ESTADO ATUAL DO CONHECIMENTO SOBRE AS ROCHAS GRANITÓIDES DA PORÇÃO SUL DA AMAZÔNIA ORIENTAL

ESTADO ATUAL DO CONHECIMENTO SOBRE AS ROCHAS GRANITÓIDES DA PORÇÃO SUL DA AMAZÔNIA ORIENTAL

dc.contributoren-US
dc.contributorpt-BR
dc.creatorDALL'AGNOL, ROBERTO
dc.creatorVIEIRA, EDUARDO ANGELIM DE PONTES
dc.creatorSENA SÁ, CARLOS AUGUSTO
dc.creatorMEDEIROS, HAMILTON DE
dc.creatorGASTAL, MARIA DO CARMO PINTO
dc.creatorTEIXEIRA, NILSON PINTO
dc.date2018-04-05
dc.date.accessioned2022-12-15T20:16:33Z
dc.date.available2022-12-15T20:16:33Z
dc.identifierhttps://ppegeo.igc.usp.br/index.php/rbg/article/view/12017
dc.identifier.urihttps://repositorioslatinoamericanos.uchile.cl/handle/2250/5360456
dc.descriptionThe granitoid rocks found in the Amazonian Craton, between the Xingu and Araguaia rivers (SE Pará State, Brazil) can be dívided into two groups: (1) granitoid and gneissic rocks of archean of late proterozoic ages (related to the 2,000 Ma Transamazonían event or older), and (2) post-tectoníc or anorogenic granites of medium proterozoic ages (younger than the Transamazonian event). The first group is very poorly studied, making it difficult to establish the limíts and evolution of the main geotectonic provinces wíthin the craton. In the Rio Maria Region older (Archean?), gneisses and mígmatites, greenstone belt sequences, and granodiorite batholiths were distinguished. The latter are the youngest unit, exhibitíng ages of aproximately 2,600 Ma. Transamazonian ages are frequent in the "basement" Xingu Complex, but petrological studies of granitoids and gneisses related to this event are lacking. The second group includes many massífs, consisting of typícal high-level granítes, grouped in fíve different magmatíc suítes. These suítes are not clearly defined and must be rediscussed the sítuation of each massif needing to be evaluated a case by case. Supposing the 1,700-l,800 Ma Rb-Sr age of the Central Serra dos Carajás Massif to be correct and accepting the Rb-Sr isochron ages of the Jamon (1,601 ± 21 Ma) and the Redenção (1350 ± 80 Ma) massífs, the existence of at least three post-Transamazonian periods of granitic magma generation is deduced. The needs for additional geochronological data and the introduction of different radiometric methods U/Pb, Pb/Pb) are emphasized. A comparison is attempted between the studied granites and the various granitic types recently defined in the literatura. However, taking ínto account that theír tectonic settings are very different, a perfect correlation can not be expected. The Jamon Massif is a magnetite granite and exhíbíts strong analogíes with the Caledonian I type granítes. The Serra dos Carajás, Velho Guilherme, Antônio Vicente, and Mocambo Massifs have affinities with the A type granites and are generally mineralised (Sn, and less Nb, Cu, Mo). S type granitoids are not known in the studied region.en-US
dc.descriptionThe granitoid rocks found in the Amazonian Craton, between the Xingu and Araguaia rivers (SE Pará State, Brazil) can be dívided into two groups: (1) granitoid and gneissic rocks of archean of late proterozoic ages (related to the 2,000 Ma Transamazonían event or older), and (2) post-tectoníc or anorogenic granites of medium proterozoic ages (younger than the Transamazonian event). The first group is very poorly studied, making it difficult to establish the limíts and evolution of the main geotectonic provinces wíthin the craton. In the Rio Maria Region older (Archean?), gneisses and mígmatites, greenstone belt sequences, and granodiorite batholiths were distinguished. The latter are the youngest unit, exhibitíng ages of aproximately 2,600 Ma. Transamazonian ages are frequent in the "basement" Xingu Complex, but petrological studies of granitoids and gneisses related to this event are lacking. The second group includes many massífs, consisting of typícal high-level granítes, grouped in fíve different magmatíc suítes. These suítes are not clearly defined and must be rediscussed the sítuation of each massif needing to be evaluated a case by case. Supposing the 1,700-l,800 Ma Rb-Sr age of the Central Serra dos Carajás Massif to be correct and accepting the Rb-Sr isochron ages of the Jamon (1,601 ± 21 Ma) and the Redenção (1350 ± 80 Ma) massífs, the existence of at least three post-Transamazonian periods of granitic magma generation is deduced. The needs for additional geochronological data and the introduction of different radiometric methods U/Pb, Pb/Pb) are emphasized. A comparison is attempted between the studied granites and the various granitic types recently defined in the literatura. However, taking ínto account that theír tectonic settings are very different, a perfect correlation can not be expected. The Jamon Massif is a magnetite granite and exhíbíts strong analogíes with the Caledonian I type granítes. The Serra dos Carajás, Velho Guilherme, Antônio Vicente, and Mocambo Massifs have affinities with the A type granites and are generally mineralised (Sn, and less Nb, Cu, Mo). S type granitoids are not known in the studied region.pt-BR
dc.formatapplication/pdf
dc.languagepor
dc.publisherSociedade Brasileira de Geologiapt-BR
dc.relationhttps://ppegeo.igc.usp.br/index.php/rbg/article/view/12017/11561
dc.rightsDireitos autorais 2018 Revista Brasileira de Geociênciaspt-BR
dc.sourceRevista Brasileira de Geociências; v. 16, n. 1 (1986); 11-23en-US
dc.sourceRevista Brasileira de Geociências; v. 16, n. 1 (1986); 11-23es-ES
dc.sourceRevista Brasileira de Geociências; v. 16, n. 1 (1986); 11-23pt-BR
dc.source0375-7536
dc.subjecten-US
dc.subjectpt-BR
dc.titleESTADO ATUAL DO CONHECIMENTO SOBRE AS ROCHAS GRANITÓIDES DA PORÇÃO SUL DA AMAZÔNIA ORIENTALen-US
dc.titleESTADO ATUAL DO CONHECIMENTO SOBRE AS ROCHAS GRANITÓIDES DA PORÇÃO SUL DA AMAZÔNIA ORIENTALpt-BR
dc.typeinfo:eu-repo/semantics/article
dc.typeinfo:eu-repo/semantics/publishedVersion
dc.typept-BR


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