Tipos e estilos de alteração hidrotermal do vulcano-plutonismo paleoproterozóico da região de Vila Tancredo, N de São Félix do Xingú (PA)

Abstract

The São Félix do Xingú region has extensive paleoproterozoic volcano–plutonic rocks coverage included in the Sobreiro and Santa Rosa formations. Petrographic and SEM studies revealed hydrothermalized lithotypes associated, as evidenced by overlapping zones of potassic, propylitic, and sericitic alteration in several styles and intensity. The Sobreiro Formations shows propylitic alteration in pervasive, selectively pervasive, and fissurecontrolled styles, identified by the paragenesis epidote, chlorite, clinozoisite, zoisite, pyrite, chalcopyrite, galena, quartz, carbonate, and albite. In the Santa Rosa Formation there is sericitic alteration in rhyolites and some volcaniclastic rocks, developed in styles selectively pervasive and pervasive and its paragenesis is sericite, quartz, monazite, rutile and carbonate. This unit has important selectively pervasive style potassic metasomatism in the granite porphyry, composed of biotite, K-feldspar, hydrothermal chlorite, iron oxide, allanite, and zircon. The presence of these zones is a pathfinder for eventual rare and base metals epithermal and porphyry-type mineralizations.