ALTERAÇÃO HIDROTERMAL PERALUMINOSA NA SEQUÊNCIA VULCANO-SEDIMENTAR PALEOPROTEROZÓICA DE SILVÂNIA, REGIÃO DE VIANÓPOLIS, GOIÁS

The small aluminossilicate deposit of Vianopolis, southeastern part of the state of Goias, is hosted by the paleoproterozoic island-arc-type Silvânia volcanic-sedimentary sequence and associated intrusions of granite and granodiorite. Pyrophyllite, kyanite, white mica, diaspore, tourmaline and chlorite are the products of the peraluminous hydrothermal alteration, inside a N50 o -60 o W trending shear zone. The presence of gold, pyrrotite and chalcopyrite in rocks from the alteration zone indicates potencial resources also for metallic mineral deposit in the Silvânia sequence.