Application of radiometric analysis in the study of provenance and transport processes of Brazilian coastal sediments.

Natural gamma radiation of beach sand deposits was measured along the south coast of Rio de Janeiro State, Brazil, with the aim of studying the provenance and transport processes of sediments in this area. Concentrations of thorium, uranium and potassium were evaluated using γ-ray spectrometry and a behavioral study of eTh/eU and eTh/K cross plots was performed, reflecting the mineralogical properties of beach sands, as well as their history of transport and sorting processes. The results show that such technique can be efficiently used to map heavy mineral distributions and to distinguish the different origins of coastal sediments disclosing the influence of nearby rivers.