Western Siberia experienced rapid shifts in moisture source and summer water balance during the last deglaciation and early Holocene

Abstract

The Russian Arctic is an extensive region, with relatively few long‐duration paleoclimate reconstructions compared to other terrestrial Arctic regions. We present a 24 000‐year reconstruction of climate in the Polar Ural Mountains using n ‐alkanoic acid hydrogen isotopes from Lake Bolshoye Shchuchye. Major last deglaciation climate changes in the North Atlantic are present in this record, including transitions associated with the Bølling–Allerød, Younger Dryas and Holocene. However, the magnitude of the last deglaciation isotopic shifts at Bolshoye Shchuchye are small relative to the North Atlantic, and are dwarfed by a shift to 2 H‐enriched values starting at 10.5k cal a bp at this site that is not present in most other records. The last deglaciation changes may be due to variations in local temperature, sea ice cover in the Barents and Kara seas, and plant community shifts impacting transpiration. The enrichment starting at 10.5‐k cal a bp probably records a shift towards modern climate conditions, caused by the loss of the Scandinavian Ice Sheet, increased locally sourced moisture from the Barents and Kara seas, and northward treeline migration causing enhanced transpiration. Future warming may increase summer precipitation in this region, with changes to local ecosystems and carbon cycling.

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