1.57 Ga protolith age of the Neoproterozoic Forquilha eclogites, Borborema Province, NE-Brazil, constrained by U-Pb, Hf and Nd isotopes

Autor(es)

Amaral, Wagner ; Santos, Ticiano Jose ; Ancelmi, Matheus Fernando ; Fuck, Reinhardt Adolfo ; Dantas, Elton Luiz ; Matteini, Massimo ; Moreto, Carolina Penteado

• Tipo de documento: Artigo Científico
• Fonte: Journal of South American Earth Sciences; v. 58, p. 13-pg., 2015-03-01.

Resumo

The 30 km-long, N-S-trending Forquilha eclogite zone, occurs within a Paleoproterozoic block mainly composed of gneisses and migmatites, in the Ceara Central domain, Borborema Province, NE Brazil. The Forquilha eclogite zone contains lenses of high to ultra-high pressure metamafic rocks, found as granulites and amphibolites associated with kyanite-sillimanite gneisses. Three samples of clinopyroxenegarnet amphibolite yielded the U-Pb zircon ages of 1566 +/- 9 Ma, 1547 +/- 37 Ma and 1532 +/- 24 Ma, interpreted as the timing of igneous crystallization of the mafic protolith. Additionally, zircon grains of a leucocratic layer of a metamafic rock and a retrograded eclogite provided the less precise U-Pb ages of 1613 +/- 40 Ma and 1454 +/- 120 Ma, respectively. Lu Hf and Sm-Nd model ages provided TDm (HO between 1.55 and 1.81 Ga with positive stif values of +7.50 to +10.48, and TDm (Nd) ranging between 1.57 and 1.92 Ga with positive eNd values of +1.84 to +4.36. It is believed that part of the rocks of the Forquilha eclogite zone were emplaced as mafic dikes in an extensional setting at ca. 1.57 Ga. (C) 2014 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 03/07663-3 - Evolução tectônica do arco magmático de Santa Quitéria, NW da Província Borborema
• Beneficiário: Ticiano José Saraiva dos Santos
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 07/58535-6 - Rochas metabásicas da região entre o arco magmático de Santa Quiteria e o lineamento transbrasiliano: importância de suturas colisionais no Domínio Ceará Central - noroeste da Província Borborema
• Beneficiário: Ticiano José Saraiva dos Santos
• Modalidade de apoio: Auxílio à Pesquisa - Regular