Stabilization of the southern portion of the São Francisco craton, SE Brazil, through a long-lived period of potassic magmatism.

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MetadadosDescriçãoIdioma
Autor(es): dc.creatorRomano, Rafael Cotta-
Autor(es): dc.creatorLana, Cristiano de Carvalho-
Autor(es): dc.creatorAlkmim, Fernando Flecha de-
Autor(es): dc.creatorStevens, Gary-
Autor(es): dc.creatorArmstrong, Richard-
Data de aceite: dc.date.accessioned2019-11-06T13:25:27Z-
Data de disponibilização: dc.date.available2019-11-06T13:25:27Z-
Data de envio: dc.date.issued2012-10-22-
Data de envio: dc.date.issued2012-10-22-
Data de envio: dc.date.issued2012-
Fonte completa do material: dc.identifierhttp://hdl.handle.net/123456789/1709-
Fonte: dc.identifier.urihttp://educapes.capes.gov.br/handle/capes/555076-
Descrição: dc.descriptionAlthough the southernportion of the SãoFranciscocraton in southeast Brazil encompasses one of the largest segments of Meso- to Neoarchaean crust in the South American plate, there is little understanding of the processes leading to cratonization of this region. Our combined field and U-Pb age data show that the crust experienced massive intrusions of potassic (K-rich) granitoids between 2750 and 2600 Ma, and that this magmatic event marked the beginning of a fundamental change in the tectonics of the terrain, with the ensuing billion years being dominated by the deposition of a series of thick clastic and chemical sedimentary successions. Thus, deep crustal partial melting and subsequent transport and intrusion of these granites in the upper crust is a likely mechanism by which this segment of the SãoFrancisco crust attained buoyancy to survive recycling. Regional mapping indicates that the potassic granitoids are distributed over an area of ∼25000 km2, and are related to one of the most prolific periods of potassicmagmatism in the craton. LA-ICP-MS and SHRIMP U-Pb data from 16 samples of potassic granitoids together with published TIMS ages suggest alonglivedperiod of magmatism from 2750 to 2700 Ma, and a small pulse of granite crystallisation at ca. 2612 Ma. The U-Pb SHRIMP and LA-ICP-MS data also indicate that the Archaean granitoids do not record evidence of U-Pb zircon resetting. Our interpretation is that partial melting and transport of granitoid melts (rich in heat producing elements) to the upper crust gave rise to a thermally stable lower crust and that this lower crustal segment (in the craton area) became sufficiently refractory and resistant to further partial melting.-
Idioma: dc.languageen-
Direitos: dc.rightsO Periódico . precambrian research concede permissão para depósito deste artigo no Repositório Institucional da UFOP. Número da licença: 3315440594042-
Palavras-chave: dc.subjectBrazil-
Palavras-chave: dc.subjectSão Francisco craton-
Palavras-chave: dc.subjectPotassic grantoids-
Palavras-chave: dc.subjectU-Pb geochronology-
Palavras-chave: dc.subjectNeoarchaean-
Título: dc.titleStabilization of the southern portion of the São Francisco craton, SE Brazil, through a long-lived period of potassic magmatism.-
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