta showed a general agreement between geochemical and pollen cycles and d14C anomalies from 2600 to 850 yr cal. BP. Despite the anthropogenic influence geochemistry and mesic tree percentages show at least three cycles. During the last millennium the fan delta aggradation is characterised by a strong human impact, derived from deforestation activity for the purpose grazing, farming, local mining, foundation of new settlements and tourism. The drop of arboreal pollen percentages and mesic trees, as well as the absence of organic-rich layers, show that the sedimentary and geomorphic pattern on the Lütschine fan delta changed reducing wetland environments. The coarse-grained layers of the Lütschine fan delta, deposited during paleofloods about 400 yr BC, 100, 700, 1100, 1550, and 1850 yr AD, correlate with positive radiocarbon anomalies, suggesting that aggradation during the focused period was triggered by solar forcing. According to our pollen data and the traced correlations, the Lütschine river floods occurred mainly during cold and wet periods. For the period from 1425 to 1880 AD the building inventories of 21 municipals of the Lake Brienz and Thun area were used as palaeoflood-proxies according to three classes: house building on fan deltas, steep gradient alluvial fans and on not flood influenced landforms. The 31-year moving average of number of constructed houses per year of the fluvial influenced municipals and the radiocarbon anomalies shows similar tendencies. Two of the three minimums of construction correlate with two gravel layers of the Lütschine fan delta and with periods of increased flooding in the Swiss Alps (around 1550; 1815–1835 AD).


Acknowledgements: The research was supported by the Alexander von Humboldt-Foundation (V-3.FLF-DEU/1070630) and the MEC (CGL2006-0111, PCI2005-A5-0208). 1028 A remote sensing based record of modern playa inundation events in western North America: Analogues for Holocene monsoon and westerly variability? Louis A Scuderi, Christine K Laudadio, Peter J Fawcett Department of Earth and Planetary Sciences, University of New Mexico, United States

Lake-level variations preserved as beach ridges in modern playa basins in the Chihuahuan Desert, northern Mexico, record millennially spaced episodes of increased precipitation during the Holocene. Periods during the early, middle, and late Holocene were wet enough to establish large pluvial lakes, many of which correlate temporally with lake highstands in the Mojave Desert. These playa lake filling events in western North America are related to both the influences of cold season Pacific frontal and warm season monsoonal precipitation. Over the Holocene the influence of these precipitation inputs to has varied considerably and we hypothesize that periods of regional lake highstands are characterized by an increased influence of cold season frontal precipitation. In most regions inundation regimes of playas over time-scales of years to decades are poorly known or have not been recorded. We used SPOT and Landsat to determine playa edges with high precision. Coarser resolution MODIS and AVHRR imagery was used to determine playa surface area and to develop a chronology of playa inundation over the past 35 years. We compared this time series of inundation events with weather station data to determine the relationships between playa filling events and current climate conditions. Since the period of analysis from 1978 to the present includes several El Nino events, and ~30 monsoon and winter seasons with frontal precipitation, we statistically analyzed the relationships between climate and inundation events. By comparing the results of the inundation chronology with gridded precipitation data for northern Mexico and the western United States, we determined the dominant season of water filling events, the kinds of weather systems and precipitation events that are most significant for filling the playas, and the relative roles of the summer monsoon runoff versus winter precipitation runoff. We also evaluated the importance of ENSO and PDO type modulation of winter precipitation over southwestern North America to determine if this is a dominant factor in the modern playa hydrology. During El Nino years, the Pacific subtropical jet strengthens and tends to steer winter storms along a southerly track into central and southern California. The increased frequency of storms passing through the southwest enhances wintertime precipitation in northern Mexico, southern California, Arizona and New Mexico. During La Nina years, the Pacific subtropical jet weakens and the Pacific polar jet strengthens steering storms further north, which greatly reduces the frequency of winter storms and precipitation amounts in southwestern North America. 0788 Uranium-series dating results of peat deposits from Central Europe to Siberia Melanie Sierralta, Manfred Frechen Leibniz Institute for Applied Geosciences, Germany

Interstadial and Interglacial peat deposits are widespread in a transection between Central Europe, Lithuania, Russia, and Siberia, and en-

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able us to reconstruct the vegetation history of the Northern Hemisphere. Multidisciplinary studies including lithostratigraphy, palaeontology, and palynology were performed by partners all over the transect. The reliable chronological frame for the reconstruction of climate and vegetation history was investigated by uranium series dating. The suitability of the peat layers for dating strongly depends on two essential prerequisites: (1) during the initial formation process any thorium was absent and (2) a geochemically closed system behaviour excluding uranium and thorium migration after deposition. However, peat may contain varying amount of admixed thorium by dust and clay minerals, while water passing through the peat layer can cause migration of uranium. Therefore, dating has to be carefully checked for the fulfilments of the prerequisites. Uranium series dating was performed on peat and organogenic deposits applying the thermal ionisation mass spectrometry (TIMS). Coeval peat samples were burned to ash and prepared by the leachate/leachate technique, spiked, and chemically separated for measurements of the isotopic composition. Once isotope activities are determined, age calculation depends on the evaluation techniques used to obtain reliable ages. The evaluation procedure includes (1) estimation of the thorium index by the isochron method to (2) correct the activity ratios for admixed detrital thorium, (3) calculation of corrected single 230Th/U ages, (4) checking corrected ages with the Chi-square test, and (5) calculation of weighted mean of isochron derived detritally corrected age for the deposit. The study of a variety of sections of burial peat on the transect gave a widespread overview on the suitability of peat deposits. Several case studies were investigated by uranium series dating. At the Netiesos section located in Lithuania, the age determination for the peat failed owing to the impossibility of determining an isochron to correct the single ages for the admixed detrital thorium. Furthermore, the investigation of the peat section of Gröbern, Germany, failed due to wide spreading activity ratios clearly demonstrating open system behaviour. Comparisons with radiometrically investigated uranium series ages retrieve the possible reasons. An isochron derived detritally corrected age of 219±8 ka was successfully determined for the peat layer from Krivosheino in Siberia, which is in excellent agreement with independent age control. 0821 Physico-geochemical characteristics and recent sedimentation history of Lake Nam Co, Southern Tibet Philip Steeb1, Robert van Geldern2, Gerhard Daut3, Antje Wittenberg4, Dieter Rammlmair4, Liping Zhu5, Antje Schwalb1 1

Technische Universität Braunschweig, Germany Leibniz Institut für Geowissenschaftliche Gemeinschaftsaufgaben, Germany 3 Friedrich-Schiller-Universität, Germany 4 Bundesanstalt für Geowissenschaften und Rohstoffe, Germany 5 Institut of Tibetan Plateau Research, China 2

The reconstruction of Monsoon history from lake sediments demands a solid characterization of the lake system and its sedimentation dynamics. Lake Nam Co is the second largest saline lake on the Tibetan Plateau and the target of a multi-disciplinary research effort. Here we present results from fieldwork carried out in August/September 2005. The water column temperatures displayed a distinct thermocline and indicate that Nam Co was stratified in early September 2005. Water temperatures drop from about 12 to 6 °C between 20 and 30 m and reach minimum values of about 5 °C below 70 m water depth (maximum depth at sampling site: 85 m). The oxygen content varies between 4 and 6.5 mg/l. This shows that even during stratification the lake bottom water is well oxygenated. Salinity was 0.9 ‰ and pH was about 9.4. Secchi depth was 8.5 m. Elemental concentration of the lake

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water is very low, with Ca2+ and Mg2+ being the most prominent ions. Bor, a typical element of terminal lakes, occurs in significant quantities. Three 60 to 80 cm long cores consisting of homogenous silts were processed for 210-Pb/137-Cs dating. Sedimentation rates determined from a 67 cm long core taken from 50 m water depth was about 1.15 mm/yr and constant over the past 150 years. EDXRF scans provide high-resolution records of environmental changes. We will present results from EDXRF scans combined with geochemical data from conventional lab methods in order to validate EDXRF results. Preliminary EDXRF scans of a 2.7 m long core show higher and more variable counts for Ca and Sr above 2.45 m accompanied by a distinct decrease in counts of K and Rb. Concomitantly, grain size changes from sandy silt to silts at this level suggest that there was a significant change in sedimentation dynamics in Lake Nam Co. This is a contribution to the research program ‘The Tibetan Plateau – Geodynamics and Environmental Evolution’ within the framework of a Sino-German co-operation. 1153 Conserving native biological diversity in the Galápagos Islands: Determination of ecological conditions over the last 4000 years Alistair Seddon, Cynthia Froyd, Kathy Willis Oxford University Centre for the Environment, United Kingdom

The current biodiversity status of the Galápagos archipelago sits at a crisis point, where the threat from extensive habitat degradation and the spread of invasive, non-native species have led to the islands experiencing some of the highest extinction rates in the world. Although 95% of its native ecosystem remains intact, this famous ‘natural laboratory’ may no longer provide such a unique opportunity to study evolutionary and ecological concepts first-hand. Establishing the ‘Ecological Baseline Conditions’ has been identified as critical for a successful conservation effort, since this will provide understanding of the ecological status of the islands prior to the initial colonisation by humans in 1535. The ecological baseline is a theoretical term which encompasses former community compositions and dynamics, successional cycles and responses to environmental change on a series of temporal scales. Palaeoecological techniques have been employed in order to provide high resolution analysis of the palaeoenvironments of Galápagos over at least the last 4000 years, complementing a wider study investigating the presence and behaviour of a number of doubtful natives. Results presented here focus on sea-level changes and climatic variability and the associated ecosystem response, using geochemical, fossil pollen and diatom data from a 4.5 m non-lacustrine core collected from the main island, Isabella. A long-term temporal perspective is too often neglected in conservation science, and this study represents an exciting breakthrough in which palaeoecology is used to solve one of biodiversity’s most significant contemporary issues. 1217 New computer based methods for high resolution analyses of fine laminated sediments in thin sections Klemens Seelos1, Knut Jaeger1, Frank Sirocko1, Bert Rein2 1

Institute for Geoscience, University of Mainz, Germany GeoConsultRein, Germany

2

Laminated sediments are excellent climate proxy archives, in particular if the laminations are annual varves. To analyse the internal structure and the composition of these sediment sequences, we developed two auto-mated detection methods. RADIUS is a particle-size mea-

surement tech-nique, based on evaluation of digital images of thin sections, to achieve a sub-mm sample resolution and study sedimentation process in the range from medium silt to coarse sand size (RADIUS – Rapid Particle Analysis of digital images by ultra-high-resolution scanning of thin sections). The application identifies typical particle size distributions and detects auto-matically the processes which are responsible for these numerical pat-terns (Seelos and Sirocko, 2005, Sedimentology 52, 669–681). Thereby it is possible to separate dust sequences from turbidites and to identify vol-canic ashes/ tuffs and organics with a sample interval of 500 µm.

COMPONENTS is a new method (Rein & Jäger, 2007, Sedimentology, in press.) to automatically quantify sedimentary components in thin sec-tions. The thin sections are photographed under polarized and under un-polarized plain light. Then, the two images are stacked to a single 6-band (multispectral) image file. The next step is the discrimination of the major sediment components by their transmission spectra. We use an ap-proach based on ratios in order to eliminate illumination differences. By combining specific ratios we are able to detect all major components in the investigated sediments. After classification, each pixel is attributed to one component. To identify varves we need information on the abun-dance of components in the layers. We use a filter kernel to integrate the classification data within horizontal units. Each pixel of the maps now carries the information about the relative frequency of all components in the neighbourhood. Finally, component occurrences along profile lines can be visualized as diagrams. Both RADIUS and COMPONENTS to-gether allow a quantitative analysis of sedimentation processes (grain size) and sediment composition (pyrite, diatoms, wood, quartz, clay and carbonate content) in fully automated algorithms directly from digitally scanned thin sections. 1089 Littoral palaeoenvironmental changes throughout the last 3500 years in central New Caledonia inferred from Fournier swamp Anne Marie Sémah1, Denis Wirrmann2, Magali Chacornac-Rault3, 1

IRD, France IRD, New Caledonia 3 Muséum national d’histoire naturelle - Paris, France 2

Our study of Fournier swamp provides the first proxy record of the local coastal environment from central New Caledonia. The reconstructed history of environmental change, based on lithostratigraphy, mineralogy, pollen and radiocarbon dates covers the last 3.5 millennia. It was found that the swamp history initiated sometime around 3405 calibrated years BP. The pollen content of the sediments, due to the localisation of Fournier Swamp, reflects a mixed local origin, issued preferentially from the three neighbouring environments, i.e. the swamp itself, the coastal and the hinterland areas. The changes recorded by these environments since 3500 years underline light climate fluctuations and retrace also the coastal morphology evolution. The account of microcharcoal is quite homogeneous from 1800 cal yr BP showing that the climate fluctuations have not infer on the microcharcoal loads and that the most likely is that they are of mainly anthropogenic source.

Unexpected late Holocene homogeneity in the sediments’ content and in their variability at this place is revealed. There is no evidence of significant sedimentary changes caused by cata-


strophic climatic events (cyclones, west storms, El Niña/Niño episodes). The constancy in the sedimentary facies through the last 3.5 millenia cannot be considered only as the result of a high degree of climatic stability. It is also the consequence of site insensitivity which is catchment specific. 1090 Palaeoenvironmental studies in Vanuatu – Prospections and first results Anne Marie Sémah1, Denis Wirrmann2 1

IRD, France IRD, New Caledonia

2

In order to compare the palaeoenvironmental and palaeoclimatological data between New Caledonia and Vanuatu, we prospected the swampy potential in Efaté, Santo and Tanna Islands, in Vanuatu. In Efaté, three swamps and lakes have been sampled and especially Emaotfer swamp in the south of the Island. Emaotfer is particularly interesting for its rather deep and contrasted bore records and for the proximity of the ‘Lapita cemetery’ recently discovered. The boring Emaotfer 06 record (4.8 m.) is 6000 BP old and palynological and sedimentological studies are undertaken. In Santo, during the ‘Santo 2006’ mission, we studied the karst environment which consists in many caves, rock shelters and dolines. The pluridisciplinary approach of this mission devoted to biodiversity allows us to integrate our data in a general environmental context. 0540 Quaternary Glacial History of the Central Karakoram Yeong Bae Seong1, Lewis Owen1, Michael Bishop2, Andrew Bush3, Luke Copland4, Robert Finkel5, Ulrich Kamp6, John Shroder2 1

University of Cincinnati, United States University of Nebraska at Omaha, United States 3 University of Alberta, Canada 4 University of Ottawa, Canada 5 Lawrence Livermore National Laboratory, United States 6 The University of Montana, United States 2

The timing and extent of glaciation in the central Karakoram was defined using remote sensing, geomorphic mapping, and 10Be terrestrial cosmogenic nuclide (TCN) surface exposure dating of boulders on the moraines and glacially eroded surfaces. These data show that glaciers advanced at least eight times over at least the last two glacial cycles. The timing of glaciation for seven of these glacial advances was numerically defined at: ~90–170 ka, but are likely much older (Skardu glacial stage); ~16 ka and 11–13 ka (Mungo glacial stage); and 5.7 ka, 4.4 ka, and 0.8 ka (Askole glacial stage). During these times, the extent of glaciation dramatically decreased from > 200 km long extensive valley glaciers from the present snout of the Baltoro glacier during the Skardu glacial stage to ~130 km long valley glacier that was at least 2000 m thick during the Mungo glacial stage to restricted (~70 km long) tributary valley glaciers during the Askole glacial stage. The most recent glacial advance is not defined but likely occurred about a few hundred years ago. Glacier oscillations in this region likely respond to changes in Northern Hemisphere oceans and ice sheets teleconnected via the mid-latitude westerlies, although we can not rule out the possibility of a monsoonal influence on glaciation during the Last Glacial cycle.

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0361 North-European pollen-climate calibration model: quantitative reconstructions of the Holocene temperature changes and comparisons with independent records Heikki Seppä1, John Birks2, Karin Antonsson3, Anne Bjune4, Thomas Giesecke5, Maija Heikkilä1, J Sakari Salonen1, Siim Veski6 1

Department of Geology, University of Helsinki, Finland Department of Biology, University of Bergen and Environmental Change Research Centre, University College London, Norway 3 Department of Earth Sciences, Uppsala University, Sweden 4 Department of Biology, University of Bergen, Norway 5 Department of Geography, University of Liverpool, United Kingdom 6 Institute of Geology, Tallinn University of Technology, Estonia 2

The North-European pollen-climate calibration model consists of 389 pollen surface samples from Norway, Finland, Estonia, Sweden, and Russia. All samples are collected from the centres of small to medium size lakes ranging from the tundra to the northern temperate forest. All samples are treated and analysed using harmonized methodology and taxonomy. The transfer functions for July mean temperature (Tjul) and annual mean temperature (Tann) are developed based on samples obtained from Norway, Finland, Estonia, and Sweden, using the weighted averaging partial least squares regression (WA-PLS). All terrestrial pollen and spore types are used in the WA-PLS models. The statistical performance of the models is tested by means of leave-one-out crossvalidation. The root-mean square error of prediction between the predicted and observed values is about 0.9 ˚C for Tann and 1.0 ˚C for Tjul, and the R2 between the predicted and observed values is 0.88 for Tann and 0.72 for Tjul. The reconstructions based on the models are carried out from well-dated, high-resolution pollen stratigraphies obtained mostly from the northern tree-line region and from the ecotone between the boreal and temperate zones. All records indicate a steady rise of Tjul and Tann from the onset of the Holocene at 11,700 cal yr BP towards a clear Holocene Thermal Maximum (HTM) at about 8000 to 4000 cal yr BP, when the Tann was about 2.5 ˚C and Tjul about 1.5 ˚C higher than at present. The 8.2 ka event is the only unambiguous cold event that can be observed in many records. It is reflected by a decline of 1.5 ˚C in the records from the boreal-temperate ecotone, but, intriguingly, is missing from the records from the tree-line area. The neoglacial cooling starts abruptly at about 4200 cal yr BP. Human interference distorts the southern records particularly during the last 1000 years. The results produced by the pollen-climate calibration model are compared with independent palaeoclimate records, based, for example, on chironomid, plant megafossil, lake varve, and stable isotope records. The records are in general consistent but there are some differences regarding, for example, the timing of the HTM and the occurrence of the 8.2 ka event in northern Europe.

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0721 Synchronisation of the EDC and EDML EPICA ice cores via volcanic stratigraphies in the framework of the construction of a common EPICA age scale Mirko Severi1, Emiliano Castellano1, Roberto Udisti1, Andrea Morganti1, Hubertus Fischer2, Urs Ruth2, Frederic Parrenin3, Eric Wolff4 1

Department of Chemistry, University of Florence, Florence, Italy, Italy Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany, Germany 3 Laboratoire de Glaciologie et Géophysique de l’Environnement, CNRS and Joseph Fourier University, Grenoble, France, France 4 British Antarctic Survey, Cambridge, UK, United Kingdom 2

In the framework of the EPICA project, a common time scale for the two deep EPICA ice cores from Dome C (EDC - 75˚06′S, 123˚23′E, 3233 m a.s.l., Pacific/Indian sector) and Dronning Maud Land (EDML −75˚00′S, 00˚04′E, 2892 m a.s.l., Atlantic sector) was set up. Since EDML core was not drilled on a dome, the development of the EDML1 time scale for the EPICA ice core drilled in Dronning Maud Land was carried on by creating a detailed stratigraphic link between this core and the one drilled in Dome C, dated by a simpler 1D ice-flow model. The synchronisation between the two ice cores was built via the identification of several common volcanic signatures. Here we describe the rigorous method that was employed for the synchronisation of the last 52 kyr of the two records using the signature of volcanic sulfate, obtained by high resolution analysis by Fast Ion Chromatography (FIC) and supported by the independent matching of spikes in the solid and liquid electrical conductivity records. More than 200 isochronous volcanic events were identified by comparison of the high resolution sulphate profiles in the two cores. The high number of contemporaneous eruptions found in the two records allows the reconstruction of the glaciological accumulation rates at the two sites (after correction of the snow depths for density, thinning and upstream contributions) and the comparison with the thermodynamic accumulation (based on the thermodynamic relationship between content of stable isotopes in the ice and accumulation rate). Deviations between glaciological and thermodynamic accumulation rates reflect either a combination of thinning anomalies not reflected by the glaciological model as well as changes in the spatial variability of the upstream surface accumulation rates at DML which differ from the present one. Finally the ratio among snow accumulation rate at the two sites gives information on the different climatic history in Antarctic areas which may be characterised by different atmospheric and oceanic regimes. 0923 Evaluating the effect of spatial resolution on data-model comparisons for topographically complex regions Sarah L Shafer1, Robert S Thompson1, Patrick J Bartlein2, Laura E Strickland1 1

U.S. Geological Survey, United States University of Oregon, United States

2

The ability of climate models to simulate past climates is often evaluated by comparing simulated climate data with paleovegetation data. Output from general circulation model (GCM) simulations of climate can be used as input for vegetation models to simulate paleovegetation. Paleovegetation simulations are then compared with paleovegetation proxy data, such as pollen from lake sediments and macrofossils from packrat middens, to evaluate the match between the simulated paleovegetation and the actual distribution as interpreted from the paleoen-

vironmental record. Good agreement between the simulated and observed paleovegetation data is taken as an indication of the ability of a GCM to accurately simulate past climate. These data-model comparison efforts are limited, however, by the coarse spatial scale of the climate simulations. GCMs are often run at grid resolutions on the order of thousands of kilometers, which limit their ability to resolve important topographic features, such as mountain ranges, that influence the distribution of vegetation. The coarse spatial scale presents particular problems in topographically complex areas, such as the western United States. To examine the effects of spatial resolution on datamodel agreement, we spatially downscaled 6 ka and 21 ka GCM climate simulations produced for the Paleoclimate Modelling Intercomparison Project, Phase 2 (PMIP2). We use these data with BIOME4 to simulate the distribution of plant functional types and biomes for the western United States at spatial resolutions of 30-minutes and finer. We compare these simulations with fossil pollen and macrofossil data represented as biomes in the BIOME6000 dataset for the western United States. Our results demonstrate the importance of concordant spatial scales for evaluating data-model agreement. 0148 Compositional heterogeneity in tephra deposits resulting from the eruption of multiple magma bodies: implications for tephrochronology Phil Shane1, Ian A Nairn2, Shannon B Martin1, Victoria C Smith3 1

University of Auckland, New Zealand GNS Science, New Zealand 3 University of Bristol, United Kingdom 2

Tephra deposits of unknown age, and/or occurring in distal sequences that lack stratigraphic markers, are commonly identified by their glass compositions and mineralogical assemblages. Recent studies of widespread rhyolitic tephra deposits from Okataina Volcanic Centre (OVC), New Zealand, reveal a hitherto unrecognised geochemical and mineralogical diversity within individual deposits, and sometimes between and within individual lapilli in these deposits. These variations, subtle in some units, can occur both vertically and laterally through a tephra deposit, and result from the sequential or simultaneous eruption of separate batches of rhyolitic magma. This process often includes mingling of magmas in the eruption conduits, as demonstrated by disequilibrium mineral assemblages in pumice clasts. Some eruption episodes (e.g., 36 calibrated ka Hauparu, 17.6 cal. ka Rerewhakaaitu) have tapped two or more magmas simultaneously, while others (0.7 cal. ka Kaharoa; 15.4 cal. ka Rotorua) have tapped multiple magmas sequentially. Some tephra deposits display the sequential and/or simultaneous emissions of different magmas from multiple vents through temporal phases of the episode (5.5 cal. ka Whakatane). The resulting deposits can also show variations between different azimuths around the vent due to changes of wind direction during the episode. The internal heterogeneity in OVC tephra deposits was only recognised after comprehensive sampling through their thick proximal pyroclastic sequences and associated lavas. The internal heterogeneity highlights the inadequacy of fingerprinting tephra deposits from a small number of samples of restricted dispersal. Magma mingling at a single-clast-scale also has implications for geochronological techniques that use accessory phases (U-series) and/or require uniform melt geochemistry (fission-track on glass).


1201 Is Magnetic Susceptibility a Proxy for Rainfall in the tropical milieu? R Shankar1, C N Prabhu2, Anish K Warrier1, G T Vijaya Kumar1, B Sekar3 1

Mangalore University, India Centro de Dados Geologico-Mineiro Alfragide, Portugal 3 Birbal Sahni Institute of Paleobotany, Lucknow, India 2

The Indian monsoon is of paramount significance to the people of the Indian sub-continent and hence there is a dire need to predict its future pattern. To do this, proxy rainfall data have to be collected. So far, scientists have considered wind strength, primary productivity, terrigenous input and salinity variations in the Arabian Sea as proxies for monsoonal rainfall. Obviously, they are indirect and not a measure of rainfall per se. We have explored the possibility of using magnetic susceptibility (χlf) as a potential candidate in this regard. We determined the rock magnetic properties of sediments from Thimmannanayakanakere (140 12′N; 760 24′E), a small tank near Chitradurga town, Karnataka. The chronology for the 3.7-m sediment profile is provided by two 14C dates. Magnetic susceptibility exhibits significant variations. Discounting the possibilities of magnetite from biogenic and anthropogenic sources and of magnetic mineral dissolution, we suggest that χlf is principally related to rainfall in the catchment: Pedogenesis is driven by both temperature and rainfall. As temperature variations are minimal in tropical Southern India, pedogenesis (measurable as pedogenic magnetite) is principally controlled by rainfall. Thus, the amount of pedogenic magnetite produced in the catchment and transported to the tank during rainy season (related to χfd of sediments) is a reflection of the amount of rainfall. We documented positive correlation of χlf with instrumental rainfall data (r = 0.65 for Peninsular India; r = 0.45 for Chitradurga Station) and historically recorded rainfall events. Presuming that χlf variations result primarily from rainfall variations and that there was no significant human impact in the catchment and no slumping or bioturbation of sediments, we have reconstructed the paleorainfall variations during the past 3700 years for Chitradurga region. Many events of drought and high rainfall, and onset of aridity are correlatable with similar events documented in speleothems from different parts of India, a tree-ring from western India and lake sediments from Rajasthan. Thus, we have shown that χlf is a proxy for rainfall in tropical regions and that tank-bed sediments from tropical India are an important archive of paleorainfall / paleoclimate data. This study opens up the prospect of obtaining paleorainfall data from thousands of lakes/ tanks in Southern India that have not been studied so far. These future investigations may provide a geographically widespread data set on paleorainfall that would help construct an All India “Paleo” Summer Rainfall Time Series and to better predict rainfall. 0944 A 2800-Year Record of Drought History over the Northeastern Tibetan Plateau Obtained from Living and Subfossil Trees 1

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responsible for decadal to century-scale Holocene climatic variability, high resolution proxy records of climatic spanning multiple millennia are needed. Qilian Junipers (Sabina przewalskii) growing on mountains along the eastern margin of the Qaidam Basin, northeastern Tibetan Plateau have been found promising for such paleoclimatic research. In previous studies, a 2326-year ring width chronology and an annual precipitation series since 515 BC had been developed for Dulan based on living and subfossil samples, and a 1437-year annual precipitation record had been reconstructed using well-replicated samples from 11 sites at Delingha and Wulan County.

In recent years, new samples have been collected at Delingha sites to update and expend these chronologies, especially by collecting well-preserved sub-fossil wood from tombs of Tang Dynasty or even earlier periods. After completing crossdating, new chronologies were developed. We used many cores with piths to estimate the growth trend of Qilian juniper in the aims to preserve as much low frequency information as possible. Previous studies have revealed that tree-ring width was positively correlated to early summer precipitation but negatively correlated to temperature during the same time. To evaluate the impact of the combined effects of temperature and precipitation changes over time, we performed Thornthwaite-Mather water balance modeling using 1955–2002 meteorological data. We found that the tree ring widths were strongly correlated with variables representing soil moisture conditions obtained from the water balance model. Specifically we determined that the deficit (DEF) calculated as the difference between potential evapotranspiration and actual evapotranspiration can represent the severity of water use stress, therefore can be used as a drought index. Using linear regression method, we reconstructed the drought history back to 837 BC when we have 10 tree ring cores from 6 living trees. The reconstructed record of the drought index displayed significant low-frequency variation patterns during the past 2800 years, including prominent dry periods during 700– 600 BC, 560–400 BC, 400–600 BC, 700–800 AD, 1100–1200 AD, 1425–1525 AD, and 1650–1750 AD. A trend to a wetter condition is seen during the most recent 300 years. By comparing with other proxies in the region, we concluded that the drought history reconstructed from tree ring widths very well reflected the climate variability at the multi-decadal to century scales. 1248 SAR Data For Subsurface Target Detection And Lop Nur Lake Evolution And Extinction Study Yun Shao, Huazhe Gong, Qing Dong, Xiangtao Fan Institute of Remote Sensing Applications, Chinese Academy of Sciences, China

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Xuemei Shao , Zhi-Yong Yin , Eryuan Liang , Yan Xu , Haifeng Zhu1 1

Institute of Geographic Sciences and Natural Resources Research, CAS, China 2 Department of Marine Science and Environmental Studies, Univ. of San Diego, United States 3 Institute of Tibetan Plateau Research, CAS, China

To address the issue of the range of natural climate variability in regard to current climatic trends and to better understand the mechanisms

Lop Nur Lake is located in east end of Tarim Basin, Xinjiang region, western of China, lost its last drop of water in 1972. It is well known for its “Ear Shape” feature in optical Remote Sensing images. Lop Nur Lake was the catchments basin and water collecting end in Tarim Basin. With the penetration capability, Synthetic Aperture Radar (SAR) is capable of detecting the subsurface targets, the water and salt contents. Canadian Radarsat SAR and European Envisat ASAR images delineated the conjectural shorelines underneath the “salt crust” surrounding the “Ear shape” features. We believe that SAR penetrate the “salt

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crust” then detected the underneath shorelines of Lop Nur lake. “Ear shape” features and the surrounding shorelines all showed up as very bright targets in SAR image. That is because of high water and salt content within the soils underneath the dry and hard “salt crust”. SAR also revealed buried river channels which are not visible on optical images. A field trip was conducted from October 25 to November 8, 2006 to collect sail samples underneath the “salt crust”. The samples were collected at 40 points along a profile from the center to the edge of Lop Nur Lake. Taking measurements on dielectrical constant, chemical component and dating of all samples collected in field trip are in progress. Lop Nur was a big lake with total area of 4900 square kilometers reported by previous study. However, with more shorelines has been revealed by SAR image, it is believed that the total area of Lop Nur Lake is 5600 square kilometers. Why Lop Nur dried up and why forming the “Ear Shape” feature? When its drying up process started? Are they shorelines or other features are still questions remaining not answered. A big lake like Lop Nur dried up within not very long period of time that is an important indicator for environment and climate change in arid region. When Lop Nur started to loss water is significantly meaningful for climate change research in Tarim Basin. 0719 Population structure, migration, and identifying refugia in Late Pleistocene Beringia Beth Shapiro1, Greg Ewing2 1

Oxford University, United Kingdom Center of Integrative Bioinformatics, Vienna, Austria

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Understanding how populations react in response to changes in their habitat is important in determining the genetic consequences of periods of climate change. Previous phylogenetic analyses using ancient DNA have shown that large mammal populations fluctuated considerably in size over at least the last 40,000 years, and have suggested this fluctuation to be a consequence of large-scale climate change associated with the last glacial maximum. It is well known, however, that population subdivision, such as occurred via formation of glacial ice across the Canadian shield, will confound the results of standard coalescent analyses, possibly leading to spurious results. Here, we present a new analysis of several ancient DNA data sets in which we employ the structured coalescent as a means of predicting the number of isolated subpopulations in a larger Beringian population, the amount of migration between these subpopulations, and changes in migration patterns through time. Based on changes in the distribution of subpopulations, we also identify potential sites of refugia both inside and outside of Beringia. This model makes it possible to predict a more realistic scenario of the changing community structure Beringia during the last ice age, with significant consequences for understanding the effect of climate change on large mammal populations. 0047 Geomorphic evidence of postglacial terrestrial environments on Atlantic Canadian continental shelves John Shaw Geological Survey of Canada (Atlantic), Canada

Changes in the geography of Atlantic Canada since the Last Glacial Maximum (LGM) are grouped into three phases. In phase 1, glaciers reached continental shelf edges at LGM and had retreated to near modern coasts by 13 ka BP. In the second phase, from 13 ka BP to ca. 10 ka BP, glaciers were mainly on land, except for scattered small ice caps

on continental shelves. Relative sea levels were high in coastal areas, but an emergent archipelago existed on the outer shelves. In the third and final phase, beginning ca. 10 ka BP, glaciers were largely absent. The outer-shelf archipelago was gradually submerging. In coastal areas of New Brunswick, Nova Scotia, Prince Edward Island and Newfoundland, relative sea level dropped to a (spatially and temporally varying) lowstand in the early to mid-Holocene. Submergence became prevalent by the late-Holocene. Multibeam sonar mapping has revealed the geomorphic evidence of submerged terrestrial terrains of the second and third phases. Examples of fluvial, deltaic, and coastal systems are described. The best-preserved fluvial channels are in Northumberland Strait and the Bras d’Or Lakes, Nova Scotia. In some areas, submerged channel systems may have formed at the base of glacier ice, and cannot be linked to sea-level lowering. Elsewhere, channels formerly identified as fluvial in origin are shown to have been formed by glacier readvance. A suite of submerged deltas has been mapped in Newfoundland fiords, created and preserved by special circumstances: abundant sediment supply, rapidly falling relative sea levels, and low wave-energy. Submerged deltas are absent elsewhere, excepting the Bras d’Or Lakes. Submerged coastal systems are rarely observed, mainly because of the brevity of the postglacial sea-level lowstand, and high levels of wave energy on exposed coasts. However, they have been preserved in former lake systems that became marine during the Holocene transgression. The Bras d’Or Lakes – Canada’s largest inland sea - contains numerous examples of submerged spits, barrier beaches, erosional platforms, and other coastal landforms. Their preservation is due to the long period of constant lake level, the rapid onset of transgression when sills were overtopped, and low wave-energy levels. 0046 Late Wisconsinan glacial landsystems on Atlantic Canadian shelves: new evidence from multibeam and single-beam sonar data John Shaw1, Brian J Todd1, Denise Brushett2 1

Geological Survey of Canada, Natural Resources Canada, Canada Memorial University of Newfoundland, Canada

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Multibeam sonar surveys in the last decade, augmented by single-beam data from the OLEX charting system, reveal complex landform-sediment assemblages on Atlantic Canadian shelves that are diagnostic of Late Wisconsinan glacial dynamics. Several landsystems are described. The German Bank landsystem off southwest Nova Scotia is comprised of glacially-fluted terrain heavily overprinted by fields of De Geer moraines and cuspate recessional moraines. These landforms occur in water depths of 30 to 240 metres. A flow of glacial ice out of the Bay of Fundy was followed by steady retreat of grounded ice, punctuated by at least one major re-advance. The Bay of Fundy landsystem includes a bedrock-controlled ice-stream channel flanked by marginal moraines which in turn are flanked by fields of drumlins and complex sub-glacial landforms. This landsystem is linked with the (onshore) drumlin-dominated landsystem of southwest Nova Scotia, and indicates fast-flow of ice into the Gulf of Maine. The Placentia Bay landsystem consists of a convergent field of drumlins and megaflutes, overprinted by De Geer moraines. The De Geer moraines are commonly found in modern water depths of 130 m, but occur in depths as shallow as 20 m. In depths >200 m the drumlins and megaflutes disappear beneath a drape of glaciomarine mud with a heavily furrowed surface; in the extreme southwest they have been overridden by later ice. This landsystem indicates convergent flow into an ice stream, retreat of grounded ice up the bay, and a late readvance of ice from offshore. The south coast of Newfoundland fiord land-


system includes a series of arcuate, fiord-mouth moraines developed at the boundary of basement rocks. The fiords contain basins of thick glaciomarine mud, and massive rock falls where glaciation has over steepened the sidewalls; where the basement boundary lies farther offshore, the former ice margin is marked by a coast-parallel, heavily-fluted moraine. The south coast landsystem indicates strong topographic control on a retreating ice margin. These shelf glacial landsystems are consistent with a model showing Late Wisconsinan ice advance to shelf edges, rapid calving retreat along deepwater channels, and slower retreat of ice margins grounded in shallow water. 0107 Progress towards a national morpho-dynamic framework for Canadian continental shelves John Shaw, Vladimir Kostylev Geological Survey of Canada, Natural Resources Canada, Canada

Recognizing that physiography and surficial geology are critical to understanding the distribution of living marine resources that economically sustain coastal communities, Natural Resources Canada has begun a 4-year project to establish a national perspective of the geoenvironment and habitats on Canadian continental shelves. In this poster we present an overview of the physiographic units on Canadian shelves. The shelves were glaciated in the Quaternary era, and are overprinted by deep, glacial troughs. The temperate and boreal Atlantic Canadian shelves are sub-divided into a series of sub-units (e.g. basins, banks and troughs). The cold, sediment-starved Arctic shelves comprise the Baffin Shelf (impacted by sea ice and icebergs), the Arctic Islands (annual sea ice) and the Polar Shelf (dominated by sea ice). The Pacific shelf is relatively narrow and shallow, and consists of a mosaic of distinct physiographic sub-units. For the Atlantic shelf we use Placentia Bay, Newfoundland as an example of how terrain complexity poses a challenge to classification. Unique properties of habitat and associated seabed communities are defined by the interaction of physical and ecological processes through recent and geological time. Physiographic classification is merely a small step towards the goal of interpreting and mapping emergent properties of seabed habitats in Canadian EEZ based on the integration of knowledge of geologic, oceanographic and ecological patterns and processes on different spatial and temporal scales. To put the challenge into perspective we provide results of a newly-completed geo-environmental and habitat synthesis for the Scotia Shelf. 0260 Specificity in development of glacial processes in the high mountains of Siberia as a key to gain a better insight into the ancient glaciation of North and Central Asia Vladimir S Sheinkman Institute of Geography, Russian Academy of Sciences, Siberian Branch, Russia

Cold environment, when climatic continentality promotes the spreading of permafrost under arid conditions (‘cryoaridization’), is a background to develop glaciation in high mountains of North and Central Asia both at present and during the Pleistocene. There are very representative evidences to demonstrate this matter by such environmental characteristics as low annual temperature and scanty snow accumulation. These are repeated ice-wedges, widespread at present all over the area from North Mongolia to Northeast Siberia, while Pleistocene icewedge casts occur even in Tibet and Gobi. In such a situation glaciers exist rather ought to their cold storage (using alimentation by superim-

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posed ice), than owing to snow diagenesis. As a result they develop as valley bodies, which closely interact with permafrost, whereas the limited moisture supply did not allow forming ice sheets.

Another surface ice form, so-called icings (naleds), becomes then an important component of the glaciation. Under the progressive cryoaridization, icings could turn into perennial features comparable to glaciers both with regard to ice volume and as landscape-forming agents. This explains occurrence of many landforms which ostensibly confirm previous ice-sheet development in high mountains of the region. What actually happened during the Pleistocene is that large icings and attended cryogenic processes affected the valleys and foothills in front of glaciers, which rarely overfilled enclosing valleys and turned, as the maximum, into reticular features. Thus, in the case of high mountains of North and Central Asia glaciation has to be taken up as a totality of different ice bodies, which may be considered as a specific cryoglacial system. Depending on the relationship between glaciers, icings and cryogenic ice (which form the system together), it may subdivide into subsystems; each of them will demonstrate then, by the proportions between the ice components, regularities of the corresponding environments, whereas geological activity of the subsystems make the specific mark in deposits and landforms. We have followed different features of glaciation of this kind, as well as its evidences in past, along a continuous mountain belt surrounding Siberia from the south and east. Since a modern difference in environmental cryoaridization increases along the belt gradually, we extrapolated this trend to obtain data for the palaeogeographical reconstruction. Moreover, the difference in outer points of the belt is comparable to the changes between glacial and Interglacial conditions during the Pleistocene. Hence, we may consider such an approach as a key to gain a better insight into the ancient glaciation. 0092 Sratigraphy and Chronology of Loess Formation, Ukraine Vladimir Shelkoplyas, Tatyana Khristoforova, Eugene Solyanik Institute of Geological Sciences, Kiev, Ukraine

Quaternary sediments in Ukraine can be subdivided into Eopleistocene, Neopleistocene and Holocene in age. The lower boundary of the Eopleistocene is placed at the surface of the Kuyalnik marine deposits (1,8 Ma, Olduvai magnetochron). Eopleistocene units belong mainly to red formation. Loess formation began 900 ka, resulting in the Pryazovsk loess unit. The Lower Neopleistocene (900-400 ka) began with the formation of the Martonosha paleosol (800 ka) at the Brunes-Matuyama boundary. Formation of the Sula loess unit (650 ka, oxygen isotope stages 13-15) corresponded to a short-term cooling event with temperatures close to modern day but with decreased humidity. The Lower Neopleistocene is completed with the Tiligul (Oka) loess unit (500 ka, oxygen isotope stage 12) and contains the Tiraspol mammalian faunal complex, which is characteristic of the Lower Neopleistocene. The Zavadivka soil unit (440 ka, oxygen isotope stages 9-11) is Middle Neopleistocene (440–160 ka) in age and contains a Singilsky faunal assemblage suggesting a warm and humid interglacial climate. The Dnieper complex of glacial deposits testifies to long cooling (300– 260 ka) and corresponds to the Chegan magnetochron (280 ka, oxygen isotope stage 8). At that time, loess formed in the territory adjacent to

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the glacier. Formation of the Pryluky (wurm-riss) soil unit (140–70 ka, oxygen isotope stage 5) occurred at the beginning of the Upper Neopleistocene, which represents the last interglacial macrocycle (150–10 ka, oxygen isotope stages 2-5). The soil unit is overlain by the Uday loess unit, with the TL-age of 75–78 ka. A warming trend is recorded in the Vytachiv paleosol, which has an age of 45–35 ka. The last cooling in the Upper Neopleistocene is represented by the formation of the Bug loess, which occurred at 30–35 ka. Loess formation during the Upper Neopleistocene is completed with the Dofinovka soil (25 ka) and the Prychernomorsk loess at 17–18 ka. The Holocene is represented by modern soils, marsh and lacustrine deposits (oxygen isotope stage 1). 0436 Rapid uplift events of the Qinghai-Tibetan Plateau and evolution of southwest monsoon since 2.78 Ma BP, recorded in a long lake sediment core in Heqing, China Ji Shen1, Sumin Wang1, Zhisheng An2, Xiaoke Qiang2, Haifeng Xiao1, Xiayun Xiao1

lithologic methods to determine the age of the section, which includes Paleogene deposits overlain by Quaternary sediments. The Quaternary is subdivided stratigraphically based on paleoclimate records. Examination of the Quaternary deposits yields the following conclusions: (1) Quaternary amber-bearing deposits are confined to Middle Neopleistocene, Upper Neopleistocene and Holocene glacial, glaciofluvial, glaciolacustrine, alluvial, lacustrine and aeolian deposits; (2) Middle Neopleistocene glaciofluvial deposits of the Styr-Goryn interfluve are the most prospective for Quaternary amber of commercial concentrations; (3) Lower Neopleistocene rills of glacial plucking and washout are potentially amber bearing within the limits of Volhyn Polessye. The Paleogene Volhyn Polessye deposits, which underlie mainly Quaternary sediments in this area, correlate to the Bartonian, Priabonian, Rupelian and Chattian stages based on dynocyst, calcareous nannoplankton, spore and pollen stratigraphies. Commercial concentrations of amber occur in the Mezhygorska Formation (Early Oligocene). As a result of this investigation, we contributed to a Volhyn Polessye amber-bearing deposit stratigraphy, which is correlated to stratigraphies of adjacent regions (Poland, Byelorussia, Lithuania and the Kaliningrad region of Russia).

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Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China 2 Institute of Earth and Environment, Chinese Academy of Sciences, China

Recently, it’s noticed that a number of tectonic fault lakes in the southwestern part of China, which are in close relationship with the Qinghai-Tibetan Plateau’s uplift, are not only desirable archives for the Plateau’s uplift because of their tremendous depth of sediment which can be dated back to millions of years ago, but also precious records for the southwest monsoon. Therefore, drilling work in Heqing of Yunnan Province was carried out in July of 2002, which was supported by the “Chinese Terrestrial Environment Drilling Project”. A very continuous sediment core of 737.72 m in length was successfully obtained with recovery of 97%. Paleomagnetic chronology result shows that the sediment core records environment change and tectonic activities since 2.78 Ma BP. Based on the analyses of lithology, grain size, carbonate contend and ignition loss of this core it can be found that this area underwent the following stages: 2.8–2.5 Ma BP, the lake basin formed as a result of the Plateau’s uplift (B episode of the Qinghai-Tibet Movement). The uplift also strengthened the southwest monsoon, resulted in the rainfall increase and the form of water body in the lake basin at about 2.65 Ma BP; 2.46–2.02 Ma BP, the lake level continued to rise with a flood occurred in 2.2 Ma BP; 2.02–1.55 Ma BP, the lake level decreased slightly due to the weakening of the southwest monsoon and the humidity decline; 1.55–1.45 Ma BP, gravels can be found with 28 m depth in sediment core, corresponding to C episode of the QinghaiTibet Movement; 1.45–0.99 Ma BP, the lake level fluctuated during this stage; 0.99–0.95 Ma BP, sediment with big gravels implied that the Plateau uplifted intensely, when the fluctuation cycle of global climate switched from 41 Ka to 100 Ka. After that lake level fluctuated according to the strength of southwest monsoon. 0224 Stratigraphy of the amber-bearing deposits of Volhyn Polessye (NW Ukraine) Tatyana Shevchenko, Eugene Solyanik Institute of Geological Sciences, Ukraine

Here we present the results of a stratigraphic study of Cenozoic amberbearing deposits from Volhyn Polessye (northwestern Ukraine). This study used paleontological, geochronological, geomorphologic and

0410 Middle Pleistocene Environmental change in Northern Xinjiang inferred from loess sediments in the North Slope of Tianshan Mountains Zhengtao Shi1, Yougui Song2, Xiaomin Fang3, Zhisheng An2 1

School of Tourism and Geography,Yunnan Normal University, China Institute of Earth and Environment,Chinese Academy of Sciences, China 3 Institute of Tibetan Plateau Research,Chinese Academy of Sciences, China 2

Loess sediments in Xinjiang in the interior of Asia possess important environment information such as the formation and development of deserts,air-circulation,and the uplift of Tibetan Plateau. A 71 m-thickness eolian loess section was found at Dongwan town in Shawan County, which is located at the north slope of Tianshan Mountains in Central Asia. The eolian sequence is consisted of 8 loess-paleosol couplets. Paleomagnetic results indicate that B/M boundary is located at the depth of 68.3 m, the bottom age is 800 ka by linear extrapolation. We collected power samples at 5 intervals for magnetic susceptibility, grain size and carbonate analyses. Environment history of North Xinjiang area since middle Pleistocene has been reconstructed according to these climatic proxies.The environment history with a gradual drying trend can be divided into three periods.The first period from 800 to 600ka is a relative wet stage,Middle Pleistocene lacustrine sediments and paleolake shorelines are widely discovered in Junggar basin. The well developed pedogenesis, higher proportion finer grain size (500ka) time scales, the global geochemical cycles of C and Si are coupled by the drawdown of atmospheric CO2 through chemical weathering of Ca- and Mg-silicate rocks, especially basalts, and the transport of the resulting cations, bicarbonate and silicic acid by rivers to the ocean, where Ca and Mg-carbonates are deposited in sediments and eventually recycled by plate tectonics. Although geochemical models of the long-term C cycle take account of the acceleration of weathering by land plants, this has not been accorded similar importance in models of the impact of glacial/ interglacial changes in weathering on atmospheric CO2. Even more serious is the omission of the global biogeochemical cycle of Si. Accumulator plants such as grasses, sedges, palms, tropical hardwoods and some deciduous trees pump silicic acid from soils and store it in their roots, stems, leaves and fruits in the form of opal phytoliths, thereby accelerating silicate weathering. Furthermore, modern monitoring has revealed that the fluxes of Si through many terrestrial ecosystems are ~2–10 times larger than the net release of Si by weathering. Freshwater siliceous organisms such as diatoms and sponges also cycle large amounts of Si. Under Holocene conditions, large quantities of biogenic Si have accumulated in aggrading terrestrial ecosystems, in soils, in lakes, in tropical swamps, in the floodplains of tropical lowland rivers and on the continental

New Zealand was the last major landmass in the world to be discovered and settled by people. Despite the short time-depth of human presence in the country there is ongoing debate about the date of earliest arrival of people. Two contrasting colonisation hypotheses have emerged: the ‘Early hypothesis’ and the ‘Short prehistory’. To provide a means to decide between both hypotheses a range of multi-proxy investigations (geochemistry, stable isotopes and mineral magnetism) was employed on two lacustrine sequences from Lake Pupuke (36º47´15´´S, 174º46´15´´E), a maar lake in the northern part of the city of Auckland, and an area potentially among the first places in New Zealand to have been settled by early people. The environmental history reconstructed from the multi-proxy evidence identified a prominent shift in all investigated parameters, implying severe catchment disturbance at Lake Pupuke several decades before the 638 cal. yr B.P. eruption of the Rangitoto volcano. The nature and abruptness of disturbance unambiguously points to anthropogenic forcings and is likely to mark the onset of prehistoric human settlement at the site. Linear interpolation between independently-dated chronostratigraphic marker beds present in the sediments allowed to date this event to c. 695 cal yr B.P. This date is in compliance with the ‘Short prehistory’.

School of the Environment and Society, University of Wales Swansea, United Kingdom 2 Lancaster Environment Centre, Lancaster University, United Kingdom

Department of Geological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand, New Zealand 2 GeoBio-Center, Ludwig-Maximilians-Universität, Richard-Wagner-Str. 10, D-80333 München, Germany, Germany


1214 Chronology and dynamics of the Yukon sector of the northern Cordilleran ice sheet Arjen P Stroeven1, Johan Kleman1, Derek Fabel2, John J Clague3 1

Department of Physical Geography and Quaternary Geology, Stockholm University, Sweden 2 Department of Geographical and Earth Sciences, University of Glasgow, United Kingdom 3 Department of Earth Sciences, Simon Fraser University, Vancouver, Canada

The history of the Cordilleran ice sheet (CIS) of western North America is relatively poorly understood despite over one hundred years of field studies. In contrast to other ice sheets, except for the West Antarctic ice sheet, the CIS was largely resting on mountainous terrain. Due to its physiographic characteristics, of having been fed by confluent flow from both the Coast Range and the Rocky Mountains, it appears to have been one of the most dynamic ice age features on Earth. There is a reasonably good understanding of the timing of maximum glaciation for the last glacial cycle (LGM) and for the almost instantaneous onset of postglacial conditions, based on radiocarbon dates. This generalized picture is better-documented for the southern than for the northern CIS. We focus on the succession of flow patterns of the CIS by mapping glacial lineation systems and ribbed moraine. These landforms define the spatial flow organisation, and give insight into the subglacial thermal regime. In addition to the dominating Late Wisconsinan flow pattern, we discovered numerous fragments of older, overridden and partially destroyed lineation systems. These shed light on older, albeit undated, ice sheet configurations with more easterly ice divide locations than during the late Wisconsinan ice sheet configuration. Mapping in the Pelly Mountains region, Yukon Territory, shows remnant relict glacial lineation systems, relict upland surfaces, welldefined end- and lateral moraine systems and abundant LGM lineation systems in the major glacial troughs. We test the hypothesis that subglacial preservation of relict lineation systems and relict uplands define the subglacial temperature distribution of subsequent ice sheets (i.e LGM), particularly the potential occurrence of frozen bed conditions. We will present cosmogenic 10Be ages on end- and lateral moraines that define the upper/distal limit of the CIS in this region, to test whether mountain summits were likely overridden (and preserved beneath cold-based ice) or were in effect nunataks during maximum of glaciation. A preliminary study of fabric of two superimposed till sheets exposed in a section along the Nisutin River, in an area inferred to have relict lineation systems, showed consistency with inferred ice flow directions from satellite imagery. The presence of a till sheet above the till sheet which, based on till fabric analysis, forms the relict lineations in the area, potentially shows that preservation may have been under influence of slow-flowing ice rather than (just) cold-based conditions. 0862 Abrupt climate change in the Sahel caused by changes in thermohaline circulation?

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arid environment. In addition, due to its bathymetric position of about 2000 m water depth, it also registers Late Quaternary changes in deepwater circulation. Here we present a study of both the marine and terrestrial environmental conditions in subtropical Northwest Africa using a suite of proxies including stable isotopes as proxy for deep- and surface water circulation and grain-size analyses as proxy for terrigenous sediment composition, related to continental climate. We infer abrupt changes in the hydrologic cycle that governs precipitation in the Sahel zone that are contemporaneous with abrupt changes in the global thermohaline circulation. This observation has major implications for the moisture balance in the Sahel region should global warming persist. 0968 Seasonal variability of present-day aeolian dust collected off NW Africa inferred from a multiproxy study combining grain size, chemistry, mineralogy, n-alkanes, C and N isotopes and satellite observations Jan-Berend W Stuut1, Gaute Lavik2, Enno Schefuss3, Matthias Zabel1 1

MARUM - Center for Marine Environmental Research, Germany Max Planck Institute for Marine Microbiology, Germany 3 Christian-Albrechts-University, Germany 2

Atmospheric dust samples collected along a transect off the West African coast aboard research vessels during different sampling campaigns, during different seasons, have been investigated using a suite of analyses including grain-size distribution, mineralogy, major-element chemistry, n-alkanes, and C and N isotopes. On the basis of these data the samples were grouped into sets of samples that most likely originated from the same source area. In addition, shipboard collected atmospheric meteorological data, modelled four-day back trajectories for each sampling day and location, and the Aerosol Index data of the Total Ozone Mapping Spectrometer for the time period of dust collection were combined and used to reconstruct the sources of the dust samples, and their seasonal variability. It appears that the bulk of the wind-blown sediments that are deposited in the proximal equatorial Atlantic ocean is transported in the lower-level (~ 900 HPa) NE trade-wind layer, which is a very dominant feature North of the Intertropical Convergence Zone (ITCZ). However, South of the surface expression of the ITCZ, down to 5°S, where surface winds are from the South and West, we still collected sediments that originated from the North and East, carried there by the NE trade-wind layer, as well as by easterly winds from higher altitudes. We conclude that –although it is a major advantage to have a relative control on the stability of the dust-source areas- it is difficult to express the size of the aerosols in absolute wind speed since the latter depends on (1) the strength of the transporting agent, (2) the distance to the source, as well as (3) the vertical distance the particles have travelled. Finally, after comparison between atmospheric dust and terrigenous sediments collected in submarine sediment traps off the West coast of NW Africa, we conclude that knowledge of the composition of aeolian dust is a prerequisite for the interpretation of palaeo-records obtained from sediment cores in the equatorial Atlantic.

Jan-Berend W Stuut, Stefan Mulitza MARUM - Center for Marine Environmental Sciences, Germany

A marine sediment core from offshore Senegal records abrupt changes in marine- as well as continental environmental conditions in the Sahel region throughout the last 57 kyr before present. Due to its unique location directly offshore the Sahel zone and under the major dust path from Northwestern Africa into the Atlantic Ocean, it can be used to study Late Quaternary palaeoenvironmental conditions in this sensitive semi-

0973 Antartic timing of South American Quaternary climate? Jan-Berend W Stuut, Dierk Hebbeln MARUM – Center for Marine Environmental Research, Germany

With the data we present in this study we try to stimulate the discussion on the importance of the Southern Hemisphere in global climate

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change. Present-day precipitation data (New et al., 2001) for South America, Africa and Australia, which show a clear seasonal latitudinal shift of the rain-bearing Southern Westerlies of about 9° latitude, are compared with palaeo-aridity data from Chile; We present grain-size distributions of the terrigenous sediment fraction from cores from the Chilean continental margin in the SE Pacific. The grain-size distribution data of two sediment cores were ‘unmixed’ into subpopulations, and interpreted as ‘coarse’ aeolian dust, ‘fine’ aeolian dust and fluvial mud, respectively. The downcore ratios of the proportions aeolian dust and fluvial mud represent palaeo-continental aridity records of Chile’s winter rainfall region for the last 20,000 yr, showing relatively wet conditions during the Last Glacial and drier conditions during the Holocene. Synchronous changes in the Sajama ice core (Bolivia) suggest that the source of moisture – the Southern Westerlies - extended northward during the LGM up to 18°S. Further North, ice cores record a clear Atlantic signal (Quelccaya (14°S) and Huascarán (9°S), Peru). We hypothesize that a hemisphere-wide atmospheric circulation system influenced climate along the entire Chilean coast up to about 18°S during the Late Quaternary; the northward displacement of the Southern Westerlies during glacial times was also observed in southwestern Africa and most likely also influenced palaeoclimate in Australia. 0709 Change of organic production in lakes during the Last Glacial - Interglacial transition: synchronous event? Dmitry A Subetto Herzen State Pedagogical University, Russia

High organic productivity in the lakes around 10.5 ka BP in NW Russia indicates the delayed response of the lakes to the distinct temperature rise at the Pleistocene/Holocene transition which may be explained by a different circulation pattern in the East Europe compared to that around the North Atlantic. The extreme continentality and strong anticyclonic circulation due to strengthened easterlies south of the Scandinavian ice sheet could have preserved extensive stagnant ice and permafrost in western Russia. The high pressure cell over permafrost regions and/or strengthened easterlies south of the ice sheet could have blocked warm air masses coming from the west as long as 2000 years. Different proxy records show that climate warming apparently started abruptly and synchronously at 14.7 ka BP with the BøllingAllerød warm period (Greenland Interstadial 1) followed by the Younger Dryas (Greenland Stadial 1) cooling reversal between 12.65 and 11.5 ka BP and that the early Holocene also was punctuated by short-term climatic oscillations. A lacustrine pollen record from Japan, however, indicates an earlier onset of the Bølling-Allerød interstadial and a delayed Younger Dryas Event by several hundred years, respectively (Nakagawa et al., 2003). Lake sediment studies in Northwestern Russia demonstrate that climate warming at the Pleistocene/Holocene boundary commenced about 300 –500 years later than in Western Europe (Subetto et al., 2003). Climate warming during the last glacialinterglacial transition in Northern Eurasia might have occurred asynchronously between the different regions of Northern Eurasia. It would be timely to develop a new transeurasian project to reconstruct lake geoecosystems in relation to climate and environmental change on a west-east transect at high- and mid-latitudes, at high temporal resolution, spanning the time frame from the onset of climate warming at 15 ka BP until the early Holocene climate optimum at 8 ka BP.

0718 Ladoga Lake – Baltic Sea water system and human migration during the Holocene Dmitry A Subetto1, Pavel M Dolukhanov2, Khikmat A Arslanov3, Ganna I Zaitseva4, Anvar M Shukurov5 1

Herzen State Pedagogical University, Russia School of Historical Studies, Newcastle University,, United Kingdom 3 Geographical Institute of the State St. Petersburg University, Russia 4 The Institute for the History of Material Culture, Russian Academy of Sciences, Russia 5 School of Mathematics and Statistics, Newcastle University, United Kingdom 2

The ancient water connection between Lake Ladoga and the Baltic in the northern lowland of the Karelian Isthmus has been originated after the ice retreating ca 14,000 –12,000 cal BP. At that time, until the catastrophic dropping of the Baltic Ice Lake (BIL) water-level happened ca 11,500 cal BP, Lake Ladoga was a deep easternmost bay of the BIL. After 11,500 cal BP a straight/river existed in the northern part of the Karelian Isthmus during ca 8000 years. The earliest evidence of human settlement in north-eastern Baltic Area is attested at Antrea-Korpilahti (9200 –8250 cal BC) where artifacts were found in the deposits of a channel between the Ancylus Lake and the Ladoga Lake. Around 4000 –3000 cal BP a new outflow - the River Neva, was formed due to the influx of fresh water and tectonic uplift caused a rise of the water level of the Ladoga Lake known as ‘Ladoga transgression’, which afterwards completely reshaped the waterways of the entire area. New results of the both paleolimnological and archeological studies which is carrying out in the area of the Ladoga-Baltica connection in the frame of INTAS-sponsored project (INTAS 03-51-4261) “Waterways and Early Human Movements in NW Russia” will be presented during the XVII INQUA Congress. 0294 Dust and glacier fluctuations in Patagonia since the LGM and links with Antarctic climate David E Sugden1, Andy S Hein1, Chris J Fogwill1, Robert D McCulloch1, Aloys Bory2 1

GeoSciences, University of Edinburgh, United Kingdom University of Lille, France

2

We present glacial records from Patagonia, a region north of Drake Strait and less than 1000 km from the Antarctic Peninsula. At the LGM an ice sheet with a span of over 200 km was centred on the crest of the Andes, a mountain range lying athwart the southern westerlies. The high mass balance of the ice sheet was dependent on sea surface temperatures in the Southern Ocean and precipitation in the cool maritime climate. High rates of ablation in the lee of the Andes nourished large meltwater streams which created outwash plains extending to the Atlantic that were the source of much of the dust recorded in Antarctic ice cores. The chronology of events as the ice sheet withdrew and meltwater was diverted to the Pacific Ocean is important for understanding events in Antarctica. The glacier fluctuations tell of changes in sea surface temperatures in the Southern Ocean and the latitude of the westerlies during the LGM-Holocene transition. There is remarkable similarity between climatic events in Patagonia and those recorded in Antarctic ice cores; indeed Late-Glacial changes are out of phase with the Northern Hemisphere and point to the operation of a bi-polar seesaw. The dust record is largely controlled by the effect of glacier extent on meltwater flow routes in Patagonia and is marked by stepped changes.


1123 Model-based reconstruction of vegetation and landscape using fossil pollen – implications for the interpretation of landscape openness and the role of climate change and human impact Shinya Sugita1, Marie-José Gaillard2, Sofie Hellman2, Anna Broström3 1

Department of Ecology, Evolution and Behavior, University of Minnesota, United States 2 Department of Natural Sciences, University of Kalmar, Sweden 3 Geobiosphere Centre, University of Lund, Sweden

Reconstruction of past vegetation and landscape using fossil pollen has long been hampered by a lack of theoretically-sound methods. We present applications of the Landscape Reconstruction Algorithm (LRA), a two-step framework of quantitative reconstruction of vegetation and landscape based on an up-to-dated theory of pollen analysis. LRA first uses the REVEALS (Regional Estimates of VEgetation Abundance from Large Sites) model to estimate regional vegetation using pollen from multiple sites c1–5 × 102 ha. Background pollen coming from beyond the relevant source area of pollen is expected to change through time, because changes in natural and anthropogenic factors affect regional vegetation. Given the regional vegetation, the second step of LRA uses the LOVE (LOcal Vegetation Estimates) model to calculate background pollen and incorporate it into reconstruction of vegetation composition within the relevant source area for smaller sites 1.45 Ma), Kd24 and Kd25 (1.60 –1.65 Ma), Kd 38 (1.75 Ma), Kd 44 (1.78– 1.97Ma) and Tmg-R4 (2.0 Ma). Sedimentary facies and stratigraphic positions of these tephras suggest that the sedimental environment in the central Tokyo had changed from semi-pelagic in the Kazusa Trough to shallow marine on continental shelf around 1.3 Ma. Inclination of strata containing U8 to Kd18 tephras indicates that south-side up in central Tokyo and west-side up in west Tokyo had occurred. This structure is concordant with the present tectonic movement of Kanto Tectonic Basin transferred from the formation of the Kazusa Trough. 0633 Tectonic geomorphological survey of the Itoigawa-Shizuoka Tectonic Line, Japan, toward forecasting the behavior of active faulting and strong earthquake motion Yasuhiro Suzuki1, Hiroshi Sawa2, Mitsuhisa Watanabe3, Masayoshi Tajikara4, Nobuhisa Matsuta4, Daisuke Hirouchi5, Nobuhiko Sugito1, Takashi Kumamoto6 1

Nagoya University, Japan Tsuruoka National College of Technology, Japan 3 Toyo University, Japan 4 University of Tokyo, Japan 5 Aichi Institute of Technology, Japan 6 Okayama University, Japan 2

The Itoigawa-Shizuoka Tectonic Line (ISTL) is estimated to be one of the most hazardous active faults in Japan, therefore, the Ministry of Education, Culture, Sports, Science and Technology of Japan has began intensive and multi-disciplinary surveys since 2005. We conducted a tectonic geomorphological survey of the ISTL under this project. Our survey clarifies the detailed location of fault traces and estimates distribution of the slip-rates of the fault, which would enable us to forecast the behavior of the fault and to estimate the strong ground motion associated with an earthquake. Firstly, the digital elevation model with high density and high precision was constructed photogrammetrically by using 1:10,000 scale aerial photographs. The aerial photographs taken in the 1940s or 60s are also used in areas where tectonic landforms had already been artificially modified; this was intended to reconstruct the original landforms. Then the landform deformations by faulting were analyzed from more than one hundred transections that were measured under the photogrammetrical system. The transection interval along the fault line is on an average 500 to 800 m. The distribution pattern of the slip-rate probably enables us to estimate strong ground motions. Several sections along the fault is recognized with large slip-rates, and thought to be the “asperity” which would generate strong ground motion. Furthermore, careful interpretation of large scale aerial photographs of different ages brought us the significant discoveries of active fault traces at locations where no active traces had been found and thought to be the “gap”. Finally, the geographical information with regard to active faults (for example: precise location, cumulative amount and shape of deformation, and slip-rate) is compiled on the “Active fault GIS” and is intended to be provided by webGIS. This can be a compilation of the basic information not only for earthquake anticipation but also for land use planning in order to mitigate earthquake disaster.


1283 Ice Age humans and paleoenvironment in the Russian Arctic John Inge Svendsen1, Herbjørn Heggen1, Jan Mangerud1, Pavel Pavlov2 1

Dept. of Earth Science, University of Bergen, Norway Inst. of Language, Literature and History, Komi Scientific Center, Russia

2

The transition from the Middle- to the Upper Paleolithic, approximately 40,000 – 35,000 14C BP, marks a crucial turning point in the history of humans in Europe. Some years ago it was a common opinion that the Eurasian Arctic was not colonized by humans until some 13-14,000 yrs BP and that much of the Arctic was glaciated during the Last Glacial Maximum (LGM) some 20 –25,000 years ago. It has now been demonstrated that the Russian mainland to the east of the White Sea region has remained free of ice throughout the last 50,000 years and that humans crossed the Polar Circle not later than about 40,000 years ago. However, the northern landscapes were indeed affected by dramatic climatic and environmental changes that must have had a profound impact on the human occupation. Here we go through the available evidences and present new data from investigated paleolithic sites in the Pechora Basin, European Russia. The stratigraphic context of the finds will be presented, with a focus on the geochronology and the paleoenvironment/climate. The chronostratigraphy is based on numerous radiocarbon dates of animal remains as well as a number of optically stimulated luminescence (OSL) dating of the sediment sequences. The earliest traces of human occupation were found at the site Mamontovaya Kurya that is located along the Usa River at the Arctic Circle. At this site, 36,000 14C years old artifacts, including a mammoth tusk with incision marks, were uncovered from alluvial deposits. At Byzovaya, which is located along the Pechora River, approximately 300 km further to the south, some 300 artifacts and more than 4000 animal bones have been unearthed. A large number of radiocarbon dates reveal that this latter site was occupied during a short lived period around ~28,500 14C yrs BP at which time the bones and artifacts were covered by thick eolian deposits, probably as a result of a sudden climatic shift. Situated at 67˚30′ N, Pymva Shor is the northernmost Paleolithic site in this part of Russia. Radiocarbon dates from bones that were found together with some few stone artifacts suggest that humans reconquered the Arctic only a few thousand years after the LGM and well before the Holocene climatic amelioration. 0193 The End of Late Pleistocene - Holocene Ponto-Caspian Paleogeography Alexander A Svitoch Moscow State University, Geographical Faculty, Russia

Research goal. A staged paleogeographical reconstruction of events in the Black Sea – Kerch Strait – Azov Sea – Manych Depression – Caspian Sea system during the last 30 ky. Research methods. Analysis of radiocarbon dates, malacofauna, relief, lithofacial composition of sections; highlighting and correlation of reference events. Results. The main event of the Ponto-Caspian paleogeography in the end of Late Pleistocene - Holocene was the Khvalynian transgression which displayed itself in all its regions. 30 – 15 ka the Caspian Sea was in regression, the level decreased to −50 m and lower. Khazarian Didacnaewere replaced by Khvalynian fauna. Subaerial deposits accumulated on the drained shelf. The Manych Depression was a system of communicating lakes and the accumulation of Burtass-Gudilian deposits took place. In the Black Sea basin the Tarkhan-

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kutian regression subsided, the level decreased to -80 m, the connection with the Sea of Marmara ceased, a half-isolated basin formed and was populated by fresh-water fauna. The Kerch Strait and the Azov Sea were drained; influxes of the rivers Don, Dnieper, Danube were located on the edges of Black Sea depression. 15 - 10 ka the Khvalynian transgression of the Caspian Sea commenced. This was a vast brackish water basin (13‰) populated by Caspian Didacnae. About 15 ka Caspian transgressive waters overpassed the Manych threshold (+45 m) and the overflow into the Black Sea Depression which initiated the Neoeuxinian transgression began. The transgression evolved in stages. In the epoch 15 – 12 ka the level of the basin rose to −45 m, then temporarily decreased and eventually rose (approximately 11 ka) to its peak level −20 m. This was a highly desalinated basin populated by fresh-water species of the Azov Sea type. Later than 11 ka the level of the Caspian Sea fell lower than the Manych threshold and the connection between the basins terminated. The Holocene transgression of the Black Sea was caused by the continuing Mediterranean transgression. During this time the Caspian Sea regressed. Conclusions. 30 – 15 (18) ka Ponto-Caspian basins are in deep regression, there is no connection between them. 15 – 11 ka a single system of one way Khvalynian water inflow into the Black Sea existed. In spite of its transience the Khvalynian transgression was not disastrous. The rate of sea level rise was a few cm per year at the most. In Holocene the Black Sea and Caspian basins evolved in antiphase. 0262 The Quaternary Stratigraphy and Correlation of the PontCaspian Region Alexander A Svitoch, Tamara A Yanina, Vera M Antonova Moscow State University, Geographical Faculty, Russia

Research goal. Detailed stratigraphy schemes were derived based on systematization and critical analysis of all known findings of fossil molluscan fauna of Didacna Eichwald - genus from the Ponto-Caspian region and the Manych Depression. The major stratigraphical units were generally synchronous. Methods. Didacnae represent the Cardiidae group that rapidly evolved within species and subspecies. That is why Didacnae are relevant for stratigraphical differentiation and correlation of Ponto-Caspian quaternary deposits. In the Caspian region, the succession of Didacnae in the sediment sequence forms several assemblages: Bakunian, Urundzhikian, Early Khazarian, Late Khazarian, Khvalynian and New Caspian. Faunas were distinguished by various criteria: taxonomic composition of faunal groups, index-species, and occurrence in certain layers separated from neighboring beds by tracers of disconformities. These faunal groups were the base for biostratigraphical subdivision of the Caspian Pleistocene, represented by the Didacna Eichwald biozone. It is subdivided into subzones. Subzones are the basis for establishing certain horizons: Bakunian, Urundzhikian, Lower Khazarian, Upper Khazarian, Khvalynian and After Khvalynian. Further on paleo-Caspian deposits are subdivided into subhorizons according to faunal assemblages. Subdivision of sediments into beds is based on determination of subassemblages. A succession of molluscan faunas is typical for Pleistocene and Holocene deposits of the Pontian region: Chaudian, Ancient Euksinian-Uzunlarian, Karangatian, Neoeuxinian and Chernomorian. The Pontian Pleistocene faunas are distinguished by the relative abundance of ecological groups: fresh-water, slightly brackish-water, brackish-water and marine. Didacnae that include Ponto-Caspian species are the main component of brackish-water Chaudian and Ancient Euxinian-Uzunlarian faunas. The Uzunlarian assemblage includes Didacnae and marine euryhaline species. The latter gradually become more abundant up the

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sequence. The Black Sea and the Caspian Pleistocene represents a biozone, i.e. deposits accumulated during the Didacnae existence interrupted by intrusions of Mediterranean fauna. This biozone is subdivided into five subzones, which are used for establishing of horizons: Chaudian, Ancient Euksinian-Uzunlarian, Karangatian, New Euksinian and Chernomorian. Faunal assemblages comprising a fauna are the base for establishment of subhorizons. Several subhorizons were established based on assemblage studies of Didacnae from brackish-water faunas: Lower Chaudian, Upper Chaudian, Ancient Euxinian, and Uzunlarian. Subassemblages. In the Manych valley Didacnae form three faunal assemblages: Bakunian, Anciant Euxinian – Early Khazarian and Khvalynian. Conventionally the Karangatian – Late Khazarian assemblage is distinguished. Conclusion. Malacological analysis emphasized the role of the Manych passage in the forming of PontoCaspian fauna and allowed to correlate Pleistocene sediments of the Ponto-Caspian region. 0247 Bedding structures in Indian tsunami deposits provide clues to the dynamics of tsunami inundation Adam D Switzer1, S Srinivasalu2, N Thangadurai2, V Ram Mohan3

gests it extends continuously up to 600 m inland and tapers landward rising to ~1.6 m above principle datum (AHD). In places the sand is overlain by accumulations of organic-rich silt that contain charophytes indicating re-establishment of lagoon conditions. Hypotheses considered for the deposition of the sandsheet are higher Holocene sea-level, storms and tsunami. Ground penetrating radar transects of the seaward dune system suggest a penecontemporaneous erosional contact between a series of truncated pre-event dunes and several small overlying post-event dunes. Dating the sandsheet was problematic but it is confined to the last 800 years. The young age combined with a lack of associated beach deposits and evidence of wave scouring suggest that a higher sea level hypothesis is unlikely. This sand lens is attributed to a large-scale washover event from the southeast. Based on comparisons with modern storm deposits from the same coast and differential criteria derived from studies of modern storm and tsunami deposited sandsheets, we conclude that this sand deposit is the product of a shortlived, large-scale overwash event attributed to a possible late-Holocene tsunami. 0459 Quaternary palaeoenvironments of the western Hong Kong inner continental shelf

1

The University of Hong Kong, China Anna University, Chennai, India 3 University of Madras, Chennai, India 2

Adam D Switzer1, Wyss W-S Yim1, Terri TO Chan2, Sam YS Chik2 1

The University of Hong Kong, China The University of Hong Kong, Hong Kong

2

The 24 December 2004 Indian Ocean tsunami deposited extensive sandsheet deposits on the coastal plain of Tamil Nadu in southeast India. The siliciclastic deposits are up to 1.5m thick and extend up to 2km inland. Trenching of these deposits in several locations indicates that changes in the hydrodynamics of tsunami inundation are recorded in the bedding structures of the deposits. The high velocity initial surge of the tsunami causes considerable bed shear stress resulting in erosion at the shoreline which changes landward to an initial sedimentation stage characterised by upper flow regime plane bedding. Following initial inundation sedimentation then becomes dominated by a period falling flow velocity and quiescence where sediments settle out of suspension often resulting in graded (fining-up) beds. After the maximum inundation level is reached water levels begin to retreat. Initial retreat may cause the formation of inversely graded (coarsening-up) beds as flow velocities once again increase. Sheet flow across the coastal plain can result in a shift back to upper flow regime conditions where upper flow regime plane bedding is once again observed. The final stages of tsunami inundation often involve channelisation of the flow as water retreats as backflow or runs into low lying topography. Small channels are observed to have an erosional base and a channel morphology that is filled with graded sediments that often exhibit complex patterns of sedimentation. A new model for tsunami sedimentation is provided based on the features observed in these deposits and other global examples.

A continuous 35 m vibrocore collected from the inner continental shelf area off the north coast of Lantau Island, Hong Kong SAR, China was measured using a Geotek multi-sensor core logger and colour imaging system and sediment samples were analysed for sedimentological properties, basic geochemistry and microfauna. Magnetic susceptibility, particle size, moisture content, density, unconfined strength, microfossils and elemental mineralogy were used to define facies within five main lithological units. Three marine units were identified which are capped by palaeo-dessicated crusts that record periods of sub-aerial exposure during glacial periods. The marine units have a combined thickness of 27.7 m and consist of marine to estuarine facies and record the last two glacial cycles. The marine units overlie two terrestrial units. These units include a swamp facies approximately 6.7 m thick that overlies ~1 m thick fluvial facies found at the base of the core. The depositional environment for each facies was reconstructed and the results confirm that the variation of properties of the sediments relates closely to the eustatic sea-level changes during the Quaternary period. 0128 The Relative role of orbital and CO2 forcing in the interglacial to early glacial transition: Implications for the next glacial cycle Jozef Syktus1, John Chappell2 1

0248 Large-scale washover sedimentation in a freshwater lagoon from the southeast Australian coast: sea level change, tsunami or exceptionally large storm? Adam D Switzer The University of Hong Kong, China

A distinct lens of marine sand, up to 90 cm thick, confined vertically by peat, is found in the upper fill of a closed freshwater back-barrier lagoon on the southeast Australian coast. Coring of the deposit sug-

Queensland Climate Change Centre of Excellence, Department of Natural Resources and Water, Australia 2 RSES, Australian National University, Australia

The relative roles of both insolation and CO2 forcing have been assessed through the analysis of a series of CSIRO fully coupled model simulations. The CSIRO9 Mk2 R21/L9 coupled atmosphere-ocean-sea ice model was used to simulate the Last Interglacial conditions at 126 ka and glacial inception at 116 ka, whilt the CSIRO4 R21/L4 coupled atmosphere-dynamic upper ocean model was used to complete detailed mapping of the Last Interglacial to early glacial transition in high latitudes of the Northern Hemisphere.


In order to assess the relative role of both insolation and CO2 forcing an extensive evaluation of CSIRO4 equilibrium simulation timeslices at 131, 128 126, 121, 118, 116, 115 114 110 and 104 ka was undertaken. The glacial inception was simulated using realistic CO2 levels measured from ice cores and cold northern summer orbit insolation conditions. The model simulated perennial snow cover over the northern region of Labrador, Siberia and Scandinavia starting at 118 ka. The area of positive snow balance increased significantly during the 116-110 ka period, consistent with proxy information. Additional experiments were undertaken to further assess the role of CO2 using insolation conditions typical of a cold northern summer orbit at 116, 115 and 114 ka in combination with CO2 levels of 240 ppm, 260 ppm, 280 ppm, 350 ppm, 410 ppm and 560 ppm. The area of perennial snow cover, calculated for land areas of Northern Hemisphere showed that glacial inception is simulated only at CO2 concentrations less than 350ppm. As CO2 levels rise above this critical threshold, the model no longer simulates perennial snow cover outside of Greenland. These results would suggest that the future transition from interglacial to glacial may be significantly modified by increases in anthropogenic greenhouse gas concentrations. Supporting evidence is also presented illustrating changes in thermohaline circulation and heat transport in the Gulf Stream during the Last Interglacial, glacial inception at 116 ka, mid-Holocene at 6 ka and pre-industrial times. 0033 Late Quaternary climates in Africa, South America and Australia Florence Sylvestre1, Francoise Gasse2, Martin Williams3, Francoise Chalié2, Annie Vincens2, David Williamson2 1

IRD PALEOTROPIQUE/CEREGE, Europôle de l’Arbois, France CEREGE, UMR 6635 CNRS -Université Paul Cézanne, Europôle de l’Arbois, France 3 University of Adelaide, Geographical and Environmental Studies, Australia 2

We have examined Southern Hemisphere climatic changes between 30 ka and 12 ka using archival evidence from pollen, lake sediments and shorelines, speleothems and cave deposits, groundwater, dunes, fluvial, periglacial and glacial deposits, ice and near-shore marine cores. Our reconstruction of regional climatic patterns during the LGM (21±2 ka) and ensuing deglaciation was designed to clarify possible climatic links between the three continents, the tropical oceans and higher latitudes. LGM temperatures in South America were 5 – 6°C lower than today, with the Amazon basin drier and the Andes and eastern lowlands wetter. The winter rainfall zone in SW Africa expanded up to 17°S, in response to the equatorward migration of the Antarctic vortex and of the temperate westerly rain-bearing winds, but maximum winter rainfall preceded the LGM. Elsewhere in southern Africa the LGM climate was drier than today, consistent with precessional insolation forcing by the Northern Hemisphere in equatorial and subequatorial Africa. The pattern is less clear in the southeastern tropics, which may have been the zone of maximum tropical rainfall; large uncertainties still remain for the central interior where data are scarce, poorly dated and sometimes conflicting. Deglaciation in SW Africa began at 20-18 ka with a marked decrease in Atlantic SE trade wind intensity and in winter rainfall following the first post-glacial increase of Indian-Atlantic warm water leakage through the Agulhas current. Terrestrial data in SW Africa correlate with changes in Antarctica, including a dry event during the ACR. All records south of ~ 9°S indicate a dry early Holocene. In the SE tropics, a major humid phase occurred at ~ 17–16.5 ka. In equatorial and subequatorial Africa, a minor humid interval occurred at 17–17.5 ka, followed by two humid episodes at 15–14.5 and 11.5 ka. The wettest episode is at 15–14.5 ka in subequa-

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torial Africa (e.g., the Congo basin), and occurred at the onset of the early Holocene further north. H1/YD events coincide with dry episodes in equatorial and subequatorial Africa. In Australia conditions were drier and colder across the continent. Sea level lowering increased the land area by ~25%. Australia was connected to Papua New Guinea in the north and to Tasmania in the south. This probably induced an increase of the aridity inside the continent. Some places show wetter conditions in lakes or wetlands due to local effects. 0639 Lobelia lakes – history recorded in plant and faunal (Cladocera) remains Krystyna Szeroczynska1, Krystyna Milecka2 1

Institute of Geological Sciences, Polish Academy of Sciences, 00-818 Warsaw, Twarda 51/55, Poland 2 Department of Biogeography and Paleoecology, Adam Mickiecz University, 61-680 Poznan, Dziegielowa 27, Poland

The Late Glacial and Holocene sediments from two lobelia lakes have been investigated to understand the transformation from lobelia to eutrophic lake. Lobelia lakes are soft-water, oligotrophic lakes occurring at the area of the Last Glaciation. They are classified according to presence of Lobelia dortmanna, Isoëtes lacustris and/or Littorella uniflora. The changes in flora and fauna composition of species living in such lakes allow to describe the water temperature fluctuations and trophy status, and then indirectly – the climate and human impact. Such information is provided by the remains of plants and zooplankton (Cladocera). The poster presents the results of palynological and subfossil Cladocera analyses. Lake Moczadlo and Lake Sierzywk (Tuchola Forest, North Poland) were selected for the study. During the development of these lakes the species composition and the specimens of Lobelia dortmana, Isoëtes lacustris and Cladocera abundance often changed what resulted mainly from the climate changes, but also from the human activity. Pollen analysis showed the postglacial and Holocene vegetation history, since the tundra-like and steppe communities during the cool period to the development of forest. It showed also the changes in local plant communities. Their succession was mainly related to trophy conditions in the lake. The species composition of subfossil Cladocera in the lobelia lakes was a little different from other studied lakes in this region. There existed Rynchotalona falcata, Alonopsis elongata and Alona intermedia, the rare species in Polish lakes. These littoral species and some planktonic ones indicated high oligotrophic condition, especially in the Late Glacial and early Holocene. Quality and quantity of Cladocera species were compared to the presence and/or abundance of Lobelia dortmanna, Isoëtes lacustris and some other plants (e.g. algae) reflecting climatic changes and human activity. The regularity was observed that usually during the periods of isoetids presence the Cladocera species preferring the higher water trophy decreased and Rynchotalona falcata was much more abundant than in the other periods. Some phases of the lake trophy increase were distinguished on the basis of the eutrophic Cladocera species. According to the palynological analysis, these phases correlate with periods of isoetids absence. Some of these phases are related to the periods of stronger human activity and anthropogenic changes of the landscape. The presented study is an attempt to evaluate the influence of climatic and anthropogenic factors on the development of presently existing Lobelia lakes and the evolution of oligotrophic water bodies into eutrophic ones.

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0100 The glacio-eustatic contribution to sea-level rise in the mid to late Holocene constrained by relative sea-level data from western Denmark Katie Szkornik1, Roland Gehrels1, Sarah L Bradley2, Glen A Milne2 1

School of Geography, University of Plymouth. UK, United Kingdom Department of Earth Sciences, University of Durham. UK, United Kingdom

2

The eustatic contribution to global sea-level change during the mid to late Holocene (post 7000 yrs) has been the subject of great debate within the scientific community. Modelers of the glacio-isostatic adjustment process (e.g., Lambeck, Peltier and others) in particular, are in disagreement about estimates of late Holocene ice melt. This study aims to provide further constraints on this process by use of relative sea-level data from the Ho Bugt embayment in western Denmark. The area is of interest because certain areas of Denmark lie close to the hinge line between the uplifting and subsiding coastlines. This means that, potentially, very little land movement has occurred in these areas in the past millennia. A sea-level history from this region is therefore relevant for testing geophysical and empirical models of glacio-eustatic sea-level change in the late Holocene. The evolution of the salt marshes around the Ho Bugt embayment was investigated using lithoand biostratigraphical (diatoms) analyses and AMS 14C and optically stimulated luminescence (OSL) dating. In addition, diatoms were sampled from the modern salt-marsh environment to establish their relationship to contemporary water levels. From 39 calibrated AMS 14C ages and 3 OSL ages, a mid to late Holocene relative sea-level history for the embayment was reconstructed using two methods: (1) a qualitative, lithology-based approach and (2) a quantitative, transfer function approach. Both methods document around 7 m of sea-level rise in the last 7000 yrs however, the transfer function approach was found to over-estimate relative sea level prior to 2000 cal. yr BP. Relative sealevel data produced by both methods are compared with a series of relative sea-level curves, predicted by models which stimulate the glacial isostatic adjustment of the Ho Bugt embayment. Results show that the Ho Bugt relative sea-level data are best matched by a glacial isostatic adjustment model that includes a zero eustatic function for the last 5000 cal. yr BP. The dominant process controlling relative sealevel change in the Ho Bugt embayment during the mid to late Holocene appears to be glacio-isostatic rebound, following decay of the Fennoscandian Ice Sheet. 0284 Differentiating records of recent climate change from anthropogenic impact in the coastal margin: an example from eastern Australia Kathryn H Taffs Southern Cross University, Australia

Coastal lakes are under increasing pressure from a rising global human population living in the coastal zone. Management of these areas is often a focus as their ecological values are recognised despite often being degraded from a multitude of anthropogenic activities. Coastal lakes contain important records of recent climate change and anthropogenic impact that can assist future management of coastal resources. In Australia, the eastern coastal margin contains many coastal lakes that retain important records of both recent climate change and anthropogenic activities, which is of significant benefit in a country where historical documentation is sparse and short term. The role of palaeolimnology to provide baseline data to interpret such records is thus

essential yet rarely utilised. This study investigated the paleolimnology of three coastal lakes in eastern Australia. The three lakes were in similar geomorphological locations but had very different anthropogenic influences. The first, Lake Arragan, is located within a national park and remains pristine; the second, Hearns Lake, is located on the outskirts of a town and in the past received treated effluent which was diverted 6 years ago; the third, Salty Lagoon, is adjacent to a very popular coastal village with a large tourism industry. Sediment cores were extracted from each lake basin from the central, deepest section of the lake using a mini Glew gravity corer. Sub-samples were extracted using the core extruder at 0.25 cm intervals. Sub-samples were processed using the method of Parr et al. (2002) for diatom extraction. Chronology of the samples was obtained using Pb210 dating techniques. The selection of these lakes allowed the recent climate change signal to be differentiated from anthropogenic impacts. Lake Arragan, contained a record of climate change over the past 80 years reflecting changes in precipitation and ocean influence. Hearns Lake showed signs of both climate and anthropogenic impact, with a marked change in diatom assemblage in the past 10 years, relating to its recovery from euthrophic conditions. Finally Salty Lagoon showed signs of increasing eutrophication over time. This study has enabled the recent climate signal for this area of eastern Australia to be differentiated from anthropogenic impacts and also determine remediation targets for coastal lakes affected by human activities. Therefore this study is a useful example of how palaeolimnology can aid management of coastal resources, particularly where recent and long term environmental records are not available. 1204 Pollen record over the last 450,000 years dated by widespread tephra layers from Kamiyoshi Bashin, Kyoto, western Japan Hikaru Takahara1, Ryoma Hayashi1, Kyoko Tanida1, Toru Danhara2, Hideo Sakai3 1

Graduate school of Agriculture, Kyoto Prefectural University, Japan Kyoto Fission Track Co., Ltd., Japan 3 Faculty of Science, Tayama University, Japan 2

We have taken a long core over the last 450,000 years from Kamiyoshi Basin, anout 20 km northwest of Kyoto City in western Japan (altitude 335 m, 35°06'08”N, 135°35'10”E, the diameter of the basin is 0.5-0.8 km). This core will provide a continuous vegetation history of the glacial-interglacial circles from the Marine Isotope Stage (MIS) 2 to MIS 12. The chronology was based on widespread tephra (AT: 29 ka , Aso4: 87 ka, K-Tz: 91 ka, Aso-1: 24.9 ka, Ng-1 29.4 ka, Kkt 33.4 ka, BT72, 34.9 ka and B271 and B277-2 , the age of tephra after Nagahashi et al., (2004)) and several AMS 14C dates. Detailed pollen analysis of this core has been conducted. In this paper, we present the pollen data since MIS12. Also, detailed pollen data since MIS5 will be presented in Hayashi et al. (this congress). During the glacial/interglacial cycle, characteristic taxa in the cycle are as follows. Quercus subgenus Cyclobalanopsis (evergreen oaks) in the maximum of the interglacial (warm and wet condition), temperate conifers such as Cryptomeria japonica, Sciadopitys verticillata in the next stage (cool/wet), pinaceous conifers such as Picea, Tsuga, Abies and Pinus (cold/dry), and then Fagus (cold/wet) occurred in this order. In the late-glacial (MIS2), pinaceous conifers were replaced by beech (Fagus) and deciduous oak, then in the early Holocene (around 8 ka), Celtis/Aphananthe increased in western Japan. After the mid-Holocene, without the stage of strong human disturbance (almost after 2000 –1000BP), evergreen broadleaved trees such as Cyclobalanopsis became dominant with Cryptomeria japonica. Prominent increase of Cyclobalanopsis pollen were


recognized in MIS5.5(5e) and MIS11. For other interglacial periods, in MIS7, Cryptomeria japonica and Fagus are dominant pollen taxa with very low percentages of Cyclobalanposis. For MIS9.3, Fagus pollen was dominant with several persentages of Cyclobalanopsis. After the dominance of pinaceous conifers in MIS12, Cyclobalanopsis increased in MIS11.3. Cryptomeria japonica became dominant with Sciadopitys verticillata and Fagus quickly after MIS11.3. The period of the dominance of Cyclobalanopsis was relatively short. This pollen data can be compared with the data from Lake Biwa (BIW 95–4, Miyoshi et al. 1999) using tephra layers. (References : Hayahi et al. (this congress) Vegetation response to past climate changes since the last interglacial based on long pollen records from the Kamiyoshi Basin and Lake Biwa, western Japan. Miyoshi et al., (1999) Rev. Palaeobot. Palynology 104, 267–283. Nagahashi et al. (2004) The Quarernary Research (Daiyonki-Kenkyu) 43, 15–35) 1244 Effects of Radiation and Convection on the Near-Surface Air Temperature Yoko Takamura Japan

Simulations of the near-surface air temperature for the present climate performed with one-dimensional (in the vertical) non-convective and radiative-convective coupled models. The three types of convection models employed were the dry convection, the 5K/km adjustment, and the 6.5K/km adjustment models. The necessary parameters used in the numerical experiments were provided by the conditions based on January standard atmospheres at 30N and 60N, and those of July , at 30N and 60N. The results demonstrated that the simulated near-surface air temperatures are higher and the tropopause heights lower in order of the model results of the 5K/km adjustment, the 6.5K/km adjustment, the dry convective, and the non-convetive models. This was due to the upward transport of convective heat being less active in the same order of the model results. The differences in the near-surface air temperatures among the models under January conditions were much larger than those in July. This resulted because under January conditions, the downward longwave radiation emitted by the atmosphere was greater than the downward shortwave radiation at the surface. In addition, the downward longwave radiation at surface varied due to the differences in simulated temperatures which were strongly affected by the convective activity associated with water vapor evaporation at the vicinity of surface. These results suggest that the modeling of radiation and convection are crucially important when simulating the near-surface air temperature, especially for numerical experiments of the past climate using a simple heat budget model. 0471 Late Holocene climate changes recorded in composition of benthic microfossils from the Laptev and Kara seas Ekaterina E Taldenkova1, Henning A Bauch2, Anna Yu Stepanova3, Yaroslav S Ovsepyan1, Irina A Pogodina4 1

Geographical Faculty, Moscow State University, Russia Mainz Academy of Science, Humanities and Literature, c/o IFM-GEOMAR, Germany 3 Paleontological Institute RAS, Russia 4 Murmansk Marine Biological Institute, Russia 2

In order to understand the natural instability and development of the Arctic climate system which is not assessable by the short-term

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observational data solely, it is necessary to study long-term geological records with millennial to centennial resolution. In the marginal Laptev and Kara seas the primary concern is the high-resolution investigation of sediments accumulated after the sea-level stabilization at 5–6 cal.ka. The postglacial and early Holocene sediment sequences accumulated on the continental margin under rapid sea-level rise and high sedimentation rates document past environments, which were non-analogue to the present ones due to the absence of shelf water masses, stronger inflows of Atlantic derived waters, and direct shelf-to-coast coupling. Although accumulated under lower sedimentation rates, sediment sequences which correspond to the last 5–6 cal.ka possess evidence of climate induced changes, i.e. variations in atmospheric and water circulation patterns, sea-ice extent, freshwater runoff. High-resolution paleontological investigations (foraminifers, ostracods) of several AMS14C-dated sediment cores from both seas revealed well-pronounced changes in the composition of benthic microfossil assemblages after 3.5–3 cal.ka, which indicate climate cooling and intensification of water mass circulation. On the middle and outer shelf this is manifested by abundant riverproximal ostracods and foraminifers ice-rafted from the inner-shelf regions, and re-introduction (for the first time after the early Holocene) of deep-water species due to the advection of offshore and possibly Atlantic-derived water with wind-induced reversed bottom currents. Enhanced advection of these saline bottom waters was recorded between 3 and 1.5 cal.ka even in the river-affected inner-shelf region as shown by the occurrence of rare planktic foraminifers and deep-water species. On the upper slope, enhanced abundances of planktic foraminifers, benthic foraminifer Cassidulina neoteretis, ice-rafted river-proximal species, and iceberg-rafted rock fragments, all point to an increase in Atlanticderived water inflow in association with climate cooling, probably as a consequence of a major change in the general pattern of the atmosphereocean circulation regime after approximately 3.5–3 cal.ka. 1062 Late Holocene shoreface erosion in response to rapid sea-level fall along a tectonically-uplifted strand plain, Pacific coast of Japan Toru Tamura, Futoshi Nanayama, Yoshiki Saito, Fumitoshi Murakami, Rei Nakashima, Kazuaki Watanabe Geological Survey of Japan, AIST, Japan

A relative sea-level fall in response to either uplift or a eustatic sealevel fall has an important impact on coastal deposition. This study documents two rapid relative sea-level falls along a tectonically-uplifted coast during the late Holocene that caused lowering of the surf zone (i.e., the upper shoreface) leading to intra-shoreface erosion, and the characteristics of the resultant prograding shoreface deposits. These findings are based on high-resolution analysis and radiocarbon dating of three new drill cores obtained from the Kujukuri strand plain, Pacific coast of eastern Japan, combined with a previously published borehole data and information on modern shoreline profile adjustments. A shallowing-upward sandy succession composed of lower and upper shoreface facies, foreshore and backshore facies was recognized in the drill cores. Two rapid falls in relative sea level at 2.3–2.6 ka and 1.8–2.0 ka are recorded by downstepping of the base of the foreshore facies, and farther seawards by the lowering of an erosional boundary between the upper and lower shoreface facies. Superimposed bed profiles of an adjacent modern beach define an envelope, the base of which reflects shore-normal migration of longshore bars and troughs. The base of the envelope represents a composite erosional surface that separates the mobile bar sediments above from preserved deposits beneath. The surface is concave upwards and steeper than the mean beach profile, and exhibits a flat platform approximately at the lower limit of

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the upper shoreface equating to the storm surf zone. The seaward transition of this surface, rather than the mean equilibrium profile, controls the metre- to decimetre-scale internal structure of the Kujukuri shoreface deposits. A rapid sea-level fall caused the erosional surface to be dropped down, thus enhancing erosion of previous lower shoreface sediment, lowering of the base of the foreshore deposits, and seawards, downstepping of the erosional boundary between the upper and lower shoreface facies. Multiple falls in relative sea level thus caused repeated lateral changes in the thickness of the upper shoreface facies. Erosion in the lower shoreface was not revealed, but it seems to be quite different from that in the upper shoreface. The dynamic responses of these two sub-environments in the shoreface to the change in relative sea level and/or other forcing need to be properly examined for understanding of the depositional record. 0508 Millennial temperature reconstruction and simulation for China basted on annually resolved multi-proxies and ECHO-G model Ming Tan1, Xuemei Shao2, Jian Liu3 1

Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China 2 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China 3 Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China

We present here the first reconstructed large-scale temperature patterns with annual-resolution over the last millennium (1000 –1985AD) for China via combining two annually resolved proxy records, the Beijing stalagmite layer series (Tan et al., Geophysical Research Letters, 2003) and the Qilian tree ring sequence (Liu et al., Science in China, 2005). In this study, we attempt to find a way to synthesize the climatic proxies which are affected by different seasonal temperatures. Meanwhile, a 1000-year climate simulation with the ECHO-G model is made for whole China to compare the synthetic temperature reconstruction as well as to understand the causes of climate change over the last millennium. The correlation coefficient between the simulated and reconstructed time series is 0.44, 0.58 and 0.61 for yearly data (n=986), 11-year running mean and 31-year running mean, respectively. And the range of the simulated anomalies (1.55 K) is comparable with that of the reconstructed (1.86 K). This result, in general, shows a rather strong coherence between the two time series although some discrepancies still exist. 0513 Calcretes in Ganga plains: a proxy for paleoprecipitation and paleovegetation during MIS 3-5 in the Himalayan foreland Sampat K Tandon1, Rajiv Sinha2, Prasanta Sanyal2, Martin R Gibling3 1

University of Delhi, India Indian Institute of Technology Kanpur, India 3 Dalhousie University, Canada 2

Calcretes are abundant in Late Quaternary channel and floodplain strata of the southern Ganga plains. An unusually wide range of carbonate types are associated with a Late Quaternary floodplain (interfluve) succession at Kalpi in the southern Ganga Plains. At Kalpi, pedogenic carbonates (nodules, rhizoconcretions, and powdery carbonate) are present within aggradational floodplain deposits, where they correspond to relatively high monsoonal precipitation and river discharge. In contrast,

groundwater carbonate are associated with cemented degradational surfaces (discontinuities), which correspond with periods of relatively low precipitation. Mixed groundwater and pedogenic calcretes are present in the deposits of small interfluve channels, and reworked nodules line degradational surfaces, and locally fill channels. Most carbonates show alpha fabrics that include floating textures, shrinkage crack fills, and grain coatings. Because the strength of the monsoon is known from regional climatic modeling to have varied greatly during this period, the carbonates have been used to test the response of the isotopic system and vegetation to precipitation changes for a period spanning much of MIS 3 to 5. Interpretation of delta-13C and delta-18O values of bulk and microdrilled calcrete samples suggests relatively little variation in precipitation and vegetation types through the sampled interval at Kalpi. Floodplain deposits were vegetated with a mixture of C4 and C3 plants (predominantly C4), with a higher proportion of C3 plants associated with channel deposits. This apparent lack of variation is surprising because the sampled interval represents at least 60,000 years of Marine Isotope Stages 3-5, during which climate models suggest that Asia experienced radical fluctuations in monsoon intensity and precipitation. Some of the apparent lack of variation may be explained by preferential preservation of aggradational strata that represent relatively active monsoonal periods, as well as by the mixing of drier floodplain (C4) and riparian (C3) vegetation. However, local departures from the regionally based climate model cannot be ruled out. A modest upsection increase in C4 plants may represent increased aridity and lower atmospheric CO2. Isotopic analysis of organic matter from floodplain pedogenic nodules suggests a higher C3 plant contribution than carbonate-based data would suggest. The preserved organic matter may reflect the annual average biomass in the soil, whereas carbonate formation may have taken place mainly during the drier season when respiration of C4 plants was more important. In interfluve settings such as Kalpi, seasonality may strongly affect the C3-C4 system, with preferential preservation of only part of the biomass. 0836 The impact of the Nile River on Holocene sediments and benthic foraminifera of the inner shelf of the southeastern Mediterranean Ilanit Tapiero1, Ahuva Almogi-Labin2, Chaim Benjamini1 1

Department of Geological and Environmental Sciences, Ben Gurion University of the Negev, Israel 2 Geological Survey of Israel, Israel

The Nile River, one of the longest rivers on Earth, carries signals of climate variability of east equatorial and NE Africa into the eastern Mediterranean region. We here present new results from the inner shelf off the southern and central Israeli coast, constituting the laterally distal part of the pro-delta of the Nile River. This is a high resolution study based on two ~7 m long vibrocores taken at 33 and 36 m water depth off the southern and central parts of the Israeli coast. The sedimentary environment was categorized by sand fraction and % carbonate of the shallow water sediments, along with benthic foraminiferal assemblages recording change in the biotic environment. Dating was by AMS 14C. Sedimentation rates during early Holocene were high, exceeding 140 cm/1000y, indicating that enhanced hydrological activity at the headwaters of the Nile River operated in tandem with warm, humid conditions in the southeastern Mediterranean. During the late Holocene the sedimentation rates decreased drastically to below 60 cm/1000y, reflecting reduced hydrological activity from both sources and increasing aridity. This dual subdivision of the Holocene is separated by a transitional period of ~1000y, with the early and late Holocene climatic regimes each marked by characteristic benthic


foraminiferal assemblages and sediment properties. During the early Holocene, between 8.4 and 6.3–6.7 kyr BP the climate was relatively humid with small seasonal fluctuations. The inner shelf was populated by a benthic foraminiferal assemblage showing high abundance, high diversity and equitability, indicating that productivity was high and food supply reaching the sea floor was stable. From 6.3–6.7 to 5.5 kyr BP the climate regime changed from humid to semi-arid, with the transition apparently accompanied by periodic storm activity. Over the last 5500 y, the climate becomes drier and seasonality more pronounced. The earlier Holocene benthic foraminiferal assemblage was almost entirely replaced by a low diversity, low equitability assemblage dominated by opportunists, indicating that the environments became unstable, nutrient input was low and intermittent, and seasonality was more pronounced. During those last 5500 y, about 10 cycles in which two dominant species alternate may be correlated with historical and geological records of Nile River discharge variability.

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since about 126 kyr BP. After ca. 121 kyr BP conditions became gradually cooler with a sharp turn towards a dry climate after ca. 118 kyr BP. The early stage of the last glaciation (ca. 117.5–114.8 kyr BP.) was cold (Tc ~ −28 to −30 ºC, Tw ~ 14–15 ºC) and dry (Pann ~ 250 mm and alpha ~ 0.5). The reconstructions suggest that the Holocene ‘climatic optimum’ was less pronounced than that of the LI. On the other hand, pollen records from the area demonstrate that the Holocene ‘forest phase’ lasts some thousand years longer than that of the LI. 0694 Late glacial-Holocene climate and vegetation dynamics in arid Central Asia and China reconstructed from biological proxies: a comprehensive overview Pavel Tarasov1, Miroslaw Makohonienko2, Nadezhda Dorofeyuk3, Guiyun Jin4, A. N. Uwe Heußner5, Mayke Wagner5, Frank Riedel1 1

0034 Vegetation and climate dynamics in South Siberia during the Holocene and the Last Interglacial Pavel Tarasov1, Elena Bezrukova2, Eugene Karabanov3, Takeshi Nakagawa4, Mayke Wagner5, Polina Letunova2, Anna Abzaeva2, Wojciech Granoszewski6 1

Free University, Institute of Geological Sciences, Palaeontology Department, Berlin, Germany 2 Institute of Geochemistry, Siberian Branch Russian Academy of Sciences, Irkutsk, Russia 3 Baikal Drilling Project, Department of Geological Sciences, University of South Carolina, Columbia, United States 4 Department of Geography, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom 5 Department of Eurasian Archaeology, German Archaeological Institute, Berlin, Germany 6 Polish Geological Institute, Carpathian Branch, Skrzatow 1, Krakow, Poland

Changes in the last interglacial (LI) and Holocene annual precipitation (Pann), mean temperature of warmest (Tw) and coldest (Tc) month and moisture index (alpha) were reconstructed from continuous pollen records from Lake Baikal. The Holocene record (52°31'N, 106°09'E) was recovered from a 355 m water depth in the Buguldeika saddle separating the southern sub-basin of Lake Baikal from central sub-basin. The biome reconstruction shows that tundra and steppe biomes have highest scores in the late glacial and that taiga becomes a dominant vegetation type after ca. 13,300 cal. years BP. Our quantitative reconstruction indicates an onset of relatively warm and wet conditions soon after ca. 10,000 cal. years BP. The warmest and wettest climate (Tw~16° C, Pann~480 mm and alpha~0.9–1) has been reconstructed for ca. 9000 –7000 cal. years BP. In the Lake Baikal region this interval is characterized by the first appearance and spread of hunter communities (Kitoi culture). Consistently a hiatus in the regional archaeological record (4900 –4200 years BC or 6850–6150 cal. years BP) coincides with the interval of major climate deterioration which followed the ‘climatic optimum’. The Continent pollen record from Lake Baikal (53º57' N, 108º54' E) covers the complete LI corresponding to MIS 5e. For the pre-LI time ca. 130–128 kyr BP a severe ‘glacial’ climate (Tc ~ −38 to –35 ºC and Tw ~ 11–13 ºC, Pann ~ 300 mm and alpha ~ 1) is noticeable. The LI lasted from ca. 128 kyr BP, when shrubby tundra was replaced by taiga, until ca. 117.4 kyr BP, when boreal forest vegetation became largely replaced by cool grass-shrub communities. The most favourable climate conditions occurred during the first half of the LI. Soon after 128 kyr BP. Pann reached 500 mm and maximum values of Tc ~ −20 ºC and Tw ~ 16–17 ºC are reconstructed

Free University, Berlin, Germany Adam Mickiewicz University of Poznan, Poland 3 Severtsov Institute of Ecology and Evolution, Moscow, Russia 4 Archaeology Research Center of Shandong University, Jinan, China 5 German Archaeological Institute, Berlin, Germany 2

The past twenty years of palaeogeographical studies in Central Asia and China have yielded much evidence for the environmental changes that occurred during the late glacial and Holocene. The German, Russian and Chinese scholars and international research teams have made great efforts to extract local- to regional-scale palaeoenvironmental data from the available archives. Among the records analysed and frequently used to derive palaeoclimatic information are the following: botanical data (pollen, plant macrofossils, tree rings); aquatic organisms (diatoms, foraminifers, ostracods, molluscs); sedimentary data (loess, paleosoils, peat, sand dunes, speleothemes), geochemical and stratigraphical data; lake and sea levels; archaeological data (artefacts, animal bones). However, similar changes in the analysed proxy can often be caused by different factors and allow alternative interpretations. As example, an increase in herbaceous pollen may reflect a shift towards drier conditions or equally it could be a result of deforestation caused by man. The use of several lines of evidence and arguments is usually the best method to obtain a strong, highly plausible and reliable reconstruction. We tend to see the ‘Holocene world’ as consisting of natural environments and humans. Studies of these two principal components are separated between the natural and social sciences, which have different subjects and research methods applied to different proxies. In reality, however, there is no such clear separation. Living in certain environments, people consciously or unconsciously interact with all components of nature. On the other hand, gradual or abrupt changes in the regional environments and climate influence all aspects of people’s spiritual and material culture, including folklore, religion, art, house construction, diet, tools and weapons. The role of nature in people’s lives (and vice versa) has been interpreted from different standpoints, including such extremes as geographical or cultural determinism. However, it is an objective reality that humans modify natural landscapes and create cultural ones, and that the traces of human activities and natural processes stored in biological, geological and historical archives can be investigated. The results of these investigations, transformed into environmental reconstructions, are then spread among specialists via scientific publications and the mass media, as well as among a wider public, contributing to the prevailing perceptions of the past. In the present paper we provide an overview of the postglacial environmental changes in arid China, Kazakhstan, Uzbekistan, and Mongolia reconstructed from different biological proxies. The results are then discussed together with archaeological and historical data in hands.

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1174 High-resolution analysis of the late Pleistocene climate in central Japan based on total organic Carbon (TOC) content of lacustrine Takano Formation, Japan Takaharu Tawara1, Yoshitaka Nagahashi2, Sayuri Kawai3, Atsuko Kanauchi4, Fujio Kumon5 1

Interdisciplinary Graduate School of Science and Technology, Shinshu University, Japan 2 Faculty of Symbiotic Systems Science, Fukushima University, Japan 3 Faculty of Science, Shinshu University, Japan 4 School of Arts and Letters, Meiji University, Japan 5 Japan

We have tried to reconstruct the late Pleistocene paleoclimate in Japan on high-resolution and -accuracy, based on TOC content and pollen composition in TKN-2004 core. TKN-2004 core taken at the central part of the late Pleistocene Takano Formation is 53.88 m long, and recovery rate was almost 99%. The cored sediment is mainly composed of homogenous black-gray clayey silt intercalating more than 80 tephra layers. Age of the sediment was estimated from the relationship between the ages and calibrated depths of dated marker tephras such as BW1466, Aso-4, Aso-3 and Aso-2 (Nagahashi et al., submitted). About 4900 samples in 1cm interval were analyzed for total organic carbon (TOC) content and total nitrogen (TN) content using Thermo Finnigan Flash EA 1112. The TOC content varies mainly between 1 and 8 %, and relatively high zone and low zone repeat alternatively four times in several meters interval. The values are 3–8 % in the higher horizons and 1–5% in the lower ones. Further, asymmetrical jagged variations of which amplitude is 1–4 % are observed in a few meters interval. We use TOC content as paleotemperature proxy. This assumption is supported by pollen analysis and modern observation (Kumon et al., 2005). The reconstructed paleoclimate covers during 158-38 ka with 19–29 years interval. The long-term fluctuations of tens millennial scale observed in TOC profile is divided into 8 phases named as Takano Climate Phase (TCP) 1 to 8. This long-term fluctuation is concordant with the SPECMAP curve (Martinson et al., 1987), and TCP 1 to 8 can be correlated to MIS 6 to 3. The short-term fluctuations of millennial scale are also distinct, and they show asymmetrical jagged variation which has similar periodicity with stadial-interstadial cycles in Greenland ice core records (Stuiver and Grootes, 2000; NGRIP members, 2004). Warm periods of the short-term variation are also named as T1 to T21. Most of the episodes can be correlated to IS 9 to 25. Therefore, it is concluded that the late Pleistocene paleoclimate in central Japan has been highly variable, and are basically concordant with global change both in long and short term fluctuation. However, as the unique short-term climate changes are also observed in TCP 2 and TCP 4 periods, the regional variations of climate might exist around Japanese Islands. It may be due to regional atmospheric circulation of East Asian Monsoon. 1424 Environmental variability and early agriculture on the Yangtze Delta, eastern China David Taylor1, John Dodson2, Pia Atehan3, Hongbo Zheng4 1

Trinity College, University of Dublin, Ireland Institute for Environmental Research,ANSTO, Australia 3 Freea Itzstein-Davey 4 School of Ocean and Earth Science, Tongji University, China 2

This paper utilises AMS 14C-dated sediment-based evidence - largely charcoal, phytoliths and pollen – from several locations on the Yangtze

Delta to examine the interactions between highly dynamic environmental conditions and early agriculturalists. Specifically research presented in the paper seeks to determine the extent to which local environmental conditions may have restricted the development of domesticated rice-based agriculture. 0344 Recent estuarine sedimentation rates from shallow intertidal environments in Western Scotland: implications for future coastal development Phillip A Teasdale School of the Environment, University of Brighton, United Kingdom

During the mid-late Holocene large sections of the Scottish coastline have been characterized by falling relative sea-levels resulting from differential glacio-isostatic uplift of this region of northern Britain. A number of geophysical models predict ongoing uplift of the Scottish landmass. A detailed geochemical study has been undertaken on selected sediment cores from mature coastal marsh environments in Argyll, Western Scotland. This provides an opportunity to investigate the linkages between current estimated crustal movements, Twentieth century sealevel rise and historical rates of sedimentation recorded within marsh sediments across the proposed Scottish glacio-isostatic uplift dome. Vertical distributions of 210Pbexcess and 137Cs activity have been measured and used to develop models of historical marsh development. Down-core activity profiles of radionuclides can be used to model recent marsh evolution provided no early-diagenetic, (redox) reactions have compromised the historical depositional record contained within the marsh sediments. Solid-phase major and trace element core geochemistry has therefore been examined to assess the extent to which post-depositional reactions may have influenced the reliability of the radiometric dating methods. Geochemical data are also used to examine changes in sediment source, local chemical environment, and possible in-wash of material from storm flooding events. Dating of the marsh cores reveals subtle variations in the rates of sediment accumulation over the last c. 70 years between sites. For much of the Twentieth century sedimentation rates have been in good overall agreement with various estimates for sea-level rise during this period, although at sites across the Firth of Lorne these rates do exceed such estimates. Comparison with available storm frequency data indicates that the evolution of these marsh environments has not been greatly influenced by storm activity. Over the most recent period of marsh development a significant increase in marsh surface sedimentation is recorded across the study region. Microfossil (diatom) analysis of the cores supports these data, highlighting an increase in the relative abundance of marine taxa in the near surface sediments. This may signify the response of the mature marshes to a very recent increase in the rate of regional relative sea-level rise which is now outpacing predicted rates of crustal uplift. The findings indicate that these coastal marshes are extremely sensitive to changes in coastal forcing (sea-level rise). The implications of the study with regard to current geodynamics in Scotland and future coastal development are discussed.


