Skip to Main Content
Book Chapter

Deformation mechanisms of plagioclase and seismic anisotropy of the Acebuches metabasites (SW Iberian massif)

By
Manuel Díaz-Azpiroz
Manuel Díaz-Azpiroz
Departamento de Sistemas Físicos, Químicos y Naturales. Universidad Pablo de Olavide, Crtra. Utrera, 41013 Seville, Spain
Search for other works by this author on:
Geoffrey E. Lloyd
Geoffrey E. Lloyd
School of Earth & Environment, University of Leeds, Leeds, LS2 9JT UK
Search for other works by this author on:
Carlos Fernández
Carlos Fernández
Departamento de Geodinámica y Paleontología, Facultad de Ciencias Experimentales, Universidad de Huelva, Campus de El Carmen, 21071 Huelva
Search for other works by this author on:
Published:
January 01, 2011

Abstract

Samples of the Acebuches metabasites (SW Spain), deformed under low-pressure/medium-to-high temperature metamorphic conditions, have been analysed via electron backscattered diffraction (EBSD) to obtain their plagioclase crystal lattice preferred orientations (LPO). Plagioclases from the highest temperature amphibolites show moderate LPO and a good correlation between 180° misorientation angles and both the crystal and the kinematic coordinate systems, which is attributed to dislocation glide accommodated by mechanical albite+pericline twinning. Plagioclases from medium-temperature amphibolites exhibit well-developed LPO, suggesting that dislocation creep was active during plagioclase deformation. Plagioclases from the more intensively deformed mafic schists exhibit weak LPO, indicating the activity of LPO-destroying deformation mechanisms. Evidence points to grain-boundary sliding accompanied by limited fracturing. The observed LPO are characterized by the alignment of [100] parallel to the kinematic X-direction. This association suggests that [100] was the preferential slip direction during dislocation creep of plagioclase, with (010) and/or (001) appearing to have acted as the dominant slip planes. The observed plagioclase LPO is combined with hornblende LPO to define the seismic fabric of the Acebuches metabasites. In samples with strong plagioclase LPO, the resulting seismic fabrics are highly influenced by this phase.

You do not currently have access to this article.

Figures & Tables

Contents

Geological Society, London, Special Publications

Deformation Mechanisms, Rheology and Tectonics: Microstructures, Mechanics and Anisotropy

David J. Prior
David J. Prior
University of Otago, New Zealand
Search for other works by this author on:
Ernest H. Rutter
Ernest H. Rutter
University of Manchester, UK
Search for other works by this author on:
Daniel J. Tatham
Daniel J. Tatham
University of Liverpool, UK
Search for other works by this author on:
Geological Society of London
Volume
360
ISBN electronic:
9781862394483
Publication date:
January 01, 2011

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal