magnitudes of different environmental parameters are not weU ..... ing group structure needed some revision and reorganization. ... overlapping recommendations of areas of future research were ... sphere models is currently a major effort in climatology, but ..... biosphere, hydrosphere, and lithosphere-a stability that was,.
Geological Society of Americ;1 Special Paper 288
1994
Introduction: Project Pangea and workshop recommendations George D. Klein New Jersey Marine Sciences Consortium, Building #22. Fort Hancock, New Jersey 07732
BenoitBeauchamp Institute of Sedimentary and Petroleum. Geology, Geological Survey of Canada, 3303 33rd Street NW, Calgary, Alberta,
T2L 2A7, Canada
With contributions by:
AymonBaud Musee Geologique, UN/L-BFSH 2, CH-10/5 Lausanne, Switzerland
Boris I. Chuvashov Institute of Geology and Geochemistry, Academy of Sciences, Uralian Branch, Pochtovyi per 7, 62009 Cateriniburg, Russia
Oscar R. Lopez-Gamundi Frontier Exploration-South America, Texaco, 4800 Fourace Place, Bellaire, Texas 77401-2324
Judith T. Parrish Department of Geosciences, Gould-Simpson Building 77, University of Arizona, Tucson, Arizona 85721
Charles A. Ross Geostrat Consultants, 600 Highland Drive, Bellingham, Washington 98225-6410
Peter A. Scholle Department of Geological Sciences, Heroy Building, Southern Methodist University, Dallas, Texas 75275
Christopher R. Scotese Department ofGeology, University of Texas at Arlington, P.O. Boz 19049. Arlington, Texas 76019
W. Lynn Watoey Kansas Geological Survey, 1930 Constam Avenue, Lawrence, Kansas 66047-2598
PREAMBLE
tectonics, including the assembly and breakup of superconti nents, and solar-driven processes (extrinsic) that influence
A major number of problems concerning the nature and consequences
of
natural
or
anthropogenic
environmental
long-term and short-term climatic changes, such as advance and retreat of continental glaciers, changes in upweUing cy
change can be solved only by the geological sciences. Many of
cles, changes in monsoonal climate patterns, and desertifica
these problems require separation of first-order driving mecha
tion. Study of the sedimentary record involves examining the
nisms from background processes. Long-term as well as short
preservation of both intrinsicaUy controlled and extrinsically
term
variations
during
geological
time
in the
magnitudes of different environmental parameters
numerical
controlled depositional events during Earth's history. Ex
are not weU
pressed in another way, the sedimentary record can be viewed
understood, however. The maximum and minimum rates of en
as a strip-chart recording of the intrinsic and extrinsic record
vironmental change that occurred during geological time also
of Earth history.
remain unknown, and their global as well as local scale and consequences are poorly understood.
Among the most spectacular manifestations of concurrent intrinsic and extrinsic changes
are the assembly of the super
To address these problems and correlate them to current
continent Pangea during late Paleozoic and early Mesozoic
environmental concerns, an intensive study of the sedimentary
Lime and its subsequent breakup and dispersal during latest
record is mandatory because that record is the only source
Triassic and earliest to middle Jurassic time that led to the pres
from which critical data can be obtained. Additional data are
ent-day disposition of continents. Thus studies of Pangea's
needed to calibrate the sedimentary record in terms of first
sedimentary record to determine long-term and short-term
order processes characteristic of Earth as a planet. These in
magnitudes of environmental changes must involve multidis
clude both mantle-driven processes (intrinsic) that drive plate
ciplinary aspects of geodynamics and climate modeling. This
Klein, G. D., and Beauchamp, B., 1994, Introduction: Project Pangea and workshop recommendations, in Klein, G. D.• ed., Pangea: Paleoclimate. Tectonics,
and Sedimentation During Accretion, Zenith, and Breakup of a Supercontinent: Boulder, Colorado. Geological Society of America Special Paper 288.
