New constraints on the limits of the Barents-Kara ice sheet during the Last Glacial Maximum based on borehole stratigraphy from the Pechora Sea

摘要

A new, ~(14)C-verified borehole stratigraphy provides the first age-controlled reconstruction of the late Quaternary glacial history of the Pechora Sea (southeasternmost Barents Sea). A complete glaciation of the Pechora Sea is confirmed for middle Weichselian time, prior to ca. 35-40 ka. Composition of glacial erratics indicates that ice was moving from or across southernmost Novaya Zemlya and Vaygach Island. After a brief interstadial period with normal marine conditions, the Pechora Sea was affected by a drop in sea level and a drier climate. Subsequently, the late Weichselian Barents-Kara ice sheet occupied the northwestern part of the Pechora Sea, but did not reach the coast of the Pechora lowland, as previously believed. These data provide a new constraint on the Last Glacial Maximum (LGM) ice-sheet limits in the Eurasian Arctic. The inferred direction of the Last Glacial Maximum ice movement in the Pechora Sea was from the northeast, but with a stronger northern component than the penultimate glaciation. The ice sheet retreated early, ca. 13 ka, after which the shallow Pechora Sea was subjected to strong erosion during the postglacial sea-level rise.