Miocene to Recent contourite drifts development in the northern Weddell Sea (Antarctica)

Five main seismic units separated by regional unconformities are recognized above the oceanic basement. The age of the deposits is based on the magnetic anomalies of the oceanic crust and the overlying seismic sequences. The external geometry and acoustic character of the seismic units indicate strong bottom-current processes, except for the basal deposits attributed to the Early Miocene. The development of extensive drifts in the deposits of Unit 4 (∼Middle Miocene) shows the initial influence of the Weddell Sea Bottom Water (WSBW). The opening of the connection of Jane Basin with the Scotia Sea also is marked by a regional unconformity that records a reorganization of bottom flows. The two uppermost Units 1 and 2 (Late Miocene to Recent) indicate intensified bottom currents, which may reflect the increased production of WSBW. The evolution through time of the contourite deposits and the distribution of regional unconformities reflect the ice sheet dynamics that controlled the production of Antarctic Bottom Water (AABW).