2
G. D. Klein and B. Beauchamp
volume focuses on the current state of the art of research about these changes during tbe evolution of Pangea. Many major resources are known to occur within the stratigraphic record represented by the 145-m.y. record of Pangea. These include extensi-ve source beds and reservoirs of petroleum and natural gas, coal, evaporites including potaSh, and phosphate deposits. Their occurrences appear to be con trolled in part by the mantle-driven tectonic history of Pangea, whereas other occurrences can be attributed to solar-driven climatic change and associated changes in oceanic circulation and upwemng. An intensive study of the sedimentary rock record of Pangea wiiJ improve prediction of occurrences of these resources and establishment of their origin. This volume focuses on the sedimentary record associated with the evolution of the supercontinent Pangea. The chapters represent state-of-the-art research summaries of wbat is known and what work is expected in the future relevant to the chang ing role of paleoclimate on the sedimentary record during the accretion, zenith, and breakup of a supercontinent. These pa pers were presented during an international workshop held in Lawrence, Kansas, in May 1992 to define the research direc tion of Project Pangea, the second research effort of the Global Sedimentary Geology Program (GSGP) of the International Union of Geological Sciences (lUGS). Project Pangea focuses on the most recent time of super continent accretion and dispersal when continents merged toward a geoid low, and much of Pangea's climate appeared to be disposed in an icehouse mode. The accretion and dispersal of Pangea are the most recent examples of a recurring long term global cyclic phenomenon. The 145-m.y. interval of Pan geas's history, however. was characterized by considerable climatic variability that belies the broad-scale icehouse climate suggested for tjmes of supercominent development Conse quently, Pangea's sedimentary record represents an ideal inter val during Earth history from which to evaluate the processes and magnitude of environmental variability and develop a pre dictive rationale for evaluating current global environmental concerns. Study of Pangeas's sedimentary record is justified further as a baseline for study of intrinsic and extrinsic proc esses and effects associated with Precambrian supercontinents and of the history of continental growth and evolution because that record can present maximum and mjnimum values of the qualitative and quantitative variability of climatic-driven proc esses on the sedimentary record. RESEARCH PROBLEMS The following research problems were identified as po tential salient components in Project Pangea during prelimj nary planning prior to the Project Pangea Workshop held in Lawrence, Kansas. from May 23 through 28, 1992. These ini tial problem sets included: I. What is the causal connection between large-scale global climatic change, such as the icehouse-greenhouse
change and the history of flux of C02 from the mantle? To what extent is that climatic change providing a signal of intrin sic, mantle-driven processes influencing climatic change both for the long term and the short term? 2. What is the record of variation of oxygen, sulphur, strontium, and carbon isotopic composition of seawater during Pennsylvanian, Permian, Triassic, and Jurassic time? How does this record constrain paleoclimatic models calibrated from the sedimentary record? 3. What was the role of astronomical forcing factors (Mi lankovitch orbital parameters) in driving solar-driven climatic change, and how complete is the record of such deposition that is preserved in cyclic sequence such as the famous cyclothems of the Pennsylvanian or the lacustrine cycles of the Triassic? Is this forcing dominant or subordinate? What is their record of preservation of forcing factors in both cyclic and noncyclic stratigraphic sequences? What short-term, intrinsically forced, tectonic processes can mimic, mask, or override the preserva tion record of astronomical forcing? 4. What mechanism controls relative changes in sea level that existed at time scales ranging from glacial (tens of thou sands of years), to intermediate (one to I 0 million years). to changes in seafloor spreading rates (tens of millions of years)? To what extent are these changes representative of conver gence and separation of intrinsic and extrinsic forcing factors? 5. What does widespread occurrence of Permo-Triassic evaporites indicate about global climatic change during devel opment of the supercontinent Pangea? How did storage of large quantities of salt in Permo-Triassic basins modify oce anic chemistry? To what extent did such evaporation develop a more brackjsh global ocean, and to what extent did such a chemical change contribute to late Permian extinctions? 6. What are the structure, strength, and effect of both in trinsically forced and extrinsically forced climatic change on the preservation, life history, and evolution of terrestrial and marine flora and fauna? What are the consequences of climatic changes on the distribution, deposition, and preservation of petroleum and metalliferous source beds? How did these cli matic changes influence the distribution of warm- and cold climate coals? Of evaporites? Of phosphates? What specific combmation of intrinsic and/or extrinsic processes favored the deposition and preservation of glacial sedimentary facies? How did these changes influence the history of sea level dur ing the accretion, zenith, and dispersal of Pangea? 7. What combination of intrinsic and extrinsic forcing factors influenced the variability of Permo-Triassic reef fa cies? How did these forcing factors influence the temporal dis tribution and evolutionary history of the reef facies? What was the rate of change in evolution and facies sryle of these reefs, and how can they be compared to different Holocene reef communities? 8. What are the combined or separated intrinsic and ex trinsic forcing factors that produced profound biological changes during the Permo-Triassic? What were the driving
3
lmroduction forces that caused rapid change (collapse?) of existing ecosys
clostratigraphy: Depositional response to climate change
tems? Were the causes extraterrestrial or mantle driven?
and basin evolution.
9. How do changing continental paleoposition, paleocli mates, and sea-level change influence the evolutionary record of continental flora and fauna during the accretion, zenith, and
Ethan L. Grossman, U.S.A.-The stable isotope record during the evolution of Pangea: Progress and prospects. John J. Veevers and S. E. Shaw, Australia-Turning point in
dispersal of Pangea? How did changing paleogeography influ
Pangean environmental history at or about the Permian/
ence paleobiogeography during the history of Pangea? What
Triassic boundary.
were the dynamics of floral and faunal replacement and the evolution of terrestrial ecosystems? How did these changes in terrrestrial life history interface with changes in marine Life history? What do associated paleobiogeographic changes indi
Sarah Fowell, U.S.A.-Late Triassic palynoflora! evolutions and climate cyclicity, eastern North America. Benoit Beauchamp, Canada-Carboniferous to Triassic tec tono-climatic evolution of northern Pangea.
cate about the magnitude and rate of climatic change?
Erik Flugcl, Germany-Pangean shelf carbonates: Controls of
WORKSHOP ACTIVITIES
Aymon Baud, Switzerland-Late Permian to Late Triassic of
Permian and Triassic reef and platform development. the Tethys: Existing problems, new facts, and theories�a An international workshop, from May
23 through 28,
review.
1992. was held to organize the research effort for Project Pan gea, which is the second project sponsored by the GSGP, a
To assist in developing synergism between sedimentary
commission of the JUGS. The goal of the workshop was to
geology and paleoclimate modeling, a separate special plenary
recommend international and multidisciplinary research objec
session dealt with paleoclimate modeling and model-geologi
tives within the framework of Project Pangea. Principal objectives for Project Pangea
cal observations and comparisons. Organized by Dr. Bette
are to (I) under
Ouo-Bleisner and Mark Chandler, both of the U.S.A., this ses
stand global processes, their magnitude and temporal varia
sion not only included the following presentations but also
tions during the time of accretion, zenith, and breakup of the
brought together the paleoclimate modeling community with
supercontinent Pangea;
the sedimentary geological community for the ftrst time.
