Controle estrutural da mineralização de estanho da Mina Campinas, Encruzilhada do Sul – RS

Abstract

The Campinas Mine is located in the central-eastern portion of Sul-Rio-grandense Shield and contains tin mineralization associated with Biotite Granites of the Campinas Intrusive Suite. These intrusions are located laterally to the mylonite bands related to the final stages of kinematic evolution of transcurrent tectonics of the Dom Feliciano Belt, exercising control over the genesis and structural pattern of the mineralization. Mineralization is related to hydrothermal alteration and is limited to the contact areas of granitic injections within enclosing rocks and is mainly of micaceous changes in association with quartz veins. Mineralization consists of cassiterite disseminated in quartz and greisen veins. Mineralized structures have been investigated by structural analysis in the field and remote sensing, consisting of geometric and kinematic analysis. Mineralized veins strike to NE (preferred), dip between 70º and 80º to NW or SE and define a "stockwork" geometry. Faults and fractures also have preferred direction NE, subordinately NW and N-S and high angle of dip. The lithologies present in the mine area are granitic rocks corresponding to Granite Campinas and schist corresponding to Metamorphic Complex Porongos. The integration of these data contributed to the definition of the structural framework and the relation of these geological structures with tin mineralization in the region of Campinas Mine in Encruzilhada do Sul - RS.