Study on variation of productivity on the continental slope in the last thousand years in the Santos Basin, Southeastern Brazilian margin

Abstract

Since 2011 is being developed within the Núcleo de Apoio à Pesquisa (NAP), sponsored by the University of São Paulo, the "Geodynamics of Sedimentary Basins and implications for exploration potential (oil, natural gas and water underground) - project GEO SEDex". The IOUSP participates with the subproject "Sedimentation of the Southeast Brazilian continental margin: basis for paleoclimate, paleoceanographic and gas generation models". This project is included under the subproject of NAP and aims to understand the possible variations in ocean circulation and productivity in the last thousand years on the continental slope in the Santos Basin, based on grain size and planktonic foraminifera analyses. The study area is located in the northern portion of the physiographic sector Embayment of São Paulo, which extends from Cape Santa Marta Grande (SC) to Cabo Frio (RJ). The study material comprises samples which were collected north of São Sebastião Island (24°50.44'S,44°19.00'W) at a depth of 828m. According to Mahiques et al. (2004), the island marks the boundary between two main sedimentary zones separated due to their different sedimentation patterns. In the south of the island, the depositional processes are associated with seasonal penetration of the River Plate plume, interacting with the meanders of the Brazil Current. And in the north of the Island, the deposition of mud on the inner shelf is related to the Cabo Frio upwelling and coastal processes. The main aim of this project is to understand the oceanic productivity and current intensity changes on the continental slope in the last thousand years, contributing for the understanding of ocean circulation in the context of climate changes and in the southeastern Brazilian margin. (AU)