OSL dating of sediments from Negro and Solimoes rivers - Amazon, Brazil

Abstract

In this work, the OSL dating results of Quaternary fluvial deposits from the confluence of Negro and Solimoes rivers were studied. the equivalent doses (D-e) of sediments were obtained using a Single Aliquot Regeneration (SAR) protocol. Statistic studies were made using frequency histogram, weighted histogram and Radial plot in order to analyze the D-e fluctuations. Ages from 74.5 to 205 thousand of years (Pleistocene) were recorded. the gamma-ray spectroscopy was used to evaluate the natural radioisotopes concentrations of the samples and low concentrations were found with values between 0.64 and 3.71 ppm for U-235 and U-238; 2.01-9.77 ppm for Th-232; already, for K-40, the concentration was negligible. the OSL dating of sediments has contributed to a better understanding of the evolution of Negro and Solimbes rivers, in Amazon, Brazil. (C) 2013 Elsevier B.V. All rights reserved.