0546 Ice-Rafted Debris (IRD) in the South Atlantic: Comparing four ways (plus one) of examining the data Lora F Teitler, Detlef A Warnke California State University, East Bay, United States

A primary issue in the interpretation of ice-rafted debris (IRD) from marine cores is that the true pattern of IRD flux may be obscured by non-ice-rafting-related changes in the other components of the sediment sample. Normalizing the data relative to some other measurement of the sediments is intended to remove the effects of such changes. However, each method of normalization is dependent on some aspect of the total sediments present, and therefore the resulting signal may still be vulnerable to changes in factors other than the IRD flux. At South Atlantic site TN057-6-PC4/ODP 177-1090, just north of the Polar Front Zone, we have completed a study of IRD, based on the count of IRD versus other types of grains present in a random split taken from the medium to very coarse sand sized fraction (250 microns to 2 mm). We then compared the results of normalizing the IRD data using four different widely-used methods: IRD Index, Apparent Mass Accumulation Rate (AMAR), IRD mg/g, and IRD grains/g. Each method has a different approach to the data, and different assumptions. By comparing the results obtained with the different methods to each other, therefore, we propose that possible confounding factors can be eliminated. We also noted the presence/absence of ‘background rafting’ (the occurrence of IRD in amounts too small to show up in the counted split). The results suggest that at this distal site, over the last ~600 ka, sea surface temperatures strongly control the delivery of IRD. However, the presence of some IRD through even warm times (sometimes as background rafting only) suggests that at least the East Antarctic Ice Sheet remained stable, and capable of launching large icebergs, some of which reached this distant drill site. 1287 Aeolian palaeoenvironments of the southwestern Kalahari: Advances from an intensive chronometric investigation at Witpan, South Africa Matt W Telfer, David SG Thomas Oxford University, United Kingdom

The southwestern Kalahari is a semi-arid dryland characterized by a range of landforms which have been interpreted as evidence of past environmental and climatic conditions different from those of today. These include currently inactive linear dunes, closed basins known locally as ‘pans’, and the crescentic lunette dunes which often accompany the pans on their lee side. However, palaeoenvironmental interpretation of these landforms has been hampered by incomplete understanding of their development and the difficulty in dating such sediments. Witpan is an hourglass-shaped, 5 km long pan with a well-developed lunette dune, and is set amongst a linear dune field. This study applies a variety of physical and geochemical sedimentological analyses to the range of aeolian deposits found within the locale, set within a detailed timeframe provided by 113 Optically Stimulated Luminescence (OSL) dates. The current lunette at Witpan has accumulated predominantly within the past 2000 years, in a spatially complex manner reflecting differences in local sedimentary sources. The discovery of such complex sedimentation within a single landform has implications for future studies which

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attempt to use lunette sediments in palaeoenvironmental reconstruction (Telfer and Thomas, 2006). The linear dunes at Witpan are considered to respond primarily to variations in aridity forced by atmospheric circulation changes, and record sedimentary accumulation of different intensities dating back to around 100 ka. Most notable in the record is a period of particularly intense accumulation following the last glaciation, and culminating at around 9–16 ka. The Holocene has seen much reduced linear dune accumulation. The basin at Witpan contains a limited sedimentary record which is suggested to have accumulated during conditions wetter than those at present. The alkaline sediments are not conducive to the preservation of biogenic proxies, but OSL dating has potential for constraining a palaeoenvironmental record derived from physical and geochemical proxies. 1293 Do Standardized Growth Curves really work for Optically Stimulated Luminescence dating? Results from an inter-regional compariso Matt W Telfer1, Mark D Bateman2, Andrew S Carr2, Brian Chase1 1

Oxford University, United Kingdom University of Leicester, United Kingdom

2

Standardized Growth Curves (SGCs) have recently been proposed (Roberts and Duller 2004) as a means to reduce measurement times when determining palaeodoses (De) for Optically Stimulated Luminescence (OSL) measurement when compared to the widely used Single Aliquot Regenerative methods. The strategy has now been used to produce dates for a number of large-scale chronometric surveys, (e.g. Lai, 2006; Telfer and Thomas, 2006; Chase and Thomas, in press). SGC theory suggests that, in some cases, quartz luminescence behaviour may be sufficiently consistent to allow a summary curve to be used, rather than calibrating every aliquot measured against a number of ‘regenerated’ calibration points. We test the performance of SGCs derived from samples from the southwestern Kalahari of South Africa, west coast South African coastal dunes, and a relict dune cordon in Florida, United States of America. Data presented here suggest that the method performed well at estimating low (9000 –6000BP. However, the sand ridge was not directly dated. As part of a region-wide lake palaeo-shoreline research programme, the Chilwa sand ridge was cored for intensive OSL dating of the sediment body, providing a record of the timing and rates of ridge construction. Five cores, to a maximum depth of 13m, were drilled, using special sampling heads to extract light-tight samples at 0.5–1m intervals for OSL dating using SAR laboratory protocols. Sample moisture contents were modelled to account for the effects of repeat basin filling on lower sample depth matrix water content variability, while cosmic doses were also modelled to account for the effects of changing burial depths over time. 29 ages, in the range 0.28±0.02ka to 41.54±2.88ka were determined. Cluster analysis of the age data set identified four periods of ridge construction: centred at 37.65±1.51ka, 23.33±0.82ka, 15.77±0.19ka and 13.04±0.31ka. These represent phases of moisture content and wave action in the Chilwa basin sufficient to supply sediment for major beach ridge construction, This may imply a more vigorous Indian Ocean Monsoon at these times, periods which may be correlated tentatively to North Atlantic Heinrich events H4(~37ka), H2(~23ka), H1(~15.5ka) and H0(~12.5ka).An intermediate resolution GCM has been used to investigate any such possible connections and mechanisms. 0568 Climate, conifers and fire: the vegetation of western Tasmania during the Holocene Ian Thomas, Michael S Fletcher University of Melbourne, Australia

Many pollen based studies have been published which describe the overall pattern of climate forced vegetation changes from the LGM to the present in Tasmania, a stronghold of temperate rainforest and flora with Gondwanan affinities. In the Southwestern Tasmanian World Heritage Area, the overall trends in vegetation changes which occurred during the Holocene are well known. Prior to 10K BP, grassy open structured plant communities were favoured by colder and more arid climatic regimes than those experienced today. As warm humid conditions developed in the early Holocene, many alpine plant communities were replaced by cool temperate rainforest or eucalypt dominated forest. However, a dependence on over-represented pollen types and a reliance on alpine and sub-alpine field sites has fostered an impression that the change from grassland to rainforest was inevitable and synchronous. This is not the case. In this paper we present examples of asynchronicity, the long term stability of some plant communities, and short term changes in others. Confounding yet fundamental processes, including the somewhat cryptic influence of fire, mediated by Aborigines, and landscape processes such as soil development and hillslope instability are discussed. Pollen diagrams from the Walls of Jerusalem, Lake Pedder, Central Plateau,and southwestern plains are presented with an emphasis on the history of endemic conifers in relation to climate, fire and the archaeological record. 0717 Interpreting landscape response to Late Quaternary climate change from sediment history and multi-proxy records in the humid tropics Michael F Thomas University of Stirling, United Kingdom

Evidence for major landscape change during the Late Quaternary is now well documented from many areas of the humid tropics, and evidence of fluvial response to environmental change is available for most extra-glacial regions. Common themes are the persistence of moist conditions through OIS3, the onset of braided and fan-forming regimes in OIS2, around the Last Glacial Maximum (LGM), due largely to reduced runoff and plant cover, and the transformation to incised, meandering channels during the Pleistocene-Holocene transition or in the early Holocene, correlating with the recovery of rainfall and vegetation. Although regional and local variations are observed, common patterns emerge from different climates during the Late Pleistocene. In the Holocene, however, there is far less agreement and common patterns have not been established. Important regional differences between tropical regions have probably resulted from differentiated climates, resulting from the evolving regional patterns of ITCZ and El Nino (Zonal Walker Cell) activity. This raises issues concerning the timing and establishment of the modern climate and plant cover, and the amplitude and duration of climate change during the Holocene in relation to the capacity of river systems to adjust. The geomorphic role of extreme events within past and present climatic regimes is also usually recorded in terms of the immediate impact rather than any long-term influence on system behaviour, and coupling of hillslopes and channels is often poorly defined. Published models describing system responses to climate and vegetation changes are re-examined in the light of current understanding of Late Quaternary climates in tropical areas, and recent work on rivers draining to the Coral Sea in northeast Queensland is used to illustrate and discuss these issues alongside evidence from palynology and other sources concerning the timing and rate of land cover changes. Evidence for high energy fluvial processes through OIS3 and the response of fluvial systems to the environmental changes leading towards the LGM, will be re-evaluated, and a possible rapid response to significant climate change after 14.2 ka is discussed. Issues regarding scale, magnitude of change, and the complexity of possible threshold crossing ‘events’ are discussed and modified models matching known transitions are offered for discussion. 0731 Landscape features denoting Late Quaternary environmental change from the Cairns region, northeast Queensland, Australia Michael F Thomas1, Jonathan Nott2, Andrew S Murray3, David M Price4 1

University of Stirling, United Kingdom James Cook University of North Queensland, Australia 3 University of Aarhus, Denmark 4 University of Wollongong, Australia 2

The impact of Late Quaternary climate change on the landscapes and river systems of the coastal ranges and plains around Cairns has been demonstrated. In this poster additional detailed information on field sites is presented, illustrating how features of the hillslope and fluvial systems are related to their local settings. Sediments dated by thermoluminescence (TL), optically stimulated luminescence (OSL), and radiocarbon methods are considered in relation to their sedimentary environments and other proxy evidence for late Quaternary climate change in northeast Queensland. Records span the period from OIS5e to OIS2 and reveal the distinctive nature of the OIS2 fan and terrace deposits. The fans accumulated for ~14 k yr and became incised after 14 ka. The importance of local catchment morphology and bedrock weathering to the character of fluvial sediments formed during the Late Pleistocene is demonstrated by reference to sediments forming prominent alluvial and debris fans on the rivers flowing to the Coral Sea in northeast Queensland (including the Daintree, South Mossman, Mow-


bray, Mulgrave and Russell Rivers; Freshwater and Liverpool Creeks plus several smaller creeks and fans). The Barron River, which drains a large catchment and flows direct to the sea near Cairns has deposited Holocene and recent sediments above a deep (~90 m), Pleistocene buried channel,a consequence of the low, glacial sea level. The problems of establishing a chronology for the Holocene are demonstrated in relation to the nature and impacts of modern flood hydrology, and the way in which the rivers are influenced by and modify the Pleistocene deposits and forms is demonstrated. Complex behaviour by rivers during the Holocene has created difficulties for deciphering fluvial changes and events during this period. 0840 Regional-Scale Comparisons of Paleoclimatic Data with Model Simulations: Examples from Western North America Robert S Thompson1, Steven W Hostetler1, Patrick J Bartlein2 1

U.S. Geological Survey, United States University of Oregon, United States

2

Comparisons of paleoclimatic data syntheses and model simulations provide the means for testing models and for explaining the patterns recorded by the data. A fundamental disparity in scale can exist between paleoclimatic observations and the output from global climate or Earth-System models, even with recent increases in the spatial resolution of global models. Many models still represent topography in a highly smoothed fashion and land cover in a fairly stylized way, which limits regional scale detail and expression of surface-atmosphere feedbacks in model simulations. In contrast, paleoclimatic observations include climatic heterogeneity observable at present, such as those related to: (a) mediation of the effects of large-scale atmospheric circulation by physiography, (b) orographic controls of precipitation, and (c) variability in soils, vegetation, and landscape-scale topography that influence surface climates. Several approaches have been used to deal with the spatial disparity between data and models. Aggregating paleoclimatic data to the resolution of models unfortunately can produce an inferred climate for a particular model grid cell that occurs nowhere in the real world, a point that can be easily demonstrated using high-resolution observed climate data. A second approach, statistical downscaling of the paleomodel output to a spatial scale comparable to that of the data, relies on calibration from modern climate data sets and thus makes the critical assumption that relationships between synopticscale atmospheric circulation fields and surface climate do not vary over time. This assumption is difficult to support, given the large circulation changes that can be inferred from the data (or simulated by models), and the equally great changes in boundary conditions that are known to have occurred. Moreover, most statistical downscaling techniques do not conserve heat (temperature) or mass (precipitation). Here we use a third approach, employing a regional climate model to downscale global climate simulations for comparisons of time-slice simulations for western North America at 21,000, 11,000, and 6000 calendar years ago with syntheses of pollen, plant macrofossil, lake status, and glacial data. This approach has become feasible due to improvements in data storage, processor speed and integration, and in the approaches for linking global and regional models. Initial results indicate that this approach works reasonably well, even in the physiographically complex region of western North America.

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0535 Into and out of the Last Interglacial: the coral record of sea level William G Thompson Woods Hole Oceanographic Institution, United States

The Last Interglacial is the most recent period when Earth’s climate was at least as warm as it is today, and the higher Northern hemisphere summer insolation levels of the Last Interglacial may be a reasonable proxy for future global warming forced by rising levels of greenhouse gasses. Understanding the mechanisms of climate change during this particular period in Earth’s history is crucial. The record of global sea level change inferred from U-series dating of fossil reef terraces represents a globally integrated index of climate change. However, U-series dating of Last Interglacial corals has, to date, produced conflicting results, due to significant problems with U/Th dating. Here we present more than 200 new U-series coral ages covering the entire Last Interglacial from Termination II to glacial inception. These ages have been corrected for the well-documented open-system behavior of U-series nuclides in corals. In a significant departure from standard practice, we estimate age uncertainties associated with sea level events from the reproducibility of replicate measurements of individual corals and of adjacent corals within individual stratigraphic units. This approach assesses the combined uncertainty stemming from analytical error, sample heterogeneity, and age model assumptions, avoiding the potential for underestimating age reproducibility that is inherent in the standard approach of propagating the statistical uncertainties of isotope ratio measurements. Furthermore, age reproducibility can be used to test the effectiveness of both conventional U-series age equations and the newer age correction equations. Uncorrected conventional U-series ages produce conflicting ages for adjacent corals within a single stratigraphic unit. In sharp contrast, corrected ages are highly reproducible. The resulting sea level curve is robust and well resolved, with discrete sea level events that are reproducible from location to location. Rather than a smooth rise to a stable Last Interglacial highstand and gradually falling sea levels during glacial inception, the sea level curve is punctuated with several discrete sea level events. The traditional framework of sea level change driven solely by changes in Northern hemisphere summer insolation is not well suited to the interpretation of these results. In addition to insolation forcing, mechanisms of climate change that operate on shorter timescales must be invoked. 1304 Models of land movements in north-eastern Hokkaido, Japan Katie H Thomson1, Antony J Long1, Benjamin P Horton2, Yuki Sawai3, David Healy1 1

Durham University, United Kingdom University of Pennsylvania, United States 3 Geological Society of Japan, Japan 2

The deformation of Pleistocene marine terraces along the north-eastern coast of Hokkaido (Japan) is the result of the subduction of the Pacific Plate under the overriding continental plate. The pattern and rate of deformation has generally remained steady over the last few interglacial cycles. Chronological and height data relevant to the fossil shorelines indicate that Hokkaido was affected by uplift with a maximum rate around the Shiretoko Peninsula, 200 km from the Kuril Trench. In contrast to the long term uplift, present-day land movement suggests maximum subsidence along the eastern coast of Hokkaido of ca. 8 mm/yr (120 km from the trench). We compare modern vertical rates of deformation derived from continuous Global Positioning Sys-

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tem (GPS) observations and tide gauge measurements to help interpret interseismic deformation around the island. Deformation over the last earthquake cycle is evaluated using microfossil-based reconstructions of former sea-levels. Holocene crustal movements are assessed by comparing re-calibrated index points from the coastal area, with theoretical predictions of relative sea-level. The morphology of the island, with terraces and coastal environments stretching orthogonal to the trench, provides the unique opportunity to test models of land movement over a variety of temporal scales. We apply forward elastic dislocation modelling using our estimates of crustal deformation on Hokkaido to test the predictions and constrain the parameters in models of the Kuril subduction zone. As such, the pattern of deformation over different timescales provides further insights into the behaviour of the subduction zone and thus seismic hazard in this part of the Pacific. 1318 Late Holocene coastal deformation in Hokkaido, northern Japan Katie H Thomson1, Antony J Long1, Benjamin P Horton2, Yuki Sawai3 1

Durham University, United Kingdom University of Pennsylvania, United States 3 Geological Society of Japan, Japan 2

Characterising patterns of earth motion (uplift and subsidence) associated with great earthquakes is an important first step for assessing seismic hazard. Research using intertidal sediments in eastern Hokkaido (Japan) provides evidence for repeated emergence events over the mid to late Holocene, which have recently been attributed to land movements associated with interplate earthquakes at the Kuril subduction zone. Litho-, bio-, and chronostratigraphical techniques are used to quantify land movements along the coast of eastern Hokkaido to improve our understanding of past earthquakes in this region. A critical first step of using such quantitative predictions (e.g. transfer functions), is to assess the extent to which a high-resolution fossil core may reveal decadal changes in sea-level as shown in a tidal gauge record. Two long tidal gauge records spanning 100 years are available on the eastern Hokkaido coastline, at Hanasaki and Kushiro which record interseismic subsidence. The transfer functions were then applied to a short fossil core at Mochiruppu, and the tide-gauge record used to validate the reconstructions. Quantitative reconstructions of former sea-levels over the last earthquake cycle, together with modern vertical rates of deformation derived from continuous Global Positioning System (GPS) and tide gauge observations are used to understand models of land movement in Hokkaido. As such, the pattern of deformation over different timescales provides further insights into the behaviour of the Kuril subduction zone and thus seismic hazard in this part of the Pacific. 0070 A lithofacies-based approach to optically stimulated luminescence (OSL) dating of glaciofluvial sediments Ian M Thrasher, Richard C Chiverrell, Barbara Mauz, Andreas Lang, Geoff SP Thomas Department of Geography, University of Liverpool, Roxby Building, Liverpool, L69 7ZT, United Kingdom

The advance and retreat of large ice masses characterise the last two million years of Earth history. Deposits at former ice margins play a key role in understanding this glacial history, but obtaining accurate

ages for former ice front positions is challenging. This is due mainly to the scarcity of organic remains within glacigenic sediments and thus the very limited applicability of radiocarbon dating. Optically Stimulated Luminescence (OSL) techniques circumvent this problem, in that the target quartz grains are readily available. However, OSL dating of glaciofluvial deposits has also proven problematic mainly due to poor resetting during glaciofluvial transport and low luminescence sensitivity of freshly eroded quartz grains (Duller et al., 1995). Recent technological advances in OSL dating combined with using a sample selection procedure based on sedimentary facies offer the opportunity of overcoming these problems. The preliminary research presented here combines comprehensive sedimentological and palaeoenvironmental knowledge with up to date OSL technology. Based on results from extensive sedimentological and stratigraphic studies (Thomas et al., 1985, 2004; Chiverrell et al., 2001, 2004) of a former ice marginal outwash sandur at Orrisdale, the Isle of Man, a suite of lithofacies were identified and sampled for OSL analysis. Quartz has been extracted from the sediments and recently developed OSL dating techniques (Murray & Wintle, 2000) have been applied to identify which depositional environment is best suited for OSL dating of glaciofluvial sediments. Accurately constraining the age of the Orrisdale ice-marginal sandur will improve understanding of deglaciation within the Irish Sea Basin. Preliminary results suggest that the Orrisdale sandur was deposited in front of a retreating ice margin at ~ 18–19ka, after the last glacial maximum (LGM). Recent sampling has been undertaken in Wexford (S.E. Ireland), closer to the LGM ice marginal limit, again targeting a range of lithofacies for OSL dating. Preliminary results from the glaciofluvial sediments in Wexford suggest a LGM (~22– 24ka) date of deposition. The results from the Isle of Man and Wexford analyses will inform sampling of the most appropriate lithofacies from other ice-marginal sandar around the Irish Sea Basin, at St. Bees (Cumbria) and the Llyn Peninsula (N.W. Wales). This approach should enable the reconstruction of a time-stepped retreat of the Irish Sea Ice-stream. 1378 The limnological history of selected Eastern Australian coastal lakes: the relative importance of estuarine evolution, sea level and hydrology John C Tibby, Jennie Fluin, Abby L Sims, Angus J MacGregor, Peter A Gell Geographical and Environmental Studies, University of Adelaide, Australia

In contrast to much of the remainder of the continent, the coastline of Australia abounds with permanent lake systems. Despite their long recognised value for palaeoecology (Clark, 1990, Proc. Ecol Soc. Aus., 16), coastal lakes are underutilised as locales for late Quaternary study. Here, using diatoms as our primary indicator, we focus on the Holocene history of two New South Wales (Myall Lakes, Lake Ainsworth), two Victorian (Tamboon Inlet and Lake Curlip) and one South Australian (Lake Alexandrina) system. Despite the small number of sites studied to date, and their disparate geographic, climatological and hydrologic settings, a number of general themes emerge in the sites’ histories. Firstly, with the exception of Lake Curlip, it is not apparent that the sites experience long term (variable) declines in salinity as predicted by models of estuarine evolution (see Roy et al., 2001, Est Coastal Shelf Sci, 53 for a recent iteration). Secondly, as a corollary, there is mounting evidence to suggest that salinity in coastal lakes has responded to mid to late Holocene variations in effective precipitation (e.g. those documented in Lake Keilambete, Western Victoria, see Chivas et al., 1986 Hydrobiologia 143, for a summary). Thirdly, they have


not registered Holocene sea level variability such as that described by Baker and Haworth (2000: Marine Geol., 163). Taken together these data suggest that such systems are more sensitive to catchment-driven hydrological change than previously recognised. This is observation is particularly pertinent to the post-European contact period in Tamboon Inlet. Catchment clearance, particularly on the Cann River floodplain (Brooks et al., Geomorphology, 51), has increased run-off to such an extent that its post-settlement salinity is lower than at any other time in its c. 4000 year history. Our future investigations will assess the extent to which these observations can be made more generally in Eastern Australia. 0952 Development and destruction of Holocene headwater swamps in southeastern Australia Kerrie M Tomkins, Geoff S Humphreys Dept. Physical Geography, Macquarie University NSW 2109, Australia

The Woronora Plateau located to the south of Sydney, features numerous swamps of Holocene age formed within headwater tributary streams. The swamps play an important role in sediment storage within the landscape and also act as a filter and buffer to produce clean, constant water flow. Several swamps are eroding at present resulting in the release of sediments and nutrients downstream, as well as altered swamp hydrology and vegetation composition. Various explanations on the cause of erosion have been put forward including recent drought, wildfires and dewatering of the swamps through ground subsidence associated with underground coal mining. Analysis of aerial photographs dating back to the late 1940’s and covering three eroding swamps revealed a common sequence of erosion, commencing with the formation of discontinuous scour pools cut into the swamp surface, followed by the gradual linking of the pools (often starting at the downstream end) through knickpoint retreat, leading to the eventual gully erosion through the swamp. Analysis of sediments exposed within the gully walls of the swamps revealed previous episodes of scour and gully erosion indicating that cut and fill processes are an important part of long-term swamp development and evolution over thousands of years. The gully erosion however, only results in the removal of a small slice of the swamp, rather than the whole scale removal of sediments. This is reinforced by the recent episode of erosion which shows that despite extensive disturbance and severe climatic conditions the swamps continue to remain as resilient long-lived features in the landscape. 1092 Does the evidence from the Chinese fauna support the “Out of Africa” model of modern human origins Haowen TONG Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 100044 Beijng, China

The current and dominant theory about the origin of modern human is the “out of Africa model”, which asserts that modern humans evolved relatively recently in Africa, migrated into Eurasia and replaced all the local populations which had descended from Homo erectus. It seems that most evidence points to this theory nowadays, because fossils of modern-like humans are found in Africa; stone tools and other artifacts also support African origin; DNA studies suggest a founding population in Africa too. That theory holds that populations of Homo sapiens

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left Africa 100,000 years ago and wiped out existing populations of humans. But up to now, nobody noticed the evidence from the fauna, whether they are beneficial or unfavorable to the popolar theory is not sure yet. The recent study on the Chinese fauna shows that the communication of faunan between Africa and East Asia is very limited. As the modern zoogeographical pattern of today, the Pleistocene fauna in China was divided into two distinct regions: the north China fauna and the south China fauna. The North China fauna mainly contains the following elements: Trogontherium, Myospalax, Marmota, Ursus arctos, Crocuta, Palaeoloxodon, Mammuthus, Equus, Coelodonta, Dicerorhinus mercki, Megaloceros, Cervus elaphus, Spirocerus etc. The South China fauna are mainly composed of the following taxa: Gigantopithecus, Pongo, Hylobates, Macaca, Rhizomys, Hystrix, Ailuropoda, Arctonyx, Paguma, Stegodon, Rhinoceros, Tapirus and Megatapirus etc. Among the dominant taxa of the Chinese Quaternary fauna, there is no elements can be related to the African fauna. We don’t have reliable evidence of the existence of Hippopotamus and Giraffa as well as Panthera leo in China. The two controversial taxa are Acinonyx, Crocuta ultima, they are co-generic even co-specific with the African counterparts. The two kinds of animal seem only exist in Africa today, but they also have long evolutionary history in China. So it’s difficult to say that they really have any relationship with the African fauna. Conclusionally, the direct communication between the Chinese Quaternary fauna and the African Fauna didn’t exist in Pleistocene, at least in Late Pleistocene. So it’s difficult to image that the humans went out of Africa without any accompaniment of other mammalian fauna. 0551 Relation between sea level and table water variation which controlled recent Holocene incised fluvial valley at the Pampas Plains, Argentina Roberto none Torra Nistal Departamento de Geociencias. Facultad de Ingenieria, Argentina

It is well know the fact that during recent Holocene (the last 10,000 BP) littoral marine ingressions occurred at the Argentine territories (South America). These ingressions happened on the actual Santa Fe and Buenos Aires Provinces plains embracing about of 20,000 to 30,000 square kilometers based upon marine mollusk data and silty-argillaceous facies analyses. The ingressions occurred through Rio de La Plata subestuarine environment somewhat embayment form. In just point, the Parana river flows about 25,000 cubic meter per second and a great huge of fine sediments. Ingressions rising water may be reached about of 10 to 20 meters at the climax moment of normal sea water. This alteration of the geological systems was reflected and is continuing reflected in the first, second, and third order tributaries of the Parana river both left and write margins due variation on the table waters. Speeding erosional phenomena were then triggered in the fluvial valleys constituted by friable sediments as sandy-muddy horizontal facies of Upper littoral shallow marine Miocene age. Measurements performed in the Empedrado ravines and gullies’ showed that a rate of destroying sediments ranging about 100 cm per year occurred. As the specialized literature demonstrated, the latest ingressions occurred during 6000 and 3000 BP approximately. After they retired base level decrease and so erosion increased specially in the more unstable small tributaries which are very susceptible to these changes (geological geo-indicators). Field and regional satellitary analyses of many Pampas Plains tributaries showed that they are caving these fluvial valleys in recent times. Extrapolation of Empedrado erosive values for the last 5000 BP years could correspond to 5000 meters of erosion. If we take in consideration

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that the Parana fluvial valley has an amplitude ranging 25 to 35 km in lengths, we be able to conclude that this value of erosion may be reasonable and possible. This conclusion has importance on the humankind activities as for example: civil work (collapse of bridges), collapse of ports, buildings, railroad breaking, destroy of all kind of dams, cadastre geometry, cattle rising activities, etc. Contextual analysis of “recent” historical geology is critical for sustainable development and need cooperation of geologists, surveyors, engineers and cartographers. 1319 Relationships between sea level rise and vegetation changes during mid to late Holocene from southeastern Mexico Nuria Torresscano, Gerald A Islebe El Colegio de la Frontera sur Unidad Chetumal, MEXICO, Mexico

Fossil pollen in three cores, one near the northern coast, one near the central coast of Quintana Roo and other near the Belizean border, reveal the environmental history of the mangrove and tropical forest during mid and late Holocene. Core El Palmar shows the last 5000 years from a tropical forest type to a mangrove dominated forest and later inmediately a transition to a mixture of tropical forest and mangrove due to sea-level changes. This period was probably more humid than today, Moraceae, Rubiaceae and Fabaceae dominated since 5000 to 4800 BP. After 4800 BP environmental conditions changed drastically to a mangrove ecosystem, dominated by Rhizophora and Conocarpus. The cores Tzib and MPM2 show details of the changes during last 3500 years. In core Tzib the tropical forest is represented by Ficus, Moraceae and Fabaceae which dominated the landscape since 3500 to 2500 BP. The low presence of Mangroves of Conocarpus and Rhizophora, and Tasistal (Some palms and Cyperaceae) is evidence of the early establishment of the coastline. From 2500 to 1800 BP, high percentages of Ficus and Moraceae show relatively wet conditions, but less as recorded during mid Holocene. In the last 1800 years the elements of tropical forest and mangroves show two probable drier phases, both phases are correlated with dry periods reported in others paleoecological studies of the region. This phase is probably related with the Mayan collapse. Finally the core MPM2 corresponds to the last 3400 years, the sedimentation was very slow, between 3400 and 3300 Rizophora mangrove is dominant, after 3300 BP a hiatus is registered. The last part of the sediment column of MPM2 is correlated with the last part the core Tzib. The establishment of tasistal is more evident in MPM2, this vegetation type is characteristic of transition zones between low-statured forest and mangroves. The three cores show high dynamics in the stablishment of the coast line and history of vegetation in the Caribbean region of Mexico. 1068 ESR signals in quartz as indicators of provenance of eolian dust: implications for atmospheric circulation in the past Shin Toyoda1, Takao Okano1, Kana Nagashima2, Yuko Isozaki3, Yobin Sun4, Ryuji Tada5 1

Okayama University of Science, Japan Japan Agency for Marine-Earth Science and Technology, Japan 3 University of Tokyo, Japan 4 China 5 Japan 2

Electron spin resonance (ESR) detects unpaired electrons, which have been created by natural radiation and been accumulated in minerals through geological time. ESR dating method was developed based on

this principle and has been applied to many minerals, such as calcite, aragonite, hydroxyapatite, and quartz, which record events in Quaternary. We found that the oxygen vacancies in quartz have lifetime much longer than other impurity centers (unpaired electron associated with impurities in quartz). We further proposed a method to use the signal as an indicator of provenance of quartz. Large amount of eolian dust is transported from dried areas in Eurasian continent to the Japan Sea and the Japanese islands through westerly. We have shown that the ESR signal intensity of the E1’ center in quartz associated with an oxygen vacancy differentiates the provenance of eolian dust, central Asia where Paleozoic-Mesozoic rocks with a medium ESR signal intensity, or Siberia and Mongolia where the Precambrian rocks with a higher ESR signal intensity (Toyoda and Naruse, 2002), so that the source of eolian dust accumulated in northern Japan changed between MIS 2 and 1, from southern source to northern source. Together with the crystallinity index (CI) of quartz, it was made possible to discuss the change of the source of the eolian dust accumulated in marine sediment of Japan Sea and to estimate the historical change of the route of the westerly jet (Nagashima et al., in press). Our studies on the ESR signals and CI of quartz in less than 16 micrometers fraction of surface samples collected at deserts and dry lands in inland China and Mongolia suggest that the eolian dust are explained by mixture of 5 or 6 sources including Taklimakan, Tengger, Badain Juran, Gurbantunggut, and Mongolian Gobi deserts. (Sun et al., submitted). In the present paper, we will show that other ESR signals of impurity centers in quartz, such as Ge and Ti centers (substitutional Ge, and Ti atoms trapping an unpaired electron with alkali ions), and Al center (substitutional Al ion trapping an electronic hole) can also be used as indicators to distinguish the source regions of eolian dust when the dose responses of the centers (the signal intensities increased by a unit dose of gamma ray irradiation) are examined. Results of the study on the Chinese desert samples will be presented. 0544 Extending southwest Australia’s rainfall record using speleothems Pauline C Treble The Australian National University, Australia

Annual rainfall in southwest Western Australia decreased by up to 20% from the mid-1960s onwards, resulting in approximately 50% less streamflow to Perth’s reservoirs and threatening some water-dependent ecosystems. The rainfall decrease is similar to the worst climate change scenario predicted by global climate models under enhanced atmospheric CO2 conditions although natural rainfall variability may also have contributed to the observed rainfall decrease. A critical knowledge void is the frequency, duration and intensity of past multi-decadal climate events. Planning for future sustainable water use will remain difficult without first providing a long duration rainfall record for southwest Western Australia. A previous study has demonstrated that oxygen isotopes and certain trace elements in cave stalagmites (speleothems) from southwest Western Australia can be used to reconstruct rainfall trends (Treble et al., 2003, Earth and Planetary Science Letters, 216: 141-153; Treble et al., 2005, Earth and Planetary Science Letters, 233: 17-32). Trace elements in particular, measured by laser ablation mass spectrometry, can record seasonal variation. These techniques are currently being applied to extend the speleothem based paleo-rainfall record in southwest Western Australia to at least 500 years. A 250 year record of trace elements for a speleothem from Yonderup Cave, Yanchep (50 km north of Perth) and multi-centennial oxygen isotope


records from Golgotha Cave (250 km south of Perth) will be presented. The intensity and duration characteristics of the present multi-decadal dry period will be examined in the context of previous dry periods identified in the speleothem records. 0581 Accumulation of elements in the annual rings of hardwood at a heavy metals contaminated region Pei-Shan Tsou1, Ching-Hsing Chiu2 1

Department of Environmental Engineering and Science, Fooyin University, Taiwan 2 Department if Tourism Management, Shih Chien University, Kaohsiung Campus, Taiwan

Heavy metal contamination with environmental and human hazards is the most important environmental issue with public concerns. There are some heavy metal contaminated sites in Taiwan caused by the improper waste disposal from metal related industries, especially the acidic mining/etching, surface finishing and plating plants. In this study, heavy metal concentrations in annual growth rings of Cinnamomum camphora growing around a river with Zn and Cu contamination by acidic etching industry were determined. The dendrochemical analysis results from ICP-OES show that the Zn and Cu concentrations in Cinnamomum camphora growing along river with contaminated sediments were both greater than those growing at uncontaminated reference sites. Besides that, Zn concentration in the Cinnamomum camphora annual growth ring was found to have a significant correlation with the respective annual water quality of the contaminated river. As the remediation of the contaminated river has been conducted, the heavy metals deposited in the Cinnamomum camphora show an obvious declining trends. It reveals that the contamination of Zn and Cu effectively cause the deposition to the Cinnamomum camphora, and the deposition concentrations are directly responsed to the contamination conditions. In comparison the Zn deposition in Cinnamomum camphora with Cu, it was found that Zn concentrations were much higher than Cu. The results also indicate that the Cinnamomum camphora is more useful in response to Zn contamination than Cu contamination. 1075 Ice streams in modern and palaeo-environments: recent achievments and future developments Slawek Tulaczyk1, Chris Stokes2 1

Department of Earth and Planetary Sciences, University of California, Santa Cruz, United States 2 Department of Geography, Durham University, United Kingdom

Ice streams are important because they rapidly transfer ice from the interior of an ice sheet to the margins. They also erode, entrain and transport sediment, creating distinctive erosional and depositional landscapes (subglacial bedforms, trough mouth fans, etc.) Traditionally, research on contemporary ice streams has instigated research on palaeo-ice streams, i.e. can we find where they were in palaeo-ice sheets? What landforms did they produce? What impact did they have on the ice sheet’s behaviour? More recently, however, it has been recognised that the exposed beds of palaeo-ice streams can further our understanding of the operation of active ice streams in contemporary environments. One of the main contributions of palaeo-ice stream research is the identification of landforms produced by ice streams. At the same time, velocity measurements and force balance inversions on

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active ice streams provide key information on the distribution and extent of sticky spots, the nature of which can be further explored on palaeo-ice stream beds. Likewise, borehole investigations of subglacial conditions beneath active ice streams provide key information which can be used to assist interpretation of exposed sediments on palaeo-ice stream beds and vice versa. The nature of the boundary between an ice stream and adjacent ice can also be explored using data from both active and palaeo-ice stream beds. Research from active ice streams hints at the highly dynamic nature of ice stream boundaries, which is corroborated by observations of switching flow patterns preserved in the sedimentary architecture of palaeo-ice streams over longer centennial-millenial timescales. The growing datasets from both active and palaeo-ice streams has led to the development of numerical models which seek to explain the development and distribution of subglacial bedforms and the physical processes which control ice stream motion. Future research should be aimed at quantifying subglacial sediments and landscapes to test the validity of the next suite of ice stream models. It is also important to broaden our view of ice streams and look at the wider behaviour of ice stream networks, and not just their individual motion and flow mechanisms. How do neighbouring ice streams interact via process in their catchment areas? What is the importantce of meltwater drainage patterns in determining ice stream drainage networks? Why do palaeo-ice streams seem to be wider than their contemporary counterparts? Does a deglaciating ice sheet switch on more ice streams and how strongly coupled are ice streams to a warming climate? 1091 Subglacial environments: physical, biological, and chemical dimensions Slawek Tulaczyk Department of Earth and Planetary Sciences, University of California, Santa Cruz, United States

Subglacial environments encompass a variety of conditions and processes because they simply represent a boundary between ice masses and their various substrata. They are inherently difficult to investigate since one can either study modern subglacial environments, where conditions can be measured in a limited number of places, or exposed paleo examples, where past subglacial conditions have to be inferred indirectly. Here, I will review recent developments in studies of subglacial physical processes, which have been for long time the main focus of work on subglacial environments because of their importance to understanding mechanics and dynamics of ice motion. In particular, I will focus on subglacial water budget and water flow, the question of till origin and deformation, and development of subglacial landforms due to coupled deformation of ice and subglacial materials. In spite of many years of fruitful research there are still basic outstanding questions, which are difficult to resolve, such as: What controls the thickness of subglacial tills? Is there efficient connectivity between supraglacial water drainage systems and subglacial drainage systems in polar ice masses? How can we quantify the link between subglacial water flow and ice flow dynamics? What are the physical reasons for the wide variability in geometry of subglacial landforms? In addition, I will review recent advances in researching chemical and biological aspects of subglacial environments. These are exciting areas of study, concerned with the role of subglacial environments in regional and global biogeochemical cycles and in the function of such environments as habitats for microbial lifeforms. I will consider some of the key biological and chemical research questions: Are subglacial environments anoxic? Is methane being produced and stored subglacially? Is subglacial life con-

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strained to small ice masses and subglacial lakes or is it widespread? What is the range of subglacial biochemical conditions? The fact that there are many unanswered fundamental questions concerned with subglacial conditions and with their regional/global implications demonstrates strong prospects for continuing exploration of these unique terrestrial environments. 1302 Defining characteristics of the Holsteinian (-Hoxnian-MasovianLikhvinian) Interglacial (i.e MIS 11c) in Northern Europe Charles Turner Quaternary Palaeoenvironments Group, University of Cambridge, United Kingdom

The interglacial record in Northern Europe is strongly biased towards those temperate Stages immediately preceded by major glaciations. Melting of the Elsterian and Saalian ice sheets provided ‘accommodation space’, particularly in the form of dead-ice hollows and subglacial meltwater channels, in which interglacial lacustrine deposits could be deposited and subsequently preserved. Deposits assigned to warm Stages between the Holsteinian and Saalian are extremely sparse and usually associated with fluvial sequences, frequently fragmentary in their coverage of those Stages and difficult to assign stratigraphically. Holsteinian and equivalent interglacial deposits occur in situations associated with the margins of the Elsterian (MIS 12) ice sheet across a broad swathe of Northern Europe from the British Isles to the Russian Plain, sometimes overlain by younger Saalian sediments. Stratigraphical evidence strongly supports the conclusion that the Hoxnian Interglacial of Britain, the Holsteinian of Northern Germany and the Masovian and Likhvinian of Poland and Russia can all be referred to the same Stage, but it is necessary to study fluvial terrace sequences, particularly in France and southern England, to demonstrate the presence of intervening warm stages between the Holsteinian and Eemian and so confirm the correlation between the Holsteinian and the deep-ocean record, contradicting recent published absolute datings. This correlation is, however, already clear from evidence from maar sediments in the Massif Central of France and from palynology of marine sediments along the eastern margins of the Atlantic Ocean. The Holsteinian vegetation record across Northern Europe has never been reviewed in detail. Whereas vegetational successions from different areas of Northern Europe during the Eemian show a surprising uniformity, there are marked changes both in aspect and successional features of vegetation from west to east during the Holsteinian. Superimposed on this pattern are strong edaphic influences, so that the vegetational records of the stratotype sequences in the Hamburg area and from the Lüneburger Heide of Northern Germany are by no means typical of the wider picture and have led to poorly founded comparisons of the vegetation of this interglacial with that of the Eemian. More detailed studies of vegetational and other biostratigraphical records from Holsteinian Interglacial sites are urgently required in order to provide an answer to a current and critical requirement – detailed data on the climatic development of this lengthy interglacial for comparison with that of the Holocene. 0900 Integration of ice-core, marine and terrestrial records for the Australian Last Glacial Maximum and Termination: a contribution from the OZ INTIMATE group Chris Turney GeoQuEST Research Centre, School of Earth and Environmental Sciences, University of Wollongong, Australia

The degree to which Southern Hemisphere climatic changes during the end of the last glacial period and early Holocene (30–8 ka) were influenced or initiated by events occurring in the high latitudes of the Northern Hemisphere is a complex issue. There is conflicting evidence for the degree of hemispheric ‘teleconnection’ and an unresolved debate as to the principle forcing mechanism(s). The available hypotheses are difficult to test robustly, however, because the few detailed palaeoclimatic records in the Southern Hemisphere are widely dispersed and lack duplication. Here we present climatic and environmental reconstructions from across Australia, a key region of the Southern Hemisphere because of the range of environments it covers and the potentially important role regional atmospheric and oceanic controls play in global climate change.Weidentify a general scheme of events for the end of the last glacial period and early Holocene but a detailed reconstruction proved problematic. Significant progress in climate quantification and geochronological control is now urgently required to robustly investigate change through this period. 0895 Radiocarbon Calibration and High-Resolution Correlation Through Oxygen Isotope Stage 3 Using New Zealand Kauri (Agathis australis) Chris Turney1, Keith Fifield2, Alan Hogg3, Jonathan Palmer4, Konrad Hughen5, Mike Baillie6, Rex Galbraith7, John Ogden6 1

GeoQuEST Research Centre, School of Earth and Environmental Sciences, University of Wollongong, Australia 2 Research School of Physical Sciences and Engineering, Australian National University, Australia 3 Radiocarbon Laboratory, University of Waikato, New Zealand 4 Gondwana Tree-Ring Laboratory, Little River, New Zealand 5 Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, United States 6 School of Geography, Archaeology and Palaeoecology, Queen’s University, United Kingdom 7 Department of Statistical Science, University College London, United Kingdom

Oxygen Isotope Stage-3 (OIS-3) was characterised by significant climatic/environmental changes, and hominin migration and extinction around the globe. Unfortunately, no calibration curve beyond 26 ka has been generated that can be unambiguously attributed to changes in atmospheric radiocarbon content. Moreover, a U-series dated speleothem from the Bahamas has suggested previously unidentified massive changes in the radiocarbon inventory of the atmosphere. The implications of these results, if proven, have yet to be fully realised. Here we discuss the potential of New Zealand kauri (Agathis australis) to identify the structure of the radiocarbon calibration curve using annuallyresolved tree-rings. Radiocarbon measurements have been obtained from sub-fossil material using both accelerator mass spectrometry and liquid scintillation spectroscopy. We report OIS-3 sampled radiocarbon measurements obtained from several floating millennia–length trees that span periods from within 25 ka to 55 ka. Many of the sites investigated contained multiple cohorts of preserved logs from discrete non-overlapping time periods. We demonstrate repeatable 14C measurements at the very limits of the dating method and show that ‘floating’ sections can be precisely linked to the Cariaco Basin using fluctuations in atmospheric radiocarbon content, allowing robust interhemispheric climate comparisons within OIS-3.


0093 A Regional Holocene Vegetation/Climate History of South-East Queensland Angus W Tye SAGES, The Univeristy Of Melbourne, Australia

The Holocene period has been one of rapid climatic change out of the Last Glacial period, with an optimum at approx 4,900ybp. However since then there have been several factors which have shaped climatic change, whilst temperature has been the same, studies form Northern and Southern Australia have found increasing seasonality. The limited work from the mid latitude South-East Australia has identified a ‘mid Holocene arid Anomaly’. Predominantly most studies to date have dealt with singular locations. This has been in part to a limitation on the availability of replication within the region. The giant sand islands of South-east Queensland span the latitudes of 24º40' S to 27º40' S and are all composed of predominantly sedimentary quartz. This similarity provides a solid basis for replication. Extracting cores and analysing fossil pollen and charcoal from Fraser, Moreton and North Stradbroke Island’s and the Cooloola Sandmass can establish a regional multiproxy Holocene climatic record. Rather than extracting cores from large lakes, these cores have been taken from swamps existing at community boundaries to amplify the effects of climate change. Results thus far from Fraser Island suggest that present day major plant community boundaries have remained relatively stable for long periods of time with a couple of obvious and significant exceptions. Results from Allom Swamp displays a dual record of two vegetation communities (Wet Sclerophyll and Heathland) existing side by side, the boundary appears to have remained stable with internal shifts in the rainforest species associated with charcoal level. The Northern Rd site demonstrates a relatively high proportion of Araucaria at the base of the core associated with low charcoal and an immediate decline as charcoal and fern spores rise. Both of these records show a direct response of the fire sensitive rainforest species to fluctuations in the charcoal record. Results from Stradbroke Island indicate a fire prone woodland community that has been becoming more open throughout the Holocene. 1247 Unravelling the climate signals preserved in diatom silica oxygen isotope ratios: a case study from Lochnagar, Scotland Jonathan J Tyler1, Melanie J Leng2, Hilary J Sloane2, Carol Arrowsmith2, Vivienne J Jones1, Richard W Battarbee1 1

Environmental Change Research Centre, University College London, United Kingdom 2 NERC Isotope Geosciences Laboratory, British Geological Survey, Nottingham, United Kingdom

Oxygen isotope ratios of diatom silica (d18Osilica) preserved in lake sediments offer a potentially valuable palaeoclimate record of past water temperature and water oxygen isotopes. However, the transmission of climate signals to the sediment record involves a number of competing effects and interactions which make palaeoclimatic interpretation complex. The major factors affecting lake sediment d18Osilica include: (a) changes in the oxygen isotope composition of precipitation feeding the lake (d18OP); (b) changes in the extent to which d18Olake reflects d18OP driven by residence time and lake water stratification; (c) the timing and extent of seasonal diatom productivity; and (d) the temperature dependent oxygen isotope fractionation between diatom silica and water. We investigate these processes through intensive monitoring of d18OP, d18Olake and d18Osilica at Lochnagar, a remote, high altitude loch (lake) in

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Scotland. A basic model is presented which combines each process, enabling the prediction of sediment diatom silica oxygen isotope ratios under various hypothetical climate scenarios. Using this model, the climate sensitivity of the Lochnagar sediment record is examined, and problems and potentialities concerning the use and development of d18Osilica as a palaeoclimate proxy are discussed. 1398 Establishing a chronology for MIS 11 vegetation changes in SW Europe Chronis Tzedakis1, Lucia de Abreu2, Antje Voelker3 1

Earth and Biosphere Institute, School of Geography, University of Leeds, United Kingdom 2 INETI, Departamento de Geologia Marinha, Portugal 3 INETI, Departamento de Geologia Marinha, United Kingdom

A persistent handicap of Pleistocene pollen sequences is the paucity of sufficiently precise timescale because of dating uncertainties on the order of 10% or more, which precludes any meaningful phase comparisons with other palaeoclimatic archives. One of the most promising approaches to address this is the linking of terrestrial and marine records directly through joint pollen analysis and oxygen isotope measurements on benthic foraminifera from the same sample set in marine cores. Such a coupling allows an in situ assessment of relative leads and lags and the use of the marine timescale for dating land events. While combined foraminiferal oxygen isotope and pollen analyses have long provided an insight into the broad correspondence between marine and terrestrial stages, it is only recently that coring cruises have been undertaken with the quality of the pollen signal and the issue of marine-terrestrial comparisons in mind from the initial planning stages. A prominent example of such an undertaking has been the cruises of the Marion Dufresne along the Portuguese margin, where the combined effects of major river systems and a narrow continental shelf lead to the rapid delivery of terrestrial material, including pollen, to the deep-sea environment. Coring sites have been selected so as to be near enough to the continent to derive a regional pollen signal, but deep enough to generate high-quality isotopic records from planktonic and benthic foraminifera. In the south Portuguese margin, SW of Lisbon, pollen is mainly transported to abyssal sites by the outflow of the Tagus river, while aeolian transport is limited as the dominant winds come from the northwest. Here we report high-resolution pollen results from two combined marine sequences (MD01-2443 and MD03-2699), providing a complete sequence from Termination V to the MIS 11/10 transition. A detailed chronological framework is developed by aligning the benthic d18O record to the Antarctic D/H record, following the implications of the study of Shackleton et al. (2000), who showed a remarkable similarity between the benthic d18O record off Portugal and Antarctic temperatures. This allows the derivation of a detailed chronology of vegetation events during MIS 11, which can be transferred to terrestrial sequences. In addition, the alignment to Antarctic ice core records allows an opportunity to compare the phasing of these changes relative to those in greenhouse gas concentrations.

