Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/73578
Type: Artigo de periódico
Title: The Juiz de Fora granulite complex of the central Ribeira Belt, SE Brazil: A Paleoproterozoic crustal segment thrust during the Pan-African orogeny
Author: Heilbron, M
Duarte, BP
Nogueira, JR
Abstract: The granulites of the Juiz de Fora complex occur within thick basement thrust slices associated with the Pan-African shortening process in the central segment of the Ribeira belt. Five lithological units of the Intermediate tectonic domain of the belt can be identified on the basis of detailed geological mapping: a) orthogranulites, b) orthogneisses; c) kinzigite; d) intrusive garnet charnockite and e) amphibolite facies metasediments of probable Meso to Neoproterozoic age, correlated to the cover of the belt. Petrological data indicate high temperatures and intermediate to low lithostatic pressure conditions for the Paleoproterozoic granulite facies metamorphism. Textures and CO2-rich fluid inclusions are probably related to an IBC path. Geochemical data do not show relevant compositional change as a result of the granulite metamorphism. Two calc-alkaline suites and tholeiitic to alkaline basic rocks can be related to compressional and extensional settings, respectively. The overall composition of the granulites, the lack of substantial LILE depletion as well as the composition of the fluid inclusion points to granulitization process driven by CO2-rich fluids. Orthogranulites gave rise to banded gneisses as a result of the Pan-African retrograde metamorphism and intense deformation. The U and Th depletion detected in few rocks is possibly related with the hydrated conditions of the retrograde reactions.
Subject: Ribeira Belt
Juiz de Fora complex
Paleoproterozoic
geochemistry
metamorphism
Country: Japão
Editor: Int Assoc Gondwana Research
Rights: fechado
Identifier DOI: 10.1016/S1342-937X(05)70853-4
Date Issue: 1998
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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