(2) examine the global sedimentary
record and variability from the base of the Pennsylvanian (Middle Carboniferous) through the Middle Jurassic; (3) deter mine the cause and nature of Pangea's existence; and
climate variability during
(4) determine the causes of Permo
Chris R. Scotese and Jan Golonka, U.S.A-Phanerozoic pa leogeographic maps. Malcolm
I. Ross, C. R. Scotese, A. J. Boucot, Chen Xu, and
Triassic and Triassic-Jurassic extinctions. However, during the
Anne Raymond,
workshop it became clear that the major objective for Project
simulation using a simple parametric climate model.
Pangea that is expected to lead to new, significant, and differ
U.S.A.-Late
Carboniferous climatic
John E. Kutzbach and A. M. Ziegler, U.S.A-Numerical sim
ent results is paleoclimate modeling and geological verifica
ulation of the climate of Pangea-Late Carboniferous cli
tion of such models.
matic simulation using a simple parametric climate model.
The Project Pangea workshop itself was organized into
an
Eric D. Gyllenhaal and A. M. Ziegler, U.S.A-Comparisons
opening plenary session of invited papers, a special plenary
of lithologic and paleobotanical data with predictions of
session on Paleoclimate Modeling, and breakout sessions by
atmospheric general circulation models: Examples from
the working groups who formulated recommendations for re search as well as hosted sessions of short contributed papers. The opening plenary session on Sunday, May
24, 1992,
consisted of the following invited talks:
the Late Permian. Starley L. Thompson, David Pollard, W. W. Hay, and Kevin Wilson, U.S.A.-Simulations of Triassic climate using a global circulation climate model. Peter J. Fawcett and Eric J Barron, U.S.A.-The climatic evo
George D. KJein, U.S.A.-Project Pangea: Goals and develop ments; tectonic-climatic discrimination of cyclic deposition. John J. Veevers, Australia-Pangea: Evolution of a supercon tinent and its consequences for Earth's paleoclimate and sedimentary environments. George T. Moore, D. N. Hayashida, C. A. Ross. and S. R. Jacobson. U.S.A.-The paleoclimate of Pangea during its formation (Late Permian) and disintegration (Late Jurassic). Francis,
UK-Paleoclimates
Jurassic: A comparison of climate model results with the geologic record. Bruce W. Sellwood, P. Valdes, and G. Price, UK-Climate modeling in the Jurassic: GCM predictions in comparison
Thomas J. Crowley, U.S.A.-Pangean paleoclimates.
Jane
lution of India and Australia from the Late Permian to
of
Pangea
(geological
evidence). Martin A. Perlmuuer and M.D. Matthews, U.S.A.--Olobal cy-
with the geological data base. Mark
Chandler,
U.S.A.-Pangean
climate
of
the
early
Jurassic: GCM simulations, the paleoclimate record cli mate feedbacks, and increased heat transport. Robert J. Oglesby, U.S.A.-M� the effects of orbital in solation changes on pre-Pleistocene climates and sedimen tary cycles.
4
G. D. Klein and B. Beauchamp
Thomas R. Worsley, T. L. Moore, C. R. Scotese, and Carmen M. Fraticelli, U.S.A.-Phanerozoic paleoceanography and global climate. The final closing plenary session on May 27 consisted of presentations of recommendations from each working group for future research activities within Project Pangea. These are summarized in the sections that follow. WORKSHOP RECOMMENDATIONS Project 1-'angea was originally organized into five working groups, but it became clear during the workshop that the work ing group structure needed some revision and reorganization. Principal recommendations of the new working groups (by name) are summarized below. Working group 1: Paleoclimate (Judith T. Parrish, U.S.A. chair) The scientific rationale for pursuing modeling studies of paleoclimate is twofold. For climatologists, such studies pro vide opportunities for testing the sensitivity of climate models to changing, realistic boundary conditions. Pangea represented an extreme paleogeography with an associated possible ex treme climate regime. Successful simulation of this extreme climate would demonstrate robustness of the climate models. For geologists, modeling studies enhance understanding of the effects of climate on the geological record, especially sedi mentation, diagenesis, evolution, extinction, and biogeog raphy. Climatic models also may provide a global framework within which the relatively scattered data on paleoclimate might be interpreted. WG-1 participants observed that first-order agreement was achieved when comparing the results of all climate mod els that were applied to Pangea. Thus, future work should focus on climate forcing and response. Three general and overlapping recommendations of areas of future research were offered: (I) specific studies of critical paleoclimatic processes, (2) model-model comparisons, and (3) data and model-data comparisons. Although geological participation is critical for the third recommendations, cooperation with other working groups is needed in all these areas of research. Critical paleoclimatic processes. WG-1 recommended that whenever possible, the climate modeling research com munity should target critical climatic processes for treatment with sensitivity tests. Sensitivity tests are successive model runs in which one or two variables are changed. The test per mits analysis of model behavior and helps identify processes that are particularly important for climate, given certain start ing conditions (such as paleogeography). Critical climatic processes already identified as appropriate for such treatment are (I) ocean heat transport/sea surface temperature (OHT/ SST). (2) orbital variability, (3) C02, (4) paleogeography, es-
