Title :

Crystal‐Plastic Deformation in Seismically Active Carbonate Fault Rocks

Author(s) :

Ohl, Markus [Auteur]
Universiteit Utrecht / Utrecht University [Utrecht]
NZOGANG, Billy Clitton [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Mussi, Alexandre [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Wallis, David [Auteur]
Universiteit Utrecht / Utrecht University [Utrecht]
University of Cambridge [UK] [CAM]
Drury, Martyn [Auteur]
Universiteit Utrecht / Utrecht