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Use este identificador para citar ou linkar para este item: https://repositorio.ufba.br/handle/ri/5141
Tipo: Artigo de Periódico
Título: Petrological evolution of silica-undersaturated sapphirine-bearing granulite in the Paleoproterozoic Salvador–Curaçá Belt, Bahia, Brazil
Título(s) alternativo(s): Gondwana Research
Autor(es): Barbosa, Johildo Salomão Figueirêdo
Nicollet, Christian
Leite, Carlson Matos Maia
Sabaté, Pierre
Autor(es): Barbosa, Johildo Salomão Figueirêdo
Nicollet, Christian
Leite, Carlson Matos Maia
Sabaté, Pierre
Abstract: The Salvador–Curaçá Belt, located in São Francisco Craton, Brazil, was subjected to granulite facies metamorphism during the Paleoproterozoic orogeny (c. 2.0 Ga). Well preserved in enclaves of silicaundersaturated sapphirine-bearing granulite occur in a charnockite outcrop located along a kilometric-scale shear zone. The sapphirine-bearing granulite preserves domains with distinct mineral assemblages that record interactions between melt and peritectic phases (orthopyroxene1+spinel1+biotite1). Sapphirine was crystallized in the Si-poor cores of the enclaves, sillimanite and spinel–cordierite symplectites in the intermediate Si-rich domains between cores and margins, and garnet and quartz-bearing cordierite/biotite symplectites in Si-rich margins of the enclaves. Melt-rock interactions and metamorphism occurred at ultrahigh temperatures of 900–950 °C at 7.0–8.0 kbar pressures. The mineralogical evolution of the domains reflects not only the influence of changes in bulk composition in the equilibrium volume of the reactions but also P–T changes during orogeny evolution. Electron microprobe dating of monazite both in the sapphirinebearing granulite and charnockite indicates UHT metamorphism timing at c. 2.08–2.05 Ga that is related to global Paleoproterozoic UHT metamorphic events that occurred during the Columbia supercontinent assembly.
Palavras-chave: Paleoproterozoic orogeny
Pseudosections
Electron microprobe monazite dating
Retrograde melt-reactions
URI: http://www.repositorio.ufba.br/ri/handle/ri/5141
Data do documento: 2009
Aparece nas coleções:Artigo Publicado em Periódico (IGEO)

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