Química mineral do rutilo hidrotermal nos depósitos auríferos Basílio e Pé Quente, setor leste da Província de Alta Floresta (MT), sul do Cráton Amazônico

• Autor(a) principal: Souza, Ivan Roberto de [UNESP]
• Data de Publicação: 2018
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/203404; http://www.athena.biblioteca.unesp.br/exlibris/bd/capelo/2019-05-14/000915027.pdf
• topic: Geoquímica; Depositos hidrotermais; Ouro; Crátons; Mineralogia; Petrologia; Geomorfologia; Alta Floresta (MT)

The Alta Floresta Gold Province (AFGP) is in the south-central Amazon Craton, in the northern region of Mato Grosso state. The AFGP consists essentially of Paleoproterozoic plutonic, volcanic and volcanossedimentary sequences, covered by Mesoproterozoic sedimentary sequences. The Province hosts more than a hundred medium- to high-grade and small sized gold-rich deposits along the NW-SE Peru-Trairão belt. Its primary gold mineralizations are grouped into four major types: (1) disseminated deposits of Au ± Cu (e.g. Pé Quente, X1 and Luzião deposits); (2) vein-type Au ± Cu deposits (e.g. Basílio, Peteca and Paraíba deposits); (3) vein-type Au ± Cu ± Mo deposits (e.g. Ana and Jaca deposits); and (4) vein-type Au + Zn + Pb ± Cu deposits (e.g. Francisco, Bigode and Luiz deposits). Deposits belonging from groups (1) and (2) are interpreted as equivalent to magmatic-hydrothermal, such as gold porphyry systems, while groups (3) and (4), gold- and base metals epithermal systems of low- and intermediate sulphidation. Therefore, this study goals are: (1) petrographic characterization of hydrothermal rutile; (2) its chemical composition for major, minor and trace elements; and (3) its thermal conditions. For these goals, the Pé Quente and Basilio deposits were studies due have rutile-rich hydrothermal alteration halos. Four rutile morphologies were identified in Pé Quente deposit (needle-like, fibrous, granular and prismatic), that are associated to potassic, propylitic and sericitic alterations, whereas two varieties were observed into the Basílio deposit (needle-like and fibrous), both associated to potassic and chloritic alterations. The rutile crystals of both deposits have several mineral inclusions and geochemical zoning, which were detected by the EDS. Nevertheless, it was possible to conclude that the fibrous rutile from potassic alteration in the Basílio deposit has the highest concentrations of minor and trace elements, such as Fe...