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1074 Marine Carbon Reservoir Variability in Torres Strait: Preliminary Results of AMS Dating of Live-Collected Shell Specimens Sean Ulm1, Anthony J Barham2, Bruno David3, Geraldine Jacobsen4, Ian J McNiven3, Fiona Petchey5, Mike J Rowland6 1

Aboriginal and Torres Strait Islander Studies Unit, University of Queensland, Australia 2 Department of Archaeology and Natural History, Research School of Pacific and Asian Studies, Australian Natiional University, Australia 3 Programme for Australian Indigenous Archaeology, School of Geography and Environmental Science, Monash University, Australia 4 Australian Institute of Nuclear Science and Engineering, Australia 5 Radiocarbon Dating Laboratory, University of Waikato, New Zealand 6 Cultural Heritage Coordination Unit, Queensland Department of Natural Resources and Water, Australia

Despite routine dating of marine shell by Quaternary scientists in the Torres Strait region, no systematic evaluation of the applicability of the recommended DeltaR value has been undertaken. This value can be shown to be problematic. It is based on only three samples from Torres Strait and two from the west coast of Cape York Peninsula, together spanning 125±60 to -14±60 years; the samples are from different oceanographic provinces; the dated taxa are not amongst those commonly dated by contemporary researchers; and all of the dates were obtained over 20 years ago before the advent of high precision AMS dating. This project attempts to address this deficiency through the dating of a suite of well-provenanced live-collected shell specimens using the high precision ANTARES AMS facilities at ANSTO. Dated samples are largely derived from a unique assemblage of well-documented live-collected shell specimens in the Australian Museum from Murray Island and Albany Passage collected by Charles Hedley in August-October 1907, supplemented by smaller collections from elsewhere in Torres Strait. Sample selection focused on suspension-feeders (Arcidae, Mesodesmatidae, Veneridae), although carnivores (Volutidae), herbivores/omnivores (Neritidae) and algae grazers (Trochidae) were included to examine inter-taxa variability. Preliminary results help establish more robust regional DeltaR values for the region based on shellfish commonly dated by Quaternary scientists and allow examination of localised variability in DeltaR values. These findings have broad implications for refining chronologies in coastal archaeology and geomorphology in the Torres Strait region, including studies of sea-level change, reef and coral cay development, coastal dune sequences, storm event frequency and archaeological trends. 0375 Characteristics of acid sulfate soils in relation to the Holocene evolution of the Central Plain, Thailand Masatomo Umitsu1, Naruekamon Janjirawattikul1, Sin Sinsakul2, Niran Chaimanee2, Suwat Tiyapairach2 1

Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan, Japan 2 Department of Mineral Resources, Bangkok, Thailand, Thailand

The characteristic of acid sulfate soil in the Central Plain of Thailand and its relationship with the Holocene landform evolution were studied. Landforms of the lower Central Plain were classified into alluvial fan in the west, flood plain in the north, deltaic plain in the center, and the tidal lowland in the south. The largest area of acid sulfate soil is distributed in the deltaic plain area, and the area was former tidal plain which developed to the north of Ayutthaya in 7000 yrs BP. Character-

istics of the surface geology in the area are generally classified as follows. The surface horizon is an artificial horizon cultivated by agriculture. Sequence of subsurface upper horizon begins with silt and clay containing yellow mottles. The lower part of the subsurface horizon contains organic matters or black peat with wood fragments. The lowest horizon is greenish or bluish grey silty clay and is considered as shallow marine or marine in origin. Pleistocene sediments develop beneath the lowest horizon with stiff silt or clay with redoximorphic features. Field data of pH of the artificial horizons is 5.5–7.0. That of the upper and lower subsurface horizon, however, is 4.0 –4.5 and 4.5–7.0, respectively. The pH of the lowest horizon is 6.0 –8.5. From the result, the subsurface horizon is under the strong acid condition. The lower part of the subsurface soil is considered as the sediment deposited in the intertidal condition with mangroves. And the upper part of the subsurface soil is mainly light grey to brownish grey silty clay with rich in yellow mottles. The yellow mottles are considered as jarosite and this horizon is the strongest acid horizon in the section. The sedimentary environment of the horizon is considered as intertidal to deltaic condition after the culmination of Holocene transgression. This condition also caused rich iron sulfur condition. And the iron sulfur is mainly considered as pyrite. After the drainage system was introduced in the plain, oxidation caused change of pyrite to jarosite appearing as yellow mottle. In conclusion, acid sulfate soil was formed in the sediments deposited in the tidal plain especially covered with mangrove forest and in the deltaic plain during middle to late Holocene. The subsurface soil changed to strong acidic condition under the oxidation after the drainage system was introduced. Little fluvial sediment deposited on the subsurface acid soils in the lower Central Plain. 1216 Impacts on coastal ecology and environments of past and recent tsunamis of the Andaman Islands, India Brigitte Urban1, Purvaja Ramachandran2, Ramachandran Ramesh2 1

University of Lüneburg, Germany Anna University, Chennai, India

2

This study is part of the joint BMBF-DST German-Indian collaborative project “Environmental and ecological responses to climate and tectonic events in the western monsoonal Indian Ocean”. In order to assess the impact of tsunamis on the coastal environments, field and laboratory investigations have been carried out in the highly tsunamiaffected Andaman Islands. We observed, after the 2004 tsunami, that coastlines have been eroded, with much of the sediment deposited on coral reefs, or agricultural land and in creeks, or even created new islands. Shallow soils have been stripped from some low-lying atolls. Furthermore, marked changes in the tidal amplitude at Wright Myo (South Andaman), as a result of the tsunami, have been observed. In order to understand the importance and range of impacts of natural disasters on these geotectonically active Islands in the Bay of Bengal, recent and paleotsunami sediments within coastal environments and water bodies are being studied for their geobiochemical, sedimentological and (paleo)ecological features. Geochemical indicators, such as major element enrichment (Na, Cl, S, Br etc), have been used to indicate a marine source for the particular deposits. As observed by us in this study, tsunami sands have higher SiO2, CaO and Sr concentrations, which is indicative of anincreased siliceous-sand component together with variable admixtures of limestone and marine shells. These enriched sands are found as narrow bands within sediment sequences and can be correlated with tsunamigenic sand deposits in adjacent areas. Analysis of major and trace element


variations unrelated to human activity in the sediment column indicates that, except for near-surface perturbations (0 –10cm), major compositional breaks are limited to lithological transitions. Results on the distribution and characteristics of recent tsunami sediments and geomorphological changes within the coastal areas of the Andaman islands and a knowledge of their impact on coastal ecology provide first basical data for a better understanding of those coastal hazards. 0891 The Dynamic Interaction of Climate, Annual Vegetation and Dust Emission, Mojave Desert, USA Frank E Urban1, Richard L Reynolds1, Robert Fulton2 1

U.S. Geological Survey, MS 980, Box 25046, DFC, Denver, CO 80225, United States 2 California State University, Fullerton, P.O. Box, 6850, Fullerton, CA 928346850, United States

Atmospheric dust is emitted from a variety of dryland settings, including many kinds of sparsely vegetated surfaces, playa surfaces, and dry riverbeds. Little is known in detail about dust generation in response to timing of precipitation and the consequent effects on soil and vegetation dynamics. This deficiency is especially acute at intermediate landscape scale, tens of meters to several hundred meters. It is essential to consider dust emission at this scale, because it links dust generation at scales of grains and wind tunnels with regional-scale dust examined using remotely sensed data from satellites. Three sites of slightly different geomorphic setting in the vicinity of Soda (dry) Lake were instrumented (in 1999) with meteorological sensors and sensors to measure wind erosion through saltating particle detection during high winds. Changes in vegetation in close proximity to the instrumented stations were documented through measurements of plant type, cover, and repeat photographic imagery. A succession of dry and wet years in the study area has allowed documentation of the profound influence of precipitation driven annual plant growth, (both living and remnant) on variability in dust emission. High levels of precipitation (relative to our period of record) in early spring 2001 stimulated heavy localized growth of annual grasses, shutting down dust emission at the sites within a period of three months. The year 2002 was very dry with little precipitation or plant growth, yet remnant dead grasses from the previous year continued to stabilize the surface and suppress dust emission for about six months. Modest renewal of particle saltation occurred in late 2002. In early spring of both 2003 and 2004 as well as winter/ spring 2005, heavy precipitation stimulated unprecedented localized plant growth including an extraordinary bloom of an invasive mustard species. The three-year succession of strong annual vegetation growth dramatically suppressed particle saltation and associated local dust emission. These results document the immediate role that annual vegetation plays in stabilizing desert surfaces, and elucidate the persistent influence of invasive species on landscape dynamics. 1402 New data concerning Quaternary glaciation in the Transylvanian Alps (Romania) Petru Urdea1, Anne Reuther2, Klaus Heine3, Susan Ivy-Ochs4, Peter W Kubik5, Christian Geiger3

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The aim of this study was to present some new data of Pleistocene glacial history of the some key areas of Transylvanian Alps or Southern Carpathians (Romania), Retezat, Fagaras and Parâng Mountains, using detailed geomorphological mapping and numerical ages (surface exposure dating). The Southern Carpathians, also called the Transylvanian Alps, form the highest mountain chain of the Romanian Carpathians, with 11 peaks higher than 2500 m a.s.l., the highest summit being Moldoveanu in Fagaras Mountains with 2544 m. In Parâng and Retezat Mts. the maximum altitudes are 2518 m, Parângu Mare Peak and, respectively, 2509 m, Peleaga peak. These mountain areas consist of crystalline massifs separated by transversal valleys and intermountain basins.Although the existence of Pleistocene glaciation in the Romanian Carpathians was pointed out over 125 years ago, the problem is still controversial, become much clear only in the last three years. Field work, especially for surface exposure dating samples, was carried out in Pietrele valley on the northern slopes of the Retezat Mts., in Jiet valley on the northern slopes of the Parâng Mts. and in the eastern and central part of the Fagaras Mountains for new detailed geomorphological mapping. Two major glacial advances, M1, and M2, or Lolaia and, respectively, Judele-Jiet in local terminology, have been previously recognized. The most extensive M1-advance reached in the Retezat Mts. an elevation of 1035 m a.s.l., some 250 m below the terminal moraines of the M2- advance. If in the classical works the M1 advance is correlated with Riss glaciation and M2 with Würm II, the exposure dating prove younger ages for M2 advances (Judele-Jiet), 16.8±1.8 kyr in Retezat Mountains. and 17.9±1.6 kyr in Parâng Mountains. The new investigations and geomorphological mapping in the eastern part of Fagaras Mts. (Lutele-Berevoiescu area) open the possibilities to establish, step by step, the evolution of the glaciers in the lasts stages and to make a differentiation between two ways of evolution for the glaciers in the extinction stage, one in a normal way, and other from glacier to debris rock glaciers. 0833 Climate modelling of the 8.2kyr event Paul J Valdes, Julia Tindall School of Geographical Sciences, University of Bristol, United Kingdom

The 8.2 kyr event represents a unique period within the Holocene. The rapid climate associated with this period represents an important test of climate models. We will present the results from a series of simulations using the Hadley Centre climate model (HadCM3) with a newly developed oxygen isotope enabled sub-model. The model allows us to directly compare simulated isotope distributions with palaeodata. We will show results from a suite of simulations, investigating the sensitivity of the model to variations in location and strength of the fresh water pulse, imposed on a present day and early Holocene base state. The results show that the model is able to broadly simulates the observed changes, but somewhat underestimates the magnitude and duration of the response. 0850 ENSO within the Palaeoclimate Model Intercomparison Project Paul J Valdes, Ian Ross, Rupert Gladstone School of Geographical Sciences, University of Bristol, United Kingdom

1

Department of Geography, West University of Timisoara, Romania 2 Department of Earth Sciences, Dalhousie University,Halifax, Canada 3 Department of Geography, Regensburg University, Germany 4 Switzerland

The ENSO variability during the mid-Holocene has been extensively studied, both from a modelling and palaeoenvironmental data perspective. In this paper, we will describe the results from the Palaeoclimate

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Modelling Intercomparison Project (PMIP2). These consist of stateof-the-art coupled atmosphere ocean simulations, using appropriate mid-Holocene boundary conditions. Palaeoenvironmental indicators refer to changes in the mean state of the equatorial Pacific. These suggest that the Western Pacific warm pool was warmer and wetter whereas the Eastern Pacific may have been colder than present. Thus this suggests that the existing W-E equatorial Pacific temperatures were amplified during the mid-Holocene. In addition, high resolution coral and lake sediment data provides evidence for substantial reductions in ENSO variability on both sides of the Pacific. This the data suggests two key targets for the models (a) increased W-E temperature gradient, and (b) reduced ENSO variability. Model control simulations show considerable variability in the simulation of the present day equatorial Pacific temperature gradients. Some models have very little gradient but most other models exhibit a reasonable gradient. The mid-Holocene changes in mean temperature gradient are more variable and depend on the season being considered. The changes are also very small, with even seasonal changes being less than 1C. No model shows the magnitude of change suggested by the data. Modelled ENSO variability can be expressed in several different ways. Most models show significant reductions on ENSO variability, particularly during the key winter period. Only one model exhibits a strong increase. The models are thus broadly in agreement with observations, although the magnitude of changes are smaller than suggested from the data. 0855 Transient Simulations of the Last Deglaciation Paul J Valdes, Sandy Harrison, Ron Kahana, Julia Tindall School of Geographical Sciences, University of Bristol, United Kingdom

The first results of transient full GCM simulations of the time period since the Last Glacial Maximum will be presented. The model is a low resolution version of the Hadley Centre climate model. This lower resolution (7.5 degrees in longitude x 5 degrees in latitude) version is called FAMOUS (FAst Met Office/University Simulator), and is driven by orbital forcing, trace gases, and ice sheets (based on Peltier 5G). The results of the initial simulations will be compared to time slice reconstructions of the LGM and mid-Holocene, and to regional synthesis for other periods. The temporal variability of the model will also be shown. 0919 Lead isotope variations in Antarctic dust over 6 glacial cycles in the EPICA Dome C ice core P Vallelonga1, A Marteel2, P Gabrielli3, K JR Rosman1, C Barbante3, C F Boutron2 1

Department of Imaging and Applied Physics, Curtin University of Technology, GPO Box U 1987, Perth 6845, Australia, Australia 2 Laboratoire de Glaciologie et Géophysique de l’Environnement du CNRS, 54 rue Molière, Domaine Universitaire, BP 96, 38402 St Ma, France 3 Department of Environmental Sciences, University of Venice, Ca’ Foscari, Dorsoduro 2137, 30123 Venice, Italy, Italy

Lead (Pb) isotopic compositions and Pb and Ba concentrations are presented for the past 660 ky of Antarctic snow deposition, detailing variations in the flux and provenance of dust deposited on the East Antarctic ice sheet. Climatic forcing of the Pb isotopic signature can be observed in the dust with more-radiogenic Pb signatures (206Pb/ 207 Pb~1.23) deposited in Antarctica during interglacial periods and less-radiogenic Pb signatures (206Pb/207Pb~1.19) deposited during gla-

cial and transition periods. This demonstrates that the relative strengths of dust sources in the Southern Hemisphere changes over each glacialinterglacial cycle. Concentrations of Pb (5–20 pg/g) and Ba (16 –500 pg/g) are greater during glacial periods as a result of increased continental aridity, exposure of continental shelves, reduced hydrological cycle, stronger winds and ultimately more efficient meridional dust transport over the Southern Ocean. Lower concentrations of Pb (0.2– 0.8 pg/g) and Ba (6–10 pg/g) were observed during interglacial periods. Accurate assessments of the transport of dust in Southern Hemisphere over glacial cycles are necessary as dust is a forcing factor for solar radiation and Southern Ocean biogeochemical cycles, but there is ongoing debate regarding the source or mixture of sources of dust transported over the Southern Ocean. Grousset and co-workers (Delmonte et al., 2004, Earth-Sci. Rev. v.66, p.63) have employed Sr and Nd isotope systematics and concentrations of Rare Earth Elements to conclude that Patagonia is the primary source of dust to Antarctica during all climatic conditions. Their work relied on the characterization of Potential Source Areas (PSAs) representative of the dust-producing regions within the Southern Hemisphere. These findings have been challenged by a recent study of Australian PSAs (Revel-Rolland et al., 2006, Earth Planet. Sci. Lett., v.249, p.1) and the demonstration of aeolian dust transport from Australia to Antarctica (van de Velde et al., 2005, Earth Planet. Sci Lett., v.232, p.95). Samples were decontaminated using plastic and stainless steel apparatus cleaned with purified water and nitric acid in clean laboratories supplied with High Efficiency Particle Arresting (HEPA)-filtered air. Decontaminated ice samples were analyzed using Thermal Ionisation Mass Spectrometry (TIMS) with Pb and Ba concentrations determined by isotope dilution (Vallelonga et al., 2002, Anal. Chim. Acta, v.453, p.1). 0966 Vegetation and landscape change through the last glacial cycle around the Gulf of Carpentaria, northern Australiah Sander van der Kaars, Ellyn J Cook, Allan R Chivas, Adriana García School of Geography and Environmental Science, Monash University, Australia

A detailed sequence of vegetation and landscape change through the last glacial cycle around the Gulf of Carpentaria has been constructed from palynological analysis of 296 samples from marine core MD972132 (core length 14.84 m, water depth 64 m). The earliest part of the record represents the conclusion of the penultimate glacial and pollen spectra indicate that a shallow, brackish ‘Lake Carpentaria’, fed by episodic flooding, resided in the Carpentaria basin. The lake was surrounded by open herbaceous vegetation dominated by grasses. The rise in sea-level and increased levels of rainfall at the onset of the penultimate interglacial were followed by establishment of extensive mangrove and freshwater swamps rich in sedges and grasses. As the interglacial period progressed, woodland, open forest and rainforest cover significantly increased across the regional landscape. When climatic conditions deteriorated during the early glacial, the basin was again cut off from marine influence and a long terrestrial phase ensued initially represented by development of complex swamp communities. Much poorer representation of woodland and forest taxa and greater variability across the pollen spectra indicates a drier or more seasonal climatic regime. The re-establishment of lacustrine conditions occurred shortly after 60 ka and, although initially the lake was shallow and perhaps saline, by ~40 ka the diversity and high quantity of algal taxa present suggests the lake had become considerably deeper. The record is continuous through the last glacial transition and of particular


interest is that high lake levels continued until well after the LGM. Only the early Holocene was recovered in the MD97-2132 core so additional Holocene samples from adjacent core MD97-2128 have been used for Eemian and Holocene comparisons. The establishment of present day marine conditions was initially characterised by expansion, albeit limited, of mangrove cover, increased presence of open freshwater swamps and significantly increased woody vegetation. Most conspicuous, however, are much lower representations of rainforest taxa (especially gymnosperms) and much greater representation of Eucalyptus in the Holocene than the levels represented during the last interglacial complex. 1200 Reconstruction of climate during the last 1000 years from a highresolution pollen sequence in Switzerland Willem O van der Knaap1, Christian Kamenik2, Jacqueline FN van Leeuwen3, Tomasz Goslar4 1

Switzerland NCCR Climate, University of Bern, Erlachstrasse 9A, CH-3012 Bern, Switzerland, Switzerland 3 Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland, Switzerland 4 Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland, Poland 2

We provide a high-resolution temperature reconstruction for the last millennium based on pollen from a peat sequence (Mauntschas, SE Switzerland, 1818 m a.s.l.), in the scope of the EU project Millennium. The sequence was dated using AMS (15 levels). Pollen counts were converted into pollen accumulation rates (PAR) and percentages. Monthly precipitation and temperature (AD 1864 – present) were measured 9 km from Mauntschas in the same valley at Sils Maria (1802 m a.s.l.). Pollen/climate regression and calibration was based on threeyear weighted running means of pollen and temperature time series, which minimized effects of potential dating uncertainties. Temperature explained more variance in the pollen data than precipitation. Effects of 288 different temperature time series (January of previous year to December of same year, monthly, seasonal, and annual averages) on PAR/percentages of the 14 most common pollen types were analysed by redundancy analysis (RDA). RDA suggested that temperature explained more variation within PAR than within pollen percentages (max. variation explained: 15.6% and 7.8%, respectively). Mean August to November temperature of the previous year explained most of the variation in PAR. Detrending or high-pass filtering of temperature and pollen time series did not improve their relationship. Pollen/temperature calibration based on principal components regression, partial least squares regression, or ordinary least squares regression performed equally well (model parameters assessed by leave-one-out cross-validation). A simple ordinary least squares regression model based on mean August to November temperature of the previous year and PAR of six pollen types resulted in a cross-validated R² of 0.58 and an error (RMSEP) of 0.36° C. We applied this model to the whole peat sequence, reconstructed mean August to November temperatures for AD 1000–2002 and compared our results with existing temperature reconstructions based on tree-rings, instrumental and documentary data. 1207 Reconstruction of climate during the last 1000 years from a highresolution testate-amoebae sequence in Switzerland

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Mariusz Lamentowicz1, Edward AD Mitchell2, Willem O van der Knaap3 1

Department of Biogeography and Palaeoecology, Adam Mickiewicz University, Poznan, Poland, Poland 2 Research Unit Ecosystem Boundaries, Swiss Federal Institute for Forest, Snow and Landscape Research, Station 2, CH-1015 Lausann, Switzerland 3 Switzerland

We aim to provide a high-resolution climate reconstruction for the last millennium based on testate amoebae from a peat sequence, in the scope of the EU project Millennium. Testate amoebae were analysed at annual resolution for AD 1900 –2003 of the peat section Mauntschas in SE Switzerland (1818 m elevation). On the basis of two different training sets, from N Poland (Pomerania) and from the Jura Mountains (W Switzerland), transfer-function models based on a jackknifed tolerance downweighted weighted-averaging model ‘WA(jack)tol’ were used to reconstruct past surface wetness (unit: water-table depth in cm) and to determine the errors in the reconstruction. The results of the two reconstructions are similar in their general features and seem to yield a robust reconstruction of water-table depth. However, the smaller discrepancies between the two reconstructions and the different behaviour of certain testate-amoeba taxa in the two training sets highlight the need to obtain a specific training set from the area of study. Further work will include collection and development of such a training set, comparison of reconstructed water tables with measured precipitation (data available from AD 1800 onwards), and down-core reconstruction of precipitation for the last 1000 years.

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1102 Landscape reconstruction of the western part of the Roman frontier zone in the Netherlands; the implications for human activities in a river delta Marieke van Dinter ADC Archaeoprojects, The Netherlands

In 2004, a multidisciplinary research project was set up in the Netherlands, which aims to synthesize the history of the Roman frontier, the Limes, in the western part of the Rhine delta. In trying to defend their northwestern border, the Romans had to cope with the dynamics of this landscape and the restrictions that nature imposed on the area. The geological research focuses on the reconstruction of this landscape and on the changes which have taken place in that landscape in the course of time. The main aim is to produce a detailed palaeogeographical map. This map should then reveal the factors that have influenced the location and form of the structures along the Limes. The map should also give insight into the (large scale) activities of the Romans that affected the landscape. Palaeo-environmental information is retrieved from maps, elevation data, coring data, archaeological finds and excavations. This information is combined into a new, very detailed palaeogeographical map by using GIS-methods. At the INQUA congress the map will be presented to an international audience for the first time. The Roman forts in this area, built around 40 AD, are situated exceptionally close (distance 5 – 12 km). The layout of the forts suggests that the army adapted its templates to the peculiar circumstances in this wet area. All turn out to be built on the southern levee, directly along the river Rhine, opposite or alongside river bifurcations, irrespective of terrain level or composition of the subsoil. Only bifurcations that were connected with waterways to the north or south were guarded. Watchtowers were built in every bend of the river Rhine, thereby securing a complete overview of the river. Whenever a bend migrated, a new tower was built. In addition, prove has been found that the Romans attempted to influence discharges and river migrations. Besides the historically recorded constructions of the Drusus dam, other bank works were recently excavated. Furthermore, there are indications that canals were dug out, in order to create a safer or shorter transport route. The river Rhine thus seems to have functioned as a guarded transport route along which trade was carried out from and to Frisia and England. Moreover the landscape thoroughly influenced the military infrastructure and the presence of the army thoroughly influenced the landscape. 0929 Rupture of the Awatere and Ohariu faults, central New Zealand, at ca. 1000 years ago: one big earthquake or several smaller temporally clustered ones Russ J Van Dissen1, Timothy A Little2, Nicola J Litchfield1, Russell Robinson1, Dougal PM Mason3 1

GNS Science, New Zealand Victoria University of Wellington, New Zealand 3 Opus International Consultants, New Zealand 2

In New Zealand, the written record of earthquakes extends back only to ca. AD 1840. The record of earthquakes prior to this is based almost exclusively on the results of paleoseismic investigations. Given the uncertainties typically inherent in these investigations, when adjacent sections of a fault are found to have overlapping constraints on rupture-timing, it is often difficult to determine whether rupture of the

fault sections occurred at the same time (one big earthquake) or were closely spaced or clustered in time as two or more smaller earthquakes. The active Awatere and Ohariu faults of central New Zealand provide an example of this problem, and using a New Zealand-based scaling relationship that relates rupture length to displacement, we put forward a partial solution. Both of these are major NE-striking right-lateral strike-slip faults. They are arranged roughly end-on to each other, along their strike (the Awatere Fault to the SW and the Ohariu Fault to the NE), and reach a combined length of ca. 300 km. The most recent rupture of the north-eastern section (geometrically distinct trace) of the Awatere Fault took place historically in AD 1848 with an average surface rupture displacement of ca. 5–6 m. The penultimate rupture on the same fault is narrowly constrained to have occurred at 980 –1080 cal. yr BP. The most recent rupture of the Ohariu Fault is also narrowly constrained to have occurred at 1000 –1050 cal. yr BP with an average surface rupture displacement of ca. 3–4 m. If the Awatere and Ohariu faults ruptured as one big earthquake ca. 1000 years ago, this earthquake would have had a rupture length exceeding 200 km, and scaling relations would predict an average surface rupture displacement far in excess of that observed on either of the two faults during their last events. Instead the measured single-event displacements on the Awatere Fault are consistent with earthquake rupture lengths of ca. 100 km, and those observed along the Ohariu fault with rupture lengths of 50 – 100 km. As such, the most likely scenario is that ca. 1000 years ago the length of the Awatere and Ohariu faults ruptured not as one big earthquake, but rather as a series of smaller temporally clustered earthquakes. 1212 The native or introduced status of plant species determined by fossil pollen in Galapagos and the Azores Jacqueline FN van Leeuwen1, Willem O van der Knaap2, Brigitta Ammann3 1

Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland, Switzerland 2 Switzerland 3 Institute of Plant Sciences, University of Bern, Switzerland

The status of a plant species, native or introduced, is important for nature management, especially on remote oceanic islands where many introduced species have become invasive, and species of unknown status have become troublesome weeds. Introduced species may be eradicated completely if invasive, whereas troublesome natives should be contained but not eradicated. The status of many plant species, however, is uncertain on many islands, and our study is aimed at clarifying some of the uncertainties. In an earlier study, the native or introduced status of several plant species on the Azores Islands could be determined by pollen analysis of lake sediments. Human occupation on the Azores started in the late fifteenth century. As an example, the status of Selaginella kraussiana has long been uncertain, and has now been confirmed as native by the occurrence of frequent spores at all analysed levels in a pollen sequence covering the last 2500 years from Lagoa Rasa on Flores island and in a pollen sequence covering the last 6000 years from Lagoa do Caveiro on Pico island. This successful outcome stimulated us to start a similar study in Galapagos. There, we produced a pollen sequence of a mire on the island Santa Cruz covering the last 2500 years with the aim of determining the native or introduced status of at least some of the 60 –100 plant species for which this is uncertain. The sequence was dated with eleven AMS radiocarbon dates, providing a robust age-depth model. The study of the pollen morphology of all relevant plant taxa growing in Galapagos today indicated that about


20 among the taxa of doubtful status can be distinguished on the basis of their pollen from all certainly native taxa. As Galapagos appeared to have a low but not to be neglected influx of pollen that is long-distance transported from mainland America, the finding single or few pollen grains at analysed levels is no proof that the plant grew on the islands. The threshold for the native status of a plant species was therefore set at a high abundance of pollen indicative of local occurrence of the plants close to the studied mire. Four species of uncertain status could be proven to be native, and two others that were formerly inferred to be introduced also appear to be native. 0389 Complex terrace development in a region of alternating subsidence and uplift Jef Vandenberghe1, Xianyan Wang2, Huayu Lu3 1

Vrije Universiteit, Institute of Earth Sciences, The Netherlands China 3 Nanjing University, China

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change, calibrating quantitative estimates derived from each proxy, determining the response of biota to environmental change, and assessing the reliability of any particular proxy as an environmental indicator. Here we present a review of four recent pollen and chironomid studies from southern New Zealand that provide the first quantitative, chironomid-based, Late Glacial and Last Glacial Maximum temperature reconstructions in this region. Results to date show differences between these proxies such as the duration of Late glacial cooling with some records showing more prolonged cooling inferred from the pollen than the chironomid record. We address the similarities and mismatches occurring within and between these records particularly focussing on the timing and inferred magnitude of environmental change, and comment on their likely causes. We will also outline the direction of future work aimed at refining the existing chironomid inference models including improving taxonomy, geographically expanding the existing inference model dataset, and improving the coverage of the temperature gradient for the inference model.

2

The Huang Shui river, a main tributary of The Huang He (Yellow River), is crossing a series of small tectonically subsided and uplifted areas that show different patterns of terrace formation. The continuously uplifted regions show a typically developed staircase of terraces. The Huang Shui system is particularly characterized by its long history of river erosion and terrace formation when compared with most terrace sequences elsewhere. The oldest terrace, as presently known, is supposed to be 14.3 Myrs old, and a lower one is dated at 11.3 Myrs old. Their age is defined by paleomagnetic analysis of the overlying loess cover. They occur about 500 to 600 m above the present floodplain. Terraces of Early Pleistocene age are situated c. 200 –300 m above the present floodplain. A series of 10 to 15 younger terraces may be distinguished at lower levels. Generally terraces show gravel deposits of up to 10 m thick that are overlain by a few metres of floodloam and up to more than 200 m of eolian loess. However, the tectonic basins in between those regions may show a more complicated pattern of terrace formation. On the long term also those basins are uplifted as a result of large-scale uplifting of the Tibetan Plateau but on shorter timescales this general uplift was interrupted by local subsidence. As a result, fluvial aggradation may occur in those regions simultaneously with river incision in the uplifted parts and young river deposits may overly older ones. This aggradation could be caused by tectonic downwarping, but also by tectonic uplift in upstream areas followed by intensified erosion and sediment supply from those areas leading to deposition in the downstream areas. Finally, renewed incision in the subsiding areas may be due to basin uplift or to intrinsic river evolution as a result of decreased sediment supply from the upstream area. 1349 Interpreting climate reconstructions from pollen and chironomids: Similarities, mismatches and what does it all mean? Marcus Vandergoes1, Craig Woodward, 2Ann Dieffenbacher-Krall3 1

GNS Science, PO Box 30368 Lower Hutt, New Zealand, Climate Change Institute, University of Maine, Orono, ME 04469, USA, New Zealand 2 Centre for Chronology, Environment and Climate (14CHRONO):, School of Geography, Archaeology, and Palaeoecology, Queen’s Univer, Ireland 3 Climate Change Institute, University of Maine, Orono, ME 04469, USA, United States

Multi proxy reconstructions from a single site or geographical region are critical for, refining our understanding of past environmental

0612 Late glacial climate change in Southern New Zealand: regional pollen and chironomid temperature reconstructions from the eastern Southern Alps between 18-9 ka Marcus J Vandergoes1, Ann Dieffenbacher-Krall2, George Denton2, Rewi Newnham3, Matt McGlone4, Janet Wilmshurst4 1

GNS Science, PO Box 30368 Lower Hutt, New Zealand, Climate Change Institute, University of Maine, Orono, ME 04469, USA, New Zealand 2 Climate Change Institute, University of Maine, Orono, ME 04469, USA, United States 3 School of Geography, University of Plymouth, Plymouth, PL4 8AA, United Kingdom, United Kingdom 4 Landcare Research, PO Box 69, Lincoln, New Zealand, New Zealand

Determining the regional pattern of late glacial climate change in southern New Zealand is crucial for understanding the nature and possible drivers of abrupt climate change occurring in the mid latitudes of the Southern Hemisphere during this time. Chironomid-based temperature reconstructions have been successfully used to quantify Late Glacial temperature change in the Northern Hemisphere. This technique, recently developed for New Zealand provides the opportunity to derive quantitative temperature estimates the Late Glacial, a period for which the timing and magnitude of climate change has yet to be fully resolved. Here we present continuous, isotopically dated, paleo-chironomid and pollen records of deglacial climate fluctuations from two sites Boundary Stream Tarn, and Kettlehole Bog, since 18,000 cal BP. Pollen results indicate an interruption in the deglacial warming trend that corresponds to the Antarctic Cold Reversal (ACR) between 14.5 and 12.5 ka cal. BP. Chironomid-based temperature reconstructions support a climate reversal during this time but of shorter duration. The pollen and chironomid records between 13,000 cal BP and the early Holocene show no evidence of climate reversal associated with the Younger Dryas (YD) chronozone. These results help establish a regional picture for the magnitude of late glacial climate cooling east of the New Zealand Southern Alps and provide opportunities for comparing terrestrial changes in southern New Zealand with marine and Antarctic records to help clarify Southern Hemisphere climate relationships and distinguish climate coupling mechanisms.

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0614 Last Glacial Maximum climate change in Southern New Zealand: Pollen and chironomid temperature reconstructions from south Westland between 30 and 15 ka Marcus J Vandergoes1, Ann Dieffenbacher-Krall2 1

GNS Science, PO Box 30368 Lower Hutt, New Zealand, Climate Change Institute, University of Maine, Orono, ME 04469, USA., New Zealand 2 Climate Change Institute, University of Maine, Orono, ME 04469, USA., United States

Determining the precise timing and magnitude of climate change in the mid latitudes of the Southern Hemisphere is key to understanding the role of the Southern Hemisphere in driving global glacial cycles and identifying interhemispheric leads and lags in the climate system. Here we use pollen analysis, chrironomid-based temperature reconstructions and precise AMS dating from Galway Tarn, south Westland, to outline the complex structure and timing of climate fluctuations between 30 and 15 ka including the Last Glacial Maximum (LGM) in southern New Zealand. The sequence includes the Kawakawa Tephra preserved as a visible fine ash and shows a mostly cold interval, indicated by predominance of alpine grassland, interrupted by two milder interstadials characterised by moderate increases in sub-alpine shrubs. The onset of LGM cooling marked by expansion of alpine grassland, occurred at this site ca 29,500 cal. BP, prior to the deposition of the Kawakawa Tephra. This cooling interval lasted for ca 3800 yrs and was succeeded by a mild warming lasting ca 2000 yrs. A second period of cooling (ca 900 yrs) between 23,700 and 22,700 cal. BP was followed by another milder interval, commencing at ca 22,700 cal. BP and lasting approximately 800 yrs. The final prominent cold period identified in this sequence began at ca 21,900 cal. BP, lasting ca 3500 yrs before the termination around 18,400 cal. BP. A newly developed chironomid-based temperature reconstruction from the site provides insights into the magnitude of climate change for the stadial-interstadial fluctuations. The same structure of two interstadials within the LGM is observed at two nearby pollen sites in South Westland as well as in speleothem, marine d18O, and glacial ice advance records in southern New Zealand. The high resolution multi-proxy record from Galway Tarn provides a benchmark for understanding the complex pattern of LGM climate change emerging from terrestrial climate proxies in this region. 0462 Climate versus Human-Driven Fire Regime in Holocene Mediterranean Landscapes: The record of Lago dell’Accesa (Tuscany, Italy) Boris Vanniere1, Daniele Colombaroli2, Emmanuel Chapron3, Aurélie Leroux1, Willy Tinner2, Michel Magny1 1

LCE - CNRS, France Plant Institute - Bern University, Switzerland 3 ETH - Zurich, Switzerland 2

Every year in the Mediterranean region, on average of 45000 forestfires affect about 2.6 million hectares. This is one of the strongest agents which is able to provoke severe modifications in vegetation cover and biodiversity. The establishment of forest-fire records is still rare for the Mediterranean region, despite the wide interest to understand post-fire ecosystem dynamics. Moreover, in the perspective of present-day global warming and increasing human pressure on the environment, fire history and long-term fire ecology studies could also be a key issue in landscape management. High-resolution and precision

sedimentary charcoal seriesfrom Lago dell’Accesa (42°59'17”N, 10°53'44”E, 157 m a.s.l., Southern Tuscany) reveal numerous changes of fire regime over the last 11600 yr cal BP. Time control is supported by 11 AMS-radiocarbon dates on terrestrial plant macrofossils. Mean time resolution per sample of 15 yr provides the longest detailed biomass burning record of Italy. The fire signal has been reconstructed by quantifying microscopic charcoal particles (>0.01mm) from pollen slides to reconstruct regional fire history and macroscopic charcoals (>0,1mm) by sieving method to reconstruct local fire events. The direct comparison between charcoals analyses, magnetic susceptibility measurements, pollen data and lake-levels reconstruction, makes it possible to study the interactions and linkages between fire regimes, vegetation, climate, and human practices. Our question is firstly: to what extent is the inter-centennial variability of fires determined by climatic factors. For this, the long-term trends and the variability of the fire regime are estimated by the mean fire interval (MFI) on the whole sequence as well as for each period with variable fire regime. Second, we want to determine the role of man in natural fire regimes changes since the establishment of agriculture at ca. 8000 cal. BP. At the beginning of the Holocene (11600 to 9000 cal yrs BP) and between 8000 and 5000 cal yrs BP, several high-frequency fire phases occurred during shifts towards wetter climatic conditions. Such a shift probably increased biomass production but must have been characterized by a summer drought season, necessary for ignition and burning during this period, the record illustrates the consistent role of fire in successive dynamics of vegetation. Important and frequent burnings are also documented for the Bronze and Iron Ages and are consistent with the development of settlements in the region, slash-and-burn agriculture, animal husbandry, and mine exploitation. 1095 Holocene Environments and human occupation in Northern Eurasia Andrei A Velichko Institute of geography Russian Academy of Science, Russia

The late glacial/post glacial to the Holocene are marked by drastic restructuring of the East European landscapes, and a hyperzonal type dominated by periglacial landscapes was replaced by polyzonal type, various forest zones coming into being. In Eastern Europe the Mesolithic epoch spanned the Preboreal, Boreal and the beginning of Atlantic periods (before 6 ka BP). The Mesolithic economy was based on unspecified hunting of various mammals in tundra, forest and steppe zones, with gathering and water resources management sharply gaining in importance (fishing, seafood gathering and sea mammal hunting). On the whole, the Mesolithic stage in Northern Eurasia is considered to be a transitional stage, when the Man and his economy became adapted to a new, more differentiated, structure of natural landscapes. Two principal cultural and economic regions developed within the limits of the East European Plain. Differences between them were determined primarily by specific features of plants and animal world of steppe and forest zones. Starting with the end of the Boreal time the Man penetrated into Siberian North in the Early Holocene. A campsite of early hunters on the Zhokhov Island at 76° N (De-Long Archipelago, the East Siberian Sea) proves that groups of hunters could reach high Arctic in search of polar bear and reindeer. The beginning of the Atlantic period coincides with an onset of new – Neolithic – phase in the human society evolution. At the mid-Atlantic time (6 to 5.5 ka BP, that is thermal optimum of the Holocene) tundra zone was practically absent from Eastern Europe, and middle


and northern taiga shifted northwards with reference to their position during Preboreal time. The forest belt was somewhat enlarged in Siberia as well. The 5500 to 4500 yrs BP interval featured the most active progress in early agriculture within the forest-steppe zone. It was distinct for a considerable increase in population size and density. Bronze Age cultures are attributed to late Subboreal. There are several cultures of the Bronze Age found within forest zone of the East European Plain and dated at the 3rd-2nd millennia BP. In the west of the forest zone the economy of those groups was based on cattle raising with a more or less important contributions from hunting fishing and gathering. About 3 thousand years ago an early ceramic culture appeared on the Bering Sea coasts, in northeastern Siberia and Alaska. Its economy was based of walrus and seal hunting. 0935 Human Impacts of the 1600 Eruption of Huaynaputina Volcano, Peru Kenneth L Verosub, Jake Lippman University of California - Davis, United States

We have been investigating the human impacts of the 1600 eruption of Huaynaputina volcano in Peru. The estimated Volcanic Explosivity Index for this eruption is 6, which is comparable to that of the 1815 eruption of Tambora volcano in Indonesia, which produced global cooling and led to crop failures, famine and social unrest. On the basis of treering data, Briffa et al. (1998) suggested that the most severe short-term Northern Hemisphere cooling event of the past 600 years occurred in 1601, the year following the Huaynaputina eruption. In order gain a better understanding of the nature and extent of this cooling, we have been collecting annual time series that provide information about climatic conditions during time intervals that bracket the Huaynaputina eruption. Among the time series that we have examined are ice conditions in the harbors of Tallinn, Estonia, and Riga, Latvia and in Lake Suwa in Japan: cherry blossom blooming (sakura) dates from Kyoto, Japan; records of agricultural production from China and Russia; tithe records from the Spanish colonial empire; dates of the beginning of the wine harvest in France and the rye harvest in Sweden; prices of agricultural commodities in Europe; and river flows from the Nile and the Colorado. In many cases, 1601 shows up as one of the coldest years, if not the coldest year, in these records. In addition, the worst famines in Russian history took place between 1601 and 1603, which eventually led to the overthrow of Tsar Boris Gudonov. Thus, there is considerable evidence that the human impacts of the Huaynaputina eruption were comparable to those from the Tambora eruption. This result is important because it documents that the Tambora eruption was not an isolated occurrence in the Holocene and supports the idea that such events might occur with a return frequency of as little as 200 years. Thus, any realistic discussion of the societal risk from natural perils needs to include the possibility of volcanically-induced global climate change. 1358 Metal-trace distribution among sediments, leaves, crabs (Ucides cordatus) and man in preserved mangroves of the Brazilian Amazonia Maria P S Vilhena, Marcondes L Costa, José F Berredo Universidade Federal do Pará, Brazil

The study was accomplished in the mangroves of the brazilian Amazonia, in the estuary of the Marapanim river in the Para State (00˚ 32'30”

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S / 00º 52' 30” S and 470 28' 45” W/470 45'00” W). The research has as objective evaluates the chemical transfers of metals between the sediments and the alimentary chain: crab-man through human hair. The mangrove sediments were collected (up to 50 cm), vegetation (leaves of Rhizophora mangle), crabs (Ucides cordatus) and the hair of inhabitants of the Marapanim city. Chemical analysis of As and Se were accomplished in every sample through for EAA/GH, Hg for (EAA-VF/G); other elements for ICP-MS, besides grain size and mineralogical analysis (DRX). The sediments are silt-clay mineralogically constituted by caulinite, quartz, illite and neoformated minerals: pyrite, jarosite, smectite and K-feldspars. The concentrations of As, Hg, Se and other elements occurs in crustal levels. In the leaves of Rhizophora mangle the highest concentrations belongs to Zn, Cu, Sr, Zr, As and Hg; the crabs concentrate Zn, Se, As and Sr. Zn concentrates on the muscles of the male crabs and Sr in the muscles of the females. The Se and As accumulates in the muscles and in the hepatopancreas of both males and females. The transfers of the chemical elements to the sediments for the plants, in other words, the coefficient of biological absorption (CAB) is very low, as well as the bioavailability of these elements in the sediments, except Hg, accumulated in the fabric of Rhizophora mangle tissue. CAB for plant-crab shows high values for Zn and Se in the males and in the females and it can represent the metabolic needs of the animal. The tenors of Hg, Se and As in the hair are below the limits of OMS for atmospheres without antropic influence. The nutritional, poisonous and additional elements are in the normal level of hair occurrence. The chemical analysis of the sediments, leaves, crabs and the hair analysis also suggest that the mangroves of Marapanim do not present indications of environmental impacts for metals, being constituted in reference area for comparative studies with impacted areas. 1330 Vegetation, fire and climate from SW Patagonia over the last 12600 cal yr BP: the Vega Ñandu record (51ºS) Rodrigo Villa-Martinez1, Patricio I Moreno2 1

Centro de Estudios del Cuaternario (CEQUA), Avenida Bulnes 01890, Punta Arenas, Chile. [email protected], Chile 2 Institute of Ecology and Biodiversity, Dept. of Ecological Sciences, University of Chile, Chile

We report a high-resolution pollen and charcoal record from Vega Ñandú (50º55'58’’S; 72º45'55’’W; 200 m elevation), a small mire located near the modern forest-steppe ecotone in Torres del Paine National Park, southwest Patagonia, Chile. Southwest Patagonia is a key and sensitive region to document past climate changes because its strategic position within the belt of the southern westerly wind belt and shows a strong west-east precipitation gradient, and hence, is an ideal area to study past variations of southern margin of westerlies. The pollen record shows an open landscape dominated by Poaceae, low shrubs, and herbs between 12,600 –10,800 cal yr BP, suggesting the dominance of pre-Andean shrubland vegetation under cold and relatively humid conditions. Nothofagus experienced frequent, large-amplitude oscillations between 10,800-6800 cal yr BP, indicating recurrent transitions between parkland/woodland environments, under warm and highly variable moisture conditions. A sustained increase in Nothofagus started at 6800 cal yr BP, punctuated by accentuations at 5100 and 2400 cal yr BP implying further increases in westerly precipitation. The Vega Ñandú record shows a forest decline and expansion of Rumex acetosella, an exotic species indicative of European disturbance over the last two centuries. Our results suggest variations in the amount of precipitation of westerly origin over the last 12,600 years in

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SW Patagonia. We identify three prominent increases in westerly precipitation at 6800, 5100, and 2400 cal yr BP, that led to peak precipitation regimes during the last two millennia in this part of SW Patagonia. An increase in fire activity occurred at 6600 cal yr BP, between 5500– 5000 and 2400–2000 cal yr BP, probably in response to an increase of climatic variability and/or accumulation of biomass. Variations in the position/strength of the southern margin of the westerlies most likely resulted from subpolar forcing by means of variations in the extent and persistence of Antarctic sea ice, and anomalies in sea-level atmospheric pressure anomalies in the subantarctic region. 0820 Searching for sedimentary records of the 1877–large subduction earthquake in northern Chile (23ºS) Tania Villasenor1, Gabriel Vargas1, Silvio Pantoja2, Carina Lange2 1

Departamento de Geolgía, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Chile 2 Departamento de Oceanografía & Centro de Investigación Oceanográfica del Pacifico Sur-oriental (FONDAP-COPAS Center), Chile

The continental margin of northern Chile is characterized by active tectonics and large subduction earthquakes. The last earthquake occurred in the area north of the Mejillones Peninsula (23ºS) in 1877 (Mw~8.5), triggering tsunami waves that affected vast zones along the coast. The Mejillones Bay, in the northern extremity of this peninsula, is characterized by a shallow (120 m of water depth) and narrow (15 km width) shelf where variations in primary production and hypoxic to anoxic conditions favor the preservation of laminated sediments. Previous palaeoseismic work from sedimentary records within the bay provided insights regarding the record of great historic subduction earthquakes in sea bottom sediments. Unconformities, slumps and high-density current deposits of several centimeters of thickness, are the most important features in cores retrieved near 100 m water depth (Vargas et al., 2005). New gravity and box cores were obtained in this bay at similar water depths. Radiochronological, mineralogical and sedimentological data from these cores allowed us to improve our understanding of anomalous deposits in the recent sedimentary sequence. The anomalous sedimentary features that we associate to the 1877 great subduction earthquake include an erosional underlying surface, dense and mineral-rich lenticular deposits, and an overlying dense mineral-rich deposit, giving a sequence of 1 to 2 cm thick. This has not been previously observed. The initial 210Pb chronology established an age between 1888 and 1851 AD for this sequence, interpreted to represent the 1877 subduction earthquake followed by a tsunami event. We infer that these deposits were produced by strong seismic accelerations in the sea floor during the earthquake that triggered high density bottom currents that produced reworking of material from shallower areas in the basin, probably followed by turbidity currents in the bay’s bottom. Turbidity currents may have been triggered by backwash flows associated to the tsunami event, consistent with previous interpretations of similar sedimentary features in the area (Le Roux and Vargas, 2005; Vargas et al., 2005). These observations provide new highlights concerning sedimentary records of earthquakes and tsunami events, and confirm the potential of these sediments for palaeoseismic reconstructions in the forearc of the Central Andes. References: Le Roux J.P. and Vargas G., 2005. Hydraulic behavior of tsunami backflows: insights from their modern and ancient deposits. Environmental Geology, 49: 65–75. Vargas G., et al. 2005. Paleoseismic inferences from a high resolution marine sedimentary record in northern Chile (23ºS). Tectonophysics, 399: 381–398.

0569 Evidences of subaerial exposure of the Argentine Continental Shelf during the Last Glacial Maximum Roberto A Violante1, Margarita L Osterrieth2, Natalia Borrelli2 1

Servicio de Hidrografía Naval, División Geología y Geofísica Marina, Argentina 2 Universidad de Mar del Plata, Centro de Geología de Costas y del Cuaternario, Argentina

The Argentine continental shelf covers about 1,000,000 km2 adjacent to a coastline exceeding 4,000 km long in a north-south direction extended from 34º to 55ºS. Its width varies between 170 and 850 km, its slope is gentler that 1:4000 and the shelf edge is at a water depth of 110 to 165 m. Such a large and smooth submarine region should undoubtedly records the evidences of the subaerial exposure occurred when it evolved under continental conditions during the Last Glaciation. These conditions were characterized by fluvial, lacustrine and eolian activity as well as pedogenesis, dessication and vegetation evolution, under colder and dryer climates than today as evidenced by the northward drift of the present Patagonian climatic conditions that affected the pampean region at that time. Fluvial activity left significant evidences on the bonaerensian-patagonian shelf. North of 42ºS the relict fluvial network shows subparallel patterns regionally oriented to the southeast towards the slope. Between 42º and 46ºS the pattern is more chaotic with numerous distributaries; main valleys are oriented to the south and then change to the southeast. South of 46ºS the valleys tend to converge towards a depression located south of Malvinas islands. Relict fluvial networks in coastal semienclosed areas show a more irregular branching of tributary valleys associated to submerged deltas, or a semiradial, centripetal drainage in the interior of gulfs what represents an evidence of the their isolation from marine waters during pre-transgressive low sea-level stages. On the other hand, the coastal and nearshore regions of Tierra del Fuego were covered by ice during glacial times, and hence glacial features are present in that part of the shelf so testifying the subaerial exposure of presently submerged areas at ca. 70 m depth. Moreover, gravels extended on the shelf surface south of 46ºS are associated to fluvial and glacifluvial deposits. The other significant evidence of subaerial exposure of the shelf is the presence of paleosoils in the pre-transgressive – post-transgressive boundary. Cores collected offshore the de la Plata river mouth and surroundings at water depths between 30 and 80 m penetrated pre-transgressive semiconsolidated eolian to lacustrine loess-like deposits, littoral sands, lagoonal muds, paleosoils, dessicated surfaces and partially cemented hardgrounds like calcretes and caliche horizons. Studies focused on the paleoedafic levels revealed the presence of silicophytolites which indicate a plant cover of grass and sedges in a saline paleosoil evolved under cold temperatures and periodically affected by drought conditions. 0844 The Andean Volcanism as a significant contributor to Argentina Continental Shelf Sedimentation Roberto A Violante1, Elizabeth I Rovere2 1

Servicio de Hidrografía Naval, División Geología y Geofísica Marina, Argentina 2 Servicio Geológico Minero Argentino, Instituto de Geología Regional, Argentina

The Argentina continental shelf is covered by a Post-glacial sandy mantle composed of sediments mainly originated from erosion of the underlying Neogene substratum during the coastal retreat that accom-


panied the last marine transgression that followed the LGM. The Neogene substratum is part of a sedimentary sequence regionally distributed from the Andes to the sea, which was mainly formed by primary and secondary (retransport) fluvial and eolian depositional processes as well as by direct ash supply from volcanic activity. Forcing factors that conditioned sedimentation were the regional morphology (a west-to-east sloping surface) and the predominant westerly winds acting during the Neogene. In the shelf, the sequence was deposited during its subaerial exposure in pre-transgressive times. The sediments that constitute the sequence were mostly originated in the Andean and extra-Andean regions where intense volcanism took place during most of the Cenozoic. Therefore they are composed of a volcanic-pyroclastic association. The present knowledge indicates that the mineralogical composition of the Neogene substratum is relatively homogeneous as a result of reworking processes. However, having into account that the Andes cordillera and surroundings have had changing tectonic and volcanic behaviors (both regionally and chronologically), it is probable that they could be reflected in the sediments composition. The description of piston cores samples from the Argentina continental margin reveals that around 34 cores from different locations – from the nearshore to the deep ocean- contain volcanic ashes either as dispersed concentrations or as fine layers interbedded in the Cenozoic sequence. Some cores show several superposed ash layers at different depths indicating recurrence of volcanic events. No chronological data are available and hence it is not known the timing of those events. However, preliminary biostratigraphical information indicates that some cores contain sediments ranging from Eocene to Holocene, precisely the time-span during which volcanism in western Argentina was very active associated to the Andes cordillera formation and evolution. Detailed mineralogical and geochemical studies of those ash layers are necessary in order to search for variables in the originating processes (different volcanoes and/or different kind of eruptions). On the other hand, as shelf sediments derive from the Neogene substratum, they reflect its mineralogical composition and hence demonstrate that although located in a passive margin, there is a close sedimentological relation to the active tectono-volcanic context of Southwestern South America. Consequently, volcanic components contained in shelf sediments could be useful for sea-land integration and correlation of Quaternary sequences and processes. 0812 Land-sea correlation of Tagus River (Portugal) sedimentation: evidence of strong human impact Geert-Jan Vis1, Kees Kasse1, Jef Vandenberghe1, Dick Kroon1, Simon JA Jung1, Ulrich Alt-Epping2, Heike Schneider3 1

Department of Palaeoclimatology & Geomorphology, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, The Netherlands 2 DFG Forschungszentrum Ozeanränder, Universität Bremen, Fachbereich Geowissenschaften, Germany 3 Friedrich-Schiller-Universität Jena, Institut für Geographie, Physische Geographie, Germany

We show the remarkable fact that strong Late Holocene human impact in the Tagus catchment is represented in land sediment records by coarsening and in sea sediment records by fining sediments. To understand the cause for this phenomenon, this study answers the question: How is Late Holocene human impact translated into the land and sea sediment records of the Tagus River system? We answer this question by a multidisciplinary study of land and sea sediment records, recovered in the framework of the ESF EUROMARGINS SEDPORT project. Samples were analysed for grain size, magnetic susceptibility,

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organic carbon and calcium content, pollen and radiocarbon age. Results show an increased sedimentation rate since ~1000 years ago in both land and sea sediment records. This increased sedimentation rate is coeval with an increase in grainsize on land and an unexpected decrease in grainsize off-shore. Organic deposition on land shows a strong decrease, in favour of clastic deposition. Both land and sea records show an increased magnetic susceptibility for the last ~1000 years. Further, anthropogenic indicators are present in both terrestrial and marine pollen records. Finally, topographic maps from the LowerTagus Valley since 1561 AD show a rapid silting up of the estuary in less than 500 years. We interpret these results as the effect of strong human impact in the catchment of the Tagus since Medieval times. Due to deforestation and agriculture, Holocene soils were eroded, releasing iron minerals. We think the increased sedimentation rates and grain sizes on land are the result of increased erodibility of the slopes in the catchment combined with the intensive Mediterranean precipitation type. We interpret the seemingly contradictory sediment fining off-shore combined with an increased sedimentation rate, as the result of subdued winnowing and thus an overrepresentation of fine sediment. Concluding we can state that Late Holocene human impact in the catchment of the Tagus River is translated into the sediments of both land and sea records as changes in grainsize, sedimentation rate, magnetic susceptibility, organic carbon and calcium content and pollen. We think this result illustrates the need for integrated land-sea studies along continental margins to better understand and interpret marine records. 0523 Beachrocks as Past sea levels indicators on the northeastern brazilian continental shelf: Rio Grande do Norte State Helenice Vital1, Valeria C Cordoba2, Venerando E Amaro2, Izaac Cabral Neto2, Claude A Santos2, Eugenio P Frazao2 1

Universidade Federal do Rio Grande do Norte, Brazil Brazil

2

Amongst the existing sea-level indicators formed by coastal deposits, beachrock are widely used. Notable examples of beachrock are present in the littoral zone from Rio Grande do Norte State, northeast Brazil. Submerged beachrocks are also reported along this littoral at different depths. This paper report the studies carried out on submerged beachrocks fron this state. Remote sensing, submarine movies, bathymetric and side scan sonar survey, associated with diving were the methods used on this research. A minimum of four beachrocks line are found on this shelf. The most continuous structure is situated along the 20–25 m depth isobaths, which can be followed from Natal (East sector) to Macau (North sector) but small ones can also be found along the 10, 40 and 60 depth isobaths. Elevations reach 2.5 to 5 m above the sea-floor, and the width varies between 500–1000 m. The structure along the 20–25 m depth is prominent carbonate buildup, where the corals are almost absents, algae incrustation is thin, and is classified as sandstone banks. Petrographic studies show that they are similar to these one found on the coast and they should be related to an ancient coastline.

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0983 Millennial-scale Deep/ Intermediate Water Changes at the Middepth Portuguese Margin During Marine Isotope Stage (MIS) 11 Antje HL Voelker1, Pamela Martin2, Susana Lebreiro1, Fatima Abrantes1 1

Dept. Geologia Marinha, INETI, Portugal The Dept. of the Geophysical Sciences, The University of Chicago, United States 2

Calypso piston core MD03-2699 was retrieved from the Estremadura promontory north of Lisbon from a water depth of 1895 m. Nowadays, this site is bathed by lower North Atlantic Deep Water (NADW), whose physical properties are slightly modified by diffusive mixing with the overlying Mediterranean Outflow water (MOW; 700 –1400 m). Labrador Sea Water, the upper NADW, is generally only observed up to the northern edge of the promontory. During the last glacial maximum the MOW became denser and its lower core settled as deep down as 2100 m on the southwestern Portuguese margin (Schoenfeld and Zahn, 2000; P3). This MOW core also gained in flow strength during MIS 3 Greenland stadial phases (Voelker et al., 2006; EPSL). Between 420 and 395 ky BP, i.e. during parts of termination V and the interglacial period of MIS 11, site MD03-2699 was bathed by lower NADW like today. After 395 ky BP, however, site MD03-2699 is showing millennial-scale oscillations of lighter oxygen and heavier carbon isotope values than recorded for the lower NADW at ODP site 980 (McManus et al., 1999; Science). Especially, during periods with colder sea surface temperatures (SST) in the eastern North Atlantic (390 ky BP, 382 ky BP, 374 ky BP, 371 ky BP) these oscillations are associated with maxima in the mean grain size indicating a strenghtening in the bottom current. The most likely source for the stronger and well ventilated bottom water current is a deeper flowing MOW similar to the pattern observed during MIS 3 Greenland stadials. However, some of the benthic isotope values recorded at site MD03-2699 after 395 ky BP are also in the range of the upper NADW values from ODP site 982 (Venz et al., 1999; Paleoceanography). So to better distinguish between periods of MOW and those of upper NADW influence after 395 ky BP and thus to reveal potential rapid changes in the MOW/ NADW interface on the mid-depth Portuguese margin we will generate benthic foraminifera Mg/Ca and Ba/ Ca data. 1359 Winter mixed layer conditions in the mid-latitude North Atlantic during MIS 11 Antje HL Voelker, Lucia de Abreu, Fatima Abrantes Dept. Geologia Marinha, INETI, Portugal

The stable isotope data of Globorotalia inflata, which generally reflects conditions in the winter mixed layer, together with ice-rafted debris records from four deep-sea sites are used to reconstruct changes in the surface water conditions off the Portuguese margin and within the latitudinal band between 41 and 38°N. Off Portugal sites MD03-2699 at 39°N and MD01-2443 at 38°N monitor nearshore conditions that during winter are strongly affected by the Iberian poleward current, which transports subtropical surface and subsurface waters originating from the Azores current northwards. Further offshore, the equatorward flowing Portugal current, which also transports hydrographic changes occuring in the subpolar gyre towards the western Iberian margin, becomes important and paleo-conditions in it are recorded at site MD01-2446 (39°N, 12.6°W). The Portugal and Azores currents are both branches of the Gulf Stream/ North Atlantic Drift and past vari-

ability in that major current is monitored at IODP site U1313 in the western North Atlantic (41°N, 33°W). The records of all four cores are placed on a common stratigraphy by tuning their respective benthic oxygen isotope record to the one of ODP site 980 on the LR04 timescale. On the nearshore Portuguese margin the planktonic carbon isotope data indicates a lower nutrient content in the winter mixed layer between 410 and 400 ky BP indicating that this part of the margin was – like today – dominantly influenced by the nutrient poorer, but warmer subtropical North Atlantic Central Water (NACW). After 400 ky BP the more northern site MD03-2699 reveals heavier isotope values and thus an increased influenced of the nutrient richer and colder subpolar NACW that forms the subsurface component of the Portugal current. After 390 ky BP, i.e. during the glacial inception, the winter mixed layer experienced stronger variability and 5 major cooling events at approximately 390 ky BP, 382 ky BP, 374 ky BP, 371 ky BP, and 365 ky BP were recorded off Portugal. The most prominent of those episodes with the advance of polar waters at least as far south as 38°N occurred around 390 ky BP. Comparing the Portuguese margin records with those of U1313 will allow to trace the intensity of these Heinrichtype cold events across the mid-latitude North Atlantic and may be even to distinguish differences in timing. 1093 Contrasting dust supply patterns across the north-western Chinese Loess Plateau during the Last Glacial-Interglacial cycle Mirjam Vriend1, Maarten A Prins2, Jan-Pieter Buylaert3, Jef Vandenberghe2, Huayu Lu4 1

Institute for Biodiversity and Ecosystem Dynamics (IBED), Universiteit van Amsterdam, The Netherlands 2 Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, The Netherlands 3 Laboratory of Mineralogy and Petrology, Geological Institute, Ghent University, Belgium 4 School of Geographic and Oceanographic Sciences, Nanjing University, China

Loess grain-size distributions of four loess-paleosol sequences, located on a west to east transect from the north-eastern Tibetan Plateau (TP) to the north-western Chinese Loess Plateau (CLP), are unmixed with the end-member modelling algorithm EMMA. The unmixing results indicate that the loess is a mixture of three components representing very fine sandy, coarse silty and medium silty loess. The proportional contributions of the loess components in conjunction with loess mass accumulation rate estimates reveal that during the last glacial-interglacial cycle two contrasting dust supply patterns were active over the north-eastern TP and the north-western CLP: a constant supply of medium silty loess and an episodic supply of coarse silty loess and fine sandy loess. The variable input of the two coarse dust components is the main cause for the variation in grain size patterns and mass accumulation rates between the studied sites. Alluvial fans and fluvial systems in the intra-mountainous basins of the Tibetan Plateau and the deserts of Inner Mongolia are the main dust source areas for loess deposits of the north-eastern TP and the CLP, respectively. Sensitivity of these dust source areas to climate variations determines the timing of dust transport and deposition. In general, high dust fluxes are recorded during the last glacial period (MIS 2 to 4) and low dust fluxes during the last interglacial (MIS-5). However, the loess sections in the two regions (TP, CLP) show contrasting dust flux patterns during MIS-3. The records from the CLP show a relatively low dust input in this period, most likely related to increased humidity in the northern dust sources (deserts) where an increased vegetation cover ‘prevented’ dust deflation. In contrast to this, the Tibetan Plateau records appear to


show increased and highly variable dust fluxes for MIS-3. We hypothesise that alternating periods of increased humidity and aridity on the Tibetan Plateau (during MIS-3) have resulted in an increased fluvial/ alluvial activity. Hence, the enhanced availability of exposed finegrained fluvial/alluvial sediments on the Tibetan Plateau facilitated dust entrainment which resulted in an increased dust supply towards the Tibetan Plateau sites. 0202 Relative timing of deglaciation along the Kali Gandaki (Nepal Himalaya) derived from pedochronological methods and reconstructed equilibrium line altitudes Markus Wagner Department of Geography, University of Goettingen, Germany

New investigations on the chronology of deglaciation since the last high glacial period (MIS 2-4) were carried out in subcatchments along the antecedent Kali Gandaki valley, which crosses the Himalaya main range. The spatial distribution of glaciogeomorphological indicators and calculated equilibrium line altitude (ELA) depressions allow to compile a relative glacial chronology – based on the existing scheme of Kuhle (1982). These results are used as benchmark to explore the limits of different pedological relative dating methods, which are based on the formation of pedogenic iron oxides, variances in total element contents and the shift to lower particle sizes during weathering. To reconstruct former ELA depressions within the very steep and highly dynamic landforms of the Himalaya, TSAM methods are most adequate. Only the upper and lower glacier margin need to be known, which can be identified quite certain even for pre-existing glacier extensions. The method according to Kuhle (1988) is proved to provide the most suitable results, because the strong influence of the valley topography and the degree of debris cover on the position of the ELA within the vertical extension of the glacier can be simulated. Only the extreme topographical changeover arising from the inflow of the former glaciers from the tributary valleys into the wide and flat valley bottom of the Kali Gandaki, as well as the incalculable influence of a temporarily ice inflow from Tibet leads to little uncertainness. However, the relative chronology of the glacier stages can certainly be derived. Only around the central mountain range crossing section of the Kali Gandaki, where comparable soil development conditions can be found, most of the pedochemical weathering indices mirror the relative chronology of deglaciation correctly. On the other hand most of the granulometric weathering indices are inapplicable because of the typically high textural variability within till deposits. North of the Himalaya main range, only a few very certain pedogenic relative dating methods are applicable as a consequence of the drier climatic conditions. South of the Himalaya main range pedological relative dating is completely prevented by growing human influence, strong morphodynamic processes and highly variable geological conditions and precipitation amounts. 1069 Neolithisation in northern East Asia: archaeological evidence from China, Russia, Korea and Japan Mayke Wagner Department of Eurasian Archaeology, German Archaeological Institute, Berlin, Germany

The transition from mobile to sedentary life, from foraging to food producing modes of subsistence is regarded as one of the most farreaching developmental steps in the history of mankind. Recent

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archaeological discoveries and studies concerning the earliest pottery, farming and house building in Eastern Asia have challenged our general understanding of “Neolithisation”. The term “Neolithisation” commonly implies the appearance of domestication of plants and animals, burned pottery and polished stone tools at the same time. Earliest forms of permanent settlements and the beginning of domestications are known from the Near East and have been dated to approximately 11,000 cal. years BP. Two millennia later the agrarian economy started spreading from the Eastern Mediterranean towards Europe, North Africa and Central Asia. On the Japanese archipelago the use of ceramic vessels seems to have started as early as about 16,000 cal. years BP but permanent settlements do not appear before ca 10,000 cal. years BP at the southern tip of Kyushu Island and agriculture even later. About 8000 cal. years BP the vast region of northern East Asia comprising Russian Primor’e, northeast China, Korea and Japan shares some characteristic cultural features: funnel-shaped ceramic vessels with small flat bottom and wide mouth and distinctly textured surface, small stone or nephrite rings with a radial cut (earrings) and symmetric arrangements of rectangular houses in villages. These common characteristics make the region appear as culturally closely related. In one of the settlement sites in northeast China millet has been found. Millet cultivation nevertheless dates back to ca 9500 cal. years BP in the lower reaches of the Yellow River within a cultural context which is distinctively different from the one prevailing in northern East Asia. During the presentation chronological, spatial and qualitative aspects of this early Neolithic communication system in northern East Asia and its environmental background will be outlined in comparison with developments in neighbouring parts of the Eurasian landmass. 0132 Late Glacial/Holocene Landscape Evolution at Lago Budi, Chile (38.9°S) – Paleoseismical Investigations on Lake Sediments Johannes Wallner1, Ana M Abarzúa2, Helmut Brückner3, Gerhard F Daut1, Gerhard Schellmann4, Roland Mäusbacher1 1

Department of Geography, Friedrich-Schiller-University, Jena, Germany Instituto de Geociencias, Universidad Austral, Valdivia, Chile 3 Faculty of Geography, Philipps-University, Marburg, Germany 4 Department of Geography, Otto-Friedrich-University, Bamberg, Germany 2

The coastal lagoon Lago Budi (73°17'W/38°52'S; surface: 52 km2), approx. 100 km north of Valdivia/Chile, is connected to the Pacific by a 500 m wide ephemeral channel. In contrast to numerous lakes of the adjacent Andes formed by glaciers, the fluvial genesis of Lago Budi is considered to have been controlled by tectonic factors interacting with glacio-eustatic sea-level changes. Therefore Lago Budi provides an excellent geo-archive since it has served as a natural sediment trap for past tsunami events that have hit the South Pacific coasts. Furthermore, it exhibits an ideal marker for relative sea-level changes during the Holocene. The aims of this study are: (i) origin, age and landscape evolution; (ii) identifying and dating former earth-/seaquakes by using tsunamigenic sediment layers; (iii) palynologic reconstruction of vegetation and climate history outside the glacial area. After a hydro acoustic survey several sediment cores were taken from Lago Budi and its shores with lengths of up to 15 m. Sedimentological (grain size, bulk-/clay mineralogy, magnetic susceptibility), geochemical analyses (CNS, main elements, biogenic Si, P) and transfer functions via diatoms and foraminifera, supported by several AMS-14C data, were used to decipher the environmental milieus of deposition and their changes. At least two catastrophic tsunami events were identified in different lake cores of Lago Budi which occur first clearly after 4.9 ka BP. These striking layers are blackish grey medium to fine sands consisting of

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several up to 2 cm thick sterile strata with clear normal gradation. They show a definite unconformity to the underlying stratum. The whole core stratigraphy shows terrestrial sediments with “infinite” 14C ages (>41.2 ka BP) at the base. After an erosive unconformity (LGM), terrestrial sediments with a high amount of floral macro remains (trunks, leaves) were deposited around 10,3 ka BP. Shortly after 8,1 ka BP the foraminifera and diatom association documents a first marine ingression. In the central part of Lago Budi it persisted at least until 4.9 ka BP when brackish conditions evolved, without a period of pronounced freshwater input until now. These data show, that tsunami waves couldn’t reach the Lago Budi basin before ~4.9 ka BP, although a connection to the Pacific existed. This may be due to the pre-existing coastal morphology, that shielded the potential tsunami impacts and/or due to an exceeded distance between the lagoon and the Pacific. The latter implies noticeable coastal erosion since the sea level raised to the actual position. 0714 Variations of Dust Event Frequency in the Northwest China over the Past 600 Years Ninglian Wang1, Tandong Yao2, Lonnie G Thompson3, Mary Davis3 1

Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, China 2 Institute of Tibetan Plateau Research, Chinese Academy of Sciences, China 3 Byrd Polar Research Center, The Ohio State University, USA, United States

In 1999, a 102-meter ice core was drilled at 5680 m a.s.l. from the Malan ice cap (35°50’N, 90°40’E) located in the Kunlun Mountains in the northern Tibetan Plateau, where the 10-meter borehole temperature was about −6.5°C. It was noticed that there are lots of yellow dust layers along the Malan ice core. Comparing the positions of these dust layers with the seasonal variations in =18O, we found that the most of these dust layers appear in the snow/ice deposited in the springtime, which is coincident with observations, i.e. the springtime is the high frequent dust season in the northwest China. We also realized that the thicknesses of these dust layers are different at different depths. This phenomenon, presumably, might be related with the frequency of dust events (including dust storm, blowing sand and floating dust) besides the annual ice layer thinning. In order to characterize the past dust event frequency using these dust layers, the influences of accumulation rate and annual ice layer thinning on these dust layer thicknesses should be eliminated. We suggest that the ratio of the dust layer thickness to ice thickness in a given time period can be used as a proxy of the dust event frequency, and it is referred to as dirty ratio. Here, a 600year record of dirty ratio was reconstructed. It shows that dust events occurred frequently in two periods over the past 600 years, i.e., from the early 15th century to the middle 16th century, and from the late 18th century to the early 20th century. And the Malan ice core record indicates that dust event frequency displayed a clear decrease trend over the past 200 years. The decrease trend might be caused mostly by the natural processes, including increasing precipitation and weakening westerly which might be related with global warming. By statistical analyses of the variations in dirty ratio and d18O recorded in the Malan ice core, it was found that there is a strong negative correlation between them on the decadal to centurial time scales. This is highly important for studying the effect of atmospheric dust on climate change. Moreover, this strong negative correlation also raises some questions for us to study in the future: does the atmospheric dust loading decrease in the past two century? If so, temperature change resulting from dust must be estimated, so that the greenhouse temperature signal can be detected with greater confidence.

0623 Long eccentricity cycle in oceanic carbon reservoir: Low-latitude origin and climate impact Pinxian Wang State Key Laboratory of Marine Geology, Tongji University, Shanghai, China

The 400-kyr long eccentricity cycle has been found in deep-sea isotope records over most of the Cenozoic but Pleistocene. A comparison of the last 5 myr records from various oceans shows that d13C and d18O records are coupled in long eccentricity band in the Pliocene, with d13C and d18O maxima at the eccentricity minima, but decoupled in the Pleistocene after 1.6 Ma. The best match between the isotopes and eccentricity in Pliocene is observed in the Mediterranean, suggesting a low-latitude origin of the eccentricity signal. Since the global summer monsoon intensity is controlled by precession, and the amplitude of climate precession is modulated by eccentricity, we hypothesize that the observed 400-kyr cycles in oceanic carbon reservoir originate from the global monsoon intensity. The d13C and d18O decoupling in the Pleistocene is related most probably to the growth of the boreal icesheet, and a similar decoupling occurred also in the Miocene with drastic cooling and Antarctic ice-sheet expansion. The four d13C maximum events in the Pleistocene: d13Cmax-I, which began in MIS 3 around 50-60 kyr ago, d13Cmax-II (MIS 13, 0.47– 0.53 Ma), d13Cmax-III (MIS 27–29, 0.97–1.04 Ma) and d13Cmax-VI (MIS 53–57, 1.55–1.65 Ma), correspond neither to eccentricity minimum nor to d18O maximum, but likely represent climate episodes when the carbon reservoir in the global ocean experienced profound reorganization, most probably associated with abnormally intensive global monsoons. As the same cyclicity is also found in carbonate curves, the d13Cmax events must denote major reorganization in the carbon reservoir of the global ocean. They also are associated with major changes in glacial cyclicity, such as the Mid-Brunhes event following d13Cmax-II and the MidPleistocene Revolution following d13Cmax-III, which in turn were associated with expansion of the ice-sheets. From a carbon perspective, therefore, the Pleistocene has passed through three major stages, and each appears to represent a further step in ice-cap development. Since the Earth is currently passing through a new d13Cmax and eccentricity minimum, it is crucial to understand the nature of the d13Cmax events. 1098 Studies on the Xigeda Formation and its paleoenvironment in Luding, Sichuan Shubing Wang, Zhizhong Zhao, Yansong Qiao, Fuchu Jiang Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China

A detailed re-study of the paleomagnetic polarity stratigraphy of Xigeda Formation with an approximate thickness of 400m in Haiziping, Luding Sichuan suggests that the upper and lower parts separated at a depth of 360m from the surface belongs the Gauss normal polarity chron and the Gilbert reverse polarity chron respectively. According to the Cande’s polarity time scale, the age of the Xigeda formation ranges from 4.20 to 2.60MaBP, assigned to the middle and late Pliocene, which is consistent with our previous results. The series is known to be the earliest in the Xigeda lacustrine deposition. Based on the median size, the sedimentation in Haiziping shows five cycles from coarse to fine including fifteen sedimentary stages. Furthermore, the low grain size value indicates strong hydropower showing queasy sedimentary environment; while the high value indicate week hydropower showing


stale sedimentary environment. Another, the spectral analysis of the median size shows the circle of 400ka and 100ka that belongs to the orbit cycle of the Earth. Sporopollen analysis indicates that the environment was warm and humid at early stage (4.2–3.2MaBP), then changed to warm and dry at middle stage (3.2–2.8MaBP), and finally shifted to warm and humid at the last stage (2.8–2.6MaBP). The series of carbonate content can also divided into three stages as the pollen sequence that is brackish - salt water lake, salt water lake, and excess of water lake character as zero carbonate content. The median size, lithofacies and environmental index indicate that the strongest risen of the Tibet Plateau begins at about 2.8MaBP The ancient Xigeda Lake terminated sedimentation at 2.6MaBP, which can well contrast with the obvious change of eolian sedimentary environment in the China Loess Plateau. 0911 Phytoliths in laterite reveal climate cycles in the Pleistocene lower reaches of the Yangtze River Wei-Ming Wang1, Xiao-Dan Zhou2, Zi-Ye Yu1, Hao Yang3 1

Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China 2 Nanjing Geological Museum, Nanjing 210018, China 3 Nanjing Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China

As a product of bioclimatic process, the laterite (red soil) developed extensively in the tropics, subtropics areas, and partly expanded to the temperate areas of the world, combining with loess in the North, constitute two major soil types on the continental surface. In the past decades, great progress has been made in the study of the loess, verifying its geochemical and biota contents to be significant evidence in illustrating past climatic changes on the land, while study on the biota component of laterite was scarcely recorded. Phytolith analysis was proved to be an effective approach to the palaeoclimatic study. Here we report climate variations revealed by phytoliths from a profile of the patterned laterite in the lower reaches of the Yangtze River, dated between ca. 0.817 and 0.126 Ma before present, which are possibly comparable to the past global changes. The profile with a height about 13.5 m is located in the Xuancheng County, Anhui Province (30 54 N, 118 51 E). It is composed of a basal pebble layer, a yellow sand layer, and 15 purple paleosol and brown-yellow clay interbeds in ascendant order. This datum provide the earliest evident that phytoliths in laterite can serve as a unique bio-signal to indicate the past climate cycles in the continental. To test whether the phytolith content in the profile is significant for palaeclimate, the ecological significance of C3 and C4 grasses, along with some distribution roles for phytoliths revealed by the studies on surface samples were taken into consideration. We expressed the available information into two palaeenvironment indexes, i.e. a comprehensive warm index and an aridity index. At least 16 climatic stages are well recognized which indicate 8 warm-cool cycles based on the warm index. It can also be recognized that the warm periods mostly correspond to the paleosols while the cool ones to the clay and sand layers. We could not clearly distinguish the possible relationship between the warm index and the aridity index. It seems that chance for the occurrence of dry and less dry conditions is nearly same under the warm or cool climate. Changes in aridity are more distinct and frequent at the lower part than at the upper part, and a changing tendency of less dry is recognized at the upper part of the profile. C4 grasses are dominant in the whole profile, indicating that the laterite areas were generally warm during the deposit period.

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0946 Rapid Amazonian moisture oscillations correlated with Dansgaard-Oeschger cycles Xianfeng Wang1, Augusto S Auler2, R Lawrence Edwards1, Hai Cheng1, Emi Ito1, Jeffrey A Dorale3 1

Department of Geology & Geophysics, University of Minnesota, Minneapolis, United States 2 Instituto do Carste, Belo Horizonte, Brazil 3 Department of Geoscience, University of Iowa, Iowa City, United States

Terrestrial paleoclimate records on abrupt climate events from the tropics, e.g. Dansgaard-Oeschger (D–O) oscillations, are still rare, in particular, from Amazonia, which contains the largest tropical forest in the world. We have obtained a high-resolution oxygen isotopic record of cave calcite from Caverna Paraíso (PAR, 04o04'S, 55o27'W), Amazonia, Brazil. The chronology was determined by 60 U-Th ages from 3 stalagmites. Tests for equilibrium conditions show that their oxygen isotopic variations are primarily caused by climate change. We thus interpret the PAR record, spanning the last 50 thousand years, in terms of meteoric precipitation changes at this equatorial location. The oxygen isotopic profile shows significant abrupt millennial-scale variations during Marine Isotope Stage (MIS) 3, with amplitudes as large as 2 per mil. Using independent age scales, we compare the record to contemporaneous records from caves in eastern China (Wang Y. et al., 2001, Science 294, 2345–2348) and high latitude ice cores (Grootes and Stuiver, 1997, JGR 102, 26455–26470). The PAR calcite oxygen isotopic profile during MIS 3 anti-correlates remarkably with the Hulu Cave record, indicating that precipitation histories at the two sites are anti-phased, similar to our previous observations from northeastern and southern Brazil speleothems (Wang X. et al., 2004, Nature 432, 740 –743; Wang X. et al., QSR, in press). As Greenland temperature correlates with Hulu precipitation, PAR precipitation also anti-correlates with Greenland temperature. Our record adds further support to the idea that abrupt climate events have a worldwide distribution during MIS 3 (Voelker et al., 2002, QSR 21, 1185–1212). The observed anti-correlations between the records support an oceanic meridional overturning circulation mechanism for driving the abrupt millennial-scale abrupt events of the last glacial period, coupled with strong air-sea feedbacks from the tropics. Knowledge of the meteoric precipitation oxygen isotope and moisture histories of this central Amazonian region may ultimately shed new light on the interpretation of paleoclimate records from the Andes, such as the Andean ice core and lake records (e.g. Thompson et al., PNAS 103, 10536–10543).

0620 Vegetation on the exposed Sunda Shelf, South China Sea, during the Last Glacial Maximum Xiaomei Wang, Xiangjun Sun State Key Laboratory of Marine Geology, Tongji University, Shanghai, China

The nature of paleo-vegetation on the exposed Sunda Shelf, SW South China Sea, is crucial for our understanding of the tropical climate changes during the last glacial maximum (LGM). The present paper reports on vegetation reconstruction based on pollen analyses of six cores taken by the Sonne-115 cruises. Of the six cores, four from the shelf along the paleo-Sunda River are composed of marshy sediments, while the other two from the adjacent continental slope consist of hemipelagic clay. The results show that the pollen records of the same period of time, but from different geomorphologic settings, differ significantly from each other. The LGM pollen assemblages from the four

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shelf sites are very similar, all being marked by predominance of herbs (mainly Poaceae and Cyperaceae) and ferns (mainly Cyathea). In order to find out what kind of plants were represented by Poaceae pollen, the same samples were analysed for phytoliths, and in result a fairly significant amount of Phagmites (sedge, a water or swamp plant) phytoliths was found. Sine the above mentioned pollen grains are not prone to long distance transport, the pollen assemblages in the shelf cores must have originated from local sources, mainly from the vegetation growing along the paleo-Sunda River on the exposed Sunda Shelf at the low sea level stands during the LGM. As to the cores from the continental slope, the pollen profiles are characterized by high percentages of lowland rainforest and lower montane rainforest taxa, and the pollen grains must be tarnsported from the exposed Sunsa Shelf.The above discussed pollen data enabled us to speculate, for the first time, about the vegetation growing on the exposed Sunda Shelf. Obviously, the Sundaland was covered by lowland rain forest and lower montane rain forest during the LGM. Marshy vegetation (Cyperaceae and sedges etc.) was growing along the Sunda River, and tree ferns (Cyathea) were distributed around the marshes. The climate deduced from the paleovegetation, therefore, should be cooler than the present day, but still humid. 0168 Thermally-transferred (recuperated) OSL dating in Chinese loess: from signal to method Xulong Wang1, Ann Wintle2 1

SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi’An 710075, China, China 2 Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, SY23 3DB, UK, United Kingdom

0571 A high-resolution relative paleointensity record from Holocene sediments of Lake Bilutu, Inner Mongolia, China Yong Wang1, Zhenqing Chi1, Tehquei Lee2, Peiyi Yao1 1

Institute of Geology, Chinese Academy of Geological Sciences, Beijing, China 2 Institute of Earth Sciences, Academia Sinica, Taipei, China

A detailed rock magnetic study on Holocene sediments trenched in dried-up Lake Bilutu from the central Inner Mongolia, North China, provides an opportunity to establish the relative paleointensity of the geomagnetic field since Holocene in the central Asia inland. The results indicate that the sediments from Lake Bilutu are suitable for relative paleointensity study, and anhysteretic remanent magnetization (ARM) can be used as the normalization parameter of the natural remanent magnetization (NRM). Our relative paleointensity in continuous U-channel samples of 4.5 m length provide a continuous record of the intensity variation during the last 8500 years, which correlates well with the results from marine sediments cores on the western Antarctic Peninsula continental shelf. This means the sediments records are reliable for relative paleointensity of Earth’s magnetic field, and suggests that these sediments have recorded the real changes of geomagnetic field, which would provide a new method for absolute dating and regional stratigraphic correlation. 1130 Response of climatic record in Malan Ice Core on the Tibetan Plateau to the ENSO events Youqing Wang1, Tandong Yao1, Ninglian Wang2 1

Institute of Tibetan Plateau Research, Chinese Academy of Sciences, China Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, China 2

Luminescence dating of sedimentary quartz grains using the fast component of the optically stimulated luminescence (OSL) signal has become a useful tool for dating the Malan loess (of last glacial age) from the Chinese Loess Plateau. However, saturation of the fast OSL component means that this signal cannot be used for dating loess from the penultimate glaciation and older. Recently, we have found that there is an OSL signal that does not saturate until much large doses are given. Part of the thermally transferred OSL signal (termed the recuperated OSL) has an increasing dose response back to more than 3000 Gy for fine grained quartz that has been chemically isolated from the polymineral fine-silt fraction; this would permit dating of samples with an age of 1 million years if they had a dose rate of 3 Gy/ka. In a series of experiments, we have investigated the recuperated OSL in order to optimise the measurement conditions to obtain the dose that grains have received since they were last exposed to sunlight, i.e. the time when they were deposited. We have developed two methods, one using multiple aliquots of quartz and one using single aliquots of quartz, analogous to the measurements made on the OSL signals for the Malan loess. We report on the feasibility of using these two methods for obtaining ages for the loess and paleosol sequences at Luochuan and Xifeng on the Chinese Loess Plateau. The reliability was tested using known age samples from the last and penultimate glacialinterglacial loess-paleosol sequences. In addition, samples from close to the Brunhes/Matuyama boundary at the same sites were measured. There was good agreement between our new dates based on the recuperated OSL signal and the independent ages. We thus infer that this new method is applicable to Chinese loess over the whole of the Brunhes epoch.

El Niño/Southern Oscillation (ENSO) is one of the most important coupled ocean-atmosphere phenomena to cause global climate variability on inter-annual time scales. The sign is not only well preserved in the tropical ice core, but also high-resolution recorded by the subtropical Tibetan Plateau ice core. In this paper, the response of climatic record (d18O, as air temperature proxy) revealed from the Malan ice core located in the northern Tibetan Plateau to the ENSO events in past century was investigated. The teleconnection between the d18O record in the Malan ice core and different ENSO strength indices such as the SST index in Niño 3 and Niño 3.4 regions, the Southern Oscillation index (SOI), the Global SST ENSO index, the coupled SOI and Niño SST ENSO index, and the multivaraite ENSO index, were analyzed. The results showed that the d18O record in the Malan ice core was inversely correlated with the ENSO activity, especially significant during the rapid warming period since 1950s. We also investigate the d18O anomaly change in the Malan ice core after filtered with windows of 3~10 year for El Niño years and La Niña years. We found that the d18O anomaly values were most positive before mid-1930s and significant negative after mid-1930s for El Niño years, and the accumulative of the d18O anomaly in El Niño year significant increased before mid1930s and decreasing after that time. It was evidently caused by the temperature abrupt change from cold stage to warm stage at mid-1930s in Malan region. However, the d18O anomaly had no clear tendency for La Niña years. It is reasonable that the ENSO has clearly influenced the climate variability of the northern Tibetan Plateau on inter-annual time scales.


0115 Cave ventilation impact on modern Speleothem records Chris Waring1, David Griffith2, Stephen Wilson2, Stephen Parkes2, Julia James3, David Stone1 1

Australian Nuclear Science and Technology Organisation, Australia Department of Chemistry, University of Wollongong, Australia 3 School of Chemistry, University of Sydney, Australia 2

Speleothems hold great promise of providing high temporal resolution palaeoclimate records. Because limestone caves containing speleothems are located in a wide variety of terrestrial climatic regions differential regional climatic change may be discernable. Speleothems also potentially offer very long semi-continuous records not available from other archives. However, significant issues remain regarding the quantitative interpretation of speleothem isotopic records. Many dated d18O and d13C records reported in the literature show significant fluctuations that are able to be correlated with other records, but importantly they may vary significantly in the magnitude of the isotopic fluctuations without adequate explanation. The correlation between d18O and d13C records from a single speleothem may also inexplicably breakdown. We present here a synchronous month long record with 10 min sampling of cave atmosphere CO2 concentration data from two different locations at Jenolan. These sites show a remarkably different pattern. One has a semi continuous high concentration of CO2 between 2500 and 3500ppm, whilst another site shows a diurnal fluctuation pattern between 500 and 5000ppm. We interpret these data to indicate two end members of a continuum in ventilation styles from purely drainage to fully ventilated. A speleothem grown in differently ventilated locations will have a significantly different isotopic record. These differences probably also relate to the preference of researchers to avoid so called ‘kinetically affected’ samples which have grown rapidly with a strong d18O and d13C correlation, presumably in well ventilated sites. Another continuous 2 week record of cave atmospheric d13C – CO2, H/D – H2O, CH4, T, humidity and external cave meteorological data is also presented to enable interpretation of cave isotopic fluctuations. This aversion to kinetically affected samples may be unfounded, discarding a much stronger but perhaps more complex coupling between the external climatic conditions and accumulated speleothem isotopic record from well-ventilated sites. 1127 Paleoclimatic Variations From Rock Magnetic Studies Of Sediments From a Southern Indian Lake Anish K Warrier1, R Shankar1, C N Prabhu2 1

Department of Marine Geology, Mangalore University, India Centro de Dados Geologico-Mineiro Alfragide, Portugal

2

The Indian monsoon profoundly affects the lives and economy of more than a billion people. Its past variations need to be documented in order to be able to predict its future behaviour. The thousands of lakes/ tanks in Southern India are an important source of paleomonsoonal and paleoclimatic information but have not been tapped yet. We present here preliminary rock magnetic data for a 5.5-m sediment core from Ayyanakere (130 26’N; 750 52’E), Chikkamagalur district, Karnataka. Using standard methodology, we measured lf, fd %, SIRM and ARM, and calculated inter-parametric ratios like SIRM/lf, ARM/lf, ARM/fd, ARM/SIRM and S-ratio. Carbon-14 dating, analysis of rainfall data and studies of other proxies are in progress. From the core bottom upwards, lf increases and peaks at ~ 4.3 m (~

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200 x 10−8 m3/kg) and decreases at ~ 3 m. It again increases from 2 m depth, peaks at ~ 86 cm (~ 500 x 10−8 m3/kg) and decreases towards the core-top. A similar trend is shown by SIRM and fd %. Average fd % values are 8–9% and 5–6% respectively in the lower and upper sections of the core. Based on our earlier studies (Shankar et al., 2006), we tentatively interpret lf and fd variations as indicating past monsoonal variations: Pedogenesis is driven by temperature and rainfall. As the area of study has minimal variations in temperature, pedogenesis is principally driven by rainfall. Hence, periods of high rainfall must be characterised by high concentrations of not only magnetic minerals (high lf) but also of pedogenic magnetite (high fd), and vice versa. The high S-ratio (~0.92) suggests that the dominant magnetic mineral is ferrimagnetic. HIRM data also indicate low concentrations of magnetically ‘hard’ minerals like haematite and goethite, except at four depth intervals (> 4.5m). Magnetic minerals do not seem to have undergone any significant dissolution as indicated by ARM / SIRM and ARM /lf data. SIRM/lf data suggest the probable presence of greigite at 5.34–5.35 and 4.8 m depths. ARM/lf and ARM /fd data indicate that biogenic magnetite may probably be present at 5.35–5.36 m depth. However, the presence of greigite and biogenic magnetite needs to be confirmed from GRM/RRM and SEM/TEM studies. 1260 Tephrochronology of North Europe during the last 1000 year: a contribution to the MILLENNIUM project Stefan Wastegård1, Siwan M Davies2 1

Department of Physical Geography and Quaternary Geology, Stockholm University, Sweden 2 School of the Environment and Society, University of Wales Swansea, United Kingdom

The Millennium project is a multidisciplinary consortium of more than 39 European universities and research institutes, with the aim of answering a single question: Does the magnitude and rate of 20th Century climate change exceed the natural variability of European climate over the last millennium? One aspect of this project includes highresolution investigation of different palaeoclimatic archives such as lake, peat, marine and ice-core records covering the last 1000 years. A key objective of Millennium is to examine the lead and lag responses between these different archives, which requires synchronisation of these proxy records on common timescales. Here we report on the use of tephrochronology for achieving this goal. The detection of tephras in more distal areas now provides the opportunity for improving and validating chronological models and for producing precise tie-points between sparsely located records. For the purposes of the Millennium project and also for other similar studies that focus on the last 1000 years, we demonstrate the applicability of employing tephra horizons from Icelandic volcanic eruptions for the precise correlation of palaeoclimatic archives in northern Europe. For instance, tephra associated with the Hekla-1 (AD 1104), Öræfajökull (AD 1362), Veidivötn (AD 1477) and Askja (AD 1875) eruptions have been widely dispersed in northern Europe. These isochrones are used to date and synchronise the different Millennium archives.

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1271 Tephrochronology of the North Atlantic region: linking marine and ice-core records spanning the last glacial cycle Stefan Wastegård1, Siwan M Davies2, Tine L Rasmussen3 1

Department of Physical Geography and Quaternary Geology, Stockholm University, Sweden 2 School of the Environment and Society, University of Wales Swansea, United Kingdom 3 Department of Geology, University of Tromsø, Norway

Tephrochronology has recently become a key technique for the precise correlation of Late Quaternary records in the North Atlantic region. Recent developments have extended the geographical distribution of significant tephra strata and, as a result, have established important tiepoints between diverse palaeoarchives during the last glacial cycle. We will report on the work being undertaken to identify, date and geochemically characterise tephra horizons in marine cores from the Faroe Islands region and the Greenland ice-cores. Four ash zones including the widespread North Atlantic Ash Zone II (NAAZ II; 52–53 ka BP) and three mainly basaltic ash zones here referred to as the Faroe Marine Ash Zones (FMAZ) I (ca 15.4 14C ka BP), II/Fugloyarbanki Tephra (ca 23–24 14C ka BP) and III (ca 33 14C ka BP) occur in several cores from the Faroe Islands margin. Detailed investigations of NAAZ II in high-resolution cores show that two separate layers can be distinguished; a lower mixed alkalic basalt and rhyolitic layer and an upper predominantly tholeiitic basalt tephra, separated by as much as 1500 years. FMAZ III is a thick and relatively scattered basaltic ash zone found in three cores from the Faroe area. It has not been directly dated, but extrapolation of AMS radiocarbon dates from all cores suggest an age of c. 33,000 14C years BP, slightly above Heinrich layer 4, and close to the onset of GIS8. An equivalent tephra was recently identified in NGRIP where it is situated right at the peak of GIS8. The FMAZ II/Fugloyarbanki tephra occurs in all analysed marine cores in the Faroe Islands region and in NGRIP. It is dated to 26,740 ± 390 b2k according to the Greenland Ice Core Chronology (GICC05). This tephra falls right after the warmest peak of GIS3 in both the NGRIP and marine records and provides another important tie-point. Other tephras identified within the ice-core material have revealed the presence of previously unreported tephra horizons of Icelandic origin, thus, adding considerably to our knowledge of Icelandic volcanism during the last glacial cycle. 0637 Quantifying climate change across northern Europe during the Last Glacial-Interglacial Transition (LGIT; 15-10ka BP): Testing hypotheses of climate change using two separate insect proxies Jenny Watson1, Nicki J Whitehouse1, Steve J Brooks2, Paula J Reimer1, Barbara Wohlfarth3 1

Queens University Belfast, United Kingdom Natural History Museum, United Kingdom 3 Stockholm University, Sweden 2

Sub-fossil insects are increasingly being recognized as valuable proxies for interpreting past environments and climates. Two of the most widely studied sub-fossil insect groups are chironomids and Coleoptera. These proxies can both be used to reconstruct past climates, and are especially useful in charting the rapid temperature changes that occurred during the LGIT. Previous climatic reconstructions from these two proxies during the LGIT demonstrate good agreement to established palaeoclimate patterns such as those derived from the

oxygen isotope curves from Greenland. The two proxies also demonstrate significant differences in the trends and timings of temperature variations across different parts of northern Europe during the LGIT. Temperature reconstructions derived from both insect proxies across two sites in northwestern Europe, chronologically linked using tephra horizons and radiocarbon dates, are presented here: Lough Nadourcan in Donegal, western Ireland, and Hässeldala port in Blekinge, southern Sweden. From Lough Nadourcan, we present the first high-resolution late glacial chironomid-temperature reconstruction from Ireland, derived from a transfer function approach, in addition to temperature reconstructions derived from Coleoptera using the Mutual Climatic Range method (MCR). The study of Irish deposits has previously had relatively little part to play in the study of the LGIT, despite being uniquely placed to record changes in the location of the Polar Front and associated changes in climate on the most western extreme of a transect across northern Europe. The prevailing westerly airflow combined with the strongly controlled maritime climate and an absence of a significant ice cap at the time of the LGIT allow climatic changes to be identified and quantified free from any effects of ice and continentality. In contrast to Ireland, Southern Sweden is an area which was close to the limits of the wasting Fennoscandian ice sheet during the LGIT. The climatic changes occurring here were tempered by effects of both ice and continentality, but there have been no high-resolution chironomid-temperature reconstructions generated for this region. Results of both Coleoptera and chironomids from Hässeldala port, in Blekinge, Southern Sweden are presented. Temperature estimates derived from the two insect proxies rely on substantially different numerical approaches; the results presented here indicate both the similarities and differences in the magnitude and response time between the two insect proxies, suggesting future research directions. 0992 Paradoxes in carbonate diagenesis: Implications for radiocarbon dating and trace element and stable isotope archives in terrestrial clams and marine corals Gregory E Webb1, Gilbert J Price2, Luke D Nothdurft1, Thor E Bostrom1, Llew Rintoul1 1

Queensland University of Technology, Australia University of Queensland, Australia

2

Carbonate materials contain valuable geochemical records for understanding Quaternary history. For example, freshwater clam shells provide radiocarbon dates for archaeological and vertebrate fossil sites, and scleractinian coral skeletons provide both dates and trace element and stable isotope archives that are critical for palaeoclimate studies. However, trace element and isotopic records are useful only in the absence of modification by subsequent diagenesis. Unfortunately, carbonate materials are prone to diagenetic modification, and samples must be vetted prior to analysis. Here, we describe two cases of paradoxical diagenetic change that are difficult to recognise using standard vetting procedures. Meteoric (freshwater) diagenesis of aragonite clam shells generally involves the dissolution of aragonite and its replacement by calcite. This process introduces young carbon, but vetting can be accomplished easily using X-ray diffraction. However, diagenetically altered freshwater clams from the Darling Downs, Queensland have been identified that contain abundant aragonite, rather than calcite, cement. Thus the clams return significantly erroneous radiocarbon ages, but the cement cannot be recognized using X-ray diffraction. Whether calcite or aragonite will precipitate during diagenesis depends in large part on the Mg:Ca ratio of the diagenetic fluid. Calcite is the least soluble of the two polymorphs and will generally precipitate from


freshwater where Mg:Ca ratios are generally low, commonly 5:1. Aragonite cement precipitated in the Darling Downs clams owing to unusually high Mg:Ca ratios in local, basalt-affected groundwater. Our second diagenetic paradox involves skeletons of the scleractinian coral Porites from the Great Barrier Reef. Porites is among the most frequently utilised corals for palaeoclimate studies. We have identified live-collected specimens wherein endolithic coccoid cyanobacteria bored tunnels into day- to week-old coral skeleton, and the tunnels were concomitantly infilled by low-Mg calcite cement. The cement contains palaeothermometry-sensitive trace element ratios (e.g., Sr:Ca) and stable isotope ratios that are radically different from those in the host coral. Although the cement-filled borings are too small and scattered to affect X-ray diffraction data, they could significantly contaminate microsamples used for laser ablation or microprobe analyses, thus providing erroneous sea surface temperature data. In this case, calcite precipitated in a marine environment, rather than aragonite, because the tunnels are largely closed systems, and the dissolving skeletal aragonite contains little Mg. Thus, the Mg:Ca ratio of the microenvironment was 800 ka and 1100 to 1000 masl at ~450 ka BP. While uncertainty in surface erosion rates complicate the precise timing, the ages show major phases of retreat occurred during the mid-Pleistocene, and that ice volume was no more than 100 m thicker than that at LGM times (1000 masl) since the 450 ka recessional phase. Our results largely confirm those from the marine record and cosmogenic results from the Northern Prince Charles Mountains, and are similar to Pleistocene ice changes at Taylor Valley on the opposite side of the ice sheet. Taken together, this data suggests that the major ice sheet expansion during the MPT required by the Raymo et al. (2006) model did occur, supporting the notion that the size of the Antarctic Ice Sheet influences the pacing of the global climate cycle. 0566 Ice core evidence for holocene climate change in West Antarctica James WC White1, Annalisa S Schilla1, Eric J Steig2, Kendrick C Taylor2 1

University of Colorado, United States United States

2

Holocene ice isotopic records from the two deep West Antarctic ice cores (Siple Dome and Byrd) became increasingly enriched starting around 6kyr BP, indicating that the local climate either began to warm or that both sites began to experience a simultaneous elevation drop of several hundred meters. This West Antarctic isotopic enrichment is in contrast to the record from Taylor Dome, a nearby Antarctic ice core site on the other side of the Ross Ice Shelf from Siple Dome. Taylor Dome recorded an opposite signal, an ongoing isotopic depletion throughout the Holocene. Approximately synchronous with the onset of isotopic enrichment in West Antarctica, the Siple Dome and Taylor Dome deuterium excess records, proxies for moisture source region conditions, increase in both mean and variance. One hypothesis has suggested that ongoing retreat of the Antarctic ice edge from the Last Glacial Maximum could have caused the shift in deuterium excess and would be consistent with an elevation drop in West Antarctica. But ice retreat would expose colder ocean that would likely decrease the mean deuterium excess value, and so appears to be inconsistent with observations. Furthermore, recent ice sheet modeling suggests that most of the post-glacial elevation change in West Antarctica occurred during deglaciation or in the early Holocene, rather than in the last 6kyr. We test an alternative hypothesis that the mid-Holocene shift in both West Antarctic ice core isotope records and Siple Dome and Taylor Dome deuterium excess records is the result of either the mid-Holocene intensification of El Niño-Southern Oscillation (ENSO) conditions, as noted in other paleoclimate archives and model results, or the onset of the teleconnection between tropical Pacific and West Antarctic climate which still exists today. We will discuss the results of an intermediate complexity isotope transport model used to simulate the influence of ENSO and sea ice changes on precipitation isotopes and regional climate in the Ross Sea region of Antarctica.

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0017 Highstands of Palaeolake MegaFazzan, southwest Libya Kevin White1, Nick Drake2, Simon Armitage3, Ahmed Al-Hawat4, Mustapha Salem5 1

The University of Reading, United Kingdom King’s College London, United Kingdom 3 Royal Holloway, London, United Kingdom 4 Garyounis University, Libya 5 Al-Fatah University, Libya 2

The Fazzan of southwest Libya includes a large closed basin with abundant palaeolake sediment outcrops and shorelines. Dating of these features provides evidence of lacustrine conditions during numerous interglacials spanning a period greater than 750 ka. The middle to late Pleistocene interglacials were humid enough to produce a giant lake of at least 130,000 km2 that we have called Lake Megafazzan. Most humid periods correspond to times of increased Saharan insolation, suggesting that this is the forcing mechanism. The last humid phase started at about 14 ka, continued into the Holocene, but was punctuated by brief and abrupt intensifications of aridity that are broadly synchronous with other arid events reported from surrounding regions and are probably linked to monsoon failure. The relationship between the highstands of Lake Megafezzan and other giant palaeolakes in the Sahara is important because synchronous lake highstands in these basins would allow movement of animals and hominids out of Africa. 0269 Britain’s northernmost unglaciated river system: results from the Trent Valley Palaeolithic Project Tom S White1, David R Bridgland1, Andy J Howard2, Mark J White1 1

Durham University, United Kingdom University of Birmingham, United Kingdom

2

The Trent is the most northerly British river to preserve an extensive long-timescale terrace record in which both temperate and cold stages are represented. Its catchment lies just beyond the maximum extent of the MIS 2 ice sheet in Britain, although the river was profoundly affected by that glaciation. Historically, the Trent has also been considered the most northerly British river to preserve archaeological material from the Lower and Middle Palaeolithic periods, representing the northern limit of Pleistocene human occupation. It is more probable, however, that this apparent distribution is a product of differential preservation, given that the MIS 2 glaciation removed all such evidence (archaeology + contexts) further north. Earlier glaciations (MIS 12 and ?6) are believed to have overrun all or part of the Trent system. Indeed, there are two earlier lower courses of the Trent, with separate routes to the North Sea, and diversion from the earlier of these (via Ancaster) may have resulted from glaciation in MIS 12. The later route, via Lincoln, survived until MIS 2 deglaciation, when a large proglacial lake (Lake Humber) formed to the north of this Lower Trent course, eventually inundating it. Drainage of the lake northwards resulted in the modern Trent course to the Humber estuary. This is unusual amongst British rivers affected by glaciers, the majority (e.g. the Thames) being pushed southward by advancing ice sheets, whereas the MIS 2 glaciation, which never quite reached the Trent, had the result of drawing it northwards. The Project has sought to clarify a number of issues relating to the post-MIS 12 terrace sequence in order to place the archaeological material in a secure stratigraphical context. In particular, biostratigraphical evidence has been reviewed and a number of valuable new fossil localities have come to light. Geochronology, in

the form of OSL and amino acid racemization, has been applied. Trent gravels are dominated by quartzose lithologies, with no primary sources of flint, the preferred raw material for tool production. Paradoxically, the archaeological material is almost entirely composed of flint artefacts, with only a handful manufactured from local raw materials, although the latter are probably underrepresented because of collection bias and taphonomic processes. Provision of a refined age-model (correlated with marine isotope stages) for this system, uniquely positioned close to the boundaries of several glaciations, will be of considerable value within the British Quaternary and Palaeolithic records. 0001 Beetle-vegetation relationships and landscape structure: a modern analogue approach Nicki J Whitehouse1, David Smith2, Jane Bunting3 1

Queen’s University Belfast, United Kingdom University of Birmigham, United Kingdom 3 University of Hull, United Kingdom 2

Native woodland is a scarce resource of high cultural, scientific and nature conservation importance throughout Europe. A recently published hypothesis by the Dutch ecologist Frans Vera argues that the current management policy towards closed canopy woodland is compromising the integrity and biodiversity of native woodlands across Europe. The palaeoenvironmental record, in particular via fossil insects, has considerable potential to develop our understanding of the vegetation structure in these native forests, by interrogating the early Holocene record. This paper will outline results of a recent review of the Holocene fossil insect record and present some of the problems associated with the taphonomic understanding of the significance of this fossil insect data with respect to quantifying landscape structure. We will present initial results from a newly funded NERC project which aims to generate modern and fossil beetle-vegetation relationships from a range of ancient woodlands of known value for their saproxylic fauna (=the wood decay system), under differing management regimes, to establish a fossil insect “signature” of such landscapes. Where possible, we will present findings by reference to pollen signatures of the same landscapes. We will discuss how successful the research has been in establishing vegetation structure and assessing the visibility (or not) of certain landscape and vegetational features and assess the potential of this approach to interrogate palaeoecological data. 0036 Biodiversity, Management and Restoration in “natural” and “cultural” landscapes; opening Pandora’s box Nicki J Whitehouse Queen’s University Belfast, United Kingdom

The value of palaeoecological studies to biological conservation is explored in this paper by focusing on the fossil insect record from waterlogged anaerobic deposits and draws attention to some of the areas where palaeoecology may inform on the conservation of biodiversity as well as highlighting some of the more philosophical values inherent within environmental historical approaches. In particular, it draws attention to the biodiversity of two ecosystem types: raised mires and woodlands. Fossil insect faunas preserved within mires provide a detailed record of biodiversity change at species level, where for many mobile groups, habitat continuity is essential. The similarity between fossil and modern beetle populations suggests that the faunal characteristics of some peatlands become established during the early phases of peat development and indicates that faunal biodiversity on the sites


today is dictated by complex site histories, both natural and anthropogenic. Far from being ‘stable’ these ecosystems appear to have been in constant flux; during the earlier stages of peat development mire woodlands regularly expanded upon peat surfaces. Fossil insect data associated with these deposits includes many locally extirpated and nationally endangered/rare species. Such data underline not only the major changes to forest biodiversity but also have value to recent debates such as those sparked by the ecologist Frans Vera concerning the nature of the “wildwood”. However, despite the clear evidence from palaeoecology for constantly evolving ecosystems, and the fact that we still have so much to learn about ecosystems and the complex interactions between “natural” and “anthropogenic” -induced changes, land managers are often intent on managing sites to an “idealised” version. Taking a long-term perspective, any attempt to manage and restore sites will always be something different to what once was there. But perhaps we also need to ask hard questions about what we wish to restore, what we value (“natural” or “culturally” influenced biota?) and the baselines we should be working towards. The cultural, political and historical values behind such idealised visions are complex, tend to be substantially westernised, suffer from the dualistic separation of “nature” and “culture” and, worse still, suffer from ecologically imperialistic undertones. Yet these values and issues are seldom discussed, despite their capacity to have a profound impact on the management, “re-storation” and “re-wilding” of some ecosystems and landscapes and run the risk of disenfranchising people and their cultural values from their wider environment. 0263 Controls, nature and timing of high frequency sediment supply fluctuations in Late Quaternary river systems: The Rio Bergantes, northeast Spain R Greg Whitfield1, Mark G Macklin2, Paul A Brewer2, Andreas Lang3, Barbara Mauz3, Eric Johnstone2 1

United Kingdom University of Wales, Aberystwyth, United Kingdom 3 University of Liverpool, United Kingdom 2

To investigate the effects of short-term (sub-orbital) climate change on the evolution of Mediterranean river systems during the Late Quaternary, geomorphological, sedimentological and geochronological analyses have been undertaken in the Rio Bergantes, northeast Spain, a major south-bank tributary of the Rio Ebro. In the lower reaches of the Bergantes system, the river emerges from a laterally confined valley floor, with minimal alluvial preservation potential, into a large sedimentation zone/basin. Field mapping and profiling utilising large-scale aerial photography, differential GPS and airborne LiDAR has identified five (cut and fill) axial terrace tracts as well as several associated tributary alluvial fans and gully systems. The five terraces occur at ~ 20 m, ~ 16 m, ~ 11 m, ~ 8 m and ~ 4 m above the height of the present river level. River bank and quarry sections afford exceptionally good sedimentary exposures. Age control provided by OSL, IRSL and radiocarbon dating methods has revealed the timing of valley floor aggradation at ~ 110–28 ka, ?–13 ka, ?–10 ka, ?–7.5 ka and ~ 3 ka for the five main units respectively, with significant valley floor activity also being evident during the Little Ice Age. With the exception of terrace 5 (anthropogenically driven?), the timing of all aggradational phases coincide with stadial and neoglacial events in the Pleistocene and Holocene, with phases of valley floor incision, seemingly, coincident with warmer interstadial and interglacial conditions. Sedimentological analysis of the major fluvial units both in terms of structural properties and sediment provenance, reveals phases of both tributary and trunk-

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stream driven sedimentation, and evidence of both braided and meandering systems. Integration of airborne LiDAR with laser scanning of extensive quarry and river cliff sections has enabled a reach-scale sediment storage and removal ‘budget’ to be calculated, demonstrating system sensitivity to climate changes operating at a higher frequency than Milankovitch-driven glacial-interglacial cycles. 0088 Large-scale and local controls on Holocene fire-climate linkages in western North America and southern South America Cathy Whitlock1, Patrick Bartlein2, Patricio I Moreno3, Jennifer Marlon2, Maria M Bianchi4 1

Montana State University, United States University of Oregon, United States 3 Universidad de Chile, Chile 4 CONICET-CRUB, Argentina 2

High-resolution fire history data from temperate forests of western North and South America permit examination of regional and hemispheric linkages between Holocene climate, fire, and ecosystem response. Differences in the seasonality of precipitation influence fire regimes at present, and the paleorecord suggests that the intensity of these precipitation regimes was affected by large-scale changes in the climate system in the past. At present, summer-dry areas are dominated by subtropical high pressure systems, and subsidence in these areas suppresses summer precipitation. Summer-wet areas are influenced by monsoonal circulation, which increases convectional activity and fire activity east of the Rockies and Andes. In the western US, paleoenvironmental data suggest that summer-dry areas became drier in the early Holocene, as evidenced by higher-than-present fire activity and an expansion of xerophytic communities at many sites. This is attributed to expansion of the subtropical high-pressure system during the early Holocene summer insolation maximum. Summer-wet areas, in contrast, registered wetter-than-present conditions and fewer fires in the early Holocene, presumably because summer insolation strengthened summer monsoonal circulation. South American records show: (1) an abrupt increase in fire activity at the Pleistocene/Holocene transition at high-latitudes; (2) widespread fire activity and drought in the early Holocene despite the summer-insolation minimum; (3) northsouth differences in fire activity in the mid-Holocene suggesting the onset of the current dipole climate, and (4) locally variable fire signals and a shift to smaller surface fires in the late Holocene consistent with cooler conditions and greater interannual variability. Widespread fire activity in southern South America in the early Holocene is consistent with warmer SSTs, a weakened pole-to-equator temperature gradient, and a southward shift of westerly storm tracks as a result of the strong obliquity forcing.

1100 Palaeoecology of the western Pantanal: a 45,000 year record of vegetation and climate change Bronwen S Whitney, Francis E Mayle Institute of Geography, University of Edinburgh, United Kingdom

We present a late Quaternary pollen record from Laguna La Gaiba (17°45'S, 57°35'W), a 55 km2 lake located in eastern lowland Bolivia. Laguna La Gaiba (LLG) occupies an ecotone between the eastern limit of the Bolivian Chiquitano dry forest, and the western margin of the Pantanal basin, the world’s largest tropical wetland. A suite of 12 AMS

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radiocarbon dates on terrestrial macrofossils demonstrates a continuous sediment record spanning at least the last 45,000 years. Currently, upland areas of the lake catchment are blanketed by closed-canopy semi-deciduous tropical forest, but low arboreal and high herbaceous pollen concentrations in glacial-age sediments are indicative of a climate drier than present, and a landscape dominated by open savanna. Tropical forest, floristically different than present, appeared during the glacial-Holocene transition, and rapid changes in the arboreal pollen sum suggests this site may have been subject to high magnitude/high frequency climate fluctuations. Semi-deciduous tropical forest, floristically similar to that of today, appeared during the early Holocene, but proportions of key dry forest taxa vary throughout the Holocene, which we attribute to changing precipitation. Mid-Holocene aridity is followed by rising precipitation to the present at LLG, a pattern which is consistent with other records from the southern hemisphere, such lake level change in Lake Titicaca and vegetation shifts in the Bolivian Amazon (Laguna Chaplin and Laguna Bella Vista). However, our evidence for reduced precipitation during the Last Glacial Maximum contrasts with high water levels at Lake Titicaca and travertine deposition in the caatinga region of eastern Brazil. 1307 The role of palaeoecology in managing and conserving a dynamic Earth Katherine J Willis1, Terry Brncic2, Blanca Figueroa-Rangel3

in areas along the Pacific Northwest coast. Although more northerly icefree areas had been recognized in both continents, it was assumed that their environmental conditions were unsuitable to support trees and most vertebrates. There is now emerging evidence, however, for the full-glacial survival of trees and a number of vertebrates in North America close to the margins of the Laurentide ice-sheet and as far north as Beringia; in Europe there is evidence for widespread cryptic refugia across central and northern Europe. The species that survived in northerly locations during the Last Glaciation are believed to have played a significant role in colonization of Europe and North America following glacial retreat. While a number of pollen and macrofossil studies as well as genetic studies provide evidence for survival of animals and plants in the northerly locations, it is unclear whether these species possessed certain characteristics that made their northerly survival possible. Work on ecological traits of species in presently fragmented landscapes in the northerly latitudes has demonstrated that these species possess a number of key characteristics pertinent to their survival. Some of these characteristics include cold tolerance, ability to use a wide variety of habitats and ability to disperse long distances. This paper will present results of a study in which we explored these traits in relation to the fossil and genetic evidence for over hundred species that survived in Pleistocene glacial refugia of Europe and North America and ask whether northerly survival was a matter of chance or choice. 1414 The Late Holocene rise of Sphagnum in New Zealand

1

Long-term Ecology Laboratory, University of Oxford, United Kingdom University of Brussels, Belgium 3 Centre Universitario de la Costa Sur, Universidad de Guadalajara, Mexico 2

International targets set for reducing the rate of biodiversity loss—the 2010 target—and ensuring environmental stability (Millennium Development Goals) have largely not taken into account the increasing body of data about the biodiversity change in the past. Linking knowledge to conservation action has not been widely practised, by either the palaeoecology or the conservation communities yet there are key areas where palaeoecology has much to offer biodiversity conservation. These include linking proximal palaeoecology to conservation action in specific areas of concern; using phylogeny to inform palaeoecology and the conservation of evolutionary potential; linking spatial and temporal patterns and scales of disturbance for ecosystem management and understanding the continuous role of changing climate and human activities in shaping vegetation change in the biodiverse landscapes. This paper will present results from two recent projects in the Sierra de Manatalan Biosphere reserve in Mexico and the lowland Congo basin to illustrate the huge potential of palaeoecology in conserving a dynamic Earth. 1321 Species survival in northerly glacial refugia: a matter of chance or choice? Katherine J Willis1, Shonil A Bhagwat1, Mary E Edwards2 1

Long-term Ecology Laboratory, Biodiversity Research Group, University of Oxford, United Kingdom 2 Geography, University of Southampton, United Kingdom

There is increasing fossil and molecular evidence to suggest that the geographical distribution of Pleistocene refugia in North America and Europe is far more complex than originally envisaged. The traditional refugial model suggested that populations of plants and animals survived the cold-stages of the ice-ages in southerly Mediterranean refugia in Europe, and in North America in the large region south of the ice-margin and

Janet M Wilmshurst, Matt S McGlone Landcare Research, New Zealand

Sphagnum moss is widely regarded as a crucial species in the formation of raised bogs in the Northern Hemisphere. However, although it is widespread in the cooler and wetter parts of New Zealand, and dominates some peat bogs, it is by no means ubiquitous. Restiads are widely regarded as Sphagnum-analogues but these are not always dominant either. In most areas where it is abundant, Sphagnum deposits generally overlie sedge-dominated peat deposits which have been growing over the last 15 000 years. Is this recent change in bog dominance a climatic or anthropogenic effect? We analysed 15 bogs from the South Island for Sphagnum (S. cristatum and S. falcatulum) leaf remains. The sites ranged from 30m to 1400m above sea level, with mean annual rainfall between 800 –3000 mm/yr. There were three scenarios for Sphagnum (and to some extent, restiad) abundance during the Holocene. The least common scenario was for Sphagnum to be abundant throughout the Holocene, and this only occurred in the wettest and most poorly drained bogs, not always restricted to high rainfall areas. A similarly uncommon scenario was for Sphagnum to increase suddenly at c.3000 cal BP, possibly as a result of an increase in winter rainfall at this time. The most common scenario we found was for Sphagnum to become rapidly dominant following initial human settlement c. 1250 AD or after widespread European settlement in 1850AD. The onset of intensive land use has caused these formerly drier bogs to become much wetter and dominated by Sphagnum. Although initial Maori deforestation had some positive effect on Sphagnum abundance, European burning and grazing, and conversion to pasture has had a more profound effect. These bogs have become wetter despite a trend for declining annual precipitation in the late Holocene. Our conclusion is that neither Sphagnum (nor restiad analogues) are necessary for rapid raised bog growth and that both are greatly encouraged by the removal of bog scrub, fire and grazing. It is therefore possible that these factors have been under appreciated in the northern hemisphere where human impacts have had a much longer story.


