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

Simple item page
dc.contributor.authorRomano, Rafael Cotta
dc.contributor.authorLana, Cristiano de Carvalho
dc.contributor.authorAlkmim, Fernando Flecha de
dc.contributor.authorStevens, Gary
dc.contributor.authorArmstrong, Richard
dc.date.accessioned2012-10-22T13:06:57Z
dc.date.available2012-10-22T13:06:57Z
dc.date.issued2012
dc.description.abstractAlthough 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.pt_BR
dc.identifier.citationROMANO, R. C. et al. Stabilization of the southern portion of the São Francisco craton, SE Brazil, through a long-lived period of potassic magmatism. Precambrian Research, v. 224, p.01-20, set. 2012. Disponível em: <http://www.sciencedirect.com/science/article/pii/S0301926812002173>. Acesso em: 22 out. 2012.pt_BR
dc.identifier.issn03019268
dc.identifier.urihttp://www.repositorio.ufop.br/handle/123456789/1709
dc.language.isoen_USpt_BR
dc.rights.licenseO periódico Precambrian Research concede permissão para depósito deste artigo no Repositório Institucional da UFOP. Número da licença: 3315440594042.
dc.subjectBrazilpt_BR
dc.subjectSão Francisco cratonpt_BR
dc.subjectPotassic grantoidspt_BR
dc.subjectU-Pb geochronologypt_BR
dc.subjectNeoarchaeanpt_BR
dc.titleStabilization of the southern portion of the São Francisco craton, SE Brazil, through a long-lived period of potassic magmatism.pt_BR
dc.typeArtigo publicado em periodicopt_BR
Files
Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
ARTIGO_StabilizationSouthernPortion.pdf
Size:
819.33 KB
Format:
Adobe Portable Document Format
Download
Collections
DEGEO - Artigos publicados em periódicos