Geologia, litogeoquímica e geocronologia U-Pb (SHRIMP) do plúton, associado à mineralização de Sn, Saubinha: SW do Cráton Amazônico : distrito mineiro de São Lourenço-Macisa (RO)

• Autor(a) principal: Farias, Vanderlei de [UNESP]
• Data de Publicação: 2017
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/202985; http://www.athena.biblioteca.unesp.br/exlibris/bd/capelo/2018-12-11/000908907.pdf
• topic: Granito; Geologia; Geoquímica; Tempo geológico; Intrusões (Geologia); Mineralogia; Crátons; Metalogenia; Estanho; Cassiterita; Rondonia; Amazônia

The Saubinha pluton is one of the granite masses of the São Lourenço massif, which along with Caripunas, Abunã, and São Simão massifs represent the exhibition areas of granite rocks, with or with no associated tin deposits, belonging to the Intrusive Suite São Lourenço-Caripunas. The core of the primary occurrence of tin deposits is located in the Mining district of São Lourenço-Macisa, Northwest of Rondônia and South of Amazonas, about 200 km West of Porto Velho. The rocks in the area occur in the form of a NW - SE elongated granitic stock, comprising two faciological types in a 1:10,000 mappable unit: (i) porphyritic biotite-sienogranite, which occurs laterally to the body, and (ii) biotite alkali-feldspar heterogranular granite, comprising the rest of the pluton; along with apparent transitional contacts between then. Polymetallic mineralization of Sn ± W and sulphides (Cu, Zn, and Fe) as sub-vertical greisens lenses (muscovite topaz greisen and muscovite greisen) and quartz veins with NEE - SWW direction are mainly hosted in the heterogranular type. The lenses and mineralized quartz veins are cut by a family of sterile N - S veins. They represent the most expressive confined post-magmatic phase in the pluton, which, in turn, also has a prominent sodium and potassic-more expressive in pervasive styles. The pluton represents a granite intrusion highly differentiated with geochemical characteristics of ferrous granites, subtype A2. The porphyritic type is weakly to strongly peraluminous, whereas the heterogranular is metaluminous to marginally peraluminous, both alkalialkaline alkalinity. The variations of some major and minor elements versus SiO2 and the differentiation index suggest a geochemical evolution from the porphyritic type to the heterogranular type. The granitic stock exhibits a crystallization age of 1316 ±12 Ma, which defines it as a part of the Intrusive Suite São Lourenço-Caripunas related to the development of...