pecially topography and sea level, and (5) ice. Currently, OHT/SST are either computed or specified but in both cases are artificially constrained. WG-1 recommended minimizing the constraints as well as conducting sensitivity tests. Model results already suggest that climate may be very sensitive to topography, and thus WG-1 recommended that WG-2 emphasize determining not only the distribution of highlands but also their altitudes and topographic profiles. The most complete climate models are those that couple the oceans and atmosphere. Creating coupled ocean-atmo sphere models is currently a major effort in climatology, but such models are still relatively undeveloped. Nevertheless, WG-1 foresees the possibility that such models will become available during the Lifetime of Project Pangea, and thus rec ommended as a long-term goal the creation of paleogeo graphic models of paleobathymetry that will permit effective study of deep-ocean circulation. Model-model comparisons. WG-1 recommended that, when presenting results in published papers, climate modelers specifically address differences among various models be cause these differences are important for interpreting the geo logical record. Geologists are not equipped by training to interpret differences in model results and thus depend on ex pertise of climate modelers to make those interpretations. To facilitate comparisons, WG-1 recommended that whenever possible, the modeling community use some boundary condi tions in common. Specifically, WG-1 recommended using common values of (I) percent change in solar constant, (2) ro tation rates, (3) for the present, C02 values from the Berner curve, (4) seasonal, rather than perpetual, models, and (5) va.l ues for orbital parameters, that is, eccentricity 0 and perihe lion 0. Additionally, WG-1 recommended that climate modelers address both interannual variability and long-term planetary averages. A long-term goal of WG-1 is to produce a document comparing model results and discussing the impli cations of model results from interpretation of paleoclimates. Data and model-data comparisons. WG-1 strongly sup ported efforts withjo WG-3 to gain participation of experts on various paleoclimate indicators to facilitate compilation of data in a manner exploiting the full potential of the geological record. WG-1 supports ongoing efforts to calibrate sedimento logical and paleontological indicators using modem climate. Additional, WG-1 recommended collection of data in such a manner as to capture the full range of variability of each mod eled interval to more effectively tie the geological record into model runs that examine climatic maxima and minima with re spect to, for instance, orbital parameters and sea level. WG-1 identified three major problems worthy of particular attention and requiring geological data. These problems (and some of the required data) are: (I) strong winter cooling and ex treme seasonality of temperature in the So misphere (paleobotanical and other biotic data. sedimentary evidence of freezing. soil isotopes, moisture estimates); (2} C02 (proxy data =
=
u�e
Introduction
for C02-for example, isotopes in paleosols and marine organic carbon); and (3) tropical and polar sea surface temperatures (isotopes, Sr/Ca paleothermometer). Because, for example, coals are not precise rainfall indicators but rather indicate water table levels, WG-1 advised that both modelers and geologists must be critical in interpretations of moisture balance in their models and that model outputs must be compared with appro priate data. WG- I also discussed targeting specific time slices. WG-1 concluded that their model studies should focus on time slices proposed by WG-2 and WG-3 be.cause their criteria for chos ing time slices are the same criteria WG-1 would use, namely data availability. Modeling studies are still experimental, so much studies require the best data available for distinguishing among results of various sensitivity tests. WG-1 observed that the number of modeling studies of Pangea indicates that these intervals present problems that are inherently of interest to modelers. Geological expertise is es sential to these studies for identifying important aspects of the problem of Pangean climates. Working group 2: Plate tectonics andpaleogeography (Christopher R. Scotese, U.S.A. chair)
The principal goal of WG-2 is to produce large-scale paleo geographic maps illustrating the distribution of mountains, land, shallow oceans, and deep ocean basins for five time intervals during the history of Pangea-namely, the latest Carboniferous to earliest Permian (Stephanian-Autunian), Late Permian (Kaza nian), earliest Triassic (Scythian), Late Triassic (Kantian), and early Jurassic (Pliensbachian). Preliminary versions of these maps would be distributed to other working groups and would serve as base maps on which biogeographic, oceanographic, eco nomic, sedimentological, and paleoclimatic data could be com-
5
piled. Besides the five detailed paleogeographic maps, WG-2 will produce approximately 15 plate tectonic base maps (one for each stage from the Late Carboniferous through the Middle Jurassic). Figures I through 8 show paleogeographic base maps for use by Project Pangea scientists. Final versions of these maps would show the distribution of mountains, land, and sea as weU as active plate boundaries and major structural features, major lithofacies, significant ac cessory lithofacies (reefs, coal, evaporites), important paleo geographic features (lakes, major rivers, impact sites). pojjtical boundaries and modem geographic features for refer ence, and an index map providing sources of information dis played on the maps. All this information would be compiled on a set of present-day base maps (Mercator projection, I: I 0,000,000) and then digitized and replotted on re.con structed base maps at the preferred publication scale of I :20,000,000. WG-2 formed nine regional panels (Table 1) to compile the information for these maps. Panel coordinators will com pile the paleogeographic information for each time slice. The Paleomap Project, University of Texas at Arlington, will pro vide the present-day base maps, coordinate digital compilation of the paleogeography, and produce the final reconstructions. Working group 3: Global synchroneity of the sedimentary record (Benoit Beauchamp, Caru.ula, and P. A. SchoUe, U.S.A, co-chairs)
WG-3 proposed two major recommendations: Recommendation 1. To scrutinize in great detail the sedi
mentary record of three time slices during the history of Pangea. These time slices are Moscovian (305-315 Ma), Kazanian (264-269 Ma), and Carnian (220-228 Ma). The goal in analyzing these time slices is to compile an inventory of the
Figure I. Paleogeographic map, Late Carboniferous (Westphalian), 306 Ma. (When citing this map, please cite it as follows: Scotese. C. R., 1994. Late Carboniferous paleogeographic map. in Klein,
G. D., ed., Pangea: Paleoclimate, Tectonics, and Sedimentation During Accretion. Zenith, and Brealcup of a Su percontinent : Boulder, Colorado, Geological Society of America Special Paper 288.)
