Paleoenvironmental records from permafrost sequences complemented by IRSL and 230Th/U dates from Bol'shoy Lyakhovsky Island (73?20?N, 141?30?E) document the environmental history in the Laptev Sea region for at least the past 200 ka. Pollen spectra and insect fauna indicate that relatively wet grass-sedge tundra habitats predominated during an interstadial c. 200-170 ka ago. Summers were rather warm and wet, while stable isotopes reflect severe winter conditions. The pollen spectra reflect sparser grass-sedge vegetation cover during a late Saalian stadial, c. 170-130 ka ago, with environmental conditions much more sever compared with the previous interstadials. Open Poaceae and Artemisia plant associations dominated vegetation at the beginning of the Eemian Interglacial, c. 130 ka ago. Some shrubs (Alnus fruticosa, Salix, Betula nana) grew in more protected and wetter places as well. The climate was relatively warm during this time, resulting in the melting of the Saalian ice wedges. Later, during the interglacial optimum shrub tundra with Alnus fruticosa and Betula nana s.l. dominated vegetation. Climate was relatively wet and warm. Quantitative pollen-based climate reconstruction suggests that mean July temperatures were 4-5?C higher than the present during the optimum of the Eemian Interglacial, while late Eemian records indicate significant climate deterioration.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL6-Earth climate variability since the Pliocene