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GEOREF RECORD

Strain localization and porphyroclast rotation

Albert Griera, Paul D. Bons, Mark W. Jessell, Ricardo A. Lebensohn, Lynn Evans and Enrique Gomez-Rivas
Strain localization and porphyroclast rotation
Geology (Boulder) (March 2011) 39 (3): 275-278

Abstract

It has been debated for decades whether rigid inclusions, such as porphyroclasts and porphyroblasts, do or do not rotate in a softer matrix during deformation. Experiments and numerical simulations with viscous matrix rheologies show ongoing rotation of circular inclusions, whereas using Mohr-Coulomb plasticity results in nonrotation. Because the rocks in which inclusions are found normally undergo deformation by dislocation creep, we applied a full-field crystal plasticity approach to investigate the rotation behavior of rigid circular inclusions. We show that the inclusion's rotation strongly depends on the anisotropy of the matrix minerals. Strongly anisotropic minerals will develop shear bands that reduce the rotation of inclusions. Inhibition of rotation can only occur after a significant amount of strain. Our results may help to explain why geologic rigid objects often show evidence for rotation, but not necessarily in accordance with the viscous theory that is usually applied to these systems.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 39
Serial Issue: 3
Title: Strain localization and porphyroclast rotation
Affiliation: Universitat Autonoma de Barcelona, Departament de Geologia, Bellaterra, Spain
Pages: 275-278
Published: 201103
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 36
Accession Number: 2011-028210
Categories: Structural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
Secondary Affiliation: Eberhard Karls Universitaet Tuebingen, DEU, GermanyUniversite de Toulouse, FRA, FranceLos Alamos National Laboratory, USA, United StatesUniversity of Melbourne, AUS, Australia
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201116
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