Crystal‐Plastic Deformation in Seismically ...
Type de document :
Article dans une revue scientifique: Article original
DOI :
URL permanente :
Titre :
Crystal‐Plastic Deformation in Seismically Active Carbonate Fault Rocks
Auteur(s) :
Ohl, Markus [Auteur]
Nzogang, Billy [Auteur]
Mussi, Alexandre [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Wallis, David [Auteur]
Drury, Martyn [Auteur]
Plümper, Oliver [Auteur]
Nzogang, Billy [Auteur]
Mussi, Alexandre [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Wallis, David [Auteur]
Drury, Martyn [Auteur]
Plümper, Oliver [Auteur]
Titre de la revue :
Journal of Geophysical Research: Solid Earth
Nom court de la revue :
J Geophys Res Solid Earth
Numéro :
126
Pagination :
e2020JB020626
Éditeur :
American Geophysical Union (AGU)
Date de publication :
2021-03-31
Résumé en anglais : [en]
The spatial separation of macroscopic rheological behaviors has led to independent conceptual treatments of frictional failure, often referred to as brittle, and viscous deformation. Detailed microstructural investigations ...
Lire la suite >The spatial separation of macroscopic rheological behaviors has led to independent conceptual treatments of frictional failure, often referred to as brittle, and viscous deformation. Detailed microstructural investigations of naturally deformed carbonate rocks indicate that both frictional failure and viscous mechanisms might operate during seismic deformation of carbonates. Here, we investigate the deformation mechanisms that were active in two carbonate fault zones in Greece by performing detailed slip-system analyses on data from automated crystal-orientation mapping transmission electron microscopy and electron-backscatter diffraction. We combine the slip-system analyses with interpretations of nanostructures and predictions from deformation mechanism maps for calcite. The nanometric grains at the principal slip surface should deform by diffusion creep but the activation of the (0001)<-12-10> slip system is evidence for a contribution of crystal plasticity. A similar crystallographic preferred orientation appears in the cataclastic parts of the fault rocks despite exhibiting a larger grain size and a different fractal dimension, compared to the principal slip surface. The cataclastic region exhibits microstructures consistent with activation of the (0001)< )<-12-10> and {10-10}<-2021> slip systems. Postdeformational, static recrystallization, and annealing produce an equilibrium microstructure with triple junctions and equant grain size. We propose that repeated introduction of plastic strain and recrystallization reduces the grain size and offers a mechanism to form a cohesive nanogranular material. This formation mechanism leads to a grain-boundary strengthening effect resulting in slip delocalization which is observed over 6 orders of magnitude (μm-m) and is expressed by multiple faults planes, suggesting cyclic repetition of deformation and annealing.Lire moins >
Lire la suite >The spatial separation of macroscopic rheological behaviors has led to independent conceptual treatments of frictional failure, often referred to as brittle, and viscous deformation. Detailed microstructural investigations of naturally deformed carbonate rocks indicate that both frictional failure and viscous mechanisms might operate during seismic deformation of carbonates. Here, we investigate the deformation mechanisms that were active in two carbonate fault zones in Greece by performing detailed slip-system analyses on data from automated crystal-orientation mapping transmission electron microscopy and electron-backscatter diffraction. We combine the slip-system analyses with interpretations of nanostructures and predictions from deformation mechanism maps for calcite. The nanometric grains at the principal slip surface should deform by diffusion creep but the activation of the (0001)<-12-10> slip system is evidence for a contribution of crystal plasticity. A similar crystallographic preferred orientation appears in the cataclastic parts of the fault rocks despite exhibiting a larger grain size and a different fractal dimension, compared to the principal slip surface. The cataclastic region exhibits microstructures consistent with activation of the (0001)< )<-12-10> and {10-10}<-2021> slip systems. Postdeformational, static recrystallization, and annealing produce an equilibrium microstructure with triple junctions and equant grain size. We propose that repeated introduction of plastic strain and recrystallization reduces the grain size and offers a mechanism to form a cohesive nanogranular material. This formation mechanism leads to a grain-boundary strengthening effect resulting in slip delocalization which is observed over 6 orders of magnitude (μm-m) and is expressed by multiple faults planes, suggesting cyclic repetition of deformation and annealing.Lire moins >
Langue :
Anglais
Comité de lecture :
Oui
Audience :
Non spécifiée
Établissement(s) :
Université de Lille
CNRS
INRA
ENSCL
CNRS
INRA
ENSCL
Collections :
Équipe(s) de recherche :
Plasticité
Date de dépôt :
2021-06-17T12:43:47Z
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