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Metadados | Descrição | Idioma |
---|---|---|
Autor(es): dc.creator | Romano, Rafael Cotta | - |
Autor(es): dc.creator | Lana, Cristiano de Carvalho | - |
Autor(es): dc.creator | Alkmim, Fernando Flecha de | - |
Autor(es): dc.creator | Stevens, Gary | - |
Autor(es): dc.creator | Armstrong, Richard | - |
Data de aceite: dc.date.accessioned | 2019-11-06T13:25:27Z | - |
Data de disponibilização: dc.date.available | 2019-11-06T13:25:27Z | - |
Data de envio: dc.date.issued | 2012-10-22 | - |
Data de envio: dc.date.issued | 2012-10-22 | - |
Data de envio: dc.date.issued | 2012 | - |
Fonte completa do material: dc.identifier | http://hdl.handle.net/123456789/1709 | - |
Fonte: dc.identifier.uri | http://educapes.capes.gov.br/handle/capes/555076 | - |
Descrição: dc.description | Although 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.language | en | - |
Direitos: dc.rights | O Periódico . precambrian research concede permissão para depósito deste artigo no Repositório Institucional da UFOP. Número da licença: 3315440594042 | - |
Palavras-chave: dc.subject | Brazil | - |
Palavras-chave: dc.subject | São Francisco craton | - |
Palavras-chave: dc.subject | Potassic grantoids | - |
Palavras-chave: dc.subject | U-Pb geochronology | - |
Palavras-chave: dc.subject | Neoarchaean | - |
Título: dc.title | Stabilization of the southern portion of the São Francisco craton, SE Brazil, through a long-lived period of potassic magmatism. | - |
Aparece nas coleções: | Repositório Institucional - UFOP |
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