Alteração hidrotermal e geotermobarometria do Alvo Paz, Província Aurífera de Alta Floresta (MT), Cráton Amazônico

• Autor(a) principal: Martins, Henrique Bazzo [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/11449/203403; http://www.athena.biblioteca.unesp.br/exlibris/bd/capelo/2019-06-25/000915021.pdf
• topic: Depositos hidrotermais; Ouro; Crátons; Mineralogia; Geoquímica; Mica; Petrologia; Análise com microssonda; Microscopia eletrônica de varredura; Alta Floresta (MT)

The Alta Floresta Gold Province (AFGP), northern sector of the Mato Grosso State, corresponds to a crustal fragment of WNW-ENE direction, inserted into the southernmost portion of the Amazon Craton. It consists of paleoproterozoic plutonic, volcanic and vulcanosedimentary units generated into successive orogenic events onset, with calcium-alkaline magmatism and paleoproterozoic tectonic reworking with minor of Archean material. Its Several primary small gold deposits occur along the NW-SE Peru-Trairão belt. In this context, the primary mineralizations within the province can be clustered into four major groups: (1) disseminated Au ± Cu deposits; (2) vein-type Au ± Cu deposits; (3) vein-type Au ± Cu ± Mo deposits; and (4) vein-types Au + Zn + Pb ± Cu deposits. Despite the great metalogenetic and economic potential of the province, most studies have been focused in the descriptive and genetic models of mineralizations related to group (1). Although a significant number of deposits currently explored by prospector activity, the second group represent one of the least understood in the province. Thus, the main goal of this work is the characterization of the host-rocks, the hydrothermal alteration sequence, ore paragenesis and the mineral chemistry of white mica and chlorite of Alvo PAZ, inserted into the Peteca deposit region (Matupá, MT), which belong to the second-class deposits. Therefore, this work performed of conventional petrography, scanning electron microprobe and electron microprobe. In this way, the Alvo PAZ is majorly hosted by (1) medium-grained and isotropic to slightly anisotropic granitoid, locally intruded by (2) intermediate to acid subvulcanic. These lithotypes are variably affected by intense hydrothermal alterations, temporally represented by: (i) potassic with K-feldspar; (ii) sericitic; (iii) chloritic; (iv) epidotization; (v) silica injections and silicification, eminently in pervasive-styles, nevertheless...