Resumo

PI, T et al. Autoradiography of geological fluorite samples for determination of uranium and thorium distribution using nuclear track methodology. Rev. mex. fis. [online]. 2007, vol.53, suppl.3, pp.57-60. ISSN 0035-001X.

In this paper we present the uranium and thorium distribution analysis of several samples of the "La Azul", an epithermal fluorspar deposit in southern Mexico, using nuclear track methodology (NTM), in the alpha-autoradiography mode, by placing the mineral sample in contact with a polycarbonate detector. This constitutes a non-destructive analysis, with sufficient sensitivity to provide valuable information about textural and paragenetic characteristics of the geological samples. The selected nuclear track detector was CR-39 (Landauer®). The region of interest of the geological samples was polished and put in contact with the detector material surface for 45 days in a vacuum chamber (10 ^-3 torr). After this period of time, the detectors were chemically etched, revealing the autoradiograph of the radioactive material. The results show a clear distribution of bands of uranium and thorium in the fluorite samples. This is valuable information for the genetic or geochronological studies of the ore deposits.

Palavras-chave : Geochronology; autoradiography; alpha particles; fluorite; nuclear track detectors.

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