Petrology and geochemical modeling (Ba-W-Sn) of the Peña do Seo granitoids (West Asturian-Leonese Zone, León, Spain)

Abstract

The Cadafresnas granites and granitoid breccias (Peña do Seo, W of León) are small post-tectonic stocks of Variscan age related to W-Sn mineralizations. According to their mineralogical geochemical characteristics, they are classified as granites-syenogranites, granodiorites and granitoids rich in quartz, of peraluminous/metaluminous composition. The Rb-Ba-Sr relationships allow assigning a metapelitic source for the granites and a metagreywacke source for the granitoid breccias. Using geochemical modeling (partial melting), the contribution of these sources to explain the Ba, W and Sn contents of the granites and granite breccias is investigated. The results indicate that the partial melting of these lithologies explains part of the content of these elements in the studied rocks, requiring additional processes of fractional crystallization and/or hydrothermal injections.