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The marine-based Barents Sea Ice Sheet covered the polar continental shelf north of Norway and western Russia during the Last Glacial Maximum. Initial ice sheet retreat along the western margin is well established, while the retreat pattern in the interior parts of the ice sheet remains poorly known. Here we present new geological data from the central Barents Sea, including the formerly disputed zone. The results are based on analysis of several marine geophysical datasets, including geomorphological mapping of multibeam swath bathymetry data and analysis of seismic and acoustic stratigraphy. The new results provide insights into the configuration and dynamics of the ice sheet during its retreat across the central Barents Sea. In particular they show clear changes in the location of the main ice divides and domes, with ice flow becoming gradually more topographically controlled as deglaciation progressed. Major troughs were characterised by episodic retreat and reoccurring cycles of fast and slow ice flow, sometimes leading to stagnation and ice shelf formation. Meanwhile, adjacent bank areas were covered by comparatively slowly retreating ice, although evidence of streaming ice is also seen locally. Highlights (for review)

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Our understanding of processes relating to the retreat of marine‐based ice sheets, such as the West Antarctic Ice Sheet and tidewater‐terminating glaciers in Greenland today, is still limited. In particular, the role of ice stream instabilities and oceanographic dynamics in driving their collapse are poorly constrained beyond observational timescales. Over numerous glaciations during the Quaternary, a marine‐based ice sheet has waxed and waned over the Barents Sea continental shelf, characterized by a number of ice streams that extended to the shelf edge and subsequently collapsed during periods of climate and ocean warming. Increasing availability of offshore and onshore geophysical data over the last decade has significantly enhanced our knowledge of the pattern and timing of retreat of this Barents Sea ice sheet (BSIS), particularly so from its Late Weichselian maximum extent. We present a review of existing geophysical constraints that detail the dynamic evolution of the BSIS through the last glacial cycle, providing numerical modelers and geophysical workers with a benchmark data set with which to tune ice sheet reconstructions and explore ice sheet sensitivities and drivers of dynamic behavior. Although constraining data are generally spatially sporadic across the Barents and Kara Seas, behaviors such as ice sheet thinning, major ice divide migration, asynchronous and rapid flow switching, and ice stream collapses are all evident. Further investigation into the drivers and mechanisms of such dynamics within this unique paleo‐analogue is seen as a key priority for advancing our understanding of marine‐based ice sheet deglaciations, both in the deep past and in the short‐term future.

The origin of two acoustic sediment units has been studied based on lithological facies, chronology and benthic stable isotope values as well as on foraminifera and clay mineral assemblages in six marine sediment cores from Kveithola, a small trough west of Spitsbergenbanken on the western Barents Sea margin. We have identified four time slices with characteristic sedimentary environments. Before c. 14.2 cal. ka, rhythmically laminated muds indicate extensive sea ice cover in the area. From c. 13.9 to 14.2 cal. ka, muds rich in ice‐rafted debris were deposited during the disintegration of grounded ice on Spitsbergenbanken. From c. 10.3 to 13.1 cal. ka, sediments with heterogeneous lithologies suggest a shifting influence of suspension settling and iceberg rafting, probably derived from a decaying Barents Sea Ice Sheet in the inner‐fjord and land areas to the north of Kveithola. Holocene deposition was episodic and characterized by the deposition of calcareous sands and shell debris, indicative of strong bottom currents. We speculate that a marked erosional boundary at c. 8.2 cal. ka may have been caused by the Storegga tsunami. Whilst deposition was sparse during the Holocene, Kveithola acted as a sediment trap during the preceding deglaciation. Investigation of the deglacial sediments provides unprecedented details on the dynamics and timing of glacial retreat from Spitsbergenbanken.