Space-Time Evolution of the Marine Depocenters at the Pelotas Basin, Southern Brazilian Continental Margin

This study aims to investigate space and time evolution of the marine sequences at the Pelotas basin - southern Brazilian margin, based on interpretation of about 10.000 Km of multichannel seismic lines. This work was based on the association of depth to basement map and a series of isopach maps of marine sequences (Lower Cretaceous -Recent). It revealed that the sedimentary distribution pattern changed radically from the Lower Cretaceous to the Oligocene. Through time the main depocenters shifted seawards and backwards again under the influence of a series of processes. The configuration of depocenters was primarily conditioned by basement topographic features, while depocenter segmentation occurred under the influence of dynamic processes.<br>Since the end of the Oligocene a high sedimentary accumulation rate took place, giving rise to the onset of the Rio Grande Cone. This depos ition feature corresponds to the main depocenter at the south Brazilian Margin and its evolution is not related only to thermal-mechanical but also to dynamic processes such as bottom currents.