0144 The potential of Juniperus procera tree rings to reconstruct Nile river discharge and droughts in Ethiopia Tommy H G Wils1, Iain Robertson1, Zewdu Eshetu2 1

University of Wales Swansea, United Kingdom Ethiopian Institute of Agricultural Research, Ethiopia

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secondary reworking of loess. Human impacts on the landscape and climate shifts, either separately or in combination, are considered to have been the most likely mechanisms that triggered loess erosion. Whatever the process(es) and underlying cause(s), it is evident that significant amounts of soil erosion occurred on the limestone uplands earlier than previously thought.

2

Rainfall over the Ethiopian Highlands is not only essential for agriculture in Ethiopia, but also crucial for irrigated agriculture in the downstream countries of Sudan and Egypt. Adequate water management is fundamental to mitigate droughts and subsequent low river discharges to prevent famines. Although Nile river discharge has been relatively well monitored in Egypt and Sudan during the 20th century, only short and fragmented records of systematically measured discharge, precipitation and temperature exist in Ethiopia. Dendroclimatology provides the potential to extend these records, but is complicated by the tropical climate of Ethiopia. However, Juniperus procera can produce annual growth rings in response to the alternation of wet and dry seasons. Identification of each annual ring boundary and cross-dating are accomplished with innovative strategies. Environmental signals are explored for a number of tree-ring parameters, including ring widths, blue reflectance as a proxy for relative density and stable carbon isotopes. 1403 A preliminary dating study of loessic deposits in northwest England and the implications for Holocene soil erosion Peter Wilson1, Peter J Vincent2, Matt W Telfer3, Tom C Lord4 1

University of Ulster, United Kingdom University of Lancaster, United Kingdom 3 University of Oxford, United Kingdom 4 North Craven Historical Research Group, United Kingdom 2

In northwest England shallow loess deposits occur on outcrops of Carboniferous limestone. More detailed investigation of these materials on the limestone around Morecambe Bay demonstrated similarity to loess deposits elsewhere, and it was thought that the silt derived from deflation of glacigenic sediments in the Bay as Lake District and Irish Sea ice wasted following the Last Glacial Maximum (LGM). In several locations in the region, fine quartz is also included within the matrix of cemented screes below the limestone scars, although there is limited information about its origin and characteristics. The lack of overlying soil cover at one site (Giggleswick Scar), at least, suggests that aeolian processes may be significant in transporting included quartz material to the cement. Initial Optically Stimulated Luminescence (OSL) dates are reported for loessic sediments at three sites and loess incorporated into the cement of cemented scree at two sites from northwest England, as part of an ongoing project to provide a chronology for these sediments. At two sites (New Close and Farleton Fell), the samples recovered from the loessic sediments show multimodal distributions of repeat palaeodose (De) measurements, suggesting considerable post-depositional disturbance of these deposits. The quartz from the calcareous cement of the screes is indicative of multiphase deposition and/or poor resetting of the luminescence signal at the time of inclusion. Notwithstanding the large uncertainties from these methodological difficulties, it remains clear that the depositional ages of all but one of the samples fall entirely within the Holocene period, and indicate a more complex pattern for accumulation of these materials than previously hypothesized. Aeolian reworking, overland flow and subsoil piping on the karstic substrate are possible mechanisms of

0733 Advances in luminescence dating of quartz and feldspar Ann G Wintle University of Wales, Aberystwyth, United Kingdom

Dating sediments using the optically stimulated luminescence (OSL) signal from quartz is now applied widely. The quartz signal has been shown to be made up of several components which vary in strength from sample to sample. The fast OSL component that occurs in many sedimentary grains, particularly those from desert environments, has been studied in detail and is the signal used in the single-aliquot regenerative-dose (SAR) protocol that can be used for an aliquot made up of a few thousand grains or just a single grain. The fast OSL component is almost always the most light-sensitive OSL signal and it is sufficiently thermally stable for it to be used for dating samples back to 0.5 Ma when dose rates are very low (~0.5 Gy/ka). However, the fast component saturates with dose in such a way that for dose rates of ~3 Gy/ka, typical of loess, OSL ages over 100 ka are unlikely to be attainable. In order to use light-sensitive luminescence signals for older dating samples, it has been necessary to extract other signals from either quartz or potassium feldspars. A new signal has been discovered in quartz extracted from Chinese loess. The recuperated OSL (ReOSL) saturates at doses about ten times higher than those obtained for the fast component from the same grains. The ReOSL signal has been shown to be capable of dating the Brunhes-Matuyama boundary. Several other signals, including luminescence emitted at different wavelengths than the blue-UV emission of the OSL, have also been investigated in order to obtain older ages. Luminescence signals from Kfeldspars also have high saturation doses, but as previously found when using their thermoluminescence (TL), dating with either optically- or infrared-stimulated luminescence (IRSL) gives rise to age underestimation of 30% or more. This underestimation has been linked to the loss of signal observed in laboratory experiments known as anomalous fading. However, there is experimental evidence that part of the IRSL signal from K-feldspars is stable. This part of the signal appears to be related to the internal beta dose rate, and an age can be calculated using IRSL signals from grains of different diameter in an isochron method known as iIRSL. This can be used to date grains for which the environmental dose rate is unknown or problematic. Some applications of these new luminescence dating techniques will be presented. 0146 The occurrence and structure of interglacials in the late Quaternary Eric W Wolff1, Hubertus Fischer2, Dieter Lüthi3, Valérie Masson-Delmotte4 1

British Antarctic Survey, United Kingdom Alfred-Wegener-Institute for Polar and Marine Research, Germany 3 University of Bern, Switzerland 4 LSCE, France 2

Although interglacials form cover only around 20% of the time period of the Late Quaternary, they assume a large importance because we are currently in such a period, and there are examples of periods warmer

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than the present, that may be especially relevant for the future. For these reasons we particularly need to understand what determines the natural course of each interglacials. The ice core from Dome C retrieved by the European Project for Ice Coring in Antarctica (EPICA) now extends 800,000 years into the past, including a detailed record of MIS11. Records of Antarctic climate (from water isotopes), atmospheric trace gases, and ionic chemistry (linked to Southern Ocean and southern continental processes) exist along most of the core and, taken together with existing marine and terrestrial data, give us numerous examples of how different environmental parameters react during an interglacial. In this paper, we will compare the response of different interglacials to see whether it is possible to understand the timing of the deglaciation, and the length, amplitude and trajectory of each event. The interglacials before 450 kyr BP are weaker (less warm) than later ones, but they do resemble periods of intermediate warmth that occur later in the record, suggesting that there may not be a step change at 450 kyr, but rather a particular circumstance that has led to a short run of warm interglacials. In this respect, MIS11 can be seen as the last example of a long interglacial, or the first example of a strong one! Closer examination reveals that every interglacial we can observe has significantly different characteristics, and probably a more sophisticated approach, based on an integrated history of forcings and feedbacks, is required to make further progress towards prediction of the natural behaviour in an Interglacial. By making a first compilation of these different Interglacial behaviours, we will assess how different components of the Earth System interact to provide interglacials of the kind we now enjoy. Of course a discussion of the relevance of MIS11 to the Holocene will be a mandatory part of such an analysis. 0200 Late Holocene Lake Diatoms and Climate Variability in the Eastern Mediterranean

Speleothems are widely used archives of palaeoclimate variation and have yielded some remarkable insights into climatic conditions during the Late Quaternary. Compared to other proxy methods, they offer the possibility of furnishing palaeoprecipitation as well as palaeotemperature records and are eminently suited to dating by U-series analysis, a technique which is highly robust for carbonate materials up to ~550 ka in age. Unfortunately, beyond this time their value has been limited by a lack of appropriate chronometers. We have developed a method for precise dating of speleothems beyond the range of the U-Th technique using the U-Pb decay scheme. By coupling low-blank sample preparation procedures and MC-ICPMS analytical methodologies, we find that, under ideal circumstances, U-Pb dating of speleothems is not only possible but also produces excellent age resolution—often comparable to or better than U-series studies. Corrections for initial isotopic disequilibrium, however, remain necessary in most analytical situations and exert a strong control on the achievable age uncertainty. This technique will be of immediate benefit in extending speleothem-based climate proxy records beyond ~550 ka and will also find other uses, such as the dating of associated sub-fossil remains, and providing constraints on rates of landscape evolution and neo-tectonic processes. Examples will be presented from the Nullarbor, Corchia, and elsewhere. Now that detailed chonologies can be established for older spoeleothems, our next goal is to document how well such materals preserve proxy records. To this end, we have developed innovative elemental imaging techniques (by LA-ICPMS) to help distinguish true palaeoclimate signals from alteration and grain-scale effects in speleothem samples. 0161 Mangrove and intertidal foraminifera from tropical North Queensland, Australia: their potential as proxy sea-level indicators

Jessie Woodbridge1, Neil Roberts2

Sarah A Woodroffe1, Scott Smithers2

1

1

2

2

The eastern Mediterranean is a climatically-sensitive area for which high-resolution proxy records of climate change are limited. The aim of this research is to contribute towards understanding the nature and causes of temporal climate variability in the eastern Mediterranean region. Nar Gölü is a non-outlet, stratified, weakly brackish volcanic crater lake located in the Cappadocia region of central Turkey. Lake diatoms from this site are being utilized as a proxy for salinity and climate from a continuously varved late-Holocene record. Preliminary diatom counts reveal that the chemistry of Nar Gölü has fluctuated throughout the previous 2000 years, with four distinct zones recognised in the diatom species composition throughout the sequence. Work involves applying a transfer function to the diatom data, making comparisons with other proxy data from this sequence, and calibrating diatom-inferred changes against local 70-year long meteorological observations, in order to make inferences regarding pre-instrumental climatic variability.

Using foraminifera as sea-level indicators rests on the assumption that their distribution is related to sea level in a quantifiable manner and by establishing this vertical relationship with a specified tide level, former positions of relative sea-level may be determined. In temperate areas agglutinated upper intertidal (salt marsh) foraminifera are well preserved in fossil sediments. Therefore relatively precise quantitative sea-level reconstructions are possible using modern training sets which cover short elevation gradients excluding calcareous assemblages from low intertidal and subtidal environments. However sediment cores taken from mangrove and intertidal mud in Cleveland Bay in north Queensland, Australia to quantitatively reconstruct mid/late Holocene sea-level changes contain calcareous foraminifera in minerogenic (muddy) horizons but no foraminifera in organic (mangrove) horizons. The reason for this is unknown, but may to be due to a series of interrelated factors including burrowing by fiddler crabs and molluscs, increased air and water temperature, biological turnover and predation in tropical mangrove environments. Where agglutinated foraminifera are preserved in fossil mangrove sediments they have the capacity to provide accurate and precise sealevel reconstructions. Unfortunately in this location calcareous foraminifera are the only tool available to reconstruct sea level. A transfer function developed solely using calcareous foraminifera from MTL to 5.3 m below LAT has good predictive ability, with an r2 of 0.96 and RMSEP of 0.43 m. The error term is large compared to studies using agglutinated foraminifera and a short environmental gradient, but the

University of Plymouth, United Kingdom University of Plymouth / Stanford University, United States

0395 Refining the speleothem record: new chronology and imaging methods Jon D Woodhead1, John Hellstrom1, Russell Drysdale2, Roland Maas1, Giovanni Zanchetta3 1

School of Earth Sciences, The University of Melbourne, Australia School of Environmental and Life Sciences, University of Newcastle, Australia 3 Dipartimento di Scienze della Terra, Universita degli studi di Pisa, Italy 2

Department of Geography, Durham University, United Kingdom Department of Earth Sciences, James Cook University, Townsville, Australia


error term compares favourably to the errors associated with other indicators such as coral, mangrove sediments and fossil oyster beds, also used as palaeo sea-level indicators along this coastline. 0163 Modern salt marsh environments in Greenland and their potential in sea-level reconstructions Sarah A Woodroffe1, Antony J Long1, Leanne Wake1, Melanie Leng2 1

Department of Geography, University of Durham, United Kingdom NERC Isotope Geosciences Laboratory, Keyworth, Nottingham, United Kingdom 2

This study is a first attempt to characterise the sedimentary, microfossil and isotopic characteristics of contemporary salt marshes in West Greenland, with the intention of creating modern training sets to aid in reconstructing relative sea-level change over recent centuries. Relative sea-level is rising quickly in Greenland (up to 5 mm yr), which means salt marsh sediments are eroded and buried over time, and modern salt marsh sediments only record recent sea-level changes. Active saltmarsh processes include frost heave, ice berg scour, and extensive frost-shattering of local bedrock. High temporal and height resolution saltmarsh studies in other temperate areas combine well-developed modern and fossil datasets of foraminifera and/or diatoms as well as other biological and sedimentological data to reconstruct past sea levels. Preliminary analysis of foraminifera shows assemblages in studied West Greenland salt marshes are dominated by a monospecific assemblage of Jadammina macrescens, while diatom assemblages have much higher species diversity, with ~40 different species found in high numbers across the marshes. Salt marsh plant communities are similar to those in other temperate areas, with Puccinnellia maritima and Carex rariflora dominating the low and upper marshes. Stable carbon isotope concentrations may provide an additional proxy for tidal inundation which can add to the environmental information available to reconstruct sealevel changes. No quantitiatve reconstructions of contemporary or fossil foraminifera, diatom or isotope records from salt marsh material have been attempted in Greenland to date. Our initial investigations show the potential value of diatoms in reconstructing changes in sea level, with foraminifera and isotopes as complimentary techniques to assist in defining late Holocene sea-level index points. 0525 Chironomid-based temperature reconstructions spanning the last glacial - interglacial transition (LGIT) from southern New Zealand Craig A Woodward1, Nicki J Whitehouse1, Jamie P Shulmeister2, Paula J Reimer1 1

Centre for Chronology, Environment and Climate (14CHRONO), Queen’s University Belfast, United Kingdom 2 Department of Geological and Nuclear Sciences, University of Canterbury, New Zealand

The recovery of the Earth’s climate from the grip of the last ice-age was interrupted by a series of millennial scale climatic variations. The most significant and widely studied of these variations is a return to full glacial climate conditions in the Northern Hemisphere between 12.7 and 11.6 ka. The Younger Dryas climate reversal has been reported from many terrestrial, ice, and marine records of the last glacial-interglacial transition (LGIT) from the Northern Hemisphere.

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Ice-core records from Antarctica, in contrast, indicate that whilst a climate reversal did occur in the Southern Hemisphere during the LGIT, it began before the Younger Dryas and temperatures did not return to full glacial conditions. Recent research efforts have focused on obtaining precisely dated records of climate change from the Southern Hemisphere spanning the LGIT. A reasonable global coverage of paleoclimate records is required to be able to determine the drivers of abrupt climate change and to adequately model the response of the global climate system to such perturbations. New Zealand, located in the southwest Pacific, is an ideal location to examine climate change during the LGIT in the Southern mid-latitudes. We present chironomid-based temperature reconstructions spanning ca. 17 – 10 ka BP from Lake Hawdon, located to the east of the Southern Alps in the South Island, New Zealand. Chironomid-based February mean air temperature reconstructions indicate an Antarctic-like signal with a maximum cooling of 3 ºC occurring between 14 and 12.4 ka BP, timed before the Northern Hemisphere Younger Dryas event. Chironomid-inferred temperatures and the presence of pollen from lowland podocarps suggest warm, wet conditions just prior to the climate reversal in New Zealand. We also present preliminary chironomid-based temperature reconstructions and pollen data from Cobb Valley, situated in the north-west of the South Island, New Zealand. The comparison of these records with other published proxy records from this region and period allows us to evaluate the apparent (a) synchroneity of abrupt climatic events in this region and their significance to our understanding of inter-hemispheric climate change. 0996 A comparison of beetle and chironomid-based temperature reconstructions from New Zealand spanning 23,000–27,000 cal yr BP Craig A Woodward1, Maureen J Marra2, Philip I Burge3 1

Centre for Chronology, Environment and Climate (14CHRONO), Queens University Belfast, United Kingdom 2 Landcare Research, New Zealand 3 Department of Geological Sciences, University of Canterbury, New Zealand

Over the last six years there have been major developments in Quaternary entomology in New Zealand. Maximum likelihood envelope (MLE) based techniques have been used to reconstruct summer and winter air temperatures from fossil beetle assemblages from several sites spanning the last 200,000 years. Chironomid-based transferfunctions have recently been created and also allow the reconstruction of summer air temperatures. Statistical tests show a good fit of the maximum likelihood envelopes for individual New Zealand beetle taxa for winter temperatures, but suggest that other factors, such as precipitation could be affecting the response of the New Zealand beetles to summer temperature. We compare three beetle-based summer air temperature records from the South Island of New Zealand with chironomid-based summer air temperature reconstructions spanning the marine isotope stage (MIS) 2/3 boundary (ca 23–27 ka BP). Reconstructed summer temperatures are comparable for both proxies based on the known beetle distribution, but the MLE technique suggests that summer temperatures may have been 1 ºC cooler than the chironomid-based temperatures. We also discuss possible directions for future research that will improve our understanding of the response of beetles and chironomids to environmental change.

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0963 Environmental luminescence: application to reconstruct the impact of bushfires on landscape development in the Australian Capital Territory Martin Worthy1, Ed Rhodes2 1

Centre for Resource and Environmental Studies, Australian National University, ACT 0200CRC LEME, Australia 2 Research School of Earth Sciences and Research School of Pacific and Asian Studies, Australian National University, ACT 0200, Australia

During early 2003, a series of fires burnt approximately 3,000,000 ha of land in southeast Australia. Following these fires, rainfall events washed sediment from stores across the landscape, in particular the Cotter River catchment in the ACT. As fire is not uncommon in this region, the massive volume of material redistributed in the montane Cotter River catchment following the fires has raised several questions, in particular how important is fire in controlling landscape development? The potential of fire as a geomorphic agent is receiving much global attention. During fire events, much, if not all, of the groundstabilizing vegetation is consumed. Characteristic changes also occur within the top few centimetres of the soil profile. These two effects combine to increase runoff during rainfall and therefore sediment erosion potential. However, the understanding of the impact of fire on landscape development and the history of these processes has been less well studied. Understanding this is often complex. Overbank flood deposits are typical of many fluvial systems, and it is often difficult to relate deposition directly to burning. Post depositional bioturbation can mask fine scale sedimentary structures, making it tricky to determine whether the profile accumulated gradually or rapidly. In order to understand the late Holocene sedimentary history of the Cotter River, the complete sedimentary profile of a 1m floodplain succession was sampled for OSL. We have used single grain OSL determinations to construct an age model for deposition using contiguous 3cm spits. The variation of single grain dose distribution down the profile also provides insight into the transport and deposition history of the sediment. While not every sample is equal in depositional age uncertainty, poorly zeroed samples with larger dating errors constrain transport history mechanisms. This also highlights the limitations of constructing age models with a much more limited sample set. Sensitivity variations of OSL and TL signals have the potential to identify grains that have been subjected to intense heating, and we find considerable variation down this profile. Using these observations, we present a provisional model for burning, erosion, transport and deposition events within this catchment. This project illustrates that the appropriate application of luminescence methods can deliver much more information beyond a robust depositional age model. 0824 Water depth related distribution of recent ostracodes in Lake Nam Co, Southern Tibet Claudia Wrozyna1, Peter Frenzel2, Philip Steeb1, Liping Zhu3, Antje Schwalb1 1

Technische Universität Braunschweig, Germany Friedrich-Schiller-Universität Jena, Germany 3 Institut of Tibetan Plateau Research, China 2

A pilot study tested the relationship between water depth and species assemblages of ostracodes from Lake Nam Co with the ultimate goal to reconstruct lake level changes as expression of changes in Monsoon dynamics using sediment cores. Ostracode species assemblages and

intraspecific morphological variability and geochemical analysis of shell chemistry may provide information on past lake levels, salinity and water chemistry, temperature, habitat structure, oxygen concentration, biological productivity and other environmental factors. Because little is known about the ecology of Tibetan Plateau ostracode species, we studied the depth distribution of ostracodes in Lake Nam Co, the second largest saline lake on the Tibetan Plateau at an altitude of 4718 m a.s.l. Fifteen surface sediment samples were retrieved along a depth transect ranging between 2 m and 53 m in Nam Co, and an additional nine samples were taken from small water bodies in the vicinity of the lake. All lake samples yielded high ostracode abundances of up to about 300 valves per g sediment, but showed low species diversity. The four dominating species belong to the genera Fabaeformiscandona, Ilyocypris and Leucocythere. The abundant Leucocythere dorsotuberosa Huang, 1982 shows a high morphological variability in forming prominent external ribs in the posterior, ventro-areal and antero-dorsal area of the valve as well as different forms of nodes. The proportion of rib bearing valves in L. dorsotuberosa increases slightly with greater water depths. Leucocythere sp. shows a dominance of 80 % and more within the ostracode assemblage in shallow water above 25 m depth. Below 25 m, the dominance of this species drops to about 50 % and Leucocythere dorsotuberosa, which is not present in shallow water, is frequent reaching up to 60 %. The change in proportions traces the depth position of the thermocline at about 20 m to 30 m water depth. This pattern is partly hidden by subfossil taphocoenoses between 5 m and 15 m water depth. Our results show that the depth distribution of ostracode assemblages may provide a tool for reconstructing past lake levels and also thermocline positions from subfossil and fossil species assemblages separated from Nam Co sediment cores. This is a contribution to the research program ‘The Tibetan Plateau – Geodynamics and Environmental Evolution’ within the framework of a Sino-German co-operation. 0635 Environmental evolution and tectonic events from sedimentary cores in the Tibetan Plateau during the last 2.8 Ma Jinglu Wu, Sumin Wang Nanjing Institute of Geography and Limnology, CAS, China

The Tibetan Plateau plays an important role in determining regional climate patterns in East and South Asia, as well as the general atmospheric circulation of the Northern Hemisphere. To clarify the impact of Tibetan Plateau uplift on regional environmental evolution and climatic changes, a 120-m-depth core RH dated 0.8 Ma BP and a 310-mdepth core RM dated 90 Ma BP were drilled from Zoige basion in eastern Tibetan Plateau in 1992 and 1993 respectively. Following the two cores, in 1999, 200 m-depth core CE dated to 2.8 MaBP was obtained from Cuoe basin in centeral Tibetan Plateau. This paper summarises the nature of environmental changes and Tibetan uplifts from the drilling cores and from cores in adjacent areas. The sedimentary facies change from the cores help to provide estimates of the nature of Tibetan uplift. Environmental proxies, such as d18O and d13C in carbonate, d13C in organic matter, pollen and magnetic susceptibility are used to reconstruct climatic environmental sequences. Weathering characteristics, abrupt lithologic changes and dating strata indicate that there are two intensive uplifts of the Tibetan Plateau during the last 2.8 Ma. The first occurred at ca. 2.8 Ma BP evidenced from lacustrine sediments directly overlying detrital deposits in CE core and its adjacent cores. The second happened at ca. 0.8 Ma BP recorded by cores RM, RH and CE. The evidence from core CE displays that at ca. 0.8


Ma BP lacustrine sediments were disappeared and there was not any deposited materials until ca. 0.4 Ma BP when detrital materials began to be deposited. Meanwhile, after ca. 0.8 Ma BP the sedimentation rates from cores RH and RM appeared great difference, which represented inhomogeneous response to tectonic effects between northern and southern zoige basin due to different geological units. About 0.4 MaBP, although there was not obvious lithologic difference in both cores RH and RM, environmental proxies of d18O and d13C in carbonate, d13C in organic matter indicated obvious changes. The environmental event is different from the previous two tectonic events, which directly resulted from the Tibetan uplifts. This is under investigation whether the event has a certain relationship with the uplift of the Tibetan Plateau or the uplift of the Tibetan Plateau directly ignited the global climatic event. After 0.4 MaBP the trend of climatic change on the Tibetan Plateau was colder and drier.The research was supported by National Basic Research Program of China (2005CB422000). 0281 Climatic conditions recorded by terrestrial mollusk assemblages in the Loess Plateau during marine oxygen isotope stages 12–10 Naiqin Wu1, Xiaoyun Chen1, D D Rousseau2, Fengjiang Li1, Yunpeng Pei1, Bin Wu1 1

Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, P. R. China, China 2 Institut des Sciences de l’Evolution, UMR CNRS 5554, Universite Montpellier, France, France

Past analogues for our present interglacial have been sought in order to better understand our present and future climate. Marine Isotope Stage 11 (MIS 11) has long been considered to be a good candidate and gained more and more attentions in recent studies of marine and terrestrial records. In the Chinese loess-paleosol sequences, S4 soil, the equivalent to MIS 11, is one of best terrestrial paleoclimate records of environmental changes during this period. In this study, two high-resolution terrestrial mollusk records from the Loess Plateau have been studied to characterize climate variability during the periods of MIS 12-10. The processes of ecological and climate changes, as indicated by the variations in abundance of land mollusk species, have been documented in the loess and paleosol sequences during this period. Our mollusk results show that the L5 loess, the equivalent to MIS 12, was formed under relative cold and dry conditions. Climate at this period was not so severe as indicated in marine isotopic record. An episode of warmer and humid condition occurred at the middle time of the MIS 12, reflecting a summer monsoon strengthened during the glacial interval. The same scenario was seen in the middle part of the MIS 10. Our mollusk records also provide insight into the climate conditions of the Loess Plateau during the MIS 11. A general warm- humid climate dominated during the formation of S4 soil. But at least four fluctuations happened at Xifeng region, reflecting an unstable climate condition and regional climate difference in the Loess Plateau during this period. Our study shows that the early part of S4 formation spanning over 30 ka was very warm-humid climate condition, being a unique long interglacial during the Quaternary climate history. While the late part was characterized by mild-cool conditions in the Loess Plateau. Comparison of the MIS 11 and the Holocene climates based on mollusk species compositions reveals different climate conditions. The early part of MIS 11 was warmer and more humid than the Holocene optimum period, but similar or cooler in the late part of MIS 11. Our study indicates that the extent of warming at present day might be far less than the condition of the MIS 11 Interglacial period.

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0403 Holocene climate change in the Central Tibetan Plateau inferred by lacustrine sediment geochemical records Yanhong Wu1, Andreas Lücke2, Bernd Wünnemann3, Sumin Wang1, Shijie Li1 1

Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China 2 Institute of Chemistry and Dynamics of the Geosphere V: Sedimentary Systems, Research Centre Jülich, Germany 3 Interdisciplinary Centre Ecosystem Dynamics in Central Asia, Freie Universitaet Berlin, Germany

Multi-proxies of lacustrine sediments, such as total carbon (TC), total organic carbon (TOC), total inorganic carbon (TIC), total nitrogen (TN), total sulfur (TS), hydrogen index (HI), oxygen index (OI) and stable carbon isotopic composition of organic matter (d13Corg), were analyzed using a 7.3 m core from Zigê Tangco. The source of the organic matter in the sediment was mainly from autochthonous phytoplankton, therefore the significances of proxies can be interpreted as that high TOC, TOC/TS, HI and d13Corg values, low TC, TIC values corresponded to warm and wet climatic condition, and vice versa. The process of climatic development in the Zigê Tangco region was hence recovered. During the early and Mid-Holocene, the climate was warm and wet and intensive cold events occurred during the periods of 8600 to 8400 cal a BP and 7400 to 7000 cal a BP. In the second half of Holocene, the climate became cold and dry gradually. The palaeoclimatic process during Holocene in Zigê Tangco region matched well with that in Co Ngoin region which is ca 40 km to the south-east. Therefore this palaeoclimatic process represents the Holocene climatic feature in the Central Tibetan Plateau which has the same pattern in the Northern Tibetan Plateau, but the time and duration of some climatic events might be different. We can conclude that in Holocene solar insolation controlled the climatic pattern and the different monsoon system resulted in the time and duration differences of climatic events on the Tibetan Plateau. 0572 Reservoir age in the central Tibetan Plateau: A case study in Co Ngoin and Zigê Tangco Yanhong Wu1, Liping Zhou2, Andreas Lücke3, Bernd Wünemann4, Sumin Wang1, Shijie Li1 1

Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China 2 College of Environmental Sciences, Beijing University, China 3 Institute of Chemistry and Dynamics of the Geosphere V: Sedimentary Systems, Research Centre Jülich, Germany 4 Interdisciplinary Centre Ecosystem Dynamics in Central Asia, Freie Universitaet Berlin, China

Lake sediments, which preserve abundant, continuous and high resolved signals, have the potential to recover the history of terrestrial environmental variations. The value of such paleo-environment signals depends on tying them to accurate and precise chronologies. Radiocarbon dating techniques allow lake sediments to be traced back approximately 30 to 40 ka. However, precision of radiocarbon chronology depends on several factors, among which reservoir effect is the major one. Our knowledge of paleo-reservoir ages is still very limited. A series of 14C ages were determined in two lake sediment cores from Co Ngoin and Zigê Tangco, central Tibetan Plateau, China, using

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materials of bulk organic carbon, plant remains, chitins of cladocera and carbonates. The old 14C ages of the surface sediments in both cores suggested that significant reservoir effect occurred in the lakes on the central Tibetan Plateau. The magnitude of reservoir age for 14C age of different material is variable. The authigenic carbonate has the larger reservoir age than other materials. Even in the same region like the central Tibetan Plateau, the reservoir ages are different in different lake and in the same lake the paleo-reservoir ages were temporal variable. We suggest using the approach of regression to obtain the approximate reservoir correction for 14C age of bulk organic matter, which is 3260 yrs and 2010 yrs for Co Ngoin or Zigê Tangco respectively. 0222 Late Glacial tropical savannas in Sundaland inferred from stable carbon isotope records of cave guano Christopher M Wurster1, Michael I Bird1, Ian D Bull2, Charlotte Bryant3, Chris Hunt4, Helen A Lewis5, Victor Paz6 1

University of St Andrews, United Kingdom University of Bristol, United Kingdom 3 NERC Radiocarbon Laboratory, East Kilbride, United Kingdom 4 The Queen’s University of Belfast, United Kingdom 5 University of Oxford, United Kingdom 6 Univeristy of the Philippines, Philippines 2

During the Last Glacial Period (LGP), reduced global sea level exposed the continental shelf south of Thailand to Sumatra, Java, and Borneo, resulting in the exposure of the contiguous continent of Sundaland. It remains unclear, however, whether tropical savanna or rainforest existed on this exposed landmass at this time. Extensive bird and bat guano deposits in caves throughout this region span beyond 40,000 yr BP, and contain a wealth of palaeoenvironmental information that provides insight into the local vegetation history. Stable carbon isotope values of insectivorous bird and bat guano contain a reliable record of their diet, and ultimately archive total terrestrial carbon isotope discrimination. Various physiological pathways of carbon fixation in plants yield differing stable carbon isotope ratios. Through non-specific insect predation, stable carbon isotope ratios of bird and bat guano reflect the relative abundance of major physiological pathways in plants. Stable carbon isotope values of C3 plants are lower than C4 vegetation due to different enzymatic discriminations of the heavy isotope through the carbon fixing pathways. In tropical locales, grasses nearly always follow the C4 photosynthetic pathway, whereas tropical rainforest uses C3 photosynthesis. Here we discuss three guano records that document that substantial areas of open (C4-containing) vegetation were present during the LGP via stable carbon isotope ratios of bulk guano and various organic isolates, supplemented by pollen analysis. Specifically, all sites show a C3 dominated ecosystem for the Holocene; however, two sites from Palawan, Philippines, record stable carbon isotope values of guano that document a drastic change from C3 (forest) to C4 (savanna) dominated ecosystems during the LGP. A third location, at Niah Great Cave, Malaysia, remained C3 dominated throughout the record, but does display variation in stable carbon isotope values likely linked to humidity changes. Savannas were possibly given competitive advantage over rainforest due to edaphic factors in the exposed Sundaland area as well as a reduction in rainfall. Currently, different vegetation models disagree as to the nature of vegetation during the Last Glacial Maximum LGM (LGM). Our results reveal important baseline information on carbon cycling and storage in Sundaland during the LGM. Additional cave guano sites will provide further constraints for the carbon budget at the LGM.

1211 Stratigraphy and sedimentology of the longest terrestrial record in NE-Australia: Lynch’s Crater Raphael Wust1, Peter Kershaw2, Uwe Rieser3, Geraldine Jacobsen4, Alan Deino5 1

James Cook University, Australia Monash University, Australia 3 Victoria University Wellington, New Zealand 4 ANSTO, Australia 5 Berkeley Geochronology Center, United States 2

Lynch’s Crater on the Atherton Tablelands in NE-Australia, formed some >200,000 years ago during an explosive eruption of basaltic material creating a maar more than 80 m deep. The crater walls are highly weathered and are blanketed by thick (>2 m) sequences of laterites that contain slates and other metasedimentary rocks (up to boulder size) and various types of volcanic rock fragments. Since the eruption, the maar has been filled with lake sediments that are topped by peat material and the recovered core was 64 m long. The basal sediments below 62.75 m are composed of massive grey silty-sandy clays with abundant rock fragments including basalts, vein quartz and other quartz-rich metasediments. The subsequent 50 m thick lake sediments are composed of massive and laminated sediments. The bottom lake sediments have frequent thick (up to > 2 cm) turbidite sequences while the top sediments have only few thin (max few mm) clay-rich turbidite deposits. Beside the turbidite layers, the lake sediments are either massive or laminated. Most of the sediments in particular in the upper 30 m are laminated. The varves are chemical varves with various colours from dark green, dark blue (vivianite) to black. The top 13–16 m (depending on the location in the crater) are composed of mainly minerotrophic peats and represent the past 60 ka. Geochemical analysis shows that Heinrich and Dangaard-Oeschger events can be detected. Here we present in detail stratigraphic and geochemical changes and present evidence for environmental changes of the entire core. The geochronology is based on C14 AMS, OSL and Ar-Ar dates. 1166 Low latitude moisture regime changes over the last 14,000 years recorded by diatomaceous sediments from dry tropical Australia Raphael A Wust1, Aldo Shemesh2, Peter Ridd1, Jon Stephenson1, Geraldine Jacobsen3, Andrew Smith3 1

James Cook University, Australia Weizmann Institute, Israel 3 ANSTO, Australia 2

A diatomaceous sediment deposit from Long Pocket, NE Queensland, Australia, provides new evidence for rapid climatic changes. Here we present a rare sediment record from the dry tropics that spans the last ~14,000 cal yrs. The 5.5 m thick deposit is composed of purely diatomaceous debris with little atmospheric influx. The site is unique as a basaltic flow isolated and formed the area ~13,600 cal yrs BP. Geochemical data and isotope analysis of the diatoms reveal that primary productivity was high during the onset of the deposit with little changes until the mid Holocene, when abrupt moisture regime changes occurred ~6000 years ago. Oxygen isotope data of the diatoms indicates further that changes in moisture source took place progressively. However, trace elemental data shows that marked changes in atmospheric flux composition occurred ~3800 yrs BP, most likely representing the timing of the onset (strengthening) of the monsoon system. Interestingly, the timing of some of the changes expressed in our record by the


geochemical data coincides with Bond-cycles described from the North Atlantic. With our data, we hypothesise that the monsoon system was ineffective for latitudes 17º S during the early Holocene and that moisture was primarily derived from short range trajectories, such as the Coral Sea. Around ~3800 yrs BP abrupt climate changes led to the present system that is dominated by a wet summer monsoon. Our record shows that the dry tropics received more precipitation during the late Pleistocene and early Holocene than during the late Holocene. These findings are similar to findings from the wet tropical NE-Australia. However, our record shows a marked collapse of the ocean/atmospheric system in the low latitudes and possibly an intensification of ENSO during the latter part of the Holocene. 0871 Model sensitivity of the Australian summer monsoon to Milankovitch variations 1

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Karl-Heinz Wyrwoll , Zhengyu Liu , Guangshan Chen , John E Kutzbach2, Xiaodong Liu3

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from sites from the West (i.e. Tarim basin and Junggar basin) and the North (i.e. Alxa plateau, Erdos plateau and Monlia plateau). However, when other magnetic parameters, i.e. fd%,arm,arm/SIRM,arm/lf and HIRM, are compared it is found that samples from the West generally have lower values. The samples from the West are dominated by magnetic minerals with lager grain size while that from the North are dominated by fine magnetic minerals. The similarity in magnetic mineral constitutions between the Chinese loess and the surface soils from the Central Asia imply that the loess originate from a vast area of arid, semi-arid region of the Central Asia. The low value of concentrationdependent magnetic parameters indicate that the low concentration of magnetic minerals in the surface soils from the Central Asia and the magnetic enhancement from the pedogenic take place both in the loess and the paleosols, although the progress is more stronger in the later than that in the former. 0399 Timing and style of Quaternary glaciations in the Shaluli Mountains, southeastern Tibetan Plateau

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The University of Western Australia, Australia University of Wisconsin-Madison, United States 3 Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, China 2

Liubing Xu1, Shangzhe Zhou2 1

South China Normal University, China Member of subcommission of Glaiation, INQUA, China

2

The paper will present the background and results of work that considered the response of the Australian summer monsoon to orbital forcing using a coupled General Circulation Model. It was found that unlike the Northern Hemisphere monsoons, which are dominated by precession forcing, the Australian monsoon can be enhanced significantly not only by precession forcing, but also by tilt forcing coupled to oceanic feedback. The new insights obtained from a series of experiments with differing tilt-precession configurations allow an interpretation of the Australian Late Quaternary monsoon record in which insolation forcing plays a significant role. 0167 Magnetic signatures of surface soil in arid central Asia and its environmental significance DS Xia1, FH Chen2, J Bloemendal3, JY Ma1, XM Liu2, HT Wei2 1

Key Laboratory of Desert and Desertification, Institute of Cold and Arid Regions Environmental and Engineering,CAS, China 2 Key Laboratory of West China’s Environmental System, Lanzhou University, China 3 Department of Geography, University of Liverpool, United Kingdom

Chinese loess and dust records have played an important role in understanding the evolution of Asia Monson, the uplift of Tibet plateau and the development of arid region. Magnetic susceptibility as one of main environmental magnetic parameters has been used as one of the most vital proxies for climate reconstruction in the Chinese loess studies. Progress has been made in using environmental magnetism to reconstruct climate change and environment records in Chinese loess studies, whereas there are still some issues not well understood. In this study, magnetic techniques were used to characterize the surface soil from different geomorphology (i.e. sand desert, oasis, Gobi and dry lake) in the Northwest China and Mongolia. Results demonstrate that the main magnetic minerals in the surface soil are magnetite, maghaemite and haematite with some paramagnetic material. Cross plots of Mrs/Ms vs. Bcr/Bc and fd% vs. arm/SIRM indicate that the main magnetic grain sizes in surface soil are pseudo single domain (PSD) and multidomain (MD). No significant difference is found in magnetic parameters, such as lf, SIRM, SOFT and SIRM/lf for surface soils

The Shaluli Mountains, a tectonically controlled mountain range between the Jinsha and Yalong River Rifts, is located in the southeastern Tibetan Plateau. In the central Shaluli Mountains, a huge ice cap up to ~3600 km2 once developed on the Haizi Shan. Abundant glacial landforms are present on the Haizi Shan and in the surrounding river valleys, and together with the outwash terraces in the Yazheku River on the northeastern margin of the Haizi Shan provide an ideal site to examine the Quaternary glacial history of the region. Sedimentological and morphostratigraphical analysis, field mapping, and electron spin resonance (ESR) dating define at least seven major glacial advances in the Haizi Shan area. Six major glacier advances, probably occurring during MIS-16, MIS-14/12, MIS-6, MIS-3, early MIS-2, and the global LGM, can be identified based on ESR dating and stratigraphical analysis of the glacial landforms in front of the Kuzhaori glacial trough on the southern slope of the Haizi Shan. The outwash terraces in the Yazheku River also record four major glacier advances, which occurred during MIS-16, MIS-12, MIS-6, and MIS-2. In addition, the moraines preserved on the southwestern side of the Haizi Shan suggest a glacier advance likely occurring during the Lateglacial. The extent of these glaciations on the Haizi Shan decreases with time. 0599 Paleofires and the Dynamics of Carbon Cycling in Chinese Loess Plateau Over the Last Two Glacial Cycles Xu Wang1, Zhongli Ding1, Ping’an Peng2 1

Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China, China 2 Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China, China

The spatial and temporal changes in trace gas emissions (CO2,CO and CH4) and burnt biomass by paleofires in Chinese Loess Plateau over the last two glacial cycles have been reconstructed using vegetation (C3/C4) specific fire emission factors and black carbon records in three loess-paleosol sections. Results show that during the glacial periods the average mass emission rate (MER) of total trace gases (TTG, including CO2, CO and CH4) released by biomass burning is about

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44.4~48.5 g C/m2/yr at Lijiayuan, and about 21.3~25.8 g C/m2/yr at Lingtai and Weinan, showing a clear southward decrease, whereas the average MERs of TTG (TGG-AMER) in interglacial periods is generally 1~2 times lower than in the glacial periods with about 16.6~18.3 g C/m2/yr at Lijiayuan and about 8.8~15.7 g C/m2/yr at Lingtai and Weinan. Moreover, the burnt biomass by fires (BBF) during glacial periods is about 92.7~101.5 g dm (dry matter)/m2/yr at Lijiayuan and about 40.8~50.0 g dm/m2/yr at Lingtai and Weinan; by contrast, the BBF in interglacial periods is about 33.8~37.7 g dm/m2/yr at Lijiayuan and about 16.5~29.7 g dm/m2/yr at Lingtai and Weinan. Obviously, the BBF displays the same spatiotemporal patterns as the TTG-AMER does during both glacial and interglacial periods. This pattern reflects the combined control by climate-induced fire regimes and succession of vegetation types. At Lingtai and Weinan, the average MERs of TTG in late Holocene is respectively 41.6 and 10.2 g C/m2/yr, apparently higher than those in early Holocene (e.g. 30.5 and 6.4 g C/m2/yr). The substantial increases in TTG-AMER are consistent with the increased anthropogenic fire activities occurred in middle and southern Plateau during late Holocene. To assess the influence of paleofires on soil carbon stocks, the ratios of BBF to above-ground net primary productivity (ANPP), estimated by magnetic susceptibility-based paleorainfall reconstruction, were calculated. In the northern Plateau, the BBF/ ANPP ratios during glacial periods are nearly 90%, about 2~3 times higher than during interglacial periods, suggesting paleofires may be the overwhelming force modulating the cycling of terrestrial organic carbon in the region. However, in middle and southern Plateau, the large decrease in BBF/ANPP ratios to around 20% and 10% respectively during glacial and Interglacial periods suggests that paleofires have had a minor impact on carbon storage in these areas during both glacial and interglacial periods. 0179 Environmental Changes of Large Lakes along Middle-Lower Reach of Yangtze River during the Past Century as Recorded in the Sediment Cores Bin Xue, Shuchun Yao, Sumin Wang Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China

Yangtze River basin has a very long history of human activities. Abundant large and shallow fresh-water lakes are located along middle and lower reach of the River, which the environmental changes are not only driven by a variety of natural forces but also by human impact. The interaction of these forces induces complex processes with profound and sometimes unpredictable effects on the environmental system. The environmental change can be reconstructed from natural archives, e.g. lake sediments. Two large lakes, i.e. Lake Taihu and lake Honghu, have been selected for understanding the environmental changes during the past century. Methods involve analysis of dating control and chemical components of the lake sediments. Lake Taihu, the third largest fresh-water lake in China (2339 km2), in the lower reach of Yangtze Valley and most advanced economic zone in China, has suffered from ecological destruction and eutrophication seriously. The quality of lake water has degraded 2–3 levels from 1970 to 1990’s. The onset of accelerated eutrophication was concluded to be 1980’s based on pigment and element analysis. Nutrient enrichment and metal pollution were also observed in sediment cores. Such process was thought to be associated with human activities around and in the lake. Population increase, economic development, urbanization and land use were attributed to the environment change.

Lake Honghu is located in the middle-reach of the Yangtze Valley, China. It has a history of flood control, impoldering and industry activities. Much of the anthropogenic influence has mainly occurred during the 20th century, although early signals of enhanced human activities could be traced to the cold Little Glacial period. The Honghu Lake covered an area about 760 km2 in the early 1950’s. Reclamation work in the 1960’s and 1970’s around the lake reduced the surface area to 350 km2 in 1979. Since 1950’s nutrient enrichment appeared apparently from several sediment cores. The accumulation of these nutrients is considered to be the discharge of sewage water from multiple sources and cultivation of the lake. The heavy metal concentrations analysis means that natural processes was not the unique origin of Pb between the 1980s and 2000s. Furthermore, comparison work has been done towards the palaeoenvironment change and anthropogenic process between the two lakes. 0310 The Lake Status Change of China since LGM and its Significance for Palaeoclimate Bin Xue, Ge Yu Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China

The 42 lakes compiled in the Chinese Lake Status Data Base (CLSDB), has provided the information of the spatial changes of lake status for each one-thousand year, which can be purposed for research on the atmospheric circulation changes of Chinese region since LGM. The results have shown that, the relatively wet conditions of western China from LGM to Mid-Holocene was probably related to the precipitation brought by the westlies and the low evaporation in Glacial period, and summer monsoon precipitation in Holocene. And the climate turned drier since late-Holocene. Most area in eastern China during LGM and late-Glacial was relatively dry, and turned wetter in Holocene. The summer monsoon precipitation during Mid-Holocene might reach the whole western China. In Eastern China, there exists the diachronity for the maximum effective precipitation from north to south during Holocene, occurring during late-Holocene in south china. The wet condition of southwestern China occurred clearly in late-Glacial, which is earlier than in southeast China, suggesting that a balance occurred between these two monsoon systems. The earlier occurrence of wet conditions in northeast China suggests an independent monsoon systems in this area. 0411 Preliminary study of deposition pattern of Gucheng Lake at Jiangshu during Holocene Shuchun Yao, Bin Xue, Xiaoling Wang Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China

Gucheng Lake is a relatively small, and shallow water body located in Nanjing, Jiangsu Province, China. The lake is on the lower reach of the Yangtze Valley. The lake has a triangle shape. The site is exposed to wet monsoon. Rainfall is moderately high, with a mean of1105 mm/a. Mean annual temperature is 15.5 ºC. Historically, Gucheng Lake was linked to or isolated from Lake Taihu due to human activities such as establishment or destruction of dam. And this region has suffered from frequent reclamation work since 500 BC. The total


surface area of Gucheng Lake was about 65 km2 in the early 1960s, but the subsequent reclamation work in the 1960’s and 1980’s around the lake caused the continual shrinkage of the surface area of the lake to 24.5 km2. In order to understand the sediment deposition pattern and human activities, sedimentary cores were collected from Gucheng Lake in 2005. 210Pb, 137Cs, 14C and OSL were analyzed to study chronology of Gucheng Lake during Holocene. The total organic carbon (TOC), total nitrogen (TN), elements and particle size were also analyzed. Results of 210Pb, 137Csgave average sedimentation of nearly 0.066 cm/a in the past twenty years The age is between 6500–8000 BC based on AMS 14C results from depth 0.5 m to 1.78 m, which is comparable with OSL age of 7–8 ka from corresponding depth. Sharp transition of index including TOC, TN, elements and garin size emerged at depth of 0.3 m representing about 450 years based on sedimentation rates mentioned above. The age was consistent with 1556 AD when Gucheng Lake was finally isolated from Lake Taihu due to establishment of Xia Dam. It was inferred that continual deposition may be after the isolation of Gucheng Lake from Lake Taihu, the sediments before this time might be eliminated due to erosion or human impact such as cultivation. 0634 Reconstruction of the East Antarctic Ice Sheet history along the Skarvsnes coast using in situ produced cosmogenic nuclides Masako Yamane1, Yusuke Yokoyama1, Hideki Miura2, Hideaki Maemoku3, Syogo Iwasaki2, Hiroyuki Matsuzaki4 1

Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Japan 2 National Institute of Polar Research, Japan 3 Graduate School of Education, Hiroshima University, Japan 4 Department of Nuclear Engineering and Management, Graduate School of Engineering, The University of Tokyo, Japan

Antarctic ice sheet is the largest on the Earth, and hence its fluctuations would give a large impact on the global climate change. However few geological evidence have been reported to reconstructed the past waxes and wanes of the ice sheet. Therefore we conduct to construct ice sheet history of the Enderby Land in East Antarctic Ice Sheet using in situ cosmogenic nuclides. We report here the re-sult obtained from Skarvsnes coast. The Skarvsnes is the largest ice-free area in the Soya Coast. We collected 12 gneiss samples from 10 sites of this area that consisted of 9 bedrock samples and other 3 erratic samples. The concentration of in situ produced cosmogenic nuclides in quartz provides the cumulative exposure time of the rock. This study used 10Be (half-life = 1.5 Myr) and 26Al (half-life = 0.7 Myr). Also, 26Al/10Be ratio provides buried histories of rock. 10Be and 26Al ages of bedrock were ranged from 8 to 33ka. On the other hand, ages of erratics are all younger than 10ka. Some of 26Al/10Be showed significantly below the equilibrium ratio of ~6.0 for continuously exposed samples. These samples suggest complex exposure history. According to the age distributions and measured ratio in 26Al/10Be, we could deduce following ice history of this region of the East Antarctic Ice Sheet. (1) The Skarvsnes region becoming ice free during the last 10ka. This scenario consists with the study re-ported using 14C ages of fossil shells in raised beach deposits (e.g. Miura et al., 1998). (2) A part of this region must have been under the East Antarctic Ice Sheet for at least 2-3 million years and did melt several times during this period. (3) The region was ice free like today during the few instances in the past.

