Articles | Volume 7, issue 2
Research article
09 Mar 2016
Research article |  | 09 Mar 2016

Brittle grain-size reduction of feldspar, phase mixing and strain localization in granitoids at mid-crustal conditions (Pernambuco shear zone, NE Brazil)

Gustavo Viegas, Luca Menegon, and Carlos Archanjo

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Cited articles

Archanjo, C. J., Bouchez, J. L., Corsini, M., and Vauchez, A.: The Pombal granite pluton: magnetic fabric, emplacement and relationships with the Brasiliano strike-slip setting of NE Brazil (Paraiba State), J. Struct. Geol., 16, 323–335, 1994.
Behrmann, J. H. and Mainprice, D.: Deformation mechanisms in a high-temperature quartz-feldspar mylonite: evidence for superplastic flow in the lower continental crust, Tectonophysics, 140, 297–305, 1987.
Bercovici, D. and Ricard, Y.: Mechanisms for the generation of plate tectonics by two-phase grain damage and pinning, Phys. Earth Planet. In., 202–203, 27–55, 2012.
Bons, P. and den Brok, B.: Crystallographic preferred orientation development by dissolution precipitation creep, J. Struct. Geol., 22, 1713–1722, 2000.
Bürgmann, R. and Dresen, G.: Rheology of the lower crust and upper mantle: evidence from rock mechanics, geodesy, and field observations, Annu. Rev. Earth Pl. Sc., 36, 531–567, 2008.
Short summary
This paper presents microstructural and chemical data of mylonitic granitoids deformed at the brittle-ductile transition in the continental crust. Through a combination of microstructures, chemical analyses and modelling of the strength of constituent phases, we were able to show that strain localisation in shear zones may be triggered primarily by brittle failure, without the need for reaction-softening mechanisms promoted by metamorphic fluids.