Late Glacial–Holocene clay minerals elucidating glacial history in the SW Barents Sea

Abstract

Detailed investigations of the distribution of clay minerals of Late Glacial–Holocene sediments from the SW Barents Sea provide important new information about the provenance and transport paths of the sediments. This information leads to better understanding of the onset of the last deglaciation and subsequent advances/retreats of the Barents Sea- and Fennoscandian Ice Sheets. The results show interaction and changes in the Fennoscandian Ice Sheet and Bjørnøyrenna Ice Stream during the last deglaciation. High illite content and maximum kaolinite content (> 18 700 cal yr B.P.) indicate glacial erosion from both the Fennoscandian Ice Sheet and Bjørnøyrenna Ice Stream (LGM II). The occurrence of a C. reniforme dominated benthic foraminiferal assemblage (~ 18 700 cal yr B.P.) indicates that the northern most cores site in Ingøydjupet had already been deglaciated and was probably situated in a glacier distal environment. In addition, smectite content reaching its highest level, concurrent with the presence of Neogloboquadrina pachyderma (sin) dominated planktic foraminifera can be related to the strengthening of the Atlantic Current. The inflow of the Atlantic Water may have triggered deglaciation of the Fennoscandian Ice Sheet (Bølling interstadial). A rapid increase in illite content, reflecting strong melting of the Fennoscandian Ice Sheet (~ 15 000 cal yr B.P.), indicates the onset of deglaciation in a core closer to the continent. Decrease of illite and IRD content, together with the deposition of laminated sediments during the Older Dryas stadial (15 000–14 000 cal yr B.P.) indicates colder conditions and formation of at least seasonal sea-ice. In addition, increased kaolinite content indicates increased glacial erosion of the Bjørnøyrenna Ice Stream. The highest values of illite content and increased IRD content (14 000–13 000 cal yr B.P.) can be related to strong melting of the Fennoscandian Ice Sheet. A slight indication of the Younger Dryas cold period is given by the decrease in illite and IRD contents. All clay contents are more stable during Holocene compared to LGM and the last deglaciation.