THE PERIGLACIAL CLIMATE AND ENVIRONMENT IN NORTHERN EURASIA DURING THE LAST GLACIATION AND THE HOLOCENE

Intensive field work carried out from the Laptev Sea area in the east to the north western Russian plain under the umbrella of the European Science Foundation (ESF) program “QUEEN”, has proven that with the exception of the north-western fringe of the Taimyr Peninsula, the rest of the Eurasian mainland and Severnaya Zemlya was not affected by the Barents-Kara-Sea Ice Sheet during the LGM. During the period 20-15 ka BP when the ice sheets there reached their maximum LGM-positions, the climate was extremely dry and cold. In the eastern part of the region (Laptev Sea area) due to the extensive recession northwards of the shoreline (lowered sea level), the summer effect of climatic continentality overrode the general cooling of climate during the LGM and provided more favorable biotic conditions in high latitudes. The latest Weichselian climatic change around 15 ka BP is noticed everywhere in the Eurasian Arctic, but the dynamics of climate warming and increasing humidity were different in the western (glacially affected) and eastern (periglacial) areas. In the Laptev Sea area it is marked by a development of the more productive tundra-steppe vegetation, resulting in a short but dramatic increase of mammoth population and the recovery of steppe insect diversity. The climate, however, remained very dry, with cold winters. This rather short phase of increased biological productivity (15 to 12.5 ka BP) evidently pre-dated the interval of favorable climate recorded further west as the Bølling-Allerød warming (ca 13-11 ka BP). But it was not occurred until 12.5 ka BP, when the climate became more humid and a general degradation of permafrost started, accompanied by a dramatic change from tundra-steppe vegetation to wet tundra and forest tundra, which greatly contributed to the extinction of the mammoth megafauna. The Holocene climatic optimum occurred in Siberia during the early Holocene. During that time, vegetation zones were located 200-400 km to the north of their present position. Relatively warm climatic conditions remained during the Atlantic and Subboreal periods. Since the end of the Subboreal climate and vegetation became similar to the modern.