Ice sheet instability and meltwater events along the Svalbard–Barents Sea margin during the last 60,000 years

Sediment drift records from the western Barents Sea–Svalbard margin provide key insights into the response of the marine-based paleo Svalbard–Barents Sea Ice Sheet (SBSIS) to climatic variability over the past 60 ky. Lithofacies characterization combined with clay mineral assemblages enables reconstruction of sediment provenance and depositional processes. Illite is ubiquitous and of limited provenance value, whereas smectite reflects input from the West Spitsbergen Current, chlorite records local ice streams draining through Storfjorden–Bellsund troughs, and kaolinite is linked to iceberg rafting from the Storbanken region following calving of the Bjørnøyrenna paleo-ice stream. The distribution of these minerals provides a robust proxy for SBSIS activity across central and western sectors. Sedimentation rates, away from mass-transport deposits, were unexpectedly low during glacial periods but high during deglaciations and interglacials. Episodes of intensified sediment delivery reflect short-lived, widespread meltwater pulses. A notable H2-like layer deposited ∼24.8–23.5 ky, above Last Glacial Maximum mass transport deposits, documents a prominent meltwater event driven by increased Northern Hemisphere insolation. This event destabilized the fully expanded SBSIS in areas with deeply grounded ice streams and retrograde shelf morphologies, underscoring the ice sheet's sensitivity to atmospheric warming and ocean forcing. Meltwater pulses profoundly affected the Arctic, enhancing water-column stratification, sea-ice expansion, organic matter accumulation, and bottom-water oxygen depletion, with implications for carbonate and magnetite diagenesis and for carbon storage in polar basins during glacial–interglacial transitions.