O Granito Passa Tres, PR e as minerações auriferas associadas

AUTOR(ES)
DATA DE PUBLICAÇÃO

1992

RESUMO

The proposition of a metallogenetic model to explain the origin and control of gold mineralization that occurs associated to the Passa Três Granite (PR) is the main aim of this work. This granitic body is believed to be a mesothermal NE-SW aligned intrusion wi th about 5 km2, controlled by a dextral strike-slip fault (ZCT). It has been intrusive into the Setuva Group rocks and shows tectonic contacts with younger Acungui Group. Geochemical and petrographical gathered data led it to be classified as a less evolved quartz-syenite with shoshonitic filiation and whose most probable source were garnetiferous mafic igneous rocks. Late to post-magmatic hydrothermal aI teration connected with granitic evolution and mineralization includes: potassic, phyllic, argilic propylitic and silicic alterations. Gold deposits occur as quartz-sulphide veins filling shear zones and fractures inside the Passa Três Granite. They occupy synthetic, antithetic, extensional and pressure positions in relation to the ZCT. Paragenetic assemblage is made up by quartz, fluorite, pyrite, chalcopyrite, Bi and Cu sulphosalts and gold. The latter occurs in pyrite fractures in native state. The deposit can be classified as plutogenic, with strong tectonic control by the effect of the ZCT. Gold was probably incorporated to the granitic body at some stage of its magmatic evolution, been concentrated in the final steps of the alteration-mineralization system, at temperature and pressure ranges around 265-280°C and 1240 bar, respectively

ASSUNTO(S)

geoquimica ouro - minas e mineração

ACESSO AO ARTIGO

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