Postglacial environmental changes in the northwestern Barents Sea caused by meltwater outbursts

Abstract

Abstract. The last deglaciation was marked by abrupt shifts between cold and warm states reflecting an integrated response to the gradually increasing summer insolation at northern latitudes, changing ocean circulation, and the retreat of the Northern Hemisphere ice sheets. In this study, we present new multiproxy reconstructions of water mass properties and sea surface characteristics from a sediment core from the northwestern Barents Sea (Kveithola) representing the last 14,700 years. Our reconstruction documents four sediment-laden meltwater pulses between 14,700 and 8,200 cal years BP based on biomarkers, stable isotopes, and sedimentological parameters. Deglacial processes primarily cause these meltwater pulses and are possibly supplemented with paleo-lake outbursts, paleo-tsunami currents, or a combination of at least one of these, are characterized by sudden drops in sea surface temperatures, increased sea ice formation, increased terrigenous supply, and a limited influence of Atlantic Water in the northwestern Barents Sea. The influence of the Storegga tsunami, which occurred around the 8,200 cal years BP cooling event likely reached and redistributed the sediment in Kveithola. Strong coarsening of the northwestern Barents shelf was observed after 3,500 years, which might be related to a stronger Atlantic Water inflow from the west across the bank leading to winnowing.