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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.)

U-Pb age of the coesite-bearing eclogite from NW Borborema Province, NE Brazil: Implications for western Gondwana assembly

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Author(s):
Saraiva dos Santos, Ticiano Jose [1] ; Amaral, Wagner da Silva [1] ; Ancelmi, Matheus Fernando [1, 2] ; Pitarello, Michele Zorzetti [1, 3] ; Fuck, Reinhardt Adolfo [4] ; Dantas, Elton Luiz [4]
Total Authors: 6
Affiliation:
[1] Univ Estadual Campinas UNICAMP, Inst Geociencias, BR-13083970 Campinas, SP - Brazil
[2] Univ Fed Alfenas, Inst Sci & Technol, Pocos De Caldas, MG - Brazil
[3] CPRM Geol Survey Brazil, Manaus, Amazonas - Brazil
[4] Univ Brasilia, Inst Geosci, Brasilia, DF - Brazil
Total Affiliations: 4
Document type: Journal article
Source: GONDWANA RESEARCH; v. 28, n. 3, p. 1183-1196, OCT 2015.
Web of Science Citations: 14
Abstract

The Late Neoproterozoic assembly of western Gondwana played an important role in the subduction of oceanic and continental lithospheres. Such event was also a source of arc magmatism, reworking of cratonic margins and development of ultra-high pressure (UHP) suture zones. In the Borborema province, NE Brazil, we have described for the first time UHP rocks enclosed within gneiss migmatite and calc-silicate rocks. They bear coesite included in atoll-type garnet from metamafic rocks, identified by petrographic study and Raman microspectroscopy analysis. U-Pb zircon dating of the leucosome of the migmatites and the calc-silicate rock displays, concordant ages of 639 +/- 10 Ma and 649.7 +/- 5 Ma, respectively, here interpreted as the minimum age of the edogitization event in the region. U-Pb zircon dating of the coesite-bearing rock defined a concordia age of 614.9 +/- 7.9 Ma that comprised the retrograde eclogitic conditions to amphibolite facies. The UHP rocks, mostly retrograded to garnet amphibolites, occur enclosed in the Paleoproterozoic continental block composed of calc-silicate rocks, migmatized sillimanite gneiss, mylonitic augen gneiss and granitic and tonalitic gneiss along a narrow N-S oriented belt between the Santa Quiteria magmatic arc and the Transbrasiliano lineament. This block was involved in the subduction to UHP eclogite depths, and was retrogressed to amphibolite during its exhumation and thrusting. Our data indicate an important Neoproterozoic transcontinental suture zone connecting the Pharusian belt with Borborema Province, and probably with the Brasilia belt in central Brazil. (C) 2014 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. (AU)