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0995 Geochemical characteristics of the middle Holocene peatland in Pyeongtaek area, Korea Dong-Yoon Yang, Ju-Yong Kim, Wook-Hyun Nahm, Sanheon Yi, JinKwan Kim, Jeonf-Chan Kim, Jin-Young Lee Geological and Environmental Hazards Division, Korea Institute of Geoscience and Mineral Resources, Korea, Korea

Pyeongtaek peatland is located on the old floodplain of the Ansung river along Asan bay of the western coast of Korea. The purpose of this study was to reconstruct paleoenvironments of the middle Holocene on basis of organic and inorganic geochemistry from the trench sediments obtained from the Pyeongtaek peatland. Seven sedimentary units were distinguished from bottom (altitude 3.912m) to top (altitude 5.412 m). A total of 72 samples at 1–10 cm intervals depending on lithology were collected from the trench sediments of the Pyeongtaek peatland. The samples analyzed to obtain grain-size distribution and the contents of major and trace metals and organic matter. Also eight radiocarbon ages were determined by AMS method for the trench sediments containing organic matters. The contents of major and trace elements are indicative of the peat-forming process during the middle Holocene (about 7500 – 4500 yr BP) in the Pyeongtaek peatland. The major and trace elements such as SiO2, Al2O3, TiO2, MgO, K2O, Na2O, V, Cr, Co, Ni, Ga and Sn are supposed to be transported by fluvial processes from the basement rocks around the peatland. In units-3, 5 and 6, which are characterized by typical peat layers, however, fluvial influx is decreased and authigenic minerals formed by evaporations. TS values and FeO contents reach the peak only in unit-3, whereas TOC values in both units-3 and 6. CaO values start to increase in unit-5 and show the highest point in unit-6. CaO appears to have little relation to the amount of TS, so this element has clearly been affected by precipitation of carbonates, rather than gypsum. The high Mn/Ti, Fe/Ti, Ca/Ti ratios are generally attributable to the concentrations of carbonate minerals. In unit 3(about 7300 –7100 yr BP), the increase of TS and FeO would indicate the formation of pyrite caused by influence of sea level rising. The hydrologic environment in unit 5 & 6(about 6700 –4500 yr BP) are supposed to be alternated between almost closed limnic environment and wetland. Carbonate minerals precipitated with the decrease of water depth in the lake or wetland after about 5000 yr BP. Eventually, Pyeongtaek peatland is analogous to Cheollipo coastal wetland, which is representative in western coast of Korea, in their hydrologic regime and sedimentary process. 0421 Pleistocene climate and vegetation change in Central Asia as recorded in loess deposits of Tajikistan Shiling Yang, Zhongli Ding Institute of Geology and Geophysics, Chinese Academy of Sciences, China

Thick loess-soil sequences in Tajikistan are valuable archives of longterm palaeoclimate history for arid and semi-arid regions of Central Asia. We present detailed records of d13C of bulk organic matter and major elemental composition for the Chashmanigar loess section in southern Tajikistan, for the past 1.77 Ma. The d13C record shows mostly negative values throughout the sequence, almost all d13C values falling between −23 and −26‰, indicating a predominance of C3 plants in Central Asia over this time period, despite the presence of numerous glacial-interglacial cycles. From 0.85 Ma to the present, the d13C

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values become increasingly positive, reflecting a growing C4 signal. The (CaO+Na2O+MgO)/TiO2 ratio of decarbonated residue, a newly developed proxy for chemical weathering of loess that is independent of grain size, display a relatively regular oscillation within a narrow range in the early Pleistocene, and a rapid increase in average values and in variance from 0.85 Ma to the present, indicating lowered chemical weathering intensity in both the dust source regions and the depositional areas. At present, the loess region of Tajikistan is characterized by hot, dry summers and mild, moist Mediterranean-type winters. The predominance of C3 vegetation at Chashmanigar thus indicates that winter-spring precipitation, i.e. Mediterranean climatic conditions, have characterized Central Asia for at least the past 1.77 Ma. In the context of glacial-interglacial-scale changes in atmospheric CO2, therefore, it is climate rather than pCO2 that controls C3/C4 variations in Asia’s middle latitudes. The gradual increase in the C4 component since 0.85 Ma may have been caused by an increase in summer precipitation due to an enhanced southward shift of the climate zones. This event coincides in timing with the decreased chemical weathering intensity in the arid and semi-arid regions of Central Asia indicated by the TiO2-based record. We suggest that the changes in vegetation and chemical weathering intensity was causally related to the expansion of northern hemisphere ice since the mid-Pleistocene, which has induced the southward shift of the climate zones and cooling and drying in Asia. 0322 Quaternary sediment source-to-sink history on inner shelf of the northern South China Sea: Geochemical constraints Shouye Yang1, Wyss W-S Yim2, Guangqing Huang3 1

Tongji University, China Department of Earth Sciences, The University of Hong Kong, China 3 China 2

Sediment samples were collected from several boreholes taken from the northern South China Sea, for grain size and geochemical analyses to constrain the sediment source-to-sink patterns and paleoenvironmental variability since the middle Pleistocene climate transition. The mid-Late Quaternary sediments primarily consist of marine facies, estuarine facies and fluvial facies. Geochemical indices of TOC/TN, Th/ Sc, Ti/Nb and Th/Nb ratios suggest the Zhujiang (Pearl River) was the main provenance of the inner shelf sediments of Hong Kong deposited during interglacial periods of the mid-Late Quaternary with high sealevel stands, whereas the locally-derived granitoids contributed significantly to the exposed inner shelf through the incision of local streams during glacial periods with the falling of sea level. Furthermore, the influence of the Zhujiang-derived sediments on the inner shelf of Hong Kong varied spatially and temporally with different sealevel changes during the middle-late Quaternary. Chemical weathering indices suggest hot and wet climate conditions were dominant in South China during marine isotope stages (MIS) 7, 9 and 11 whereas a dry and cold paleoclimate prevailed in Hong Kong during the MIS 6 which accounts for weak chemical weathering and coarse-grained deposition on the inner shelf. The Holocene and last interglacial period did not see more intense chemical weathering in the Zhujiang drainage basin than other interglacial periods. We argue that the East Asian monsoon evolution and the sea-level fluctuation were responsible for major paleoenvironmental changes in the northern South China Sea during the middle-Late Quaternary. Although the high resolution paleoenvironmental changes can not be easily reconstructed due to ubiquitous unconformity in the sedimentary strata and weak age controls compared to the deep sea sedimentation, the present study sheds new lights on

the understanding of the source-to-sink process of the Zhujiang sediment in the deep ocean and provides a teleconnection of East Asian palaeomonsoon activity between South China, the inland and open sea areas. 1409 An unstable Marine Isotope Stage 11: rock magnetic evidence from NW Qaidam Basin, northern Tibetan Plateau, China Taibao Yang1, Yongtao Yu1, Zhe Fan1, Xing Su1, Yongfei Li1, Liping Zhou2 1

Key Laboratory of Western China’s Environmental Systems, Lanzhou University, China 2 Laboratory for Earth Surface Processes, Peking University, China

Marine Isotope Stage 11 (MIS11, ~400 kyr BP) has been considered as a natural analogue for the present interglacial (Holocene) climate. Investigation of fine structure of MIS11 records would be of great value for understanding climate variability of this important warm interval in the recent history of the Earth. This also has significant implications for predicting the trend of climate change in the future. Most of published MIS11 records are from polar ice cores or marine sediments; continental records of environmental response during MIS11 are still limited. Here we present a high resolution record from interior Asia which displays highly variable climate signals during the MIS11. A 220-m long fluvial/lacustrine sediments core was recovered from Lake Gas Hure, NW Qaidam Basin, northern Tibetan Plateau, China. Magnetostratigraphy and orbital tuning techniques were used to constrain the chronological framework. The record reveals detailed information about regional hydrological cycles during the past 1.3 Myr. Variations in magnetic susceptibility (MS) of the sediments strikingly resemble the glacial-interglacial fluctuations commonly seen from marine oxygen isotope records, and exhibits strong asymmetric patterns of long glaciations and short interglaciations in the late Pleistocene. We interpret this striking similarity to be linked with varying stream carrying capacity. During the glacial times, decreased stream discharge impeded the delivery of magnetic minerals from the catchment to the lake, resulting in deposition of fine-grained sediments with lower MS values. In contrast, during the interglacials, enhanced stream power promoted transport of more coarse-grained magnetic minerals to the lake, giving rise to accumulation of coarser sediments with higher MS values. Our detailed rock magnetic investigations of the cored sediments from Lake Gas Hure provide new evidence for a variable MIS 11 climate in northern Tibetan Plateau in the arid NW China. The preliminary results show that the environmental conditions during the MIS11 at this site are not as stable as previously thought but rather punctuated with several noticeable fluctuations, which is inconsistent with evidence from Antarctica ice cores and deep sea sediments. This instability may reflect variations in climatically regulated river discharge associated with production and transport of detrital magnetic minerals within the catchment. Our results therefore suggest that inland fluviallacustrine sediments, especially in arid and semiarid regions, may allow us to view MIS 11 from a perspective that is different from what have been achieved using marine and polar ice core archives. 0439 Limnological response to climate change over the past 200 yrs in Namu Co, central Tibet Xiangdong Yang Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, China


Nam Co is the largest alpine lake in Tibet, with the meltwater-fed from the valley glaciers of western Nianqingtanggula mountain. Sediment analysis of independent grain-size and fossil diatoms from a short core in the west part of the lake have been employed to reconstruct the variations in water inflow and lake salinity in order to understand the limnological responses to the climate changes and its influenced glacial activities over the past two centuries. The diatominferred water conductivity shows Nam Co was once a freshwaters with freshwater Aulacoseira ambigua dominate during the last cold interval of the Little Ice Age (LIA). Water conductivity has increased since 1870 and presented a rapid increasing trend in the recent 40 years, with the marked shift in dominant diatoms from Cyclotella ocellata to Staphanodiscus minutulus towards the top sediment core. However, the progressive enhanced meltwater inputs after the LIA recorded by the gradual increases of median grain size and coarser fractions to the up core show an inverse relation to lake salinity. The consistence in changes between diatom-inferred conductivity and the instrumental temperature measurements in the recent 40 years suggests that temperature is the main factor strongly influencing the hydrological balance of the lake through the evaporation, hance resulting in the changes of lake salinity, as well as lake-level fluctuations and lake effective moisture. In addition, by the comparisons among lakes with and without melt-water supply along the section from southern to northern Tibet, the synchronous hydrological changes in lakes with different salinity were found, revealing the common responses of inland lakes to regional climatic changes and further illustrating the important role temperature plays in driving the lake hydrological balance in regional scale, albeit the strong glacier recession could maintain the lower salinity in Nam Co and other glacier-fed lakes such as Yangzhuoyong Co and Chen Co in the last century especially in the recent decades. This study also reveals the cold-wet and warm-dry environment patterns in Tibetan region during the last two centuries. 0645 Late Quaternary wetter periods in the Taklamakan Desert, Western China Xiaoping Yang1, Frank Preusser2, Ulrich Radtke3 1

Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, China, China 2 Institute of Geological Sciences, University of Bern, Baltzerstrasse 1-3, CH3012 Bern, Switzerland, Switzerland 3 Department of Geography, University of Cologne, Albertus-Magnus-Platz, D-50923Köln (Cologne), Germany, Germany

Taklamakan Desert of Western China has been widely considered as the ‘Arid Pole’ of the globe because of its long distance to the oceans. However, it was not clear whether any wetter period has occurred during the Quaternary. By investigating sedimentary and geomorphological records we are aiming to recognize climatic fluctuations in this sand sea. In addition, the palaeoenvironmental records from the Taklamakan are of great significance for understanding climatic variability in Central Asia. Our chronology is based on optically stimulated luminescene dating (OSL) and historical records. Aeolian and lacustrine deposits from the centre and southern margin of the Taklamakan Desert have been dated using OSL. The hydrological changes during the last 2000 years have been reconstructed according to historical literature and remote sensing images. Distinct variations in humidity during the last 40,000 a in this extremely arid inland basin have been identified. Lacustrine sediments were deposited in the centre of the Taklamakan during two periods of wetter than present day conditions at around

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2000 a and 30,000 a ago. Another humid period is recorded between 40,000 a and 30,000 a ago. Sedimentological evidence for a late Holocene humid period are consistent with records in ancient Chinese literature. A hydrological connection between Keriya and Niya rivers in the southern Taklamakan in former times was recognized for the first time using satellite imageries. After transferring the notes and maps of historical times into a simplified modern map, it shows that the Lop Nuer decreased in size from a large lake in the Han Dynasty (206 BC – 220 AD) to a much smaller one in Qing Dynasty (1644 –1911 AD). A review of archaeological literature reinforces that in the lower reaches of the Keriya and Niya rivers, i.e. interior of the Taklamakan Desert, irrigated agriculture was widely practiced from ca. 200 BC to ca. 500 AD. A possible climatic change toward drier conditions at ca. 500 AD is suggested as the potential cause for the abandonment of the cities in the desert and for the initial drying of the formerly large Lop Nuer. Wetter environmental conditions in the past within the Taklamakan, as indicated by the presence of lacustrine deposits and broader availability of water, are also supported by data from adjacent regions. It is assumed that changes of global westerlies triggered the fluctuations of precipitation in the study area. 0651 Late Quaternary changes of geomorphic processes in the southeastern margin of the Badain Jaran Desert, Inner Mongolia, China and their implications for interpreting regional climatic changes Xiaoping Yang, Nina Ma, Bingqi Zhu, Jufeng Dong, Liangcai Lu, Baoling Huang Institute of Geology and Geophysics, Chinese Academy of Sciences, China

The southeastern margin of the Badain Jaran Desert, Inner Mongolia of China, is spatially consistent with the northwestern boundary of East Asian summer monsoons. Therefore the variations in the geomorphic processes in this region should be indicative of changes in the system of East Asian monsoons. At present the landscape in the study area is characterized by co-existence of sandy dunes, desert pavements, wadis and lake basins. Using geomorphological, sedimentological and palaeohydrological methods, we examine the paleo-landforms and sediments indicating Late Quaternary climatic changes. Chemistry and isotopic compositions of groundwater and lake water are studied in order to understand the regional water cycles. Our chronology is based on luminescence dating of aeolian sand and radiocarbon dating of lucustrine sediments. Solute concentrations in the water samples are measured using standard approaches in water chemistries. Two older periods of strong aeolian processes, as indicated by paleo-dunes, are recognized in the areas of present-day desert pavements and the surface layers on these old dunes are dated to ca 57 – 51 ka, and ca 121 ka, respectively. Aeolian processes of loess sedimentation in the study area are dated to last glacial. In the study area of a relatively homogeneous lithology a clear spatial variation in groundwater chemistry exists. Such regional heterogeneity of groundwater chemistry means that the shallow aquifers have been recharged mainly by infiltration of local precipitation, and the different water levels of the lakes recharged by this kind of groundwater should reflect local climatic fluctuations. The present-day high salinity of the lake water is believed to be from a long-term intensive evaporation. The higher elevation of former shorelines indicates that much larger and deeper lakes occurred in the southeastern margins of the Badain Jaran Desert during the early and middle Holocene. An earlier period of occurrence of larger lakes is attributed to ca 89 ka. We argue that aeolian processes forming sand seas in the area of Badain Jaran Desert were more intensive sometimes during

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globally warmer epochs recorded in the marine isotopic stages. The wetter conditions with loess sedimentation at Last Glacial were probably related to the moisture brought by north-hemispheric westerlies. The Late Quaternary climatic trends interpreted from this study are principally consistent with outcomes from research in the mega-dune areas of the Badain Jaran Desert and from various records in the adjacent regions. 1120 Climatic changes of the Last glacial-Interglacial cycle on the Tibetan Plateau and Polar Regions revealed by ice cores Tandong Yao Institute of Tibetan Plateau Research, Chinese Academy of Sciences, China

Based on ice core records recovered from the Tibetan Plateau (Guliya), Greenland (GISP2 and GRIP) and Antarctica (Vostok), the features and possible causes of climatic changes on the Tibetan Plateau and Polar Regions during the Last Glacial-Interglacial cycle were discussed. The record in the Guliya ice core clearly indicates that the Tibetan Plateau temperature change is closely related to solar radiation, which is a major factor dominating the climatic changes on orbital time scale. Although climatic changes recorded in the three ice cores are more consistent with each other on orbital time scale, the orbital time scale climatic change recorded in Guliya ice core is typically ahead of that from Polar Regions, suggesting that the climatic changes on the Tibetan Plateau were earlier than that in Polar Regions. On sub-orbital time scale, the amplitude of climate change in Guliay ice core record is larger than that in Polar Regions. Nevertheless, climatic events such as Younger Dryas and Heinrich events occurred later on the Tibetan Plateau than in the Arctic Region on sub-orbital time scale, indicating different mechanisms. The cooling events always took place earlier in Greenland ice core record than in Guliya ice core record. We therefore propose that these climatic events were affected by the Laurentide Ice Sheet. The Tibetan Plateau and the summer monsoon on the Tibetan Plateau might also have contributed to the climatic changes on sub-orbital time scale. 0437 Problem of reconstruction of natural processes during the postglacial period in the Black Sea region Nikolay Vasilievich Yesin, Olga Nikolajevna Kukleva Southern Branch of the P.P.Shirshov Institute of Oceanology, Russia

Studies showed that the Black Sea level increase between 17 and 6 k. y. BP was accompanied by its numerous secondary fluctuations. As follows from the sea level temporal variation curve, offered by A. Chepalyga [1], the average rate of sea level rise is about 8 mm/year, but during fluctuations it reached 30 mm/year and much greater values. Thus, the most danger for the inhabitants was presented by relatively short-term and fast sea level rises. Value and a sign of the fresh-water balance define laws of sea level fluctuation. Under current conditions, it is positive and equal to +180 cubic km/year (Ovchinnikov, 1976). According Zhiljaev and Yesin’s calculations (1990), it is equal to +190 cubic km/year. Since rivers’ runoff exceeds the difference between precipitation and evaporation by many times, it was also positive during the glacial age (Yesin, 1987). A. Kislov and P. Toropov’s calculations (2006) prove this statement. They have shown, that the rivers’ runoff was 175,5 cubic кm/year during the glacial age, and precipitation volume was 30 –40 % less than the current one. Calculations according

these parameters have shown the fresh-water balance during glacial age exceeding +50 cubic km/year. The following equation describes the Black Sea level change: dh/dt = (Q−V)/S, where t - time, h – level mark, Q - fresh water excess, W - water flow through the Bosporus strait, S – sea area at h mark. Calculations made according to this equation show that sea level rise because of multiple increase of rivers’ runoff and precipitation under conditions of the Black Sea waters overflow to the Sea of Marmora can reach tens of centimeters. Geological and lithodynamical processes in the strait can cause level fluctuations with 20 –30 meters amplitude. In order to study the sea level change, Alexeev (2005) has suggested to apply the differential equation of 2-nd order, describing spring oscillation. In our opinion, it is not a good idea. . The matter is that the spring has weight, its oscillation is the inertial process described by the Newton’s second law, whereas the sea level has no weight and, for this reason, is described by the equation of 1-st order. Spring oscillation has little in common with sea level change because of evaporation and rivers’ runoff. 0432 Upper Pleistocene loess deposits of the Middle Dnieper area, Ukraine Svetlana Yevdokimenko Taras Shevchenko University, Ukraine

Results of the investigation of the Upper Pleistocene loess deposits of the Middle Dnieper area are given in the paper. In the Upper Pleistocene sequence of the Middle Dnieper area, the loess units predominate over the soil units in their thickness. The characteristic features of the Uday loess unit (70 –58 ka) are its small thickness and high percentage of clay particles. Pollen data indicate that the Uday unit was formed under more mesophytic steppe vegetation than the later loess units. Cryophytes were represented in the vegetation. The micromammal complex of the Uday unit yields Dicrostonyx guliemi and Arvicola terrestris. The upper loess deposits of the Upper Pleistocene are subdivided into two unequal parts by the Dofinovka interstadial soils: the Bug loess unit – the thickest (up to 18 m) of the Pleistocene loesses of Ukraine, with all characteristic loess features, and the Prychernomorsk loess unit, with a larger admixture of clay and sand particles than the silty Bug loess. The Dofinovka soils are weakly developed turf-carbonate soils. In the northern part of Ukraine, they have a very limited distribution, and the Bug and Pprychernomorsk units combine to form a single loess sequence. Pollen spectra derived from the Dofinovka soils indicate boreal steppe. The micromammal complex of the Vytachiv-Bug stages contains Citellus seversnensis and C. citelloides, while that of the Dofinovka-Prychernomorsk stages has only modern species. The Bug, Dofinovka and Prychernomorsk units are dated by TL and 14C as being younger than 27 ka BP old. At the stratotype localities of the Dofinovka unit, in the southern part of Ukraine, its 14C age is between 13.7 and 16.1 ka BP. 1356 Holocene glacial fluctuation in Tibet and surrounding mountains—based on radiocarbon dating Chaolu Yi1, Jianqiang Yang1, Lewis A Owen2 1

Institute of Tibetan Plateau Research, Chinese Academy of Sciences, China University of Cincinnati, United States

2

Based on the collection of calibrated 14C data as well as on the lichenometric data, we summarized the timing and spatial variations of Holocene glacial advances in Tibet and surrounding mountains.


Seven glacial stages were identified in Holocene: Little Ice Age with three substages of 1871±20AD, 1777±20AD, and 1528±20AD, but the glacial advances may occur one to six hundred years earlier in southeast Tibet and south bordering mountains in Tibet; Neoglacial with three substages of 1500 BP, 1900–2500 BP, 2700–3000 BP and 3200–3500 BP, but one more glacial advance occurred in southeast Tibet; glacial advance in the Younger Dryas was one thousand years earlier than the local cooling event. The timing of glacial advances in middle Holocene in northern Tibet and bordering mountains are synchronized with the cooling events in northern hemisphere, while more glacial advances and the earlier advances in the southern Tibet and bordering mountains may be driven by precipitation increase 0621 Moraine feature and estimating its past extent of mountain glaciaer in Tibet Chaolu Yi, Ping Fu Institute of Tibetan Plateau Research, Chinese Academy of Sciences, China

To know the extent of Quaternary glaciation is helpful for the understanding of climate changes in Tibetan plateau. By using the moraine relative heights and their corresponding glacier lengths from the field work, we analyzed the relationship of height of moraine to length of paleo-glacier in mathematical statistics. The results show that the length of lateral moraine is much more closely correlated with its corresponding glacier length than that of end moraine because the former was preserved better than the latter and can better represent the original feature of the moraine. Correlation of height to glacier length in lateral moraines in maritime climate area is as high as that in continental climate areas. However, the long paleo-glaciers were much longer in maritime climate area than those in continental climate area and if we leave off the glaciers longer than 50 km, the relationship of height to length of paleo-glaciers in maritime climate area is not as close as in maritime climate area. We suggest that.the long glaciers in maritime climate area could reach stable and developed well the moraines, and thus had a close relationship of moraine height with the glacier length. The relationships of height to length in lateral moraines are all good enough in Holocene, the Last Glaciation and the Penultimate glaciation, respectively. This suggests that the height to length relationship is still present for old moraine even if the degradation is extensive. Therefore, it is helpful for the reconstruction of the extent of Quaternary glaciation where it is lack of end moraines. 0628 Morphological Features of Moraines and their controlling factors in west Nyainqentanghula Shan and the Puruogangri icefield, Tibet Chaolu Yi1, Zhuli Qiu1, Ping Fu1, Dewen Li1, Brigitta Schuuett2 1

Institute of Tibetan Plateau Research, Chinese Academy of Sciences, China Germany

2

Puruogangri and west Nyainqentanghula Shan, Tibet were under different control of climate systems since the Last Glacial. We took moraines features in these two sites for comparison. Using using differential GPS with high resulution (Global Positioning System), we measured several lateral and terminal moraines and treated these data by using the software of GIS (Geographic Information System) such as Arcgis 9.0 and Erdas, and of the Matlab 7.0, which offer powerful

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visualization and analysis ability of data. Then, in comparison of the data visualization and data analysis, we find the factors which brought about the morphological differences of moraines in these two sites are climate, original relief and aspect of the landform 1149 How long did the glaciers stand in the Last Glaciation Maximum in Muztag Ata, northwestern Tibet Chaolu Yi1, Zhiyong Zhu2, Lewis A Owen3, Yoeng Bae Seong4, Xuefeng Lu5 1

Institute of Tibetan Plateau Research, Chinese Academy of Sciences, China Institue of Tibetan Plateau Research, CAS., China 3 University of Cincinnati, United States 4 United States 5 China 2

Timing on Quanternary glaciation is important for understanding past climate changes. Many researches focused their studies on terrestrial cosmogenic nuclides exposure dating and optical stimulated luminescence dating on moraine. The former gives minimum age of glaciations. The latter can give the burial ages of a moraine, but it is difficult to tell the duration of a glaciation because of difficulty to find successive materials for OSL dating in a moraine. Carbonate precipitation is widely present in modern till in Tibet and may be preserved in till. We selected a moraine exposure in Muztag Ata, northwestern Tibet and collected 9 samples from bottom to top in one meter interval. We separated samples into four subsamples with different grainseizes and dated them by using inorganic radiocarbon dating method. We found that the moraines were formed about 8 ka to 17ka. The minimum age is close to surface age of the moraine determined by terrestrial cosmogenic nuclides exposure dating. We believe that the Last Maximum Glaciation lasted at least 9000 years in this area. 1203 Fabric analysis and interpretation of till clasts in the Muztag Ata Mountain, Xinjiang, China Chaolu Yi Institute of Tibetan Plateau Research, Chinese Academy of Science, China

With the development in the analysis of till fabric, especially the application of the three-dimensional eigenvalue (or eigenvector) statistical method, till fabric analysis has been played a great role in glacial geology. The till presented in this paper were all observed within Yangbulake valley glacier in the Muztag Ata Mountains, Xinjiang, China. Thirteen locations were selected in the Yangbulake valley for the measurement of clast fabric. Till fabric measurement was performed at each site on 100 clasts. According to the clast fabric analysis, all the fabric strength (S1) of a-b plane (0.65–0.76) is stronger than that of aaxis (0.45–0.58). The preferred orientation of a-axis intersect the former ice-flow direction at a various angle; whereas the a-b plane with a high angle (almost perpendicular). It is concluded that (1) a-b plane show a stronger preference for parallel orientation than a-axis, and (2) the a-axis fabric is more sensitive to landforms than that of the a-b plane. The fabric data can be used to understand glacial sedimentary processes in the study area.

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0401 Wet-dry variations of Horqin sand field (northeastern China)recorded by loess deposit of the Late Quaternary Shuangwen Yi1, Huayu Lu1, Yali Zhou2, Xiaodong Miao3, Joseph Mason3

dominated shelves may be distinguished by sedimentological and engineering properties including the hiatuses formed by transgressions and regressions. Based on a combination of these methods and correlation with other proxy records including ice cores, the inner continental shelf of the northern South China Sea was found to show a sequence extending back to five Interglacial-glacial cycles.

1

School of Geographic and Oceanographic sciences, Nanjing University, Nanjing 210093, China, China 2 SKLLQG, Institute of Earth Environment Chinese, Academy of Sciences, Xi’an 710075, China, China 3 Department of Geography, University of Wisconsin Madison, WI 53706, USA, United States

Horqin sandy field, located at the transitional region between the Northeastern plain and the Mongolia Plateau of China, is sensitive to climate changes. However, paleoclimatic change in this region during the Late Quaternary remains poorly understood, partly because of the scarcity of high quality age controls. In this work, Optical stimulated luminescence dating (OSL), which is a promising method to dating aeolain deposit, has been used to obtain ages of the typical profile (Kulungou and Pingancun). Combining with the sedimentary facieses, data of magnetic susceptibility, organic content, grain size and carbonate content, which can be employed as proxy indicators of the paleoclimate and paleoenvironment changes, has been obtained. It is suggested that climate of the sandy field has been changed with dry and wet at 103–104 time scale, especially at approximately 147kaBP, 142–107ka BP and 83kaBP, the paleoclimate and paleoenvironment have significantly shifted. Accordingly, the vegetation in this area has been a succession of dry-cold grassland,desert grassland and warm-moist or milder-humid forest grassland,sparse grassland. The climate changes in Horqin sandy field are consistent with variations of the East Asian monsoon during Late Quaternary; it is also a footprint of the global Glacial-Interglacial climatic variations in the northeastern China. 0075 Absolute and relative dating of drowned terrestrial sediments on the inner continental shelf of the northern South China Sea off Hong Kong Wyss W-S Yim Department of Earth Sciences, The University of Hong Kong, China

Drowned terrestrial sediments on the siliciclastic-dominated inner continental shelf of the northern South China Sea off Hong Kong possess a number of advantages for dating. In this presentation, experiences gained over a period of about thirty years are reviewed. The conclusions drawn are: (1) Moisture content profiling of continuously sampled boreholes is useful for the identification of stratigraphic boundaries to assist dating. (2) Magnetic susceptibility profiling of continuously sampled boreholes is useful for the identification of stratigraphic boundaries to assist dating.(3) Valid radiocarbon dating normally do not exceed 8200 years calendar years for MIS 1 marine deposits. (4) A count-back stratigraphy can be used based on the recognition of marine and terrestrial deposits, the latter including episodes of sub-aerial exposure resulting in soil development. (5) Uranium-series dating can provide valid ages for molluscan shells in the absence of corals to provide relative ages for terrestrial deposits. (6) Thermo-luminescence dating of terrestrial deposits can yield valid ages of MIS 8. (7) OSL dating of terrestrial deposits can yield valid ages of MIS 2–4. (8) Amino-acid dating and electron spin resonance dating can be used to distinguish between MIS 1, 5 and 7 molluscan shells to provide relative ages for terrestrial deposits. Additionally marine and terrestrial deposits on siliciclastic-

0072 Production of carbon dioxide from sub-aerially exposed continental shelves since the Middle Pleistocene climatic transition as a driving mechanism for postglacial sea-level rise Wyss W-S Yim The University of Hong Kong, China

Out of the various parameters measured in Antarctic ice cores since the Middle Pleistocene climatic transition, the strongest positive correlation is found to exist between carbon dioxide and temperature. While it is widely accepted that astronomical forcing was responsible for the InterglacialGlacial cycles, the sharp increase in carbon dioxide following the glacial maximas requires explanation. In this presentation, the role of sub-aerially exposed continental shelves in the production of carbon dioxide is examined. The two major types of exposed shelves are siliciclastic-dominated and carbonate-dominated. Both are responsible for the production of carbon dioxide; the former through acid-sulphate soil development, and the latter through karstification or pedogenesis. Examples of each type will be presented. The chemical results obtained from the EPICA Dome C ice core by Wolff et al. (2006) is found to provide supporting evidence on the major role played by exposed shelves. Calcium, sodium, iron and sulphate show increased concentrations during glacial periods in comparison to interglacial periods. The preliminary conclusions drawn are: (1) A significant portion of the calcium was derived from loess deposition. (2) Sodium reflected wind intensification. (3) Iron enrichment through acid-sulphate soil development on the siliciclastic-dominated Patagonian shelf, the widest exposed shelf in the southern hemisphere, was the probable source. (4) Sulphate was partially derived from the oxidation of pyrite through acid-sulphate soil development in exposed shelves particularly in tropical and subtropical regions. Comparative studies between Holocene marine deposits with their pre-Holocene counterparts preserved on the continental shelves are needed to provide clues on atmospheric carbon loss during the episodes of sub-aerial shelf exposure. 0213 The Quaternary fluvial sedimentary record of a shallow bay in the northern South China Sea Wyss W-S Yim1, Gordon G Huang2, Adam D Switzer1, K Tam3 1

The University of Hong Kong, China1 Guangzhou Institute of Geography, China 3 Formerly The University of Hong Kong, China 2

Low-stand system tracts that underlie the muddy sediments of ‘low’ energy siliciclastic-dominated inner continental shelves may possess Quaternary fluvial sedimentary records since the Middle Pleistocene climatic transition. Offshore drilling in the subtropical region of Tai O Bay, Hong Kong has revealed an alternating sequence of high-stand marine deposits and low-stand fluvial channel/colluvial-fluvial fan deposits extending back at least the last four glacial cycles. The colluvial-alluvial fan deposits have been identified based on count back and limited luminescence dating to be of Marine Isotope Stages (MIS) 2–4, 6, 8, 10 and older ages. Typically the colluvial-fluvial deposits are coarse-grained and are dominated by sandy boulder and cobble units and clayey-sand units with mi-


nor gravel. The fans feed incised channels dominated by sandy facies which are overlain unconformably by clayey-silt facies. The colluvialfluvial fans represent landslides formed by the ‘rapid’ drawdown of the water table associated with the fall in sea level during glacial periods under ‘drier’ conditions with reworking by stream action. Out of the estimated 500 million tonnes of sand and gravel produced from offshore mining in the territorial waters of Hong Kong, approximately 90 percent was probably derived from such Quaternary fluvial deposits. 0317 Last glacial sea level recorded in the far field marine sediment cores from marginal seas Yusuke Yokoyama1, Kurt Lambeck2 1

Department of Earth and Planetary Sciences, University of Tokyo also Institute for Research on Earth Evolution, JAMSTEC, Japan 2 Research School of Earth Sciences, The Australian National University, Australia

Timing and magnitude of the last ice age global ice volume changes (ie. Sea-level changes) were studied using sediments obtained from Japan Sea and the Great Barrier Reef. The Japan Sea is a marginal sea separated from the open ocean by shallow sills (water depth ranges from 15 to 135m). Hence its hydrology is strongly controlled by global sea-level changes. We obtained twenty AMS (Accelerator Mass Spectrometry) radiocarbon dates, 2 tephra layer chronologies, and planktonic foraminifera d18O stratigraphy for the last 50,000 years for Japan Sea cores recovered from the Oki ridge. Our record combined with the global sea-level data suggests that the LGM (lat glacial maximum) started at about 30 ka and that the salinity of the Japan Sea became fresher than at present. Global sea-level during the MIS3 was not lower than ca. −80m. For the last deglaciation time, we recovered ooids samples from the southern Great Barrier Reef. Their ages and depth distribution were compared with numerical predictions obtained using a detailed glacio-hydro isostatic model to examine the reliability of the ice model. A step-wise dissolution technique was used to remove secondary carbon contamination and determine the exact timing of formation. The dating results indicate that ooid formation took place around 16,800 cal. yr BP, immediately prior to a period of accelerated melting of the global ice sheets, the Meltwater pulse 1a event. Sea-level predictions obtained using rheological parameters optimized for the Australian coast are consistent with the radiocarbon-derived ooid depth-age data, which suggest that at 16.8 cal. ka sea-level in the southern GBR was 100 m below its present height. Published ooids data from the Gulf of Mexico fit very well with our predicted sea-level which verified our model for the global ice volume variations. 0415 Northern South China Sea mid Holocene SST and SSS: using fossil coral and Atmosphere-Ocean GCM model Yusuke Yokoyama1, Atsushi Suzuki2, Fernando Siringan3, Ayako Abe-Ouchi4, Rumi Ohgaito5, Yasuo Maeda6, Hodaka Kawahata7, Hiroyuki Matsuzaki8 1

Department of Earth and Planetary Sciences, University of Tokyo also Institute for Research on Earth Evolution, JAMSTEC, Japan 2 Geological Survey of Japan, Japan 3 Marine Research Instite, University of the Philippines, Philippines 4 CCSR, University of Tokyo also FRCGC, JAMSTEC, Japan 5 FRCGC, JAMSTEC, Japan 6 University of Hyogo, Japan 7 Ocean Research Institute, University of Tokyo, Japan 8 Department of Nuclear Research and Management, University of Tokyo, Japan

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High-resolution record of Sea Surface Temperature (SST) from South China Sea (SCS) could provide important archives to better understanding the mechanisms of El Nino and monsoon evolution since SCS is located between Pacific Ocean and Eurasian continent and hence the region is influenced from El Nino Southern Oscillation (ENSO) and/or monsoon system. SCS plays a key role as the source area of monsoon precipitation that influence the terrestrial climate in the Asia. Mid Holocene and modern corals therefore were obtained from South China Sea (SCS) to study changes in oceanographic condition when the monsoon activity was stronger than the present. The corals radiocarbon dating using AMS indicated that the age of the fossil coral is as old as ca. 7000 ago. XRD and microscopic investigation confirmed pristine quality of this fossil coral sample. Oxygen isotope measurement of modern coral marked average value of ca. −6 ‰, whereas fossil coral showed ca. −5.5 ‰. If we attribute this d18O difference to SST changes between the present to the mid Holocene, approximately 3°C of cooling had been occurred at 7000 years ago. However, Alkenone SST thermometry and foraminiferal SST reconstruction in the previous studies did not indicate cooling as this extent. The oxygen isotopic difference recorded in corals between present day and mid Holocene therefore cannot be attributed solely by changes in SST, we have to consider the possibility of changes in d18O in water namely local salinity of sea water. Coral data were then compared with the coupled Ocean-Atmosphere GCM (MIROC3.2). The GCM experiments were conducted under the protocol of PMIP2 and the resolution of the atmosphere is 2.8 degree whereas oceanic grid was 1 degree except for equatorial regions where the resolution increased as high as 0.5 degree. We will discuss the possible mechanism inferred from GCM experiments to increase seawater salinity. 0594 Plio-Quaternary Seismic Stratigraphy and Sedimentation of Depositional Sequence on the southeastern continental shelf, Korea Dong-Geun Yoo1, Dong-Hyo Kang2, Gil Young Kim3, Ho-Young Lee2 1

Korea Institute of Geoscience and Mineral Resources(KIGAM), Korea Korea 3 Petroleum & Marine Resources Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), Korea 2

The Korea Strait, located between the southeastern tip of the Korean Peninsula and the Tsushima Island, is a seaway connecting the East Sea with the East China Sea. A Plio-Quaternary stratigraphy and sedimentation on the Korea Strait shelf was studied using a dense network of high-resolution, single-channel seismic reflection profiles. Interpretation of high-resolution seismic profiles collected from the southeastern continental shelf reveals that the shelf sequences above the acoustic basement consist of seven depositional sequences, deposited during the Plio-Quaternary, bounded by erosional unconformities. Each sequence is characterized by stratified and complex sigmoid-oblique prograding reflection configurations, reflecting a history of upbuilding and outbuilding in response to repetitive transgressive and regressive events. During the regressive to lowstand of sea level, lowstand prograding wedges prograded seaward along the present shelf margin, while during the highstand of sea level, as in the case of the present condition, inner shelf deposits were formed in the inner shelf along the coast. As the following regression began, however, the inner shelf highstand deposits were severely eroded out and/or formed condensed section. Consequently, the Plio-Quaternary sequences in this area

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comprise a succession of stacked progradational lowstand wedges, mainly formed during the regression and lowstand of sea level. 0178 Paleoclimatic change and age of Younger Dryas event in Northeast Japan Akihiro Yoshida1, Sadako Takeuti2 1

Graduate student, Institute of Geography, Earth Scinece, Tohoku University, Japan 2 Yanagimachi Laboratory of Natural Studies, Japan

Pollen and tephra analyses, Radiocarbon dating were performed on sedimentary cores obtained from the the Tashiro (N 40º 41' 34”, E 140º 55' 21”, a.s.l. 590m), Harukoyachi (N 39 º48' 04”, E 141º 03' 21”, a.s.l. 460m), Hanayama-Ohnuma (N 38º 48' 51”, E 140º 49' 44”, a.l.s. 280m), Yachidaira (N 37º 48' 23”, E 139º 48' 58”, a.s.l. 950m), and Komado (N 37º 13' 14”, E 139º 37' 11”, a.s.l. 1,100m) Mires, and Iwanuma (N 38º 06' 18”, E 140º 52' 40”, a.s.l. 1m) and Numamukai (N 38º 16' 40”, E 141º 00' 25”, a.s.l. 1m) of Miyagino coastal plain in Northeast Japan. From the results of these analyses and measurements, the local vegetational and climatic changes since the Late Glacial substage were reconstructed. After the maximum Last Glacial, the subarctic coniferous forest consisting dominantly Abies, Picea, Pinus and Tsuga and Betula forest changed gradually the cool broad-leaved forest composed mainly of Fagus and Quercus. The cool temperate broadleaved forest have distributed in Northeast Japan until present. During the Late Glacial sub-stage, the cold event which corresponds to the Younger Dryas event in the North Atlantic region occurred at 13,000 ~ 10,400 yrs BP in Northeast Japan. The cold event occurred at 13,000 yrs BP in Lake Nojiri (N 36º 49' 34”, E 138º 13' 17”, a.s.l. 685m) and Komado Mire, 10,400 yrs BP in Tashiro Mire, and 10,000 yrs BP in Habomai Mire (N 43º 21' 09”, E 145º 30' 50”, a.s.l. 33m) and Kenbuchi Basin (N 44º 03'27”, E 142º 22' 53”, a.s.l. 135m). The age of the beginning of the Younger Dryas event in Northeast Japan is not only somewhat older than in the North Atlantic region but also is gradually older toward the low latitude in even this region. There is a time lag of approximately 2000 ~ 3000 years between the northern part and the southern part. 0501 Short term records of environmental change from the Badain Jaran Desert, north-west China Adam A Young1, Jonathan A Holmes1, Melanie J Leng2, Jiawu Zhang3 1

University College London, United Kingdom NERC Isotope Geosciences Laboratory, United Kingdom 3 Lanzhou University, China 2

The Badain Jaran Desert is located in the arid / semi-arid region of north-west China and is situated close to the modern day landward limit of the East Asian summer monsoon. The climate of the desert is mainly controlled by changes in precipitation and/or evaporation rates, probably in relation to changes in the intensity of the East Asian summer monsoon. The Badain Jaran Desert contains over one hundred hydrologically closed interdune lakes, but due to the remote nature of the desert modern limnological data from the lakes are sparse. Modern limnological sampling took place in 2005 and 2006. Results from the modern sampling have shown that the salinity range of the lakes is 1.5 g l−1 to >300 g l−1 and the water balance of individual lakes is controlled by evaporation and basin morphology. Short sediment cores (1‰. These oscillations correspond to decreases of 20–80% in carbonate content and simultaneous increases in organic matter. On the basis of present sediment distribution at the lake, organic-rich peaty sediments were likely deposited during low lake levels; whereas carbonate-rich sediments were likely deposited in more open and deep water environments. The decreases in lake level at Silver Lake could reflect periods of dry conditions in the region during the early Holocene. We also observed a trend of increasing variability, especially in lithologic oscillations from 9.5 to 8 ka. This suggests an increase in the environmental instability in the region, which correlates with the increase in magnitude of the outburst floods. Our sediment records from northern New Jersey suggest that six cooldry events occurred between 9.5 and 8 ka, including the largest 8.2 ka


event. The apparent correlation of our sedimentary records with the documented outburst floods suggests a possible causal relationship. This implies that the climate in the Mid-Atlantic region was extremely sensitive to perturbations of ocean circulation. 0656 Towards revised Plesitocene stratigraphy of Western Latvia, the Eastern Baltic Vitalijs Zelcs, Tomas Saks, Andis Kalvans University of Latvia, Faculty of Geography and Earth Sciences, Latvia

Stratigraphic investigations of inter bedded glacial and non-glacial sediments suggest that deposits of four glaciations and three interstadials are present in the Eastern Baltic Region. Stratigraphically complex sections have been encountered in the areas of glacial uplands where there are thick sequences of Pleistocene deposits. The territory of Western Latvia, that occupies the eastern part of the Baltic bedrock depression, and belongs to the glacial lowland areas, makes exceptional event. There occurs vast, up to 50–80 m, in ancient buried valleys – almost 150 m thick sequence of glaciotectonically disturbed glacigenic, glacioaquatic and marine deposits which chronostratigrafical succession is still unclear. Western Kurzeme occupies a key position for recording the passage of overriding ice-sheets that originated on the Fenoscandinavian region and flowed across the Baltic Sea.

On the basis of borehole data three distinct glacial diamicton units could be distinguished in the territory. In previous studies the lowest till unit and glaciofluvial deposits occurring at the base of the Quaternary sequence have been correlated with Elsterian. The overlying dark grey silt marine sediments were referred as Holstenian. Subsequently deposited silty and sandy marine sediments and followed middle till unit were interpreted to be respectively Early and Upper Saalian. The upper till unit occurs fragmentary on top of the Pleistocene sequence, and is truncated by abrasion surface of the Baltic Ice Lake waters. In this paper we pressed new OSL dating results of sandy glaciolacustrine sediments form the top of this sequence. The results are indicating middle Weichselian age, that is in a strong disagreement with previous sediment age assessments. The age-control, reinterpretation of borehole data and glaciostructural investigations of glacial and non-glacial deposits exposed in Baltic Sea coastal bluffs in a distance up to 40 km suggest that the upper till unit is of Late Weichselian age in contrast to earlier interpretation. The OSL dates (37–46 ka) of the underlying fine grained sands indicate Middle Weichselian age. Accordingly the dark grey silt sediments between two uppermost till units could belong to Late Eemian or Early Weichselian implying the vast water body in the Baltic See depression during this time. Recognized in some boreholes between OSL dated sand and silty sediments additional till could refer to Middle Weichselian glacial advance, supporting recent reconstructions of extensive Middle Weichselian glaciation reaching northwest Latvia. 1226 Dating fluvial terraces by optically stimulated luminescence: application to the Yellow River, China Jiafu Zhang, Liping Zhou Laboratory for Earth Surface Processes, Peking University, China

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Formation age of fluvial terraces can be determined by dating river terrace deposits as fluvial sediments are directly related to the evolution of rivers. However, there has been a need for more reliable dating methods which can be applied to date fluvial sediments. Recent development in optically stimulated luminescence (OSL) dating method has led to numerous new applications in the study of landform evolution and Quaternary environments. Very few attempts have been made so far to apply this method to study the evolution of large rivers in China. One major difficulty of dating fluvial sediments using the OSL technique has been the uncertainty associated in the assessment of luminescence properties of dated samples as the resetting prior to deposition may vary from sample to sample. To obtain true burial ages therefore requires thorough investigation of each dated sample both in the field and in the laboratory. When the reliability of OSL dates obtained cannot be evaluated by comparison with independent age controls, consistency within the geomorphological context must be achieved. Another problem is the upper limit of the OSL dating method; some of OSL dates over 120 kyrs have been considered to represent an underestimation of true ages. In this study, we first seek an approach to evaluate the validity of OSL dates with emphasis on the sampling strategy for a series of samples in river terrace sequences. Terraces at two localities in the middle reach of the river have been selected for dating investigation. For each terrace, more than two samples were taken from channel deposits (sand lens), and/or floodplain sediments, and/or overlying loess and paleosols. The consistency of the OSL dates for these stratigraphically and sedimentolgically related samples is used for examining the validity of the obtained OSL dates. We discuss criteria that can be used to identify overestimation or underestimation and discuss possible causes of age uncertainty. The Yellow River has developed many terraces throughout the Quaternary, thus providing an opportunity to test the dating limit of the method. Our results show that the terraces at Hequ were formed between~10 ka and ~100 ka, and the formation ages of the terraces at Baode ranging from 3~10 ka to 150~230 ka. Based on these optical ages and field investigation, the correlation of the terraces in these two areas is established and river incision rate is deduced. 0416 Palaeoclimate and palaeoenvironment on the northern slope of central Tienshan Mountains in Xinjiang, Northwestern China during the late Holocene Yun Zhang1, Chen Zhao Kong1, Jian Ni1, Shun Yan2, Jing Zhen Yang3 1

Institute of Botany, Chinese Academy of Sciences, Beijing, China, China Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China, China 3 Institute of Hydrologic and Environmental Geology, Chinese Academy of Geological Sciences, Zhengding, China, China 2

In order to establish the correlation between modern climatic factors and surface pollen assemblages and to reconstruct paleoclimate on the northern slope of central Tienshan Mountains in Xinjiang, Northwestern China, three Holocene sections in Daxigou, Huashuwozi and Sichanghu were chosen for study, which were located in different elevations and vegetation zones. A total of 80 surface pollen samples in 86 vegetation plots were collected for pollen-vegetation relationship analysis. The Warmth Index (WI) and Moisture Index (MI) were calculated based on averaged modern climate data during 1951–2000yr at 8 weather stations in the study area. Pollen percentage of Picea, Artemisia, Chenopodiaceae, Ephedra, and Tamarix, as well as A/C (Artemisia/Chenopodiaceae) and AP/NAP (arboreal/nonarboreal pollen) ratio were selected as pollen variables, in additional, WI and MI were

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chosen as climatic variables. By using the stepwise multiple linear regression method, the relationship between pollen percentages (Picea, Artemisia, Chenopodiaceae, Tamarix), A/C, AP/NAP ratio, WI and MI values was obtained (95% confidence interval). Hence, WI and MI value for three sections were calculated, and paleoclimate for the study area could be reconstructed. The results in our study, inferred from daxigou, Huashuwozi and Sichanghu sections during the late Holocene, showed that water-temperature patterns were cool-humid and warm-dry on the north slope of Tienshan Mountain. In this region, vegetation was largely related to the effective moisture during the late Holocene. 0485 Discovery of Miocene Aeolian Sediments and its Paleoenvironmental Significances at Lingyan Hill of Nanjing, East China Zhenke Zhang, Huachun He, Haiyan Ding, Yanming Li, Wanfang Wang School of Geographic and Oceanographic Sciences of Nanjing University, China

Red clay records have important significance in the studies on Asian environmental evolution in the Era of Cenozoic, especially on the fields of inland desertification and the impacts of the Tibetan Uplifting. In the region of Nothwest China especially the loess plateau, red clay was regarded as the aeolian sediment in the past few decades. The earliest red clay in the west part of the loess plateau is about 22 Ma old. While in the eastern part of China, the oldest Quaternary loess reported was no more than 2 Ma old. A mining section of Lingyan Hill in northern suburb of Nanjing, East China was discovered and the loess-like sediment layer was covered by basalt layers. The basalt age was measured with the age of 12.17Ma. Field investigation and sampling was carried out and the whole sedimentary section was about 19 meters high not including the covered basalt layers. Under the basalt layer was the loess-like sediments. A general analysis about the loess-like sediments was carried out on the proxies of grain size, magnetic susceptibility, quartz SEM and geochemical elements. According to the sedimentary characteristics of the sediments and the laboratory analysis results, the 4-metre thickness loess like deposits in the section of Lingyan Hill was regarded as the aeolian sediments with the age of more than 12 Ma, which is the earliest aeolian deposits in East China. The deposits is the result of much cold-dry climatic event in the mid-Miocene, which was corresponding with the 15–13Ma rapidly strong deposition of aeolian sediments in north Pacific Ocean, Qin’an section in Loess Plateau and the enlargement of ice sheet in Antarctic after 15Ma. Acknowledgement: The authors are grateful to the financial supports from SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences (No.SKLLQG0405) and the NSFC project (No 40471128). 0584 High Resolution Sediment Records of Environmental changes and Human Impacts in the Shilianghe Reservoir, Juangsu Province, China Zhenke Zhang, Haitao Tian, Hongming Meng, Haiyan Ding, Yanming Li, Xiaodong Shi School of Geographic and Oceanographic Sciences of Nanjing University, China

Shilianghe reservoir has been the largest one in Jiangsu Province with the water storage of 5.0 billion cubic meters since the liberation of the new China, located in the northern part of Juangsu with the largest water area of 150 square kilometers. The reservoir is close to the boundary of Jiangsu Province and Shandong Province. The Yi-Shu River basin provides the water supply to the Shilianghe Reservoir . The Shilianghe Reservoir construction began in the year of 1958 and finished in the year of 1962. For the purpose to study the environmental changes and human impacts recorded by the sediments. In July of 2005, three 2-meter long cores were obtained from the reservoir. The sedimentological analysis and the laboratory measures of 137Cs dating, grain size, magnetic susceptibility, geochemical elements and organic carbon isotopes were carried out. The results indicate the average sedimentation rate is about 4 –5 centimeters per year. In the decade of 1990’s the environment of the reservoir began to deteriorate rapidly because of the cage fish culture and the discharge of polluted water from the upstream basin of the catchment. The diatom-TP transfer functions of the sediments indicate the increasing trend of the eutrophication of the reservoir. The TOC and TN as well as the heavy metals of the core sediments also contain the accelerating process of environmental deterioration after 1990. The grain size indicates the great changes occurred after the late of 1970’s because of the new canal connecting to the reservoir. In the decades of 1960’s and 1970’s the environment is better and stable. The decade of 1980’s is the transitional period. An interesting findings is the laminate layers in the cores, they have the precise time for analysis the results. Muti-environmental proxies and the archives of the human activities in the catchment are helpful for explain the data of multi-proxies. The reservoir sediments contain high resolution information for studying the human and environment interaction in the reservoir catchment of the Shilianghe Reservoir, Jjiangsu Province, China in the past 40 years. 1254 Coastal Sediment Records of the Largest Earthquake in Hainan Island, China Zhenke Zhang1, Kefu Yu2, Haitao Tian1, Wanfang Wang1 1

School of Geographic and Oceanographic Sciences of Nanjing University, China 2 South China Sea Institue of Oceanology, Chinese Academy of Sciences, China

Hainan Island is one of the major islands of China with an area of about 34,000 km2. It is located in the South China Sea, separated from the mainland by a 30 km strait named Qiongzhou Channel. In the Northest of Hainan island, the Dongzhaigang Bay was a famous mangrove reserve region and the local historical documents indicate the largest earthquake occured in the year of 1605. The Dongzhaibei has been regarded as the sinking area caused by the earthquake. In the July of 2005, a 248cm core (DZ1 Core)was abtained in the mangrove cosatal site close to the Changde village, northwest coast of the peninsula in the Dongzhaigang Bay. According to the radio carbon dating and multi-environmental proxies,i. e. sedimentological characteristics, grain size and magnetic susceptibility, and chemical elements, the historical earthquake in the year of 1605 was distinguished and the muti-proxies showed more clear evidence of land sinking after the earthquake. The grain size and element ratios indicate that before the earthquake the sediment records showed the evidence of fresh water condition and the sedimentary environment was relative stable.


0630 The drought events recorded by Holocene Loess-palaeosol sequences on the Chinese Loess Plateau Hui Zhao1, Fa-Hu Chen2, Sheng-Hua Li3, Yu-Xin Fan2

Key Laboratory of Desert and Desertification, Cold and Arid Regions Environment and Engineering Research Institute, Chinese AS, China 2 CAEP, MOE Key Laboratory of Western China’s Environment, Lanzhou University, Lanzhou 73 0000, China, China 3 Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China, Hong Kong 1

A series of Holocene loess-palaeosol sequences (JY, JZT, and YX) were investigated on the Chinese Loess Plateau. Two layers of loess deposition interrupted the Holocene palaeosol S0 on all the studied sections, indicating that at least two drought events took place during Holocene palaeosol development. Optical dating was applied to these sections at every loess-palaeosol unit boundary. For one studied sequence YX, The samples were collected densely from two parallel sections and measured in different luminescence dating laboratories to inspect the reliability of dating results. It concluded that OSL dating method could be applied to loess-palaeosol samples very well. The Loess-palaeosol sequence YX and JZT recorded two main dry episodes (3.7~ 2.4 ka ago and 1.2~ 0.8 ka ago) during Holocene with the present of two layers of loess in Holocene palaeosol deposition. And the Loess-palaeosol sequence JY recorded two dry episodes of 7.2~6.4 ka ago and about 1.0 ka ago during Holocene. These three aridity events were also consistent with the other global climatic records in Holocene. It is suggested that Holocene loess-palaeosol sequence in China could record global climate change even though one section may not record all the drought events. On the other hand, the same structure loess-palaeosol sequences record different climate events; the continuously dating points present big age gap; the LGM Malan loess shows the lowest mass accumulation rate. All these phenomenons indicate that the loess did not deposit continuously in millennial time scale. 0261 The environment changes around Sara Us River during late Holocene: evidences from optical dating and human activity Hui Zhao1, Sheng-Hua Li2, Fa-Hu Chen3, Bo Li2, Yu-Xin Fan3 1

Cold and Arid Regions Environment and Engineering Research Institute, Chinese Academy of Science, China 2 The University of Hong Kong, Hong Kong 3 MOE Key Laboratory of Western China’s Environment, Lanzhou University, China

The Sara Us River locates at the boundary of Mu Us desert and Loess plateau, northern of China. The river cut down the sediments and created 70–80 meters deep vales. Optical dating was applied to one Holocene section (DSGW) with aeolian sand – lacustrine sediment sequences beside the valley of the river. The samples were collected from the section and optical dating was applied. Dating results show that the vale of Sara Us River was formed about 2 ka ago. The section recorded one dry episode at about 0.9 ka BP that was evidenced by a layer of aeolian sand depositing between the lacustrine layer and an upper layer of weakly developed palaeosol. This dry episode was also recorded by the Holocene loess section from the southern area of the studied region at the Chinese loess Plateau.

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On the other hand, the Chinese history records about this area also show that there was a big sallow lake around this area before 2 ka (in Han Dynasty), and then a little town appeared at about 1.8 ka ago(Jin Dynasty), and a city Youzhou was built up at about 1.2 ka ago (Tang Dynasty). And at about 0.9 ka ago (Song dynasty), the city Youzhou was abandoned. It could be concluded that the environment changes at this area affect the human activity very much. Human being cannot live around here when the sallow lake existed. When the river cut down and the water retreated, people moved to this area and built up cities. However, when the environment became drought and desertification (maybe human activity enhanced the process), the cities have to be abandoned and people moved out of this area. 0978 Millennial-, century- and decadal-scale oscillations of Holocene sea-level recorded in a coral reef in the northern South China Sea Jian-xin Zhao1, Ke-fu Yu2 1

Centre for Microscopy and Microanalysis, The University of Queensland, Australia 2 South China Sea Institute of Oceanology, Chinese Academy of Sciences, China

Reef corals, including microatolls, are excellent indicators of past sea levels. High-precision thermal ionisation mass spectrometric (TIMS) 230Th ages for ~60 coral samples from an emerged reef terrace at Leizhou Peninsula, northern South China Sea show that ~70% of the corals were formed during the period of 7100–6300 years before present (yr BP), when post-glacial global sea level stabilised and conditions for coral growth were ideal. The remaining 30% corals grew periodically from 5700 to 1500 yr BP, with two major groupings at 4156±23 to 3675 ±23 and 2795±14 to 2509 ±10 yr BP, and three individual dates at 5717±27, 5009±54 and 1511±23 yr BP, respectively. The data suggest that multiple millennial-scale sea-level highstands of ~2 m above the present sea-level occurred when the above corals were formed. The timing of such sea-level highstands correlates well with iceberg discharge events recorded in the North Atlantic at 5900, 4200, 2800 and 1500 years ago. Sea level was also oscillating on century scales, as indicated by 16 high-precision TIMS 230Th dates for 14 rims of 6 microatolls from the same reef. The results show that the sea level during the period of 7100 – 6600 yr BP was about 1.7-2.2 m above the present with at least 4 century-scale fluctuations occurring at 7110–6990, 6990–6890, 6890–6760, 6760? yr BP. The maximum amplitudes of these century-scale fluctuations were about 40–60 cm. In addition to millennial to century scale oscillations, a detailed study of a well-developed Goniopora reef profile at the same reef also show that sea level rise process during 7500–7000 yr BP was smooth, but punctuated by multi-decadal “hiccups” or even lowering events, that resulted in the emergence and erosion of Goniopora coral heads in several layers (Yu et al. 2004, Earth and Planetary Science letters, 224: 143–155). Based on the Goniopora profile, we calculated that the sea level rose at an average rate of 6.6±2.8 mm/year during 7500–7000 yr BP, reached the present level at ~7300 yr BP, and exceeded the present level by at least ~1.8 m at ~7000 yr BP.

