Estudio geoquímico de los metasedimentos del complejo esquisto-grauváquico como posible fuente de U de los yacimientos del oeste de la provincia de Salamanca

Resum

The results of sistematic geochemical study of the different lithologies making up the Late Precambrian-Lower Paleozoic schist and graywacke complex (C.E.G.), are given in this paper. The purpose of this study was to verify if the metasediments, which are the host-rook of several uranium deposits, are the source of the uranium contained in some rich orebodies located in the western región of the Salamanca province. The study was carried out in three successive stages: preliminary, previous and sistematic. Completion of the first two stages resulted respectively in the evidence of stratigraphic levéis showing anomalous uranium contents and the feasibility of sampling to carry out the sistematic stage, in wich 796 samples, covering all C.E.G. lithologies, where anaylyzed. The results proved the existence of a direct relationship between the ampelitic character of the rocks and the uranium content, as well as a great lateral continuity of the anomalous layers. Furthermore, a perfect correlation between the uranium and some other trace elements was verified after a comparative statistical analysis. Therefore, it seems likely to admit that the uranium actually concentrated in fractures and breccias was leached from the fertile metasediments.