Evaluation of environmental variations using elemental composition from mudbelts of Brazilian southern shelf

Abstract

Continental shelves are submerged extensions of the continents, subjected to the action of different events and processes, marine and continental, natural and anthropic, whose variations can be registered in their sediments and evaluated by the study of the sedimentology of these environments. The elementary composition of the deposited sediments, and from it statistical analyzes and ratios between elements (e.g.: Fe/Ca, Ti/Ca), are able to provide information on the different sources of these sediments and variations in their input, processes that have occurred since its origin and also indicate continental climatic conditions. Mud depocenters can be found on continental shelves, being able to adsorb and incorporate organic and inorganic substances to the surface of their grains, thus being an important record of environmental changes and anthropic influence in a region. Mudbelts are a type of mud depocenter, confined and elongated, located on clastic continental shelves. On the southern shelf of Brazil, different types of mud depocenters are found, including mudbelts. The purpose of this project is to do an evaluation of the environmental, climatic, anthropic and natural variations that occurred on the southern shelf of Brazil and adjacent continent, based on the elementary characterization by X-Ray Fluorescence (XRF) and Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) and geochronology with 210Pb, of three long cores from mudbelts. Thereby, it is expected to verify variations in the contribution of sediments from different sources, if there was an increase in the content of elements of anthropogenic origin since the beginning of industrialization in Latin America and if variations in the terrigenous contribution correspond to known periods of greater / lesser precipitation on the continents. (AU)