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0982 Speleothems from Mt Etna, central Queensland, Australia: archives of climate change during the past 500,000 years Jian-xin Zhao1, Yue-xing Feng1, Scott A Hocknull2, Linda Deer3, Gilbert J Price1, Gregory E Webb3 1

Centre for Microscopy and Microanalysis, University of Queensland, Australia Geosciences, Queensland Museum, Australia 3 School of Natural Resource Science, Queensland University of Technology, Australia 2

A number of cave systems were exposed or disturbed during open mining of Mt Etna, north of Rockhampton, central Queensland for limestone over the past few decades. The cave systems contain rich records of rainforest vertebrate faunas and speleothems. Systematic U-series dating and geochemical proxy study of the speleothems will provide palaeoclimatic information (precipitation and vegetation) that will improve our understanding of the evolution and final extinction of rainforest fauna (including megafauna) in the region. Over the past two years, with the support of an ARC linkage grant, we have carried out systematic investigations and U-series dating of speleothems (flowstones, stalagmites, calcite fillings in bones) and fossil bones/teeth recovered from the site. Results from more than 100 U-Th dates suggest that some cave systems in the Mt Etna quarry developed more than 500,000 years ago (beyond the dating limit of the method). All ages of younger dated flowstone or calcite-filled samples are consistent with their formation during warmer interglacials or interstadials (despite large age uncertainties for impure samples of such old ages), with >70% of dated speleothem samples being >300 ka, and the other 30% growing between 120 and 300 ka. Such a growth frequency distribution pattern implies that climate conditions were wetter and more favourable for cave development prior to 300 ka, which is consistent with other marine and terrestrial records in northern Australia. On the other hand, a deep-seated cave (Resurrection Cave) ~100 m away from the quarry contains abundant well-developed stalagmites and stalactites, some of which are still active at present. Over 10 fallen stalagmites (broken during mining operation) were retrieved and dated by U-series. The results show that most of these speleothems were formed between 0-55 ka, with high grow rates centering around 36-50 ka and during the Holocene, implying relatively wetter conditions during those intervals. Systematic C-O isotope and trace element analyses of these stalagmites and more U-series dating are being carried out for palaeoclimate reconstruction. 0371 Glacier advance in MIS3b in the western alpine area of China Jingdong Zhao1, Shangzhe Zhou2, Shiyin Liu3 1

Key Laboratory of Cryosphere and Enivironment, CAREERI, CAS, China Member of subcommission of Glaiation, INQUA, China 3 China 2

Environmental variations in the Late Pleistocene are hot topics in the research fields of Quaternary environment and global change, including difficulties about the glaciations since the period. In recent years, the Quaternary glaciations research has entered an accurate dating stage due to the development and application of the dating techniques and a new academic theory that a great glacier advance occurred in marine isotopic stage 3 (MIS3) has been proposed. MIS3 was an unstable stage, according to the climate record in the Guliya ice core. In recent study, Stage 3 can be divided into three sub-stages (a, b and c) based on the isotopic record and corresponding climatic characteristics

and 3b (54–40ka BP is suggested on the basis of the =18O record) was a cold and wet period. Some circumstantial evidence shows that lakes with high water stage also appeared in the Qinghai-Tibetan Plateau and other northwestern inlands in the middle and late period of MIS3. In the last several years, our research group has carried out further studies in relation to glaciations in Shaluli Mountains which is belongs to Hengduan Mountains, Lenglongling in the eastern segment of the Qilianshan Mountains and the Ateaoyinake River Valley on the south slope of the Tumer in the western segment of the Tianshan Mountains in china, including 3 different areas and several sites. ESR dating technique was applied to determine these glacial tills that were collected from above areas and Ge centers in quartz grains were chose. dating results dealing with MIS3 were obtained and most of these ages are corresponding to MIS3b (54~40ka BP). Combining the previous studies and analyzing the climate characteristics of the MIS3 synthetically, a preliminary conclusion could be drawn: MIS3b glacier advance in Shaluli Mountains and Lenglongling was caused by the abundant precipitation carried by the strong monsoon circulation in MIS3 and cold period of MIS3b, the glacier advance in the Tianshan Mountains is also a result of the abundant precipitation produced by the unstable westerly fluctuation and cold period of MIS3b. 0741 Spatial and temporal patterns of Holocene vegetation and climate changes in arid and semi-arid China Yan Zhao1, Zicheng Yu2, Fahu Chen1 1

MOE Key Laboratory of Western China’s Environmental System, College of Earth and Environmental Sciences, Lanzhou University, China 2 Department of Earth and Environmental Sciences, Lehigh University, United States

Holocene variability of the summer monsoons has been documented in a variety of proxy records in east and southwest China. However, its influence on regional climate in other parts of China is still poorly understood, especially further inland in north China and northwest China. Here we review fossil pollen records available from arid and semi-arid areas of China (including Inner Mongolia, the northwestern Loess Plateau, the northern Tibetan Plateau, and Xinjiang) to document regional patterns of Holocene vegetation and climate change, and to understand the large-scale controls of these changes. Pollen records from these four regions reveal different vegetation and wet-dry climate changes during the Holocene. Vegetation at most sites in Inner Mongolia switches between forest, forest steppe, and typical steppe, except at the westernmost sites. Most sites in eastern Inner Mongolia show a dry climate after ~6 ka following early to early-mid Holocene maximum moisture conditions, while at western sites, the climate was dry in the early Holocene, wet in the middle Holocene and dry again in the late Holocene. Vegetation in the northwestern Loess Plateau switches between desert steppe, forest steppe and steppe, with corridor forests often occurring in loess valleys during the forest steppe period. All the sites in this region appear to show wet-dry oscillations, from an initial dry climate to a wet middle Holocene at 8.9–4.1 ka and then back to a dry climate after 4.1 ka. In the northern Tibetan Plateau, vegetation is characterized by steppe, desert steppe or desert, while the Qinghai Lake area was dominated by forest during the early and mid-Holocene, indicating a wet climate until 6–4.5 ka, when a drying trend started. In Xinjiang, pollen assemblages show changes between desert, steppe desert and steppe during the Holocene, with a wet period occurring briefly during 8.5–5.5 ka at most sites. All the four regions show a drying trend during the late Holocene. The complex climate patterns during the Holocene in arid and semi-arid China suggest regional


climate responses to large-scale climate forcing was controlled by interactions of competing factors including the tropical monsoons, midlatitude westerlies and topography. 0744 Extremely sensitive response of arid vegetation to change in effective moisture during the late Holocene: three pollen records from the Qaidam Basin, northeastern Tibetan Plateau Yan Zhao1, Xiuju Liu1, Zicheng Yu2, Cheng Zhao2, Fahu Chen1, Emi Ito3 1

MOE Key Laboratory of Western China’s Environmental System, Lanzhou University, China 2 Department of Earth and Environmental Sciences, Lehigh University, United States 3 Department of Geology and Geophysics, University of Minnesota, United States

We present fossil pollen data and their climatic interpretations from three lakes (Gahai, Toson and Hurleg) in the Qaidam Basin on the NE Tibetan Plateau. Our study objectives are to evaluate the response of pollen records to climate change using instrumental data and independent climate proxies, and to develop pollen index that can potentially used for highresolution palaeoclimate reconstructions. The chronologies of the sediment cores were (or will be) established by Pb-210 and Cs-137 analysis and AMS C-14 dating. Loss-on-ignition (LOI) analysis and pollen analysis were conducted at 0.5 cm or 1 cm intervals. LOI results indicate that organic matter content ranges from 5-15% at three lakes, while carbonate content oscillates greatly from 60% (Hurleg), from 35% (Toson), and from 10% to >50% (Gahai). The annual resolution pollen data for the last 50 years at Gahai Lake showed large changes in A/C (Artemisia/Chenopodiaceae) ratios from 0.95 which correlate with relative humidity as indicated by instrumental climate data from nearby Delingha. High A/C ratios represent increase in steppe pollen and plants, which correspond to high humidity in this region. Similar A/C ratio changes were observed at two other lakes during the late Holocene. Also, pollen assemblages dominated by desert pollen types including Chenopodiaceae (low A/C ratios) occur during low-carbonate periods, while abundant Artemisia, Poaceae and Chenopodiaceae (high A/C ratios) during high-carbonate periods. We use carbonate abundance as a measure of lake-level change and regional effective moisture. Low carbonate sediments were likely deposited in shallow water or wetland environments, while high carbonate intervals indicate relatively deep and open water environments. This interpretation of carbonate abundance was confirmed by LOI data from surface sediment samples along a transect of water depth at Hurleg Lake, which show that percentage carbonate increases from 20% at 1.1 m water to 45% at 8.6 m water. On the basis of correlations with instrumental record and with independent climate proxy (carbonate content), we conclude that A/C ratio is extremely sensitive to moisture change and can be a very useful index in high-resolution paleoclimate reconstruction in arid regions. 1182 A multi-model analysis of the inter-hemispheric differences in the response of monsoons to mid-Holocene orbital forcing and ocean feedbacks Yan Zhao, Sandy P Harrison University of Bristol, United Kingdom

We examine the response of monsoon circulations to mid-Holocene (6000 yr B.P.) orbital forcing in the northern and southern hemisphere,

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based on results from the Palaeoclimate Modelling Intercomparison Project (PMIP) and specifically 17 atmospheric general circulation models and 11 coupled ocean-atmosphere general circulation models. The atmospheric response to increased insolation in the northern subtropics strengthens the northern-hemisphere summer monsoons and leads to increased monsoonal precipitation in western North America, northern Africa and China; ocean feedbacks amplify this response and lead to further increase in monsoon precipitation in these three regions. The atmospheric response to reduced insolation in the southern subtropics weakens the southern-hemisphere summer monsoons and leads to decreased monsoonal precipitation in northern South America, southern Africa and northern Australia; ocean feedbacks weaken this response so that the decrease in rainfall is smaller than might otherwise be expected. The role of the ocean in monsoonal circulation in equatorial regions is more complex. There is no discernable impact of orbital forcing in central North America in the atmosphere-only simulations but a strong increase in precipitation in the ocean-atmosphere simulations. In contrast, there is a strong atmospheric response to orbital forcing over northern India but ocean feedback reduces the strength of the change in the monsoon although it still remains stronger than today. Although there are differences in magnitude and exact location of regional precipitation changes from model to model, the same basic mechanisms are involved in the oceanic modulation of the response to orbital forcing and this gives rise to a robust ensemble response for each of the monsoon systems. 0906 “Loess” inferring Asian desertification since 22 Myr ago identified being lacustrine and distal fan sediments Zhijun Zhao1, Chunhui Song2, Ana M Alonso-Zarza3, Jijun Li2, Jun Zhang2 1

College of Geography, Nanjing Normal Univerisity, China Key Laboratory of Western China’s Environmental Systems (Ministry of Education) , Lanzhou University, China 3 Dpto Petrología y Geoquímica. Fac. CC. Geológicas. Universidad Complutense, Spain 2

The eolian deposit historty in continental China has been extended back from Quaternary to Late Miocene, since the Red Clay in central Loess Plateau was regarded to be eolian orgin. More recently, the Late Cenozoic sediments near Qinan city in China, dated back to 22 Ma, was argued to be eolian loess to represent the onset of Asian desertification (Guo et al., 2002). The idea was based on the analysis on two sections, regional sedimentologic background was not mentioned. Here we report sedimentary investigation on the Tianshui-Qinan Basin, where the reported loess sections located in. The Neogene strata demonstrate asymmetric facies distribution within the basin; they are thick (up to 1400 m) and coarse at south near Qinlin Mts., thinner (300 m) and finer basinward to north. In order to reveal the evolution of the basin sedimentary system, two sections (Yaodian and upper part of QA-I sections) were analyzed in detail. The Yaodian section in central basin consists of 80 m of horizontally bedded, mostly soft deposits that include a wide association of carbonate facies alternating with red and green clays. There are continuous changes in colour from red to green, which occur in a decimetre scale, but in cases in levels of a few centimetres thick. These “Zebra facies” can be correlated all along the basin and represent very shallow lake environments. The upper part of QA-I section in northern basin is mostly red in colour in detail it consists of many cycles showing differences in the amount and texture of the carbonate that occur at the top of more clastic units, which represent the transition from distal fan/mudflat areas to shallow lakes. The sedimen-

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tary characteristic point out to a closed basin, with very flat topography in the inner parts, so that small variations in water and sediment supplies caused important changes in the sedimentation. The arrangement of the sediments clearly point out to periodical desiccation and subaerial exposure of both of mudflats and shallow lakes. The water laid carbonates, diagenetic processes related to high groundwater tables (groundwater calcretes), the size and types of some components (intraclasts, calcrete nodules or even the sorting of some of the sandstone deposits), and reworking process were occurred in the QA-I section. Therefore the composition and texture of the sediments make very difficult to consider that eolian processes formed all these deposits. 0917 Hydrologic response to Monsoonal variation since last deglaciation recorded in floodplain sedimentation, monsoonal China Zhijun Zhao, Qiang Shu, Ye Chen, Maoheng Zhang College of Geography, Nanjing Normal University, China

Multi-proxy measurements and AMS carbon 14 chronology were carried out on a core (630 cm in depth) recovered from the lower-reach floodplain of Huai He, which serves as the boundary between the present subtropic and temperate climatic zone in eastern China. The main climatic stages, such as the late glacial, Bolling/Allrod, Younger Dryas, and Holocene are recognized from the grain-size variation curve, occurring at 630–530, 530–465, 465–412, 412–0 cm respectively. The transitions between these main stages are characterized by marked changes of grain-size parameters. In general, the sediments are coarser during warm conditions (Bolling/Allrod and Holocene), and finer during cold period, e.g., the late glacial and the Younger Dryas event. At the transition from YD to Holocene, the medieval diameter increased abruptly from 7.3 to 6.5 (Fi Unit). During Early Holocene, grain size was gradually rising and reached maximum during middle Holocene (5.5 in average, Fi Unit), indicating strong fluvial dynamic transportation, corresponding to the maximum monsoonal precipitation during 9.3-4.4 ka. Afterwards, a prominent fining of sedimentation (6.4, Fi Unit) happened at the interval between 150 and 110 cm, representing weakened hydrologic dynamics, in response to decreased monsoon precipitation. This event may be attributed to the arid period prevailing between 4.4 and 2.1 ka. The dramatic 4.2 ka event has been extensively found in Chinese arid and semi-arid regions as well. It is likely that the collapse of Neolithic culture around Central China was a response to the climate change at 4.3 ka. The long-term trend of grain size record appears to follow the boreal summer insolation, suggesting a solar driving on the hydrologic evolution. Furthermore, even during Holocene, millennial-scale variations of grain-size are also observed. The fining-toward intervals could be correlated with the weakened monsoon events, revealed by oxygen isotope of stalagmites in China, and as well to the decreased Greenland temperature events registered in Greenland ice cores. This correlation suggests that changes in low-latitude monsoon are connected with climate change in high-latitude region. This record illustrates that the hydrologic process of the drainages in monsoonal China is sensitive to global climate changes and monsoon variation. 0216 Spatial analysis of modern pollen data from Eastern Asia and Indochina and its applications on climatic reconstruction Zhuo Zheng, Kangyou Huang, Celia Beaudouin, Chuanxiu LUO Department of Earth Sciences, Sun Yat-sen University, 510275 Guangzhou, China, China

ently achieved for use in quantitative calibration studies and paleoeclimatic reconstructions. The present database includes over 2600 samples from the eastern Asian sub-continent including mostly China, Mongolia, Russia, Japan, Korea, Vietnam, Thailand and India. A total of 1048 pollen and spore taxa are distinguished belonging to 432 families. Climate parameters such as temperature, precipitation, relative humidity, GDD5, warm index and cold index were used and interpolated to every site. Vegetation types and regional biomes were also assigned to all sites. By means of the best analogue method with squared-chord distances, most modern pollen samples can find their analogues within their own vegetation types and the climate values within their areas. Scatter plots shows that both temperature and precipitation inferred from best analogues are highly correlated with observed values. Spatial plots of pollen percentage distribution for the most abundant pollen types reveal the characteristics of contemporary pollen occurrences with the vegetation and climate. Comparison of pollen data with the georeferenced plant distribution provides a good model for the correspondence between pollen and plants. The project for establishing the database was supported by the National Natural Science Foundation of China (Grant No. 40331011). 0219 High-resolution Holocene Pollen Records from the Maar Shuangchi in Hainan Island, Tropical China Zhuo Zheng, Kangyou Huang, Hua Zhang Department of Earth Sciences, Zhongshan University, Guangzhou 510275 , China, China

The Maar Shuangchi is Located in the northern part of the Hainan Island where is the tropical zone of China and surrounded with tropical rain forest in the mountains and secondary shrubs on the basalt terrace. The lacustrine sediment deposited since the Late Pleistocene, contains continuous Holocene sequence, providing ideal material for high-resolution paleoclimatic researches. The core SC-1 is located in the center of the lake, drilling to a depth of 24.50 m. It consists of clay with plant debris and the brecciated tuff and dark basalt are found below 22.88 m. The chronological model was based on 14C dating results. The palynological study was carried on 282 samples and the most abundant arboreal pollen taxa are those of pioneer plants such as Casearia and Mallotus. The pollen taxa belonging to rain evergreen forest have a modest amount. However, the pollen of Poaceae and fern spore are abundant with mostly high percentages in the upper part of the Holocene. The Pediastrum is also important and periodically fluctuated since first appearing at ~2500 a BP. The pollen record from the Maar Lake clearly revealed various stages of environmental changes. From 9000 to 7200 a BP was the warming period with volatile rapid fluctuations, followed by a thermal maximum between 7200 and 2700 a BP. In addition, the precipitation during the Holocene thermal maximum was relatively low or remained a balance with evaporation. This result challenges the early contention that the warmer climate was likely associated with high precipitation during the Holocene. The result indicates 5 short-time events of Holocene environment change, respectively at 7750 –6120, 4460, 3850, 2700 –2200 and 1320 a BP. These rapid events are characterized by increase in eroded terrestrial material and decrease in organic matters, possibly related to distinct seasonality and catastrophic rainfalls. The research was supported by the National Natural Science Foundation of China (Grant No. 40331011).


0372 Application of Mixing Theory of Isotope in Investigation of Past climate and Environment with Speleothem Strontium Ratio: A Problem and Possible Solution Houyun Zhou1, Baoquan Chi2, Huazheng Guan2, Zhaoyu Zhu2, Yuexing Feng3, Jianxin Zhao3 1

Guangzhou Institute of Geochemistry, CAS, Guangzhou 510640, China; Dept. Earth Sci., National Cheng-Kung Univ., Taiwan 701, ROC, Cocos (Keeling) Islands 2 Guangzhou Institute of Geochemistry, CAS, Guangzhou 510640, China, China 3 Radiogenic Isotope Laboratory, CMM, University of Queensland, Brisbane, Qld 4072, Australia, Australia

The strontium (Sr) ratio (87Sr/86Sr) is often used to track the source of sediments and was increasingly used in speleothems-based investigations of past climate and environment in recent years. The Sr and 87Sr/ 86 Sr in a stalagmite from Central China were measured with ICP-AES and TIMS, respectively, in order to investigate the Sr sources to the stalagmite and their relationship with variation in climate and environment. The 87Sr/86Sr record displays a clear correlation with climatic variation, while the Sr record seems to be influenced by both variation in climate and environment and prior carbonate precipitation (PCP), with significant PCP leading to significantly higher Sr content due to the distribution coefficient of Sr between solution and carbonate that is much lower than unity. Therefore, the application of mixing theory of isotope, as has been done in many previous researches, become somewhat complicated in our study. On the plot of (1/Sr) versus 87Sr/86Sr, the Sr data influenced by PCP deviate remarkably from the others which display a clear linear relationship between (1/Sr) and 87Sr/86Sr and indicate an exogenic Sr source with 87Sr/86Sr close to the Sr ratio of carbonate fraction in local dust. PCP is common in karstic cave. Thus, mixing theory of isotope must be used carefully while analyzing speleothem 87Sr/86Sr and trying to find out the Sr sources to speleothems. A possible method to find out the influence of PCP is to test the correlation between Sr and magnesium (Mg). Because like Sr, the distribution coefficient for Mg between solution and carbonate is also much lower than unity, significant PCP would lead to a positive correlation between the two elements. Therefore the Sr-Mg correlation should provide us some information about PCP and how to use mixing theory of isotope in speleothem study. [Acknowledgements: This work is financially supported by the NNSFC project (40672120, 40331009) and the Key Laboratory of Marginal Sea Geology, CAS (GIGCX04-01)] 1150 A multiple-method approach for interpreting geomagnetic reversal boundaries in Quaternary loess Liping Zhou1, Yanming Zhu1, Xianting Xi1, Kexin Liu2, Wenling Jiang1 1

Laboratory for Earth Surface Processes, Peking University, China Laboratory of Heavy Ion Physics, Peking University, China

2

Loess is widely distributed in the mid-latitude of northern hemisphere. Chronological framework of the loess sequences is mostly constrained by the application of paleomagnetism. A basic requirement for the geomagnetic reversal boundaries to be used as an absolute chronostratigraphic marker is that the magnetic grains in loess must record and maintain the geomagnetic field directions of the deposition time, i.e. at the surface of the ancient dust accumulation. This is intrinsically

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difficult for loess deposits as the transformation of dust to loess would undergo complicated diagenetic processes, which may affect the recording of geomagnetic directions. Zhou and Shackleton (Earth and Planetary Science Letters, 168, 117–130) argued that there is a stratigraphic displacement of over several thousand years between the true geomagnetic reversal and the recorded reversal boundaries in loess. Here we test their remanent magnetization acquisition model using a multiple-method approach. We shall examine three geomagnetic reversal/excursion boundaries: Laschamp excursion at ~40 kyrs, Brunhes/ Matuyama reversal at ~780 kyrs and Matuyama/Gauss reversal at ~2.60 Myrs. We show that all these boundaries suffer the problem of delayed remanent magnetic acquisition. This leads to a discussion on the validity of the measured reversal boundaries as absolute chronological control points. We explore possible ways of shifting the measured boundaries to their true positions, hence improving the accuracy of paleomagnetic dating of loess. We shall present results of paired measurements of cosmogenic Be-10 and palaeomagnetism around the Brunhes/Matuyama boundary from two loess profiles of central Loess Plateau in China. This approach is based on the assumption that the increase of the Be-10 production rate due to the reduction of geomagnetic field intensity during the polarity reversal is significant and can be recorded in the loess sequence (Liu et al., Nuclear Instruments and Methods in Physics Research B 223–224, 168–171). We shall discuss the observed variability of Be-10 concentration in loess in terms of the changes in past climate and geomagnetic field intensity. —This study is dedicated to late Professor Sir Nicholas Shackleton who had strong interests in loess chronology. 0600 Glacial Advances in the Southeastern Tibet since late Quaternary Shangzhe Zhou1, Liu Bing Xu2, Patrick M Coglan3, David M Mickelson4, Jie Wang5, Xiaoli Wang5, Wei Zhong2 1

Member of subcommission of Glaiation, INQUA, China Department of Geography, South China Normal University, Guangzhou, China 3 Department of Geology, Grand Valley State University, Michigan, United States 4 Department of Geology and Geophysics, University of Wisconsin-Madison, United States 5 Department of Geography, Lanzhou University, Lanzhou, China 2

Southeastern Tibet is situated in the junction area of the Nyainqentanglha Shan, the Hengduan Shan and the Himalayas. As the marginal mountains of the Plateau, they are strongly cut down by the active rivers and present infantile landforms consisting of high mountain ranges and deep valleys. It is the moistest region in whole of the Qinghai-Xizang Plateau because of the Indian Monsoon influence. The precipitation richly feeds the mountain glaciers so that the snowline here is about 1400 –1600m lower than northern slope of the western Himalayas and the central Plateau, as low as in Qilian Shan, 1000 km northward. Southeastern Tibet is also one of the greatest extent areas for Quaternary glaciations. Two late Quaternary glaciations were recognized in this region based on glacial sediment and landforms. They were termed Guxiang Glaciation and Baiyu Glaciation respectively. During Guxiang Glaciation, the glaciers (10 –20 km long today) joined together to formed braided glaciers and reached 100 km long in the Boduizangbu Valley and 200 km long in the Chayu Valley. During Baiyu Glaciation, the glacier in Boduizangbu Valley reached 800 km long. Recent years we dated these two glaciations using CRN method, the result indicate that Guxiang and Baiyu Glaciations have exposure ages of 112.9±16.7~136.5±15.8 ka BP and 11.1±1.9~18.5±2.2 ka BP,

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respectively. It is likely that the Guxiang and Baiyu Glaciations correspond to marine isotope stages 6 and 2, respectively. Between them there still exist other moraines that are probably for MIS-4 or MIS-3. Considering the depressions of the snowlines and vegetation proofs from a lacustrine core, the annual air temperature should be 6.6 ˚C below present during LGM, and the annual air temperature descent for Guxiang Glaciation should be close to 7.8 ˚C.

0641 Holocene environmental changes reflected from the core sediments in Nam Co, central Tibet of China Liping Zhu1, Junbo Wang1, Yanhong Wu2, Manping Xie1, Minghui Li1, Gerhard Daut3, Roland Mäusbacher3, Antje Schwalb4 1

Institute of Tibetan Plateau Research, CAS, Beijing 100085, China, China Institute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101, China, China 3 Institut für Geographie, Friedrich-Schiller-Universität, Jena, Germany, Germany 4 Institut für Umweltgeologie, Technische Universität, Braunschweig, Germany, Germany 2

0377 Extracting geomagnetic signal from an 80ka 10Be record in Chinese loess Weijian Zhou1, Warren Beck2, Alfred Priller3, Zhengkun Wu1, Maobai Chen3, Zhisheng An1, Walter Kutschera3, Feng Xian1 1

Institute of Earth Environment, Chinese Academy of Sciences, China 2 NSF-Arizona AMS Facility, Physics Department, Building #81, University of Arizona, Tucson, Arizona, USA, United States 3 Vienna Environmental Research Accelerator, University of Vienna, Austria, Austria

Numerous previous studies have measured remnant magnetism or cosmogenic 10Be concentrations in loess. While these have provided useful information about climate or about fluctuations in the orientation of the geomagnetic field, attempts to extract paleomagnetic intensity records from loess have largely been unsuccessful. Although 10Be flux is regulated by geomagnetic field intensity, extracting an intensity record from loess 10Be is complicated by reworked dust that contains 10Be which fell at some time in the past. An additional complication results from the fact that the local flux of new 10Be fallout recently generated by cosmic ray interactions in the atmosphere depends on the local rainfall rate. A new approach is taken in this work to remove these effects by observing that loess magnetic susceptibility also has an inherited dust component as well as a pedogenic component which also depends on moisture availability, e.g. rainfall amount. To constrain the fraction of 10Be resulting from reworked dust we observe loess magnetic susceptibility plotted against loess coercivity defines a two component mixing curve between dust and pedogenic end-member components. This allows us to define the dust end member for loess susceptibility which corresponds to loess generated during the driest time frames. We define the 10Be dust end member as that concentration found in the same loess horizons that define the dust end member for susceptibility. To remove the dependence on rainfall amount, we make use of the correlation between 10Be concentration and loess magnetic susceptibility, which both depend on wet precipitation amount. After removal of the dust and precipitation-amount effects, we then observe the residual variance in 10Be concentration which is due mainly to geomagnetic modulation of 10Be production rate, and variations in sediment accumulation rate. Converting these concentrations to flux using sediment accumulation rates, we produce a high-resolution 10Be production rate record from the Luochuan loess for the past 80 ka. After normalization to modern flux we convert this production rate record to magnetic field intensity. The resultant record exhibits strong coherence with the SINT200 and NAPIS 75 records, and shows two geomagnetic low intensity events which we believe to be the Laschamp and Mono Lake events.

Tibetan plateau is a sensitive area to global changes due to its high elevation and frail surface ecosystem. The existence of the huge plateau induce and enhance the Asian monsoon that influences the plateau itself and east China, even the Asia areas. Pursuing the changing history of the monsoon and its impact in this environment-sensitive area is a core content for understanding the rules of climatic changes. Here, we present the initial results from a core sediments in Nam Co, central Tibet to elucidate the Holocene environment changes in this area. Nam Co is the second largest lake, with elevation of 4716m, water area of 1980km2 and catchment area of 10610km2, on the Tibetan Plateau. By using echo-seismic profiler and hydro-echo-sounder, we investigated the water depth distribution of the most areas of the lake. One 340-cm long PISTON core was successfully taken in the east part of the lake at the site of 60m water depth. 10 AMS 14C dating data from top to bottom showed a good ranking that established the time sequence of this core. TOC, TN, grain-size, Fe/Mn, Sr/Ba and CaCO3 content were analyzed with the sample intervals from 1cm to 10 cm. Results showed that Holocene environment changes in this region might be distinguished into three stages. Early stage is from 96007200 aBP that is characterized by warm climate with a cold-dry process during 8700–8200 a BP. Middle stage was from 7200-3000 a BP, in which climate changed from warm-humid to warm-dry. However, climate once appeared relatively cold and dry features from 4400 to 3800 a BP. Late stage was from 3000 aBP to present that showed a fluctuant cold-dry-toward tendency. The first temperature decline was around 3000 a BP, following which temperature was recovered. But temperature decreased again around 2000 a BP. A short period with temperature increasing occurred during 700–500 a BP, which might be the delay effects of Middle Ages Warming. 0419 The Evaluation of 14C-AMS dating Shells from Shaanxi in China Yizhi Zhu, Peng Chen, Huagui Yu, Zhihai Kang Institute of Earth Environment, Chinese Academy of Sciences, China

The datable materials in Loess Plateau are scarce. Since Fossil shell is an alternative dating material which deposit only aragonite to form their shell structure, and shell integrity can be easily observed using X-ray diffraction. Here we tested the feasibility of dating terrestrial molluscs from the semiarid and arid zone Shaanxi in China and the possibility of estimating microenvironmental changes from shell d13C values, but variations within shell populations preclude the use of these values as a reliable indicator. Reservoir ages were calculated for living shell of the same species as fossil shells by using their measured 14C ages, which were recalculated using an average value of atmospheric 14 C activity for the years spanning their time of collection as the modern standard. The results indicate that the terrestrial shell are


potentially useful as dating material, provided extreme care is taken in their collection and other datable material (in this case pollen) is within the profile to act a comparison. 0156 Holocene fluvial chronology of Tunisia: 4.7 ka hydroclimatic shift and short-term changes in climate driven fluvial dynamics Christoph Zielhofer Department of Geography, Osnabruck University, Germany

Holocene 14C cumulative probability plots of cohesive floodplains from arid to semiarid Tunisia document the preservation and the hydroclimatic interpretation potential of these floodplain types. 14C dates from redeposited charcoals, mulluscs or bones have been considered in the data set that represent ‘change dates’, indicating processes of active fluvial dynamics. In contrast to the ‘change dates’, a lot of 14C ages in Tunisian cohesive floodplains represent alluvial stability, or periods of minor floods: bulk samples of autochthonous and redeposited alluvial soils reveal radiocarbon data from pedogenetic organic material. Regardless of the sedimentological context – in situ humification or redeposited A horizon – the creation of pedogenetic organic material took place during periods of soil formation and landscape stability. Hence, for Tunisian semiarid floodplains two completely independent 14C data sets are available. The former (73 ‘change dates’) represents alluvial activity, the latter (111 ‘stability dates’) marks periods of minor floods and landscape stability. Regarding the representativeness of the two alluvial 14C data sets and from the geomorphological point of view, ‘change dates’ showing phases of fluvial activity and ‘stable dates’ should have been mutually exclusive. There is a good match for the Mid-Holocene with increased periods of flooding from 6.2 to 6.0, 4.7 to 4.5, 4.1 to 3.7, and 3.3 to 3.0 ka. These flood periods coincide with low soil formation signals. On the other hand periods of increased alluvial soil formation from 6.8 to 6.6, 5.9 to 4.8, 4.5 to 4.1, 3.7 to 3.3, 3.0 to 2.8, and 1.8 to 1.6 ka coincide with periods of low flood plain aggradation. Increased flooding after 4.7ka shows a good positive correlation with North Atlantic cooling events. However, before 4.7ka cooling events in the North Atlantic coincide with decreased flooding and soil formation. The comparison of Holocene floodplain dynamics in semiarid Western Mediterranean with those of the temperate mid-latitudes might show Mid-Holocene hydroclimatic switches with opposite signs. North Atlantic driven flooding in the temperate central European regions becomes much weaker after 5 ka and in semiarid Mediterranean North Africa it becomes much stronger. 0157 Holocene and Late Pleistocene soils in Mediterranean fluvial environments

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only few soil formation features and a correlation with soil formation duration remains difficult. In this study Profile Development Indices (PDI) of late Pleistocene initial Chromic Alfisols and slightly developed Holocene Cambisols and Fluvisols are presented, revealing clear characteristics of the local alluvial parent material. A correlation of soils of different ages with maturity stages is possible, but the approximately homogenous environment of the floodplain has to be considered. A correlation with maturity/age soil ratios from other Mediterranean environments remains speculative. Therefore, the PDI must be discussed here very carefully. However, PDIs from late Pleistocene and Holocene alluvial sequences may correspond with estimated soil ages. They reveal an useful tool for stratigraphic correlation and for calculating periods of landscape stability within a late Pleistocene to Holocene alluvial environment. 0164 Mid-Holocene change in fluvial dynamics and past human response in the Western Mediterranean Christoph Zielhofer1, Dominik Faust2, Jens Bussmann1 1

Department of Geography, Osnabruck University, Germany Chair of Physical Geography, Dresden Univeristy, Germany

2

We present Holocene average sedimentation rates and 14C cumulative probability plots from semiarid Mediterranean floodplains in Northern Africa to document their hydroclimatic interpretation potential. Beside own 14C dates more than 100 dates of other research groups have been assembled into the database. In addition, we compare the findings from fluvial records with radiocarbon data sets from archeological sites in the region. Average sedimentation rates and 14C cumulative probability density plots from Holocene floodplain sequences in West Mediterranean reveal a coupling with North Atlantic cooling. Short-term periods of fluvial activity match well with North Atlantic Bond events. The findings indicate a strong climatic link from 4.7 ka until today. Our results provide evidence that Mid- to Late Holocene fluvial dynamics in semiarid Mediterranean North Africa were chiefly driven by climate. Anthropogenic impact intensified or attenuated geomorphic processes at most. The 14C cumulative probability density function of archeological sites in Mediterranean North Africa indicates that prehistoric societies seemed to be very sensitive to environmental shifts through time. 1042 Middle to late Pleistocene sand sheets and calcic paleosols in the eastern Ezra Zilberman1, Naomi Porat2, Rachel Menashe2, Rivka Amit2, Yehuda Enzel3 1

Israel Geological Survey of Israel, Israel 3 Hebrew University, Israel 2

Christoph Zielhofer Department of Geography, Osnabruck University, Germany

Mediterranean alluvial deposits are important archives for the reconstruction of paleoenvironmental conditions within the scope of Quaternary research. Here, the interpretation and identification of alluvial paleosoils offer essential information for the reconstruction of alluvial environments. Especially in well-developed Pleistocene soils a lot of soil formation features are helpful to quantify development duration and to give relative age controls. However, slightly developed Holocene alluvial soils show

Extensive sand sheets cover the semi arid western Negev, Israel, starting ~10 km inland. This flat terrain is separated from the coast by eolianite ridges locally named Kurkar that has intermittently formed along the eastern Mediterranean coast line since the Late Pliocene. The lower part of the sand sheet sequence is exposed in Tel Sharuhen, unconformaly overlying a late Pliocene coastal eolianite ridge. It consists of 17 sand units, each containing a Stage II-III calcic paleosol. The IRSL ages of this sequence range from 532±30 ka at the bottom to 334±23 ka at the top.

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The upper part of the sand sheet sequence was exposed in a pit 20 km to the southwest. It is comprises seven sandy units with calcic paleosols, and ranges in age from more than 400 ka at the base to 14 ka at the top. The contact between the sand units is sharp and the top of most of the paleosols was slightly eroded. Combined, at least 20 units compose the middle-late Pleistocene sandy sequence in the western Negev. Each started with sand deposition, continued with a period of landscape stability and formation of a calcic soil, and terminated in minor erosion by wind deflation, marking the beginning of a new phase of sand incursion due to strengthening winds. The time of sand sheet deposition is well correlated with the incursion of the late Pleistocene coastal Kurkar ridges. During periods of calcic soil formation in the Negev sand sheets, a red loamy soil (locally termed Hamra) developed in the more humid coastal plain further to the north. The prevalence of calcic paleosols in the sand sheet sequence indicates a semi arid climate, similar to the present. In this sandy sequence, where the major source of carbonates is in dust, it takes more than 10 ky to develop stage II calcic soil and 40–50 ky to develop a Stage III calcic soil. The sand sheet sequence consists a late Pleistocene archive for climatic fluctuations in the eastern Mediterranean, manifested by episodes of sand incursions alternating with periods of soil development. 0347 ENSO and IOZM teleconnection in SST and the hydrologic balance between 1865-1994 revealed by coupled coral Sr/Ca and oxygen isotope record from Mayotte (N Mozambique Channel) Jens Zinke1, Oliver Timm2, Miriam Pfeiffer3, Wolf-Christian Dullo3, Bernard A Thomassin4 1

Vrije Universiteit Amsterdam, The Netherlands SOEST Hawaii, United States 3 Leibniz Institute, IFM-GEOMAR Kiel, Germany 4 Centre d’Oceanologie Marseille, France 2

We present the first coupled coral Sr/Ca and d18O record from the western Indian Ocean located within the ITCZ region dating back to the mid 19th century (1865 to 1994). For the first time, we can independently reconstruct SST and precipitation-evaporation changes over more than 100 years over the western Indian Ocean. We investigate the stability of the El Nino-Southern Oscillation (ENSO) and Indian Ocean Zonal Mode (IOZM) correlation in the western Indian Ocean for austral spring and summer (September to November, November-April). On interannual time scales our results indicate that the ENSO and IOZM-SST correlation at Mayotte was stable throughout the entire 127 years of record. Deconvolving the oxygen isotope composition of the seawater gives a reliable indication of the regional precipitation-evaporation balance in the northern Mozambique Channel. We find interannual and decadal variations with a most significant frequency of 5-6 years. The reconstructed oxygen isotope composition of the seawater for the rainy season (October-March) is coherent with the IOZM and East African rainfall variability on interannual to interdecadal time scales. We propose a close link between hydrologic changes over the northern Mozambique Channel and changes in the sea surface temperature difference between the western and eastern tropical Indian Ocean steered by Indian Ocean Zonal Mode and/or ENSO variability. A combined coral d18O index for the western Indian Ocean is presented that reveals stationarity in the relationship between East African rainfall and western Indian Ocean SST back to 1866. The correlation

of the d18O signal with ENSO and IOZM significantly strengthens by combining multiple coral records from the western Indian Ocean. 0348 Circum Indian Ocean marine and terrestrial records of climate variability: investigating land-ocean interaction since A.D. 1650 Jens Zinke1, Miriam Pfeiffer2, Oliver Timm3, Traute Crueger4, Wolf-Christian Dullo2 1

Vrije Universiteit Amsterdam, The Netherlands Leibniz Institute, IFM-GEOMAR Kiel, Germany 3 IPRC/SOEST Hawaii, United States 4 Max Planck Institute for Meteorology Hamburg, Germany 2

In this study we examine the relationship between three tropical and two subtropical western Indian Ocean coral d18O time series to land temperatures and rainfall over India, tropical East Africa and southeast Africa with a special emphasis on decadal to multidecadal variability. The western Indian Ocean tropical and subtropical coral d18O time series show a strong correlation with land temperatures on interannual to multidecadal time scales. We find coherent signals at frequencies ranging from 18–45 years with surface temperature over western India and East Africa. Coral d18O time series from the subtropical western Indian Ocean show a strong correlation with South African temperature variability in the 16–30 years frequency band over more then 300 years. The relationship between western Indian Ocean SST and rainfall over land areas is more complex. Running correlation analysis suggests a non-stationary relationship of tropical coral d18O time series and rainfall over India during the SW monsoon and the short-rain season over East Africa. Strongest decadal coherence is found between the subtropical d18O time series and southern Africa rainfall. Comparison with paleoclimatological reconstructions of either rainfall or temperature over land areas reveals that most relationships established for the 20th century, also hold for the last 350 years. However, we also find evidence for changing teleconnection patterns, most prominent during the late 20th century. Thus, the network of coral records from the Indian Ocean proves invaluable for a better understanding of land-ocean interaction over several centuries. 0223 Continental sediments since the mid-Pleistocene from Laguna Potrok Aike, Argentina — the proposed ICDP deep drilling project PASADO Bernd Zolitschka1, Flavio Anselmetti2, Daniel Ariztegui3, Hugo Corbella4, Marc DeBatist5, Catalina Gebhardt6, Frank Niessen6, Christian Ohlendorf7 1

GEOPOLAR, Institute of Geography, University of Bremen, Germany ETH Zurich, Geological Institute, Switzerland 3 University of Geneva, Institute Forel, Switzerland 4 Argentine Museum of Natural History, Argentina 5 Ghent University, Renard Center of Marine Geology, Belgium 6 Alfred-Wegener-Institute for Marine and Polar Research, Germany 7 Geomorphology and Polar Research (GEOPOLAR), Institute of Geography, University of Bremen, Germany 2

An international team of scientists has been attracted to coordinate the “Potrok Aike Maar Lake Sediment Archive Drilling Project” (PASADO) which has been submitted in the framework of the “International Continental Scientific Drilling Program” (ICDP). The main objective


of PASADO is to develop an environmental, climatic and volcanological science network focussing on (A) quantitative climate reconstruction in combination with proxy-model intercomparison and (B) investigation of the phreatomagmatic formation and analysis of early sedimentation in a young maar-diatreme structure. Within PASADO it is proposed to recover long sediment cores from Laguna Potrok Aike, a 770,000 year old maar lake in the dry steppe of southern Patagonia, Argentina (52°S, 70°W; max. depth: 100 m; diameter: 3470 m). Seismic surveys demonstrate that at least 400 m of pelagic sediments were deposited in the lake centre underlain by an unknown thickness of volcaniclastic breccias. Based on seismic data, three drilling sites were selected: (1) from the deepest part of the lake to (i) obtain a continuous and high-resolution record of climatic and environmental changes and (ii) unveil the phreatomagmatic history including more precise age constrains for the maar-diatreme formation from the volcaniclastic sediments below, (2) from a subaquatic lake level terrace at 35 m water depth to constrain the range of lake level variations and (3) from an angle hole passing through lacustrine sediments and the crater wall into the basement rocks (molasse sandstones) to study the impact of explosive volcanism, post-eruptive structural evolution and early processes of sedimentation in a mid-Pleistocene maar. It is anticipated that this site will develop into a key site of the Southern Hemisphere that will improve our understanding of climatic teleconnections and interhemispheric differences. Moreover, this region close to the Andean volcanic chain is subject to shifts in polar and mid-latitude pressure fields and affected by the El Niño Southern Oscillation (ENSO) as well as by the Antarctic Oscillation (AAO). This lacustrine Patagonian archive thus can potentially provide unique terrestrial records of variations in climate, hydrology and deposition of airborne particles. Furthermore, such a record acts as a cornerstone for palaeodata-model comparison. Links will also be established to ice cores from Antarctica and to marine records from the Southern Oceans where dust and tephra of Patagonian provenance have been detected. 0331 The MIS5 and MIS1 marine sequences in the Pearl River delta/ estuary, China Yongqiang Zong1, Wyss Yim2, Guangqing Huang3 1

University of Durham, United Kingdom The University of Hong Kong, Hong Kong 3 China 2

In the Pearl River delta area, China, two marine units were recorded and studied, and a six-division lithostratigraphy was suggested as the model of late Quaternary coastal stratigraphy for southern China. Based on radiocarbon dates, this model attributes the older marine unit to MIS3 in age (around 32,000 years BP) and the younger marine unit to the Holocene. Subsequently, Yim et al. (1990) examined the chronology of the older marine unit and suggested that the unit belonged to MIS5 in age. This suggestion was supported by others who have examined the unit in the Hong Kong area. This paper re-examines the lithological and microbiological evidence of the two marine units in the context of the Pearl River delta/estuary, China, to help determine their spatial distribution and understand the conditions under which these marine units were deposited. The analyses are based on the newly developed diatom-based water salinity transfer function which is applied to a number of sediment cores. The results show (1) the older marine unit exists extensively within the delta/estuary and had been cut through by palaeo-river channels during the last glacial period; (2) the preservation of microfossil is much poorer in the older marine unit than the younger marine unit; and (3) the levels of the reconstructed water salinity from both units are very similar,

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implying similar environmental conditions – height of sea level and the amount of monsoonal freshwater discharge – between MIS5 and MIS1. 0330 Postglacial sea-level change, freshwater discharge and evolution of the Pearl River delta, China Yongqiang Zong Department of Geography, University of Durham, United Kingdom

This research aims at examining the history of coastal evolution of the Pearl River Delta, as a case study for land-sea interaction in a large delta of a monsoonal region. Specifically, this research investigates, along with others, two important controlling factors in the evolution of the delta, namely sea-level change and freshwater flux, the latter also implies sediment supply. Discussions are centred at the effects of these controlling factors upon the development of the litho-stratigraphies of the deltaic complex. Based on a large number of borehole records and sedimentary studies, the palaeo-geography is reconstructed, showing landscapes of incised valleys with marine terraces of MIS 5 in age. According to the sea-level index points compiled, the history of relative sea level shows a period of rapid and continuous rising sea level between 12,000 cal. years BP at −25m and 7000 cal. years BP at present height, followed by a period of stabilised sea level with little fluctuation in the last 7000 years. Diatom data obtained from sediment cores indicate significant changes in freshwater flux since the monsoon regime started intensifying at c. 11,000 cal. years BP. Freshwater flux appeared to be strongest at about 9000 –7000 cal. years BP during which relative sea level rose at a rate of c. 7.5 mm/a. Since this period, freshwater flux became weakened towards present. Under the influence of the sea-level and freshwater flux factors, the postglacial lithostratigraphies of the deltaic complex were developed on the palaeo-landscape and comprise: (1) a sandy unit in the landward halve of delta plain, which become finer in the seawards halve of the plain as a result of strong freshwater flux that counter-balanced the effects of rising sea level between 9000 and 7000 cal. years BP; (2) a marine siltclay unit corresponding to a gradual decline of freshwater flux of 7000 –1500 cal. years BP; and (3) a sandy unit developed in the past 1500 years as sediment supply increased resulted from intensifying human activities. The delta plain emerged in the last 1500 years and its shoreline advanced rapidly. 0008 En route to Sahul: New evidence for early modern human colonization east of the Sunda Shelf Sue O’Connor Australian National University, Australia

New archaeological finds from East Timor dated to >42,000 calBP (38,255 ± 596 bp) provide the earliest evidence for migration by modern sapiens east of the Sunda Shelf into Island Southeast Asia. Until now there has been a major discrepancy between the dates for earliest occupation in Australia and those from Island Southeast Asia, with the earliest dated sites from Australia being significantly older than the oldest sites from any of the potential stepping stone islands en route (even relying purely on the radiocarbon chronology). Although a southern route through the Lesser Sunda islands (including Flores and Timor) has usually been proposed as the most parsimonious for maritime passage to Sahul (the ancient continent that encompassed Australia and New Guinea), the lack of early dated evidence on any of the stepping stone islands of this group has recently led some researchers

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to propose alternative routes (albeit totally lacking in evidence for early colonization). Perhaps the greatest recent challenge to the southern colonisation route has been presented by the recovery of Homo floresiensis from Liang Bua in Flores, Timor’s western neighbour island. These diminutive non-moderns apparently survived on Flores until 12,000 years ago and modern humans failed to colonise prior to the Holocene. The new evidence from East Timor indicates that the southern route is still the best bet for the earliest seafaring passage to Sahul, but raises many questions about how modern humans managed to colonise Timor and not Flores. The nature of the cultural evidence from East Timor is evaluated in order to demonstrate that it is qualitatively different from the assemblage produced by the non-moderns from Liang Bua, as well as for its significance in contributing to our understanding of the types of adaptations made at this early date en route to Sahul. 0079 Dynamics of the ice-dammed lake outburst floods in the AltaiMountains, Siberia Jürgen Herget1, Paul A Carling2, Pavel S Borodavko3, Peter Martini4, Barbara Mauz5, Herve Morvan6, Anne Reuther7, Ignacio Villanueva8 1

Dept. of Geography, University of Bonn, Germany School of Geography, University of Southampton, United Kingdom 3 Dept. of Geology and Geography, University of Tomsk, Russia 4 Land Resource Science, University of Guelph, Canada 5 Dept. of Geography, University of Liverpool, United Kingdom 6 School of Civil Engineering, University of Nottingham, United Kingdom 7 Dept. of Earth Sciences, Dalhousie University Halifax, Canada 8 School of Civil Engineering, University of Nottingham, United Kingdom 2

In the Altai-Mountains, located in south-central Siberia, ice-dammed lake outburst floods took place in the late Pleistocene along the valleys of Chuja and Katun River, tributaries of the River Ob. In addition to previously published reviews, new details on the dynamics of the jökulhlaups are derived from geomorphological and sedimentological evidence in the field and are supported by palaeohydraulic modelling. A network of valley glaciers blocked the course of the River Chuja near the small town of Aktash and generated an ice-dammed lake in the intramountainous basins in the headwaters with an volume of up to 600 km3. When the ice-dam failed, a flood with depths of flow of up to 350 m and peak discharges of 10 x 106m3/s filled the downstream valleys of Chuja and Katun River. Evidence by pond sediments and gravel dunes indicating flow up- and downstream reveal, that the flow went even upstream along the valley of Katun River and inundated parts of the headwaters up to the elevation of the water level in Chuja valley. In a minor tributary of Katun River, interbedded lake and suspension load deposits indicate at sleast 3 separate outburst floods of similar magnitude. Analysis of the giant bar sedimentology along the flood’s pathway hint for several flood pulses within single flood events caused by a complex failure mechanism of the ice dam. While luminescence dating is problematic due to limited bleaching of the sediments, exposure dating of large flood transported boulders shows that the last large scale flood event took place at 15.8 ± 1.8 ka; minor floods might also have occurred but are not clearly to identify by the left over flood traces. 0150 New multi-source tephra record in Auckland maars: Implications for volcanic frequencies and hazards Catherine M Molloy, Phil Shane University of Auckland, New Zealand

The study of late Quaternary tephra in New Zealand plays a vital role in constructing a chronology of paleoclimatic events and the eruptive history of the major volcanic centres. Sediment sequences in Auckland maar craters contain tephra which provide insight into the likelihood of future eruptions on New Zealand’s largest metropolitan area and age control for poorly dated basaltic eruptions from the Auckland Volcanic Field. A 49 m long core extracted from the infilled Hopua basaltic explosion crater recovered 37.5 m of mid to late Holocene marine silts. The marine silts overlie 11.5 m of finely laminated lacustrine sediments which contains 29 well preserved tephra beds ranging in thickness from 0.5 mm to 460 mm. The tephra have been derived from local and distal sources (>200 km). Six were erupted from the Okataina Volcanic Centre, three from the Taupo Volcanic Centre, one from Mayor Island, eleven from the Egmont Volcanic Centre, three from the Tongariro Volcanic Centre, and five from the Auckland Basaltic Field. The tephra beds were identified by stratigraphic position and through the correlation of microprobe geochemistry with tephra beds in other maar craters. The tephrostratigraphic framework is underpinned by five rhyolitic tephra beds, namely Tuhua (c. 7005 ± 155 cal yr), Rotoma (c. 9505 ± 25 cal yr), Opepe (c. 10,075 ± 155 cal yr), Waiohau (c. 13,635 ± 165 cal yr), and Kawakawa (c. 26,500 cal yr). Three of the Egmont tephra and one Tongariro tephra cannot be correlated with those in other maar craters and may represent previously unrecognised eruptions. New stratigraphic control provides age estimates of 10, 19.38, 19.42, 25.2 and >27.2 ka for eruptions from the Auckland volcanic field. The core contains highly deformed sediment in the following time intervals: 10–13.6, and 15.4–18 ka. This may represent previously unrecognised paleoseismic events. The tephra record indicates that the Auckland City region has been frequently impacted by ash fall from many sources. The assessment of the event frequency, from both distal and local fall deposits, can provide reliable data for hazard reoccurrence calculations. It appears from this record that volcanoes distant from Auckland present a greater civil hazard than local volcanoes. 0264 Laguna Potrok Aike — a terrestrial link to marine and ice-core records of the southern hemisphere Torsten Haberzettl1, Andreas Lücke2, Barbara Mauz3, Christoph Mayr4, Christian Ohlendorf5, Frank Schäbitz6, Sabine Wulf7, Bernd Zolitschka5 1

Sedimentology and Environmental Geology, Geoscience Center, University of Göttingen, Goldschmidtstr. 3, 37077 Göttingen, Germany 2 Institute for Chemistry and Dynamics of the Geosphere (ICG) V: Sedimentary Systems, Research Center Jülich, 52425 Jülich, Germany 3 Department of Geography, University of Liverpool, Liverpool L69 7ZT, UK, United Kingdom 4 GeoBio-Center LMU, Richard-Wagner-Str. 10, 80333 Munich, Germany 5 Geomorphology and Polar Research (GEOPOLAR), Institute of Geography, University of Bremen, Celsiusstr. FVG-M, 28359 Bremen, Germany 6 Seminar for Geography and its Didactics, University of Cologne, Gronewaldstr. 2, 50931 Cologne, Germany 7 Institute for Geophysics, Jackson School of Geosciences, The University of Texas at Austin, 4412 Spicewood Springs Road, Austin, United States

The 100 m deep Laguna Potrok Aike (52°S, 70°W), a maar lake in the dry steppe of southern Patagonia, is potentially the only site that can provide continuous, high-resolution sediment records that cover several glacial/interglacial cycles potentially back close to the Brunhes/ Matuyama boundary. The amount of precipitation in this region is not only related to the rain shadow effect of the Andes but also to the meridional migration of the Southern Hemispheric Westerlies. This factor


controls potential evaporation, too. Previous studies demonstrated that lakes in the steppe of Patagonia are sensitive to variations of the evaporation/precipitation ratio. Laguna Potrok Aike provides a unique terrestrial record of environmental changes in this area during the last 53,000 years. A 19 m piston core comprises the last 16,000 cal. BP and exhibits variations in the content of total inorganic carbon and calcite. Monitoring data suggests that these changes mirror variations in the water volume of the lake and thus reflect alterations of the hydrological cycle. Changes in the minerogenic input to the lake via runoff support this hypothesis. Comparisons with the records from Lago Cardiel show a synchronicity of long lasting paleoclimate variations in the steppe area of southern Patagonia during the last 16,000 cal. BP. New OSL-dates from an additional sediment core form Laguna Potrok Aike, however, enable a temporally more extended insight into paleoenvironmental variations during a part of oxygen isotope stage (OIS) 3, i.e., 25.5–53 ka, a period dominated by high lake levels. Moreover, Patagonia is a prominent source of volcanic tephra layers spread by the strong westerly wind. Therefore, ashes can serve as ideal isochronous marker horizons for inter-archive correla¬tion across southern South America, the South Atlantic and Antarctica. In addition to the known Holocene tephra layers, ashes from Reclús and Mt. Burney volcanoes, all erupted during OIS 3, were found in the record of Laguna Potrok Aike. Using the new OSL-dates it was possible to provide more precise ages for these isochrones. Therefore, the presented data of hydrological variability from Laguna Potrok Aike during the last 53 ka in combination with the mentioned tephra layers strengthens the possibilities to use this record to link terrestrial with marine and ice core records of mid to high southern latitudes. 0387 Radiocarbon dating of humus and carbonates in the Russian steppe paleosols on different parent rocks Olga S Khokhlova1, Alsu M Kouznetsova2, Olga A Chichagova3 1

Institute of Physical, Chemical and Biological Problems of Soil Science Ras, Pushchino, Moscow Region, 142290, Russia 2 Laboratory of Electronic Microscopy, Department of Biology, Lomonosov State University, Moscow,119899, Russia 3 Laboratory of Radiocarbon Dating, Institute of Geography Ras, Staromonetnyi Per., 29, Moscow, 109017, Russia

The radiocarbon (RC) dating of humus and carbonate accumulations (CAs) from two Holocene chronosequences of paleosols buried under the archaeological monuments (kurgans) and developed on sandy and loamy parent rocks has been carried out in the steppe Pre-Ural region of Russia. Two chronosequences studied were located in the vicinity to each other at the same geomorphological, hydrological and climatic conditions. The background soils formed on the studied area are the Southern Chernozems. In two chronosequences the background soils and paleosols buried under the same archaeological culture kurgans have been compared in pairs. The aim of the work was to detect connection between humus and carbonate profiles and its changes with time on the basis of RC dating of humus and CAs in the chronosequences of soils derived from different parent rocks. The RC age of humus and CAs collected from the same depths in the even-aged soils on the loamy rocks is older than in the soils on sandy rocks in all cases. It means that for the chronointerval studied the carbon rejuvenation in humus and CAs of the soils derived from the loamy rocks was slower than in the sandy soils. The difference between RC dates of CAs and humus in the loamy soils is higher than in the sandy soils in all cases and it increases from the middle Holocene to nowadays in both chronosequences. This is seeming evidence of slower rejuvenation of carbon in CAs in comparison with humus, as

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if it is some part of carbon in CAs does not rejuvenate with time. However, if we compare RC age of CAs in neighboring soils step by step inside the chronosequence with time-span between the dates of their burials, there were periods both of considerable decreasing and disproportionate increasing of RC age of CAs. This regularity is especially clear evident in the paleosols with distinctly expressed arid properties regardless of the date of their burial. The difference between RC dates of CAs and humus increases every time in arid epochs and at that the RC age of CAs increases quicker than that of humus. It means that the carbonates have another source of “old” carbon in addition of that from the humus mineralization. Micromorphological observations suggest that it might be a movement of carbonates in soil profile as a colloidal suspension. This work has been supported by RFBR, grant N 04-05-64303. 0518 Sediment source fingerprinting: determining the controls of longterm fluvial system development Liz Maher University of Wales, Aberystwyth, United Kingdom

Sediment provenance studies provide important information for geomorphological investigations regarding spatial and temporal variations in sediment supply, and consequently variations in catchment sediment dynamics. Such variations may be linked to climate change, tectonism, river-capture and base-level change and can occur on varying temporal and spatial scales. The Rio Alias is an ephemeral transverse fluvial system developed within the basin and range setting of the Betic Cordillera, SE Spain. The lithologically diverse catchment lends itself to studies regarding sediment provenance variations that have been caused by river –capture events, tectonic pulses as well as by the progressive development of the landscape. The Rio Alias is a gravel bed river and both coarse and fine sediment assemblages were examined. Clast analysis (lithology, shape & size) was carried out on the >2cm clasts. Petrological thin section analysis, SEM analysis and environmental magnetism was performed on the