Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/95502
Type: Artigo de periódico
Title: Petrology And Geochemistry Of The Neoproterozoic Guaxupé Granulite Facies Terrain, Southeastern Brazil
Author: Iyer S.S.
Choudhuri A.
Pattison D.R.M.
De Paoli G.R.
Abstract: Geochemical and oxygen isotopic data on the Neoproterozoic granulite facies rocks (enderbites, charnockite and charnokitic augen gneisses) of Guaxupé, Brazil are assembled. Geochemical discrimination function calculations show an igneous origin for majority of the rock types in the area. Major and trace element data, especially REE, are similar to tonalite and granodiorite. Oxygen isotope composition for charnockitic gneisses and mafic granulites yield δ18O values in the range of + 8.8 to + 11%« and fall in the range of quartzofeldspathic rocks of medium- to high-grade terrains elsewhere. A small-scale variation of δ18O values, compatible with the chemical data, imply the preservation of pre-metamorphic oxygen isotope compositions. Minimum peak pressure-temperature conditions are 8.5 kbar and 850°C. The high-grade metamorphism did not appear to have altered significantly the geochemical and oxygen isotope compositions of the protoliths. Approximately 2.5 kbar of pressure decrease accompanied by 200°C cooling has been recorded for a portion of the cooling path. The P-T path is consistent with a single event, namely the formation and uplift of the Guaxupé nappe in the Neoproterozoic Brasiliano cycle.
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Address: http://www.scopus.com/inward/record.url?eid=2-s2.0-0029774152&partnerID=40&md5=8ab132a1c423c3bdadd73d93df79b5a5
Date Issue: 1996
Appears in Collections:Unicamp - Artigos e Outros Documentos

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