Contourites and Gravitites on the Rio Grande Rise,Southwest Atlantic Ocean (Seismoacoustic Data)

Morphology of the Rio Grande Rise and the acoustic structure of different types of deposits in its uppermost sedimentary cover were discussed based on high-resolution seismoacoustic profiling of cruises #32 (2010) and #52 (2016) of R/V Akademik Ioffe. Slopes of the Rio Grande Rise are composed mainly of landslide deposits and gravitites, but contourite sedimentation is possible on its southern slope. Contourite sedimentary waves and, probably, small drifts are identified in the Cruzeiro do Sul Trough at the top of the Rio Grande Rise. Mixed gravitite–contourite sedimentary systems seem to be located at the foot of northern and southern slopes. The downslope density flows and the Antarctic Bottom Water (AABW) contourite current are responsible for the formation of these features.