Geotermobarometria da clorita e mica branca hidrotermais do depósito filonar de Au ± Cu do Edu, Província Aurífera de Alta Floresta (MT)

• Autor(a) principal: Siqueira, Lucas de Carvalho [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/11449/203408; http://www.athena.biblioteca.unesp.br/exlibris/bd/capelo/2019-05-14/000915037.pdf
• topic: Mica; Depositos hidrotermais; Ouro; Crátons; Mineralogia; Minerios; Geoquímica; Análise com microssonda; Petrologia; Alta Floresta (MT)

The Alta Floresta gold province consist of Paleoproterozoic (2.0-1.75 Ga) plutonic-volcanic sequences generated in magmatic arc settings. The province extends for a distance of over 500 km along a northwest-southeast trend in the southern portion of the Amazon craton (Brazil). Over the last decades a great number of small-size (<5 t) and high-grade granite-hosted gold and gold-base metal deposits have been discovered and exploited in the Alta Floresta gold province, mainly in the eastern segment of the province. Based on the mode of occurrence, ore mineral paragenesis, and geochemical signature, deposits in the eastern segment of the Alta Florest gold province may be subdivided as follows: (1) disseminated Au ± Cu deposits; (2) structurally controlled vein-type Au ± Cu deposits; (3) disseminated Au ± Mo ± Cu deposits; e (4) structurally controlled vein-type Au + Zn + Pb ± Cu deposits. The phyllic alteration (muscovite + quartz + pyrite), propylitic (chlorite + epidote ± calcite) and chloritic alteration (chlorite ± quartz) correspond to importants hydrothermal alteration zones in the great majority of these deposits. In this context, although the main geological attributes of the deposits in the eastern segment of the Alta Florest gold province are well-defined, mineral chemistry studies that characterize the composition of hydrothermal minerals in the course of their evolutionary path, and geothermobarometric studies are scarce, especially in relation to structurally controlled deposits. Thereby, the estimation of physico-chemical parameters of the hydrothermal fluid (temperature and pressure mainly) are fundamental to compare hydrothermal fluids of different styles of mineralization, and definition of genetic models. Therefore, the Edu gold deposit was selected for the development of this study, since it corresponds to one of the main deposits of Au ± Cu of the province, with the differential of presenting two distinct styles of...