Sedimentation on the southern Brazilian shelf mud depocenters: Insights on potential source areas

Abstract

In this paper, we investigate the characteristics of the shelf mud depocenters off South Brazil, between latitudes 27°30′S and 24°30′S. A combination of geochronological, textural (grain-size), and geochemical (metals and εNd values) analyses allowed to recognize different mud deposits in the area. It was possible to recognize changes in the sedimentation rates along with each sediment core, despite a relative homogeneity in the nature of the terrigenous sediments. The Río de La Plata discharge was confirmed as the primary source of sediments to the shelf in the area of study. Also, it is possible to recognize a limited local contribution from the adjacent land to the coastal depocenters. Finally, we identify a distinct source of the sediments deposited in the north of the study area, probably as a function of the transport by the Brazil Current. Our findings attest to the complexity of the origin of sediments to the southern Brazilian shelf as well as to the need for more detailed works in source-to-sink on the southern Brazilian shelf, which is a potential fate for anthropogenic compounds.