6
G. D. Klein and B. Beauchamp
Figure 2. Paleogeographic map, Early Permian (Artinskian), 277 Ma. (When citing this map, please cite it as follows: Scotese, C. R.. 1994, Early Pennian paleogeographic map, in Kle in, G. D .• ecJ., Pangea: Paleoclimate, Tectonics, and Sedimentation During Accretion, Zenith, and Breakup of a Supercontinent: Boulder, Colorado, Geological Society of America Special Paper 288.)
Figure 3. Paleogeographic map, Late Pennian (Kazanian),
255
Ma. (When citing this map, please
cite it as follows: Scotese, C. R., 1994, Late Pennian paleogeographic map, in Klein, G. D., ed., Pangea: Paleoclimate. Tectonics, and Sedimentation During Accretion, Zenith, and Breakup of a Supercontinent: Boulder, Colorado. Geological Society of America Special Paper 288.)
total spectrum of marine and nonmarine climate-sensitive fa
tion will provide stratigraphic data, geographic data (present
cies in order to reconstruct the global paleoclimatic-environ
longitude and latitude, volume), detailed lithofacies and thick
mental setting for each time scale and to provide a standardized
ness, tectonic setting, vertical and lateral variability (eustatic,
set of data to other specialists, especially climate modelers and
tectonics, or climatic changes), and fossil content.
paleogeographers. Data to be compiled by WG-3 will comprise both pub
Specific climatic indicators to be catalogued include:
Exposure-related features.
Calcrete
(pedogenic
and
lished and newly acquired data. Data collection, where possi
nonpedogenic), paleosols, karst, bauxites and related deposits,
ble, will be completed in digital format, through expen
red beds.
systems and questionnaires. A basic set of background infor
Glacialdeposits. Terrestrial (all typeS), marine, glendonites.
mation will accompany each data entry. This basic informa-
Eolian deposits. Sand seas (dune deposits), eolian dust.
Introduction
7
Figure 4. Paleogeographic map, Early Triassic (lnduan), 242 Ma. (When citing this map, please cite it as follows: Scotese, C. R.. 1994. Early Triassic paleogeographic map. in Klein, G. D., ed.. Pangea: Paleoclimate, Tectonics, and Sedimentation During Accretion, Zenith, and Breakup of a Super continent: Boulder, Colorado. Geological Society of America Special Paper 288.)
Figure 5. Paleogeographic map. Late Triassic (Norian).
216 Ma. (When
citing this map, please cite it
as follows: Scotese, C. R., 1994, Late Triassic paleogeographic map, in Klein. G. D .. ed.. Pangea: Paleoclimate. Tectonics, and Sedimentation During Accretion, Zenith, and Breakup of a Supercontinent: Boulder. Colorado, Geological Sociery of America Special Paper 288.)
Lacustrine deposits. General lake sediments, tufa sand travertines.
Coals and organic matter. Coal types. organic geochem istry of marine sediments.
Fluvial/deltaic deposits. Stream types, flow regimes/gra dients.
Evaporites. Terrestrial (salina/lacustrine), marine minor versus extensive occurrences.
Reefs. Distinction of types with possible paleolatitudinal sensitivity.
Bioclastic
limestone/skeletal
assocwuons.
Latitudinal
changes in faunal/skeletal assemblages.
Other carbonate. Original mineralogy of micrites; origi nal mineralogy and distribution of ooids; original mineralogy and distribution of marine cements; diagenetic patterns in car bonate rocks as paleoclimate indicators (hardgrounds, inten sity of meteoric alteration. c yclicity of alteration).
Silica deposits. Bedded chert, nonbedded deposits, associ ation with other deposit types.
Phosphorite deposits. Major deposits, inventory of lower-
G. D. Klein and B. Beauchamp
8
Figure
6.
Paleogeographic map, Early Jurassic (Pliensbachian), 195 Ma. (When citing this map,
please cite it as follows: Scotese, C. R., 1994, Early Jurassic paleogeographic map. in Klein, G. D..
ed., Pangea: Paleoclimate, Tectonics, and Sedimentation During Accretion. Zenith, and Breakup of a
Supercontinent: Boulder. Colorado, Geological Society of America Special Paper 288.)
