Late Pleistocene stratigraphy and sedimentary environments of the Severnaya Dvina‐Vychegda region in northwestern Russia |
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| Authors: | Astrid Lyså Eiliv Larsen Jan‐Pieter Buylaert Ola Fredin Maria A Jensen Denis Kuznetsov Andrew S Murray Dmitry A Subetto Aurelien van Welden |
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| Institution: | 1. Geological Survey of Norway, , N‐7491 Trondheim, Norway;2. Museum of Natural History and Archaeology, Norwegian University of Science and Technology, , NO‐7491 Trondheim, Norway;3. Nordic Laboratory for Luminescence Dating, Department of Geoscience, Aarhus University, , DK‐4000 Roskilde, Denmark;4. Department of Geography, Norwegian University of Science and Technology, , NO‐7491 Trondheim, Norway;5. The University Centre in Svalbard, , N‐9171 Longyearbyen, Norway;6. Institute of Limnonlogy, Russian Academy of Sciences, , 196105 St. Petersburg, Russia;7. Department of Geography, Herzen State University, , 191180 St. Petersburg, Russia;8. CGG, Multi‐client & New Ventures, Scandinavia‐Russia, , N‐0213 Oslo, Norway |
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| Abstract: | The Late Pleistocene stratigraphy from the Severnaya Dvina‐Vychegda region of northwestern Russia is revised based on investigations of new localities, revisiting earlier localities, introduction of about 110 new OSL dates and burial depth corrections of earlier published OSL dates, in addition to six new radiocarbon dates. Most of the OSL samples studied here are from fluvial and subaquaeous sediments, which we found to be well bleached. Six chronostratigraphical units and their sedimentary environment are described, with the oldest unit consisting of pre‐Eemian glacial beds. For the first time, Early Weichselian sediments are documented from the region and a fluvial environment with some vegetation and permafrost conditions is suggested to have persisted from the end of the Eemian until at least about 92 ka ago. The period in which a Middle Weichselian White Sea Lake could have existed is constrained to 67?62 ka, but as the lake level never reached the thresholds of the drainage basin, the lake probably existed only for a short interval within this time‐span. Blocking and reversal of fluvial drainage started again around 21?20 ka ago when the Fennoscandian Ice Sheet advanced into the area, reaching its maximum 17?15 ka ago. At that time, an ice‐dammed lake reached its maximum water level, which was around 135 m above present sea level. Drainage of the lake started shortly after 15 ka ago, and the lake was emptied within 700 years. Severe periglacial conditions, with permafrost and aeolian activity, prevailed in the area until about 10.7 ka. |
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