SEDIMENT EROSION ON THE SOUTHERN SOUTH AFRICAN CONTINENTAL MARGIN: INDICATIONS FOR THE PATHS OF OCEANIC CURRENTS?

Seismic profiles extending from the southern South African shelf into the deep sea reveal a strong erosional activity, which affects large parts of the continental margin. Recent to Oligocene sequences, and in places the whole sedimentary column, appear to have been removed. Mass movements were considered as the origin of this erosion. However, structures indicating slumping could only be identified in a few places, The erosional activity is confined to specific water depths, which correlate well with the activity levels of water masses observed here. We thus suggest that the Agulhas Current, Antarctic Intermediate Water, North Atlantic Deep Water, and Antarctic Bottomwater have intensively shaped the sedimentary sequences for a considerable period. It is difficult to estimate the duration of the erosion. Numerical simulation of sediment transport and erosion is needed to indicate the onset of the erosional activity.