Figure 7. Paleogeographic map, Middle Jurassic (Callovian), 166 Ma. (When citing this map, please cite it as follows: Scotese, C. R., 1994, Middle Jurassic paleogeographic map, in Klein. G. D., eeL, Pangea: Paleoclimate. Tectonics, and Sedimentation During Accretion, Zenith. and Breakup of a Supercontine nt: Boulder. Colorado, Geological Society of America Special Paper 288.)
concentration deposits, identification of upwelling zones. Iron-bearing mineral deposits. Glauconite, chamosite, oolitic ironstone. Shales. Clay mineralogy, distinction of primary versus diagenetic assemblages. Isotope geochemistry. Oxygen and carbon on brachio pods; other oxygen and carbon studies (whole rock, phos phates, water), sulfur on carbonates and evaporites, strontium, stratigraphic (secular) versus regional/climatic variations. Paleobiogeography, pa/eocology, paleocommunities. Nonmarine (plants, tetrapods, and other vertebrates, trace fos-
sils), marine (biogeographic patterns of marine organisms; trace fossils fburrowslboringsJ; determination of paleo-oxy genation levels [laminae/bioturbation patterns}). Recommendation 2. To examine the global sedimentary record of a long-ranging interval of Pangea's history to estab lish links between such seemingly unrelated. yet often syn chronous, aspects of the geological record as climatic evolution, sequence boundaries, biogeography, tectonic shifts, and extraterrestrial impacts. This part of Project Pangea will examine Pangea as a highly interactive and dynamic system characterized by Long periods of stability in the atmosphere,
9
Introduction
Figure 8. Pale oge ographic
map, Late Jurassic (Tithonian), 152 Ma. (When citing this map, please
cite it as follows: Scotese, C. R., 1994, Late Jurassic paleogeographic map, in Klein, G. D., ed., Pangea: Paleoclimate, Tectonics, and Sedimentation During A ccre tion, Zenith, and Breakup of a
Su percontnen t: Boulder, Colorado, Geological Society of America Special Paper 288.) i
TABLE 1. PALEOGEOGRAPHIC REGIONAL PANELS AND COORDINATORS, WG-2
bution of reefs, lacustrine carbonates, paleosols, biotic assem
Coordinator
Geographic Region
blages,
J. J. Veevers, Australia
2. Southe ast Asia
lan Metcalfe, Australia; Dietrich
4. Former U.S.S.R.
carbonate
mineralogy,
phosphates,
and
carbon
isotopes. The data recovered through this "pilot project" will
1. Gondwana
3. China
A first step toward achieving the goals of this project will
be to examine the Kazanian through Norian worldwide distri
Helmcke, Germany Wang Hongshen, Xu Xiaosong, Wang Chengshan, People's Republic
be integrated in a time scale that will also display known se quence boundaries, climatic shifts, tectonic events, and epi sodes of volcanism. Ultimately, participants in Project Pangea will
be able to rank chronostratigraphic boundaries based on
of China
the magnitude of tectonic, climatic, and depositional shifts ob
A. Egorov, L. Natapov, V. Kazmin,
include a much broader base of
Russia
5. North Europe
P. A. Ziegler, Switzerland
6. Tethys
J. Dercourte, France; A. Baud,
7. North Atlantic Margins
W. M anspeize r, U.S.A.
8. Western North America
D. B. Rowley, U.S.A.
9. North American Arctic
Benoit Beauchamp, Canada
Switze rland
served across them. ln a later stage, the project will expand to
Kazanian through Norian data.
Working group 4: Stratigraphic constraints on global syn�llroneity (C. A. Ross, U.S.A., and Aymon Baud, Switzerland, co-chairs) The major problem addressed by WG-4 was the establish ment of a detailed time-stratigraphic correlation baseline for the time interval
during which Pangea evolved (Middle Car
boniferous through Middle Jurassic). For this particular time in terval, only biosphere, hydrosphere, and lithosphere-a stability that was,
three solid radiometric dates are available to define
chronostratigraphic boundaries. WG-4 tentatively proposes a
from time to time, disturbed by geologically rapid shifts of
stratigraphic chart and time scale (Fig.
global magnitude. To achieve this goal, one major time inter
Phanerozoic to establish where stratigraphic problems exist.
val ranging from the Kazanian through and including the Norian was selected for global analysis.
9) for the Middle
WG-4 recommended the following program of research to complete the major gaps in establishing reliable temporal
The Kazanian-Norian interval was selected for two rea
constraints: (I) biostratigraphic studies to globally calibrate
sons. First, this time interval encompasses two time slices se
zonal schemes for correlation,
(2) event stratigraphy to piece
I. Second,
together provincial groupings
known to occur in Middle
lected for detailed analysis per recommendation
this Lime interval straddles the Permian-Triassic boundary,
Permian rocks;
(3) Establishment of a sequence stratigraphy
perhaps the culmination of the greatest global environmental
correlated to the global standard section and correlation of se
perturbation of earth history.
quence
boundaries
with
volcanic
ash
fall
events
for
G. D. Klein and B. Beauchamp
10
PANGEA TIME SCALE Approximate -Num. ageMa
ageM.a
Late
u
·-
C'-l C'-l
� .....
:::::::1
......,
150
u
·
�
t:: �
Eastern Europe
� �
�
0
Q.c
Late
Bajocian
Top of
�
�
us�folfo r
global
C'-l
::s
0 �
]0 �
u
300
Late
Early
-
Hettangian
Khaet•an
Carnian Ladinian Anisian Olenekian Induan
�hamian Cbanghslnglan 255 � - - ? - ? ? - Dzhulfian Wuchia ingian 259 Ochoan b Tatarian Midian . Capilanian � )(aZait� Murgabian 264 Maokou Guadaluptan t. an utuman '9 26 Kuber 2 and1an �ungunan Calhedralian no 273 - - -'""'Bolorlan Leonardian . L 275 I= Chihsia Hess!BD -t-
Artinskian
E
Sakmarian
Asselian
Maping
Westphalian
Namurian -
- -
Wolfcampian
Vi!!I!ian
Stephanian D
c B A c B A
-
.Missourian
�0
1-
Atokan 1Morro wan
Chesterian -
-
- -
- -
!Jio � � �0 � �340
Note: Line thickness is used only to highlight significant boundaries radiometric ages (tie points), all others are based on geologic inference.
