Microstructural analysis of the strain record in the Gavarnie Thrust (Axial Zone, Pyrenees)



Marcén, M, Román-Berdiel, T and Mariani, E ORCID: 0000-0002-0585-5265
(2017) Microstructural analysis of the strain record in the Gavarnie Thrust (Axial Zone, Pyrenees). Geogaceta, 61. 99 - 102.

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Abstract

The Gavarnie Thrust shows a 30m thick fault zone developed in the ampelitic and calcareous Silurian rocks, with a record of ductile deformation (myloni-tes) close to the main thrust plane and a progressive increase of the brittle deformation towards the marginal areas of the fault zone. The analysis of thin-sections under reflected and transmitted light with optical microscope reveals that calcite and phyllosilicates control the strain distribution in the fault rocks, leading to generation of mylonitic foliations and ductile-brittle S-C-C’ structures, respectively. Dinamic recrystallization, solution-precipitation and intracrystalline deformation generate shape preferred orientation in calcite grains. The main shear indicators (S-C-C’, brittle Riedel fractures, oblique foliations, pressure-shadows on pyrites…) are compatible with the South vergence of the Gavarnie Thrust, and no relevant oblique component of displacement has been observed.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 15 Mar 2019 15:36
Last Modified: 08 Apr 2021 05:10
Open Access URL: http://hdl.handle.net/10272/14548
URI: https://livrepository.liverpool.ac.uk/id/eprint/3027134