Estudio geoquímico de anomalías de uranio en el sector El Derrumbo, provincia de Loja

Abstract

Abstract: The present investigation was carried out in the Puyango canton, province of Loja in the sector El Derumbo, with the purpose of carrying out a characterization from the point of view geochemistry of rock samples, using analytical techniques such as ICP-OES, FRX, DRX and chemostratigraphic indices to determine possible geochemical anomalies of uranium and other associated elements, as well as the paleoredox conditions of sedimentation. A total of 19 rock samples were collected from 3 outcrops based on previous data of the works carried out by Jumbo (2019) and Jiménez (2021), taking into account the vanadium and uranium geochemical anomalies detected. In these outcrops They raised stratigraphic and chemostratigraphic columns. By applying statistics to the chemical data, a maximum concentration of uranium was obtained of 8.21 ppm in an argillite and a maximum vanadium concentration of 1746 ppm in a lithosandite in outcrop 2. According to the statistical analysis, anomalous values &#8203;&#8203;of thorium were detected (60.23 ppm), magnesium (0.55%), calcium (0.20%) and sodium (0.84%). With respect to chemostratigraphy, the interelemental relationship U/Th was used, to determine paleoredox conditions, defining oxic conditions with values &#8203;&#8203;(<0.75) in 16 samples and in the remaining ones in dysoxic conditions (0.75 1.25). Furthermore, according to the normalization with PAAS and NASC, the chemical composition of the samples is similar to PAAS, with enrichment of Ba, Th, U, V, Cr, Co and Ni. Normalization with NASC shows that elements that are enriched with respect to this reference material in several samples are TH, U and V, the other trace elements (Ba, Sc, Cr, Co, Ni) are impoverished.