Holocene paleoceanographic development of the eastern Baffin Bay

The 738 cm long marine sediment core (core AMD14-204C; 73°15.663' N/57°53.987' W; 987 m water depth) provides a Holocene paleoceanographic and paleoclimatic record of the eastern Baffin Bay near Upernavik Isstrøm, NW Greenland. The Baffin Bay is a semi-enclosed basin connecting the Arctic Ocean with the North Atlantic Ocean, making it an area highly influenced by both Polar and Atlantic sourced water masses and seasonally sea ice cover. In this study, we reconstructed the relative fluctuations in the advection of these water masses through a multiproxy investigation of the marine sediment core. Investigations include benthic foraminifera assemblage analysis, CT-scans, X-ray fluorescence and Rock-Eval organic pyrolysis. Our results suggest that several changes in the paleoenvironment have occurred over the past ca. 9.2 ka cal. BP. At ca. 9.2-7.9 ka cal. BP the eastern Baffin Bay was highly influenced by deglacial conditions associated with meltwater inflows supplied by the melting of the Greenland Ice Sheet and the presence of an extensive sea-ice cover. 7.9-6.7 ka cal. BP marks the onset of the Holocene Thermal Maximum with strong advection of relatively warmer northward flowing Atlantic water masses. The Neoglaciation is marked by a domination of agglutinated foraminifera around 3.0 ka cal. BP caused by increased advection of the cold corrosive Baffin Bay Deep Water possibly flowing into the Baffin Bay via the many gateways of the Canadian Arctic Archipelago and the Nares Strait. The Rock-Eval organic pyrolysis method was applied to assess down-core changes in paleoproductivity. Preliminary results of the organic pyrolysis analyses reveal that the organic matter released at a pyrolysis temperature of ca. 350 °C might indicate the presence of high primary productivity possibly linked to the proximity of a sea ice edge. This assumption is supported by correlations of the pyrolysis data with benthic sea-ice indicator species together with sea ice biomarkers. Studies of surface samples in connection with biomarker data are currently being carried out in order to fully resolve the potential of using this method on recent sediments to evaluate the paleo primary productivity.