A review of the deep and surface currents around Eirik Drift, south of Greenland: Comparison of the past with the present

摘要

The global Thermohaline Circulation (THC) is primarily driven by the cooling and sinking of northward flowing North Atlantic surface waters in the Nordic Seas to form North Atlantic Deep Water (NADW) that flows southward as a component of the Deep Western Boundary Current (DWBC). It is widely accepted that major freshwater injections have disrupted the formation of NADW in the past, causing widespread cooling over the North Atlantic. Eirik Drift, a contourite south of Greenland, was formed from deposition of sediments carried in the DWBC, so contains information about DWBC variability. Before now, the spatial and temporal variability of the surface and deep water currents, and their relationship with the associated sedimentation have not been fully understood. Here, we present a review of the key findings from the RAPID Cape Farewell project at Eirik Drift, a multi-disciplinary study which included hydrographic profiles, sub-bottom and sea-floor geophysical data, and multi-proxy analyses of a marine sediment core. We use these previously published results to further elucidate the oceanographic processes above Eirik Drift and relate these results to the sedimentation patterns. We also resolve, using a down-core record of NADW flow intensity, how bottom currents in this region changed in association with freshwater forcing during the last deglaciation.