Figure 9. Tentative Project Pangea Time Scale prepared by C. A. Ross, A. Baud, and M Menning on behalf of WG-3 (drafted by John 0. Garbisch). Asterisks indicate radiometric ages (tie poi.nts); all other ages are based on geologic inference.
ill 1-IT
1--
1-
Desmoinesian
--- "-
'2& i=o � '29o F 300
Glacial In nuwiVIQ . Go-..1. ..
*
�j
� gu 160 �� f=. � TIO 1-f= � rrso � � 1"90 VI � � '2oo � � � 0 1-� �0 � � �0 v � � �c 1-� IV � � 0 ,_ �
------
Norian
..Scythian"
-a o.e;
-
Sinemurian
no correloJion) reversed � 275- 1polarity Artinskian superchron uo 283 Sakmarian � 1287 2'90 Asselian *295±5-� 13oo 305 Gzelian Kasimovian E Middle 3io 315 Moscovian � 1Bashkirian 120 320±10 � Serphukovian 113 o - - - 333±11 Begi ruainff o t: ion "'"' 340 KitlmQit
-
Toarcian
Platfonn a&UIQS thai are not
Late
..
- - -
Pliensbachian
•234
Middle
-
Aalenian
220
ageMa
150
Bathonian
-
-Num.
S. W. North America
E
Callovian
171
Early
-
Tethys
w
A BAUD, M. MENNING
Oxfordian
Early
·
C. ROSS,
152
f= 157 160 165 Middle � �· no � t: rl§O 179 t: 186 194 190 := b; 201 � t: 208 � 0 212 f= o n f= � �0 228 t: � 241 t: 246 25o *251±2 f}.ian � £.!u ( a 1�60 � Early
·C'-l C'-l
WG 3
I
.....__
II
lmroduction geochronological calibration; (4) a systematic program of ra diometric dating to tie in with recommendations 1 and 3; (5) a program of paleomagnetic stratigraphy to tie in with recom mendations I, 3, and 4; and (6) an overall interdisciplinary chronostratigraphic approach combining all correlation tech niques so that the mid-Phanerozoic time scale represented by the evolution of Pangea is adequately constrained as a baseHne for paleoclimatic and paleographic studies. In addition, WG-4 recommended a detailed analysis, inte grating a variety of data emerging from WG- 1 , 2, and 3, to ad dress the issue of the nature of the timing and causes of extinction. Working group 5: Resources (W. L Watney, U.S.A, B I. Chuvashov, Russia, Oscar R. Lopez-Gamundi, Argentina and U.S.A.) WG-5 recognized that its activities are Likely to overlap with other working groups. Thus it will focus on the same time slices as proposed by WG-2 and WG-4. WG-5 chose to investi gate characteristics of important resources associated with Pangea and to improve the precision and accuracy of informa tion on controlling processes, including climate, that are suited for simulation modeling and improving resource prediction. WG-5's objectives included one that was short term-to constrain understanding of known resources (i.e., inventory and location-and one that was long term-to provide more refined process parameters for use in increasingly refined models. including climate, stratigraphic, and sedimentological simulations. Knowing more about the details of selected resources, in cluding their occurrence in space and time, may eventually pride other diagnostic characteristics of climate unknown to us today. For instance, known characteristics and distributional patterns of lacustrine source rocks in rift basins may further establish links to Larger-scale climate and paleogeographic fac tors that are currently being modeled. Certain thematic projects related to resource inventories and prediction are recommended. They include: Theme I. PaleocHmatic controls on the spatial and tem pora.l occurrence of suboxic and anoxic sediments: Project A: Phosphorites. Lnventory phosphorite occur rences in Carboniferous and Permian. Investigate relationship between ( I ) maximum phosphorite deposition and occurrences leading to climax event, (2) changes in ocean circulation and upwelling systems during the formation of Pangea, and (3) glacio-eustatic control of phosphate events. Case studies would include the Permian Phosphoria rock complex of the Rocky Mountains, North America, and Late Carboniferous to Early Permian phosphorites in Cis-Uralalian region of Russia. COORDINATORS: Jorg Trappe (Germany). Boris L Chuvashov (Russia). Project B: Black shales (source rocks). Inventory occur rences in the Westphalian and Stephanian because of longer
trend of black shales in Euro-American. The entire Permian or ganic-rich, high-latitude shales from Gondwana also are excel lent candidates for inventory. The goal would be to investigate (I) the origin and nature (temporal and spatial distribution) of black shales and relationship of formation and character to glacio-eustasy, (2) stratigraphic correlation of black shales over Pangea (in progress), and (3) independent, interdisciplinary means to evaluate accumulation rates, sources of organic mat ter, modes of preservation of organic matter, and contribution and nature of organic productivity. Case studies include the or ganic-rich algal shales from high paleolatitudinal sites in Gond wana (Early Permian to early Late Permian) and evaluation of black shales from low paleolatitudes of Euroamerica that con tain terrestrial organic matter and considerable ranges in total organic carbon and constituent organic and inorganic com pounds, and the use of these shales as keys to correlate individ ual eustatic events over widespread areas of Pangea. COORDINATORS: Oscar R. Lopez-Gamundi (Argentina and U.S.A.), W. Lynn Watney (U.S.A.). Project C: Occurrence of source rocks and possibly source-reservoir systems associated with