2019-08-292019-08-292015MELO JUNIOR, Reinaldo Fontoura de. Organização Estrutural das Rochas Hospedeiras do Depósito Cachoeira do Piriá (PA). Orientador: Roberto Vizeu Lima Pinheiro. 2015. 68 f. Trabalho de Curso (Bacharelado em Geologia) - Faculdade de Geologia, Instituto de Geociências, Universidade Federal do Pará, Belém, 2015. Disponível em: http://bdm.ufpa.br/jspui/handle/prefix/1802. Acesso em:.http://bdm.ufpa.br/jspui/handle/prefix/1802The gold deposit of Cachoeira do Piriá is part of the Parnaíba Structural Province located in northern Brazil means, in the Proterozóic border region between the Pará and Maranhão states. In this region outcrop metavolcanic and metasedimentary rocks of age, and sedimentary rocks of Phanerozoic age. All these metamorphic and magmatic rocks are part of the Gurupi Belt and the São Luis Craton. The Gurupi Belt has NNW-SSE trend and is located on the edge of the SSW São Luis Craton. This Belt features structural domains: the first, marked by areas of thrust and the second characterized by oblique sinistral shear zones. The Tentugal Shear Zone is sinistral strike-slip and is considered the transitional boundary between Gurupi Belt and the São Luis Craton. This deformation zone is associated with the formation of the major gold deposits in the Belt, an example being Gold Deposit of Cachoeira do Piriá. The host rocks of the deposit belong the Chega Tudo Formation and are mainly composed of metavulcanic, metasedimentary rocks beyond, both mylonitized that feature the foliation spaced anastomotic of direction NW-SE with dip angles ranging between 30º-60º/SW. There is also continuos and cataclastic foliation that occur locally in these rocks with the same strick of mylonitic foliation, however with high dip angles. The Chega Tudo formation rocks are displaced by late faults and fractures of direction NE-SW with high dip angles that are made explicit in geophysical maps. These brittle features are responsible for the rotation of the rocks located in the Cachoeira do Piriá region, where the trend of NW-SE belt is shifted to the next position of the N-S. This rotation deflects the plots of the foliation in general present in the rocks of Chega Tudo Formation and Gold Deposit of Cachoeira do Piriá. The quartz veins have preferred directions NW-SE and E-W with high dip angles and are associated with hydrothermal activity that affects the rocks of Chega Tudo Formation. These veins are shown subparallel regional plot and associated with hydrothermal are considered responsible for the concentration of gold in the Cachoeira do Piriá Deposit.Acesso AbertoDepósito Cachoeira do PiriáCinturão GurupiZona de Cisalhamento TentugalCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::GEOLOGIATrabalho de Curso - Graduação - Monografia