Alteração hidrotermal a SW do Complexo Granítico São Sepé - São Sepé/RS

Abstract

The Sw portion of the São Sepé Granitic Complex (SSGC) encloses a sequence of chistc from volcanic sedimentary association of Bossoroca Sequence. The texture, framework and paragenesis were changed by thermal metamorphism during the emplacement of the granite. After this event, the peripheric portion of the SSGC and its host rocks were submitted to hydrothermal alteration. A study is presented of the minerals that characterizes this hydrothermal alteration e the thermal metamorphism. The alteration in the granite is phylic type, located in veinning zone where veins occur as stockworks and are composed by quartz+white mica (phengitic) + locally auriferous pyrite, which are distributed for aproximately 1 km. This is the only veinning system whith auriferous mineralization in the granite. The remobilization, concentration and precipitation of gold are directly related to the hydrotermal convective system in the peripheric São Sepé granite with the host rocks as potential auriferous.