Triassic-Jurassic rift ing related to breakup of Pangea. This project would focus on Triassic-Jurassic rocks of eastern North America, Greenland, and the North Sea that were related to tectonic-structural evo lution and paleoclimate and on nonmarine grabens containing synrift lacustrine source rocks in portions of Gondwana re lated to the Paleo-Pacific margins that were related to a global transtensional event. COORDINATORS: Marty Perlmutter, Warren Mans peizer (both of the U.S.A). Theme 2. PaleocHmatic controls on the spatial and tem poral occurrences of potential hydrocarbon reservoirs. This theme would focus on the occurrence and types of carbonate rocks that may serve as hydrocarbon reservoirs in strategic time intervals and sites in Pangea. Time intervals suggested included the Westphalian and Moscovian. The approach to be taken includes (1) short-term inven tory of occurrences; (2) establishment of multiscale facies ar chitecture of carbonate buildups and surrounding strata, eva.luation of influence of paleotectonic setting, paleoclimate, and glacio-eustasy, and characterization of unusual occurrences of key relationships critical to cHmate assessment (such as cli matic occurrences of reefs; and (3) possible integration through quantitative modeling for improved prediction. Case studies include the carbonates deposited along the Paleo-Tethyan shelves during the Permian, possibly late Carboniferous. COORDINATOR: W. Lynn Watney. Marty Perlmutter (both from U.S.A.). Theme 3. Paleoclimatic controls on the spatial and tem poral occurrence of low-latitude versus high-latitude coals. Based on compilation of coal beds and related facies to date, it is advised that a localities of temperate coals be selected and compared With Tethyan coals. Temperate coals should be
�
G. D. Klein and B. Beauchamp
12
compared to peats presently forming in cold regions. This new
focusing on issues Lhat were significant but that may have
model stresses Lhe temperate, postglacial climatic conditions
failed to attract sufficient attention.
under which coaJs of AustraJia, South Africa, India, and South America
were
formed
in
contrast
to
Lhe
better-known
Among items of significance that were reviewed are the following:
( I ) data quality needs to be controlled; aJJ observa
Euroamerican model in wlllch coaJs are associated with hu
tions are to be recorded on present-day longitude and latitude
mid, low paleolatitude settings. These models need to be
so as to assure transfer to paJeogeographic base maps. (2) A
tested and refined through baJanced sampling across Pangea.
need was expressed for study of metaliferous sediments, and
(3) Paleotopographic studies need
Coordination with the U.S. Geological Survey's Predictive
WG-5 is following up on it
Stratigraphic AnaJysis (PSA) with its focus on coaJ resources
to be simulated. Mass-balancing of sediment volumes to paleo
is recommended.
topography needs to be factored in to assure relevant paleo
COORDINATOR: Oscar R. Lopez-Gamundi (Argentina and U.S.A.).
climatic modeling. (4) A strong geochronologicaJ effort needs to be established within the framework of WG-4. (5) Final
Theme 4. Metallic rnineraJ resources. A recommendation
compilation of paleogeographic maps. sedimentary data, and
be the final product of Lhe ef
from the plenary closing session reported that significant
model simulations is expected to
metallic rnineraJ deposits are known from many of the sedi
forts of Project Pangea to calibrate, sedimentologically, paleo
ment types associated with Pangea. A globaJ perspective to
climate simulations.
their occurrence needs to be made. Manganese ores, particu larly significant occurrences in the UraJs, were considered. COORDINATORS: W. Lynn Watney (U.S.A.), B. I.
ACKNOWLEDGMENTS
Chuvashov (Russia).
Working group 6: Biogeography and extinction (David}. Bottjer, U.S.A.) and Jane Francis, UK, co-chairs) This working group was proposed and developed during
The Project Pangea Workshop was funded by grants and gifts from the National Science Foundation (Award EAR-9 I-
17687), the U.S. Geologica] Survey, the Division on Sedimen tary Geology of the Geologica] Society of America, SEPM
the closing plenary session, and thus it did not meet formally
(Society for Sedimentary Geology). lntemationaJ Association
during the workshop. lnitiaJ plans include organizing research
of Sedirnentologists, Chevron Oil Field Research Corp.. and
projects to investigate the two major Pangean mass extinctions
AJJen Press, Inc. Christopher R. Scotese and the Paleomap
at the Permian-Triassic and Triassic-Jurassic
Project of the lntemationaJ Lithosphere Program provided the
boundaries.
Future discussions will prioritize some possible biogeographic
paJeogeographic maps shown in Figures I through 8. Users of
research projects.
these maps
Working group 7: Synthesis (George D. Klein, U.S.A. chair)
are
requested to reference them as shown in the
caption for Figure
I. We acknowledge with gratitude the draft
ing of Figure 9 by John 0. Garbisch.
This working group will come more into the forefront as Project Pangea develops. Workshop activities consisted of co ordinating communication between other working groups and
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Printed in U.S.A.