A rare record of late Neogene glaciation from the north east Greenland margin

Studies based on deep ocean drilling cores points to North-East Greenland as a focal point for ice sheet accumulation incurring much earlier than the Pleistocene Northern Hemisphere glaciation. The build-up of marine-based ice sheets in these parts is critical to the cooling of the Nordic Seas and the Arctic Ocean, considered as a pre-condition for the modern ocean “conveyor belt” circulation. However, proximal sedimentary records that can shed light on the timing and climate background of early Greenland Ice Sheet evolution are lacking. In 2008 a series of shallow cores were drilled by the Kanumas consortium on the NorthEast Greenland shelf and Cenozoic sediments were recovered at several sites. Here we present litho- and palynostratigraphic information, along with new cosmogenic isotope results, of a 110 m long sediment core (Kanumas 13). The core study, supported by regional seismic data, suggests that ice streams may have been active on the North-East Greenland margin since middle-late Miocene. Geochemistry and magnetic susceptibility data indicate that an abrupt change in sediment source occurred at 50.8 m. The shift in provenance is accompanied by a transition to more open marine conditions. The implications for the Greenland Ice Sheet and Artic climate development will be addressed in the presentation.