O Grupo Canastra em sua área-tipo, região de Tapira, sudoeste do estado de Minas Gerais

Autor: Wellington Leonardo Damázio, George Luiz Luvizotto, Luiz Sérgio Amarante Simões, Samuel Nunes Ferreira, Carlos Humberto da Silva
Přispěvatelé: Universidade Federal de Mato Grosso (UFMT), Universidade Estadual Paulista (Unesp)
Jazyk: portugalština
Rok vydání: 2012
Předmět:
Zdroj: Scopus
Repositório Institucional da UNESP
Universidade Estadual Paulista (UNESP)
instacron:UNESP
Geologia USP. Série Científica, Vol 12, Iss 2 (2012)
Popis: Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:26:54Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:31:43Z : No. of bitstreams: 1 2-s2.0-84866336117.pdf: 1835219 bytes, checksum: f7f9dddf09fe727e77fc0e613ae73486 (MD5) Made available in DSpace on 2014-05-27T11:26:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-08-01 This work aimed at describing the Neoproterozoic evolution of a Southern Brasília Fold Belt segment, in Tapira area (southwest of Minas Gerais state, Brazil), using detailed geologic mapping. This area, the Canastra Group type-area, has showed great tectonic and stratigraphic complexities unlike the simplicity suggested in previous works. From recognizing the main tectonic discontinuities, it was possible to subdivide the area into some domains. In the west domain, they were individualized in tectonic sheet I, marked by pelitic rocks and pelitic-graphite rocks with psammitic intercalations, and II, pelitic rocks with psammitic and mafic-ultramafic intercalations overlapped by gneisses. In the east domain, a group of three tectonic sheets was defined, in which, in the two lower tectonic sheets, pelitic and pelitic-graphite rocks with psammitic rock intercalations prevailed, which is different in metamorphic conditions. The lower tectonic sheet is marked by mineralogical associations with muscovite + chlorite + quartz ± graphite ± albite, without biotite; however, the superior one is with muscovite + quartz + garnet ± chlorite ± biotite ± chloritoid ± graphite ± albite. In the upper tectonic sheet, pelitic rocks with local contributions of psammitic and ultramafics rocks occur. In the south domain, psammitic rocks basically occur with contributions of pelitics and rudaceous rocks, where the preservation of textures and sedimentary structures is common. Rocks of the several domains are interpreted as part of a passive continental margin basin, located in the western margin of the São Francisco paleocontinent. Thus, the south domain rocks would represent the facies of proximal platform; rocks of the lower and middle tectonic sheets (east domain) and of the tectonic sheet I (west domain) are of facies distal platform; and the ones from the upper tectonic sheet (east domain) and tectonic sheet II (west domain) were acknowledged as deposited in an environment of continental shelf and/or oceanic seafoor. Departamento de Geologia Geral Instituto de Ciências Exatas e da Terra Universidade Federal de Mato Grosso - UFMT, Avenida Fernando Corrêa da Costa 2.367, Bairro Boa Esperanca, CEP 78060-900, Cuiaba, MT Departamento de Petrologia e Metalogenia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista - Unesp, Rio Claro, SP Departamento de Desenvolvimento de Projetos Minerais - DIPM, Vale S/A, Belo Horizonte, MG Departamento de Petrologia e Metalogenia Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista - Unesp, Rio Claro, SP
Databáze: OpenAIRE
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