A contourite drift succession in north-east Baffin Bay: a high-resolution Pleistocene archive of Greenland ice sheet and ocean variability

The Greenland ice sheet’s response to anthropogenic warming will have major consequences for global sea levels but its behavior and stability during past warm intervals is poorly known. To elucidate the long-term behavior of the Greenland ice sheet, high-resolution marine records in ice proximal settings are required. Here we report the first results of a study of a deep-water contourite system on the north-east slope Baffin Bay based on geophysical and shallow core data obtained during two marine expeditions in 2017 and 2019. The contourite drift is incised by channels extending from the slope that is build up by prograding ice stream deposits (Melville Bugt trough-mouth fan). As a result, the contourite system presents a complex architecture. While the mechanisms for deposition and erosion are not yet clear, it is likely that the drift accumulated as a result of interactions between a deep contour current and downslope transport of sediments, presumably of glacigenic origin and therefore constitutes an example of an intertwined contourite-turbidite system. A preliminary age-depth model of the trough-mouth fan evolution indicates that the contourite system began to form during the late Early Pleistocene, possibly around 1 million years ago. The contourite drift is a key target for IODP proposal 909, aimed at unravelling the late Cenozoic evolution of the northern Greenland ice sheet and associated changes in Arctic paleoclimate. Shallow sediment cores from this target area have been retrieved and will be analyzed to generate high-resolution multi-proxy records of ocean circulation and sea-surface conditions including sea ice and paleoproductivity for the late Quaternary-Holocene.