EROSION-DEPOSITIONAL PROCESSES IN THE NORTHERN PART OF THE CONTOURITE SYSTEM ON THE PATAGONIAN CONTINENTAL SLOPE

Series of two papers are dedicated to study of erosional and depositional processes in the northern part of the previously distinguished contourite system on the Patagonian continental slope between 46-42° at a water depth range of 2100-5200 m. The first paper is focused on interpretation of high-resolution seiscmoacoustic data collected using the parametric echo-sounder SES 2000 deep with acoustic penetration of 60 mbsf. Analysis of seismic data revealed seismic facies of contourites and gravitites as well as erosional features formed under the influence of gravity flows (gravity-driven processes) moving downslope through the canyon system. It was demonstrated that gravitites deposited by gravity flows represent a source of sediment material for contourite drift formation. Domination of erosion over deposition in the study area might be explained by the intense dynamics of bottom waters, including contour currnets, internal waves, benthic storms and gravity flows.