出版社：Instituto Oceanográfico da Universidade de São Paulo
摘要：This study focuses on the Quaternary sea level changes in the Apodi-Mossoró Estuary and adjacent shelf, Northeastern Brazil, based on the analysis of high-resolution seismic profiles, integrated with echosounder, SRTM and satellite image data.We use these data to develop a relative stratigraphy.An incised-valley extending from the Apodi-Mossoró Estuary onto the shelf dominates the investigated area.In very shallow waters (down to 10 m depth) the channel lies mainly in a NW-SE direction, changing to NE-SW in waters below10 m, in the form of a J-shaped valley.The southern flank of the shallow channel presents an abrupt morphology, probably determined by a residual scarp due to neotectonic reactivation of a pre-existing fault.This incised-valley can be correlated with a former river valley formed during the late Pleistocene fall in sea-level.The base-level change related to this drop in sea level can be regionally expressed on seismic lines as a laterally-continuous stratigraphic surface named Horizon I, interpreted as representing the sub-aerial exposure of the continental shelf.Many incised valleys were excavated on this exposed shelf, including that of the Apodi-Mossoró Estuary and its incised valley system.This incised valley has lain buried since the Holocene transgression.The Holocene sediments present sub-horizontal layers, or they have filled the incised valley with oblique features.
关键词：plataforma NE Brasileira;estuário Apodi-Mossoró;vales inciso;mudanças do nível do mar;sismoestratigrafia
