Investigations into Pb isotope signatures in groundwater and sediments in a uranium-mineralized area

ABSTRACT: This work presents the investigation in an environment that contains uranium deposits by using Pb isotope signatures. The study area, southeast of Brazil, is characterized by the lack of surface water and, as a consequence, the groundwater plays an important role in the economy of the region, such as the supply to the uranium industry and, above all serving the needs of the local population. The objective of the present investigation is the determination of the signatures of Pb in groundwater and sediments as well as the identification of environments under influences of geogenic and/or anthropogenic sources. It was determined that the Pb in the majority of sediments was geogenic in origin. Although data from the literature, related to the environmental studies, consider 206Pb/207Pb isotopic ratio values below or close to 1.2 as an indicative of anthropogenic Pb, the 206Pb/ 207Pb determined for the majority of groundwater samples ranged from 1.14 to 1.19, and are similar to the data reported for rocks samples (1.09 to 1.96) from area with U mineralization. It was also determined that the anthropogenic influence of the uranium was restricted to a single sampling point within the mining area

Estudos pormXRF-Sincrotron de fluidos mineralizadores detectados em minérios uraníferos, ferríferos e depósitos epitermais

Synchrotron radiation micro X-ray fluorescence(SμXRF) analysis is a non-destructive method that canbe used to identify, and in special cases, to quantifymajor, minor, and trace elements present in fluidinclusions. In spite of the relevant results, this techniquehas been used only in a few studies, which, moreover,are mostly focused on either synthetic or natural fluidinclusions in transparent minerals. To investigate fluidinclusions in transparent and opaque minerals, thesynchrotron radiation X-ray microprobe station fromthe μSXRF fluorescence beamline at the LNLSCampinaswas used. This analytical method has beenproven to be efficient in the chemical characterizationof the fluid inclusions constituents of some transparent(quartz, adularia, emerald, etc.) and opaque minerals(pyrargyrite and hematite).O método de análise não-destrutivo denominado Microfluorescência de Raios X. (µSXRF, radiação Sincrotron) tem sido utilizado recentemente em laboratórios de luz Sincrotron de vários países para identificar e, em situações especiais, quantificar elementos menores, maiores e traços em inclusões fluidas. Com esse intuito, a estação de µSXRF do LNLS (Laboratório Nacional de Luz Sincrotron, Campinas) foi utilizada para desenvolver estudos composicionais de inclusões fluidas em minerais transparentes (quartzo, adulária, esmeralda, piroxênio) de diferentes jazidas minerais e minérios opacos de Ag e Fe.Fil: Ríos, Francisco Javier. No especifíca;Fil: Fuzikawa, K.. No especifíca;Fil: Vieira Alves, James. No especifíca;Fil: Matos Gonçalves, Rhaine. No especifíca;Fil: de Oliveira Chaves, Alexandre. No especifíca;Fil: Moreira de Souza, Andre. No especifíca;Fil: Mônica Dalla Vecchia Chaves, Adriana. No especifíca;Fil: Passos Pereira, Ana Rosa. No especifíca;Fil: Aparecida Fernandes de Lima, Tatiana. No especifíca;Fil: Marques Correia Neves, José. No especifíca;Fil: Perez, Carlos Alberto. No especifíca;Fil: Gonzalez Guillot, Mauricio Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Carelle Mattos, Evando. No especifíca;Fil: Rosiére, Carlos Alberto. No especifíca