I * II, 196 . lI2 pp. Unpublished thesis. University of Bergen. Schytt, V., Hoppe, C., Blake Jr., l{. & Cross-. w a I d , l t { . G . ( 1 9 6 8 ) . T h e e x t e n t o f t h e W U r m.
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Reprintsof Proceedings rsBN82-519-0863-9 T A P I RP U B L I S H E R S T R O N D H E I-MN O R W A Y
GLACIAL HISTORY AND PERMAFROSTIN THE SVALBARDAREA J.Y. Landvikl, J. Mangerudl and O. Salvigsen2 lUniversity of Bergen, Department of GeologJt,Section B,All6gt. 41, N'5fi)7_Bergen, Norway iNorsk Fohrinsiitutt, Rolfstangveien 12' N'l330 Oslo Lufthavn, Norway
Clacial and sea level history play an inportant role as preconditions for the SyNopSIS the llJeichof reconstruction of pernafrost in arctic areas. Based on development and distribution of Svalbard and the Barents Sea, we propose seven zones each of which Holocene history selian and development. The main to permafrost conditions pertaining widely different has been subject to subject to subaerial periglacial have been: areas whether are characterisLics distinsuishing sea level; lowering of subaerially exposed due to eustatic conditions during the last glaciation; rebound; or, renained as nunataks' recently raised irom sea due to glacio-isostatic
I I { T R O D U C ITO N area of land the entire covers Pernafrost varying between 100 Svalbard riith known depths l9?7t . Thawed zones occur and 460 D (Liestol, and glaciers lakes, major and underneath with warrn ground in connection sonetines also water (Salvigsen & Elgersma, 1985). For several years He have studied the geologicwith special emphasis of Svalbard, al history changes. In level sea history and on glacial paper the consequences this we discuss this and thickness distribution history has for the of pernafrost in the area. the physics of frozen into delve H€ do not ground, but deal with the change of the physicPermafrost needs through tine. environnent al with equilibrium adJust to long tine spans to permafros t thus and tenperatures , surface past thlcknesses and tenperatures often reflect focused on the ue have conditions. cliratic change the of clirnatic effects iost proilinent last lO0,e0O years, nanely the growth and decay changes. sea-level and reLat'ed of ice sheets Based on these studies and other available data to fron Svalbard, we use the geological history outline sore boundary conditions for permafrost within the region. developmentand distribution
l/ svnr-anno
z5"1;
0
so
lookm
|tap of the Svalbard archiFi9. I pelago and the Earents Sea. Locations of the sea-level curves in Fig" 3 are s h o w n.
at situated is archipelago Svalbard The between the cold 8l " north ?4" to latitude water in Barents Sea (Fig. I ) and warn Atlantic Seas. Present nean the Norwegian and Greenland west coast is the along tenperature annual it is somewhat the east while to about -5"C, has lower. The northern coast of Nordaustlandet a probable nean annual temperature below -10'C. feichsel ian Late the during Te[peratures glaciation are suggested to have Svalbard in today. I n conlower than been cons iderably periods of the long during climate trast, than the rnuch warner so been Holocene has present that it have caused significant nust reduct ion in permafros t .
