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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Relics of eclogite facies assemblages in the Ceara Central Domain, NW Borborema Province, NE Brazil: Implications for the assembly of West Gondwana

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Author(s):
Saraiva dos Santos, Ticiano J. [1] ; Garcia, Maria da Gloria M. [2] ; Amaral, Wagner Silva [1] ; Caby, Renauld [3] ; Wernick, Eberhard [4] ; Arthaud, Michel H. [5] ; Dantas, Elton L. [6] ; Santosh, M. [7]
Total Authors: 8
Affiliation:
[1] Univ Estadual Campinas, UNICAMP, Inst Geosci, BR-13083970 Campinas, SP - Brazil
[2] Univ Sao Paulo, IGc, BR-05508900 Sao Paulo - Brazil
[3] Univ Montpellier 2, Lab Tectonophys, F-34095 Montpellier - France
[4] Univ Estadual Paulista, UNESP, IGCE, BR-13506900 Rio Claro, SP - Brazil
[5] Univ Fed Ceara, Dep Geol, BR-60455760 Fortaleza, Ceara - Brazil
[6] Univ Brasilia, UnB, Inst Geociencias, BR-70910900 Brasilia, DF - Brazil
[7] Kochi Univ, Fac Sci, Kochi 7808520 - Japan
Total Affiliations: 7
Document type: Journal article
Source: GONDWANA RESEARCH; v. 15, n. 3-4, p. 454-470, JUN 2009.
Web of Science Citations: 35
Abstract

The Borborema Province, in the NE of Brazil, is a rather complex piece in the Brazil-Africa puzzle as it represents the junction of the Dahomeyide/Pharusian, Central African, Aracuai and Brasilia fold belts located between the West-African/Sao Luis, Congo/Sao Francisco and Amazonas craton. The correlation between the Dahomeyides from W-Africa (Ghana, Benin, Togo, and Mali) and the Borborema Province involves the Medio Coreau and Central Ceara domains. The inferred continuation of the main oceanic suture zone exposed in the Dahomeyides of W Africa is buried beneath the Phanerozoic Parnaiba Basin in Brazil (northwest of the Medio Coreau domain) where some high density gravity anomalies may represent hidden remnants of an oceanic suture. In addition to this major suture a narrow, nearly continuous strip composed of mainly mafic pods containing relics of eclogite-facies assemblages associated with partially migmatized granulite-facies metapelitic gneisses has been found further east in the NW Borborema Province. These high pressure mafic rocks, interpreted as retrograded eclogites, are located between the Transbrasiliano Lineament and the Santa Quiteria continental arc and comprise primitive to evolved arc-related rocks with either arc- or MORB-type imprints that can indicate either deep subduction of oceanic lithosphere or roots of continental and oceanic magmatic arcs. Average peak P-T conditions under eclogite-facies metamorphism (T=770 degrees C and P = 17.3 kbar) were estimated using garnet-clinopyroxene thermometry and Jd content in clinopyroxene. Transition to granulite-facies conditions, as well as later widespread re-equilibration under amphibolite facies, were registered both in the basic and the metapelitic rocks and suggest a clockwise P-T path characterized by an increase in temperature followed by strong decompression. A phenomenon possibly related to the exhumation of a highly thickened crust associated with the suturing of the Medio Coreau and Central Ceara domains, two distinct crustal blocks separated by the Transbrasiliano Lineament. (C) 2009 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. (AU)