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Geochimica Brasiliensis
Article . 2016
Data sources: DOAJ
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ORIGEM, SIGNIFICADO PETROGENÉTICO E IDADE DOS ORTOGNAISSES TERRA NOVA: REGISTRO DE MAGMATISMO ALCALINO EXTENSIONAL NEOPROTEROZOICO NO DOMÍNIO DA ZONA TRANSVERSAL DA PROVÍNCIA BORBOREMA

Authors: Haroldo Monteiro Lima; Valderez Pinto Ferreira; Edilton José dos Santos; Marcio Martins Pimentel; Lauro Montefalco de Lira Santos;

ORIGEM, SIGNIFICADO PETROGENÉTICO E IDADE DOS ORTOGNAISSES TERRA NOVA: REGISTRO DE MAGMATISMO ALCALINO EXTENSIONAL NEOPROTEROZOICO NO DOMÍNIO DA ZONA TRANSVERSAL DA PROVÍNCIA BORBOREMA

Abstract

Os ortognaisses sieníticos de Terra Nova ocorrem encaixados na Faixa Feira Nova do Complexo Vertentes, no extremo leste do terreno Rio Capibaribe da Província Borborema, Nordeste do Brasil. Os ortognaisses ocorrem como intrusões tabulares dobradas por tectônica transcorrente relacionada à atividade da zona de cisalhamento brasiliana de Glória de Goitá, que separa o embasamento paleoproterozóico da faixa Feira Nova. Composicionalmente as rochas variam de álcali-feldspato sienitos a álcali-feldspato granitos exibindo bandas máficas de aegirina-augita e magnetita que se alternam com bandas ricas em ortoclásio e rara albita. Quimicamente são rochas peralcalinas a ligeiramente peraluminosas, com razões FeO/MgO e Ga/Al e concentrações Zr, Nb, Ce e Y típicas de granitóides anorogênicos derivados do manto. Altas razões Rb/ Sr (até 100), por outro lado, sugerem fonte na crosta. Os padrões de elementos terras raras (ETR) normalizados em relação ao condrito mostram enriquecimento de ETR leves em relação aos ETR pesados e forte anomalia negativa de Eu sugerindo fracionamento de feldspato, compatível com as variações interelementares Rb, Sr e Ba, e Rb/Sr vs. Sr/Ba. Diagramas discriminantes de ambiente tectônicos são sugestivos de ambiente pós-colisional a intra-placa. Datação U-Pb em zircão revelou a idade de cristalização dos ortognaisse sieníticos em torno de 617 ± 8,8 Ma, sugerindo a existência de um evento extensional ediacarano no Domínio Transversal da Província Borborema.

Keywords

QE1-996.5, Chemistry, sienito alcalino, granitos tipo a, regime transtensional, Geology, QD1-999

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
0
Average
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