LATE QUATERNARY ICE SHEET HISTORY OF NORTHERN EURASIA

The limits of the Eurasian ice sheets have been reconstructed for four glaciations during the Quaternary: 1) the Late Saalian (c. 160-140 ka) 2) the Early Weichselian (90-80 ka), 3) the early Middle Weichselian (60-50 ka) and 4) the Late Weichselian (20-15 ka). The reconstructed ice limits are based on satellite data and aerial photographs combined with comprehensive geological field investigations in Northern European Russia and Siberia, as well as interpretation of marine seismic- and core data from the adjacent continental shelf and deep sea. This is a synthesis of results obtained during the Eurpean Science Foundation Program "Quaternary Environment of the Eurasian North" (QUEEN). A huge glaciation that covered vast areas of northern Eurasia occurred during the Late Saalian (MIS 6) just prior to the last interglacial. The maximum extent of the post-Eemian glaciation in the Eurasian Arctic occurred around 90-80,000 years ago (Early Weichselian – MIS 5b), when the Barents-Kara Ice Sheet expanded far onto northern Russia and Siberia and blocked the northbound draiange towards the Arctic Ocean. A regrowth of the ice sheets occurred during the early Middle Weichselian, culminating about 60-50,000 years ago. During the Last Glacial Maximum (LGM) around 22-17,000 years ago the Scandinavian Ice Sheet attained its maximum position. At this time the Barents-Kara Ice Sheet embraced a much smaller area over the Russian Arctic than shown in most earlier reconstructions. The proposed ice sheet history in the Barents- and Kara Sea region is supported by core data from the Arctic Ocean. In the Arctic Ocean sediments the ice sheet maxima are recognized as layers with a high concentration of ice rafted debris (IRD) and the deglaciations are seen as meltwater spikes from the oxygen isotope record. A comparison of empirical ice sheet reconstruction with glaciological model simulations suggest that that the Eurasian ice sheets during the Quaternary to a large extent can be explained by the interaction of sea level regressions, negative shifts in isolation and regional variations in precipitation rates.