Postglacial variability in near-bottom current speed on the continental shelf off south-west Spitsbergen

This study documents changes in the sedimentary environment on the outer continental shelf off south-west Spitsbergen during the last approximate to 14 000 cal a BP using sedimentological, mineralogical and geochemical data from a sea-bed sediment core. We use the sortable silt fraction to infer fluctuations of near-bottom current speed and determine sediment provenance and sediment transport paths. For most of the record length, sediments were derived from distal sources by the West Spitsbergen Current (WSC) and the East Spitsbergen Current (ESC). However, before approximate to 12 000 and after approximate to 1800 cal a BP sediments were also sourced from proximal sources in south-west Spitsbergen. The slowest near-bottom currents were recorded between 10 300 and 9700 cal a BP when an increase in water stratification occurred, probably due to the strengthening of the ESC and an associated reduction in the northward water and heat flux. Near-bottom currents related to WSC activity were at their maximum between 9000 and 7500 cal a BP, i.e. during a period of elevated water temperature, probably resulting in maximum relative heat fluxes to the Arctic.