Cicatriz de remoção no talude da região norte da Bacia de Pelotas

Abstract

The detailed morphology of the continental slope in the North of the Pelotas Basin was obtained using multibeam data, which allowed the identification of seafloor small features. Larger features and its regional context were obtained using singlebeam data. A digital terrain model was calculated and with this model, integrated with 3,5kHz profiles, important information regarding features, morphogenesis and sedimentary processes in the continental slope was obtained. It was observed that slump and slide regions described by Mello et al. (1992), and regions with scarps and faults described by Lima (2004), seem to be part of a huge region of sedimentary removal in the upper and intermediate slope, if inserted in a regional context. This region remains as a removal scar with related slump/slide lobes that generated a slope retreat. Scarps and ridges were identified in shallow waters. They individualize steps and small channels where the removal process was probably initiated. The sediment removal by gravitational and mass flows sculpted the scarps and channels. In deeper waters two huge channels were observed. Those channels must have been the pathway to deeper water of the sediments removed from shallow waters, helping to develop the huge removal scar.