Sortable silt variations on the continental slope of Campos Basin (SW Atlantic): implications of oceanographic processes

Abstract

An indirect way to measure the speed of bottom currents granulometric parameters such as the proxy sortable silt ( This proxy is associated with the sedimentation process and can estimate paleocurrents. This study aims to evaluate the range of the near-bottom current flow speed through the and related to oceanographic processes in the southeastern Brazilian continental slope. The values ranged from 17.08 to 26.23 μm, presenting a mean value of 19.87 μm. The flow speed values were obtained using Ledbetter's (1986) and Miller and Komar (1977) formulas, varying from a minimum of 0.07 and 0.21 m s−1 to a maximum of 0.24 and 0.26 m s−1. The changes in bottom velocities observed in the Campos Basin are influenced by off-shelf export of the sediment, hydrodynamic parameters (Brazil Current, Intermediate Western Boundary Current, and the Deep Western Boundary Current), and the geomorphological characteristics (island, ravine, and halokinesis movement).