Weichselian geology and palaeoenvironmental history of the central Taymyr Peninsula, Siberia, indicating no glaciation during the last global glacial maximum

Abstract

Bergsten, H. 1999 (March): Weichselian geology and palaeoenvironmental history of the central Taymyr Peninsula, Siberia, indicating no glaciation during the last global glacial maximum. Boreas, Vol. 28, Oslo. ISSN 0300-9483. The Taymyr Peninsula constitutes the eastern delimitation of a possible Kara Sea basin ice sheet. The existence of such an ice sheet during the last global glacial maximum (LGM), i.e. during the Late Weichseliad Upper Zyryansk. is favoured by some Russian scientists. However, a growing number of studies point towards a more minimalistic view concerning the areal extent of Late WeichselianLJpper Zyryansk Siberian glaciation. Investigations carried out by us along the central Byrranga Mountains and in the Taymyr Lake basin south thereof, reject the possibility of a Late WeichseliadUpper Zyryansk glaciation of this area. Our conclusion is based on the following: Dating of a continuous lacustrine sediment sequence at Cape Sabler on the Taymyr Lake shows that it spans at least the period 39-17 ka BP. Even younger ages have been reported, suggesting that this lacustrine environment prevailed until shortly before the Holocene. The distribution of these sediments indicates the existence of a paleo-Taymyr lake reaching c. 60 m above present sea level. A reconnaissance of the central part of the Byrranga Mountains gave no evidence of any more recent glacial coverage.The only evidence of glaciationan indirect oneis deltaic sequences around 100-120 m a.s.1.. suggesting glacio-isostatic depression and a large input of glacial meltwater from the north. However, I4C and ESR datings of these marine sediments suggest that they are of Early WeichselianiLower Zyryansk or older age. As they are not covered by till and show no glaciotectonic disturbances, they support our opinion that there was no Late WeichselianiLower Zyryansk glaciation in this area. We thus suggest that the Taymyr Peninsula was most probably glaciated during the early part of the last glacial cycle (when there was only small-to mediumscale glaciation in Scandinavia), but not glaciated during the later part of that cycle (which had the maximum ice-sheet coverage over north-westem Europe). This fits a climatic scenario suggesting that the Taymyr area, like most of Siberia, would come into precipitation shadow during times with large-scale ice-sheet coverage of Scandinavia and the rest of north-western Europe.

Radiocarbon Chronologies and Extinction Dynamics of the Late Quaternary Mammalian Megafauna of the Taimyr Peninsula, Russian Federation

“…During the LGM, Taimyr may have experienced extreme polar desert conditions (Siegert & Marsiat, 2001), perhaps including some amount of terrestrial-ice cover (but this is debated; cf. Grosswald, 1998;Mö ller et al, 1999;Grosswald & Hughes, 1999). Other regions along the high Arctic coast are similar, in that there are few dates on fauna which correlate with the period that includes the LGM and its immediate aftermath.…”

“…For example, the beach along the east side of Cape Sabler, Lake Taimyr (Figure 1), is acknowledged to be one of the best collecting areas on the peninsula. From simple positional considerations it is obvious that bones which end up on the cape's beach must be eroding out of the cliff face that towers above it, which is composed of unconsolidated silts, peats, sands, and gravels at base (for a detailed description, see Mö ller et al, 1999). However, it is quite uncommon to see bones actually in situ in the cliff face before they erode out, and articulated elements are almost never encountered as such.…”

“…As a result, the divide between the Khatanga and Taimyra basins is very low (<50 m asl). According to Mö ller et al (1999), on at least one occasion during the late Quaternary the water level in Lake Taimyr rose far above its current elevation (5 m asl). Overflow from the lake would have drained into the Khatanga basin via the headwaters of the Bol'shaya Balakhnya, with the result that large areas of the lowlands on either side of the river would have been shallowly submerged for a time.…”

Severnaya Zemlya, Arctic Russia: a nucleation area for Kara Sea ice sheets during the Middle to Late Quaternary

“…Mo¨ller et al (1999a) and Alexanderson et al (2002) concluded that northern Taymyr were subjected to extensive glaciations in Early to Middle Weichselian times (ca 90-80 and 70-60 ka BP; MIS 5 and 4), but evidence of older glaciations is sparse. Evidence of multiple pre-LGM glaciations is also present on Severnaya Zemlya (Bolshiyanov and Makeyev, 1995).…”

Maximum extent of the Eurasian ice sheets in the Barents and Kara Sea region during the Weichselian

“…In addition to satellite and aerial photographic interpretation, the mapping was carried out through land-based geological field investigations in several sectors of the Russian Arctic from the White Sea region to the Taimyr Peninsula ( Fig. 1) Hahne & Melles 1998;Larsen et al 1999;Möller et al 1999;Tveranger et al 1999). Exposed sections along rivers, lakes and coasts and sediment cores from lake basins have been investigated and dated.…”