Late-glacial and Holocene paleoceanography and sedimentary environments in the St. Anna Trough, Eurasian Arctic Ocean margin

Based on stratigraphical analysis of twelve sediment cores from the Saint Anna Trough, we reconstruct changes in paleoceanography and sedimentary environment during the last deglaciation and the Holocene. Detailed analysis of benthic and planktic foraminiferal fauna, stable oxygen and carbon isotope analysis, lithostratigraphy and radiocarbon dates, are used to reconstruct the following evolution: After the deglaciation of the Saint Anna Trough >13,300 yr B.P. until 9500 yr B.P., the environment was mainly characterised by low biogenic production, carbonate dissolution and deposition of proximal to distal glaciomarine sediments. Intervals with high abundance of the benthic foraminifer Cassidulina teretis, may indicate influx of Atlantic Water at bottom. The transition into the present interglacial started at 9500 yr B.P. reflected by increased production of foraminifera and bivalves. After 8000 yr B.P. there was a marked drop in planktic δ18O followed by a rise in planktic foraminifera and subsequently an increase of C. teretis. These paleoceanographic changes reflect increased heat transport into the area and are coupled to changes in Nordic seas. The early Holocene warming of the Saint Anna Trough were delayed by ca. 2000 years relative to the northeast Nordic seas. Early Holocene sedimentation rates were relatively high (>100 cm/1000 yr), declining drastically after 8000 yr B.P. (<50 cm/1000 yr). This was presumably caused by reduction in winnowing and/or riverine input.