Fabrics of migmatites and the relationships between partial melting and deformation in high-grade transpressional shear zones: The Espinho Branco anatexite (Borborema Province, NE Brazil)

Autor(es)

Viegas, Luis Gustavo F. ^{[1, 2]} ; Archanjo, Carlos J. ^[1] ; Vauchez, Alain ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Geociencias, BR-05508080 Sao Paulo - Brazil

^[2] Geosci Montpellier, F-34095 Montpellier 5 - France

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF STRUCTURAL GEOLOGY; v. 48, p. 45-56, MAR 2013.
• Citações Web of Science: 10

Resumo

The Espinho Branco anatexite, located within a transcurrent, high-temperature shear zone in NE Brazil, was the subject of a comprehensive petrostructural study (Anisotropy of Magnetic Susceptibility - AMS, Anisotropy of Anhysteretic Remanence - AAR, Electron Backscatter Diffraction - EBSD) to evaluate the compatibility of different fabrics with the kinematics of melt deformation. Magnetite dominates susceptibilities larger than 1 mSI and biotite displays {[}001] lattice directions consistent with AMS k(3) axes. In contrast, migmatites with a susceptibility lower than 0.5 mSI and no visible mesoscopic foliation provide crystallographic fabrics distinct from AMS and AAR. However, AAR remains consistent with the regional strain field. These results suggest that the correlation of field, AMS and crystallographic fabrics is not always straightforward despite the relatively simple organisation of the magnetic fabric in the anatexite. We conclude that AMS recorded the final stages of the strain field in the migmatite irrespective of its complex mesoscale structures and contrasting crystallographic fabrics. (C) 2012 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 10/50060-1 - Domos migmatiticos e milonitos do lineamento patos (provincia borborema, ne brasil): estudo estrutural e geocronologico dos eventos e alta temperatura.
• Beneficiário: Carlos José Archanjo
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 09/17537-1 - Mecanismos de deformação e cronologia de eventos na zona de cisalhamento Patos, Província Borborema (Nordeste do Brasil)
• Beneficiário: Luís Gustavo Ferreira Viegas
• Modalidade de apoio: Bolsas no Brasil - Doutorado