Datação por luminescência opticamente estimulada: aplicabilidade em fácies rudáceas de leques aluviais do Quadrilátero Ferrífero, Minas Gerais

Abstract

This paper presents data related to the optically stimulated luminescence of alluvial fan facies sediments from the Quadrilátero Ferrífero region. Such data were obtained by dating 9 Exception, by the SAR-15 protocol, aliquots, carefully collected with a sampler and lever to remove the metal tubes from the sedimentary package. Such criteria were important to avoid mistakes that could underestimate or overestimate the ages. The objective of this work is to discuss the characteristics of the luminescence of quartz grains from rudaceous deposits with those existing in the literature and to demonstrate that it is possible to use the method also with deposits of higher granulometry, such as alluvial fans. With regard to the annual dose rate, the percentage of water in 8 samples are consistent with adequate parameters for establishing a reliable dose rate, only 1 of the sample, with a value greater than 15%, necessary to consider a margin of greater error in age calculation. Irrelevant values ​​of cosmic radiation did not compromise the establishment of Th, U and K concentrations. When analyzing the parameters for obtaining the equivalent dose, good sensitivity of the quartz grains was verified, confirmed in the recycling and recovery tests. Complete photoemptying of quartz grains was also observed in all samples.