To understand the climatic links between oceans, atmosphere and continents we need further knowledge on the timing and extent of late Pleistocene glaciations in the Arctic. Glacier activity in the Arctic regions has great impact on the global climate. This project focuses on the Eurasian ice sheet. There are contradicting views on the location of centra, extent and timing of Late Quaternary ice sheets over Eurasia. One advocates full coverage of a marine-based ice sheet over the Barents Sea, Kara Sea and the northern Eurasian continent, with thick ice over Novaya Zemlya, and with its centra located in the Kara Sea. Another view proposes local ice caps over the arctic archipelago and thin ice on the Kara Sea, only reaching the western Yamal Peninsula. In addition, some Russian scientists completely deny the existence of any Eurasian ice sheets during the Pleistocene. The different models are largely based on interpretation of morphological features, stratigraphy, geochronology, tilt of the level for raised beaches, seismo-acoustic data, erratics, foraminiferal analysis and radiocarbon datings.
The heart of diverging ice sheet models lies in the southern Kara Sea. For a better understanding of the Late Weichselian Eurasian ice sheet, more stratigraphical data is needed from this area. During the summer of 1997 we did stratigraphical and chronostratigraphical work along the coastal sections at Marresale, south-western part of the Yamal Peninsula. During the summer of 1998 we continued our project at Cape Spindler, 40 km east of the town Amderma, on the Yugorsky Peninsula.

The 1998 fieldwork

After transportation by airplane to Amderma the party went by bandwagon on the tundra to Cape Spindler. Here we stayed in a hut that had been transported out on the snow by bandwagon in late spring. We enjoyed great geology, beautiful nature and good food, such as reindeer meat, fish and canned meat. Fieldwork encompassed long walks along the cliffs to describe the geometry of the different sedimentary units. Certain sites were cleaned and investigated in more detail. Stratigraphical descriptions were made in vertical sections, so called ”logs”. Each sedimentary unit, which represents a sedimentary environment, was described. Samples were collected for various dating and other laboratory analyses.

Preliminary results

Marresale, Vamal Peninsula
The stratigraphical work during the 1997 expedition to Yamal Peninsula revealed a glacial diamict, related to a glacial overriding by ice originating from the Kara Sea. Pieces of wood from an underlying sandy unit yielded 14C ages >30 ka. Above the till there occur peat and lacustrine deposits, in which plant remains gave minimum limiting ages of 15 to 30 ka. In turn those sediments are unconformably overlaid with fluvial and eolian sediments. Cryogenic convolutions and ice wedges at the top of the fluvial sediments indicate a significant period of subaerial exposure. This paleosurface formed under very cold and arid conditions, possibly in connection with the last glacial maximum (Late Weichselian). The uppermost part of the sequence contains interdigitating eolian and fluvial sediments. Plant remains from the eolian facies yielded AMS 14C ages of 13 to 14 ka. The sequence is capped by peat, which contains rooted birch trees yielding 14C ages of 8.2 to 8.8 ka. A discontinuous cover sand buries the sections, reflecting a drying of the landscape in the latter half of the Holocene. Thus there is no evidence for a glacial coverage of the area during the last glaciation.

Spindler Cape, Vugorsky Peninsula
Fieldwork at Spindler Cape, Yugorsky Peninsula during the summer of 1998 revealed a complex stratigraphy with at least six lithostratigraphic units. There is evidence of at least one glacial advance, with ice moving from the north and with glaciotectonic thrusting and stacking of the underlying sediments. Another diamicton, interpreted as a subglacial deposit was documented in the upper part of the sections. At a few localities, underlying deformed sediments show stress directions from the southeast. Except for the different stress directions, those diamictons can be distinguished from each other in that the lower diamicton contains shell fragments and the upper diamicton does not. However it cannot be excluded that they both originate from the same glacial event, and that the peculiar southeasterly stress directions are only results of backsliding of the ice sheet. The lower diamict may originate from the same glacial event that deposited the Kara Diamicton, described last year at Marresale, Yamal Peninsula. Datings from the sedimentary units overlying the Kara Diamicton suggest that this event took place before 30 ka. This would imply that ice coming out of the Kara Sea reached both the south-western Yamal Peninsula and the Yugorsky Peninsula earlier than the Late Weichselian glaciation. A younger ice advance from the Polar Urals only reached Yugorsky Peninsula. Results are preliminary and evaluation of field observations and interpretations will proceed as samples for 14C and OSL dating, micro- and macrofossil analysis are being processed.

Continued research

Another field season at Spindler Cape is planned for the summer of 1999. This will contribute to a more complete story of the complex stratigraphy. We will concentrate on documenting the glaciotectonic stacking and on describing the upper diamicton.