194
GLACIALHISTORY
M a.s.l
history of Svalbard and the Barents The glacial glacial has been cycle last the Sea during quite models have conflicting and disputed, been proposed. Boulton ( 1979) suggested a very peaking around ll,0ee years limited glaciation assumed that ago, whi le Denton & Hughes ( l98l ) and the Barents Svalbard archipelago both the ice sheet 18"00e a large covered by Sea were by Elverhoi & years ago. Later investigations ( ls83 ) an ice 'sheet that indicate Solheim parts of the the northern at least covered in field investigations Based on Barents Sea. llangerud et al. central and western Svalbard, ( 1987) proposed a with a Barents icenodel ice dones over separate east, to the sheet rnargins along ice free w e st e r n S v a l b a r d , a n d coasts ' They propose and northern the western Van llijenfjorden, filled stream that an ice was probably ice free of Isfjorden while most during the Late lveichselian (Fig. 2) '
110
of this nodel ii The most important implication the Late Ueichselian, there l{ere during that were that the coast along areas ice free Reconarctic conditions. severe exposed to fron that period structed ice surface profi les mountains must have that several demonstrate quite thus experienced and nunataks, been history than the glaciertenperatur€ another covered lowlands around them"
30
i00 90 80 70 60 50 40
20 10
CU
parts of the Due to the warmer clinate during ice was probably less glacier Holocene, there for I'linimum linits today. than in Svalbard glaciers Holocene are not known, and the in probably nonglaciers were many of the smalI for long periods. existent
40 JU
20 10
70 OU
BELLSUND (Landvik,Mangerud& Salvigsen1987)
40 30 20 10
Fig . Z R e c o n st r u g t e d L a t e H e i c h s e l pos i t i o n s the in i ce front i an V a n l . li j e n f j o r d e n a r e a and I s f j orden are Glaciers central Svalbard. of shaded. From llangerud e t a l . ( 1 9 8 7 ) .
from curves Sea-level Fis. 3 of Locations archipelago. Svalbard curv€s are shown in Fig. L
195
t he the
S E A . L E V E LH I S T O R Y The Iate glacial and Holocene sea-Ievel history for Svalbard is noH well known. As demonstrated by Schytt et al. (1968), the Holocene sea-leveI changes in the area were governed by a glaciothe Barents over rebound centered isosiatic from Kong KarIs Land in Sea. Sea Ievel curves (Fig. show a 3) sea Barents northern the the Iast l0'000 some lO0 m during rebound of rising today at is still vears, and the land the west 0.3 m /lOo vears (Salvigsen,l98l).0n uplift was a very rapid initial there coast, areas emerged land the (Fig. 3) and most of wi thin some few thousand years as a response to Sheet Ice Barents the of deglaciation the The emergence Has (f,langerud et 1987). aI., t'lid-Holocene transgression a by inteirupted (Forman et 1 9 8 ? ; L a n d v i k e t a l ' ' 1 9 8 7) ' al. , that a transgression and there arelndications progress today (Rudberg, 1986; Forman et is in a1., 1987: Sandahl,1986). Z O N A TI O N O F P E R I ' { A F R O S TD I S T RI B U TI O N L ISTORY T H E C E O L O G I C AH
BASED ON
4 , He have out I ined 7 Figure map in the 0n geological history different zones each with a pregiven rise to different have would that pernafrost developnent' conditions critical'for 1 . T h e B a r e n l sS e a z o n e
l.
The Barents Sea zone
the zone comprise This areas and shal low banks in
previously glaciated t h e B a r e n t s S e a'
( l98l ) and ElverAs demonstrated by Salvigsen at least the northern & Solheim ( 1983), hoi glaciated during parts of the Earents Sea were inferred from seaAs l{eichselian. Late in" load disice this level curves on Svalbard, I 0 , 0 0 0 y e a r s a g o' T h e appeared some I 2 ,000 to by the rising was probably forced deglaciation that caused a rapid calving sea-Ievel "uit"tic of the ice front. temperatures close to 0"C expect that We thus sea by replaced glaciers were the beneath 0'C' Thus temperatures that were also close to exposure and subaerial for there was no time present sea bed' permafrost development on the This is in contrast to parts of the Alaskan and shelves where pernafrost Siberian continental is widespread.
2.
The western and nortfrern shelf
zone
ice free areas that includes former This zone the end of Here transgressed by the sea during were that and areas t{eichsel ian the Late transgressed in periods of the Holocene. I f the reconstruct ion of the last glaciation by the present Yangerud9l a1. ( 198?) is correct' parts of shelf off beach zone and continental depth of 50 t h e w e st a n d n o r t h c o a s t d o w n t o a level, were subaerially I 50 m below sea to l{eichselian maximum Late the exposed during Thus. i f there indeed exists any permafrost on the continental shelf around Svalbard, this is the most probable area. At present we nave
ffi'', l
2. The western and norlhern shell zone BoundatYbelween: 3. The emerging coast zone and 4 The transgtessivecoast zone
ftt' !
5. The central lowland zone
I
6. The central mountalns zone
W*
7. The western and nolhern non-glaciatodzone
A schematic pres€ntation of the Fig.4 zones discussed in the text. different the nagnitude of isoknonledge about little the during crust the of depression static the shal lower parts at least U ei c h s e I i a n , b u t have been exPosed for should shelf the of thousands of years. The warnt of tens several reach the west coast of that Haters Atlantic thawing of cause raPid would S v aI b a r d t o d a y comPared to e.g. the permafrost as possible during the Alaskan sheIf. However, some time permafrost must have l a s t 1 0 ,0 0 0 y e a r s r e l i c t present sea the below existed at sone depths floor.
3 . T h e e r n e r gi n g c o a s t
zone
zone along the coast I ine in a narrori This is emerging from sea, is still Iand where areas i.e. mostly in the eastern parts of the archipelago. zone no permafrost is exPected below this In those areas that have In present level . sea short the relativelY level, sea above ri sen exposure poses a limiting subaerial tine of
196
factor for the thickness of permafrost. The present rate of emergence at Kongsoya is around (Fig" 4), 0.3 m /100 years and areas at l0 m at Kongsoya have been above sea level a.s.l. for 2000 years. Permafrost is probably in near equilibrium with present surface tenperature.
4.
level that were outside the l{eichsel ian ice sheet.
I ini ts
of
the Late
Several studies have shown that the westerrr and northern margins of Svalbard were not subject glaciation t{eichselian to during the Late (Salvigsen & Nydal, l98l ; MiI ler , 1982; llangerud et al., 1987; Forman, in press). If we consider the eustaticly low sea-leveI during present land area l{eichsel ian, the both the outside the L a t e f e i c h s e l i a n m a x i m u ma n d o a r t s of the continental shelf were subaerial ly exposed.
The transqressive coast zone
This zone comprises the coast along the line Hest and north coast of SvaIbard. This zone is mainly a transition zone betHeen zone ? and zone 5. or between zones 2 and 7.
The general climatic history for this zone has been paral lei to the history for the nunataks (zone 6), but topographical differences between the zones Iikely caused Iarge local differences in permafrost developnent.
The possible ongoing transgression cornbined with coastal erosion, leads to capture of small areas along the coast by the encroaching sea. Thus permafrost can be expected beneath the Dresent beach in such areas.
A C KN O I L{ E D G E M E N T S 5.
The central
lowland
ne paper This is a result of a co-operat lve project between the research University of and the Norwegian Polar Bergen Research xork Institute. The has been financially supported by t h e N o r w e g i a n C o u n c iI f o r S c i e n c e and Humanities (NAVF)and Statoi 1. The staff of our two institutions and Statoil's representative Alv Orheim have been most helpful for project. accomplishment of the 0lav Liestol critically read the manuscript, and Edward King inproved the text. English Jane El I ingsen, EIlen Irgens and Else Lier drafted the figures. To aIl these persons and institutions we proffer our sincere thanks .
This zone comprises the land areas that irere glaciers Yeichselian covered by the and subsequently deglaciated at ca. 10,000 years B.P. present day tde exclude the area covered by glaciers situated within this zone. The zone was covered Harm based glaciers by during the Late t{eichselian, and the permafrost must have developed after the deglaciation about 10,000 years ago.
6.
The central
mountains zone
penetrated the surface of Al I mountains that t h e L a t e t r / e i c h s e li a n i c e s h e e t a s nunataks are included in this zone. The upper parts of the ice sheet certainly also had temperatures weII below zeroi thus the zone includes the upper parts of the mountains, even if they were ice covered.
REFEREN CES Boulton, c.S. (1979',. clacial history of the problern of Spitsbergen archipelago and the a B a r e n t s S h e lf sheet. ice Boreas (8) , 3t-57.
As shown by the reconstructed margins of the Late ldeichselianice sheet (Fig.2) and profiles of val Iey and fjord glaciers, parts of the mountains in central Spitsbergen, i.e. within the central lowiand zone, nust have been nunataks during the last glaciation. Ue assume that the last extensive glaciation that covered these mountains occurred during the Early ( S a i v i g s e n t { e i c h s e li a n & NydaI, l98l; l.liller, lq82| , or even earI ier.
( e d s .) Denton,G.H. & Hughes, T.J. great The last ice sheets, 484 U i l e y & S o n s, N e w Y o r k .
(1983). Elverhoi, A. & Solheim, 4. The - a sedimentological Barents Sea ice sheet discussion. Polar Research(l n.s.r, 23-42. (in press). Forman, S.L. Late ldeichselian glaciation and deglaciation of the Forlandsund area, west Spitsbergen, Svalbard Archipelago. Boreas.
Thus the s u m m it areas have been exposed to severe arctic conditions for some80"000 to 100,000 years. Immediately after deglaciation, years I 0,000 ago, the permafrost tenperature and thickness in these nountains was probably glacial time temperain equilibriurn with the t ures. Yet as this t ime the air temperature present rose to the vicinity of day temperatures " Thus the temperature in the permafrost m u st h a v e i ncreased, and t h e s e n o u n t a i n s m u st have experienced a net thawing of the pernaf r o st .
7 _ _T h e w e s t e r n This
and northern
zone includes
al I
non-qlaciated
areas above
F o r n a n , S . L . , l ' l a n n ,D . & t t t i l l e r , C . H . ( 1 s 8 7 ) . Late tdeichselian and Holocene relative seaIevel history of ErtiggerhaIvciya, Spi ts bergen. Quaternary Research (2?,, 4I-50. Landvik, J.Y., I'langerud, J. Salvigsen, 0. & ( 1987). The Late t{eichselian and Holocene shorelrne dispiacement on the west-central coast of Svalbard. Polar Research(5 n.s. ). 29-44. (1977). Liestol, 0. Pingos, springs and permafrost in Spitsbergen. Norsk polarinst itutt Arbok t975, 7-29.
zone
present
( 1 9 8 1) . pp. John
sea
197
Bolstad, lt., Elgersna, A., l,tangerud, J.. Helliksen, D., Landvik, J.Y., Lycke, A.K., salvigsen, 0., Sandahl, T. & Lonne, I., Sejrup, H.-P. ( 1987). The Late Ueichsmaxinun in western Svalbard. el ian glacial P o l a r R e s e a r c h( 5 n . s . ) . (19821. I*filier, G.H. Quaternary depositional western Spitsbergen, Norway: episodes, history. aminostratigraphy and glacial A r c t i c a n d A I p i n e R e s e a r c h ( I 4 ) , 3 2 1- 3 4 0 . Rudberg, S. ( 1986). Present-day geonorphological processes on Prins Oscars Iand, Svalbard - wi th appendix: Recent transgress ion in SvaIbard. Geografiska Annaler (68A), 283-29t. ( l98l ). Radiocarbon dated Salvigsen, o. raised beaches in Kong KarIs Land, Svalbard , and the i r consequences for the glacial history of the Barents sea. ( 6 3 A ) , Geografiska Annaler 28-291.
Salvigsen, O. & Nydal, R. (1981). The t/eichsSvalbard before I 5,000 eI ian glaciat ion in B.P. Boreas(10). 433-446. (1985). Salvigsen O. & Elgersma, A. Large scale karst features a n d o p e n t a I 1i k s a t Vardeborgsletta, outer Isfjorden, Svalbard. P o l a r R e s e a r c h( 3 n . s . ) , 1 4 5 - 1 5 3 . (1986). Kvartargeologiske Sandahl, T.J. omrAdet Lewinodden - Kapp undersokelser i Linn6vannet Ytre I sfj orden, Staros t in Svalbard. I * II, 196 . lI2 pp. Unpublished thesis. University of Bergen. Blake Jr., l{. & CrossSchytt, V., Hoppe,C., ( 1 9 6 8) . w a I d , l t {G . . The extent of the WUrm glaciation in the European Arctic. A prereport about the Stockholm Univerlininary sity Svalbard Expedition 1966. International Society of Scientific Hydrology, ceneral Bern 1 9 6 7, Publ . no. 79, Assenbly in 287-2t6.
198
