Variação do nível do mar com base na análise organofaciológica de um testemunho do talude continental recente da bacia de campos, RJ, Brasil

Abstract

SEA LEAVEL CHANGES BASED ON ORGANIC FACIES ANALYSIS IN A SEDIMENTARY CORE FROM CONTINENTAL SLOPE OF CAMPOS BASIN, RJ, BRAZIL. Eighty-five samples collected in a core belonging to the BU91-GL-77, well located in the continental slope of Campos Basin, were analyzed by microscopic techniques (palynofacies) and organic geochemistry (TOC). The objective was to provide information about the organic composition of the sedimentary section analyzed. The variation in organic composition found in this sedimentary section can be a reflection of sea level and climate changes that not only affected the production, transport and preservation of organic matter but also its supply and sedimentation in Campos Basin's recent continental slope. A ternary diagram was used for the paleoenvironmental characterization of the succession studied. It was prepared from the abundance of data on the three main groups of organic matter used to define nine paleoenvironments based on marine palynofacies data. Using these diagrams, it was possible to draw the curve of relative sea level based on the proximal-distal trends during the sedimentation of particulate organic components. The data point to a general trend of marine transgression marked by small cycles of lowering/rising of the relative sea level caused by variations in sediment influx, reflecting the climatic fluctuations during the Quaternary. © 2010 by the Sociedade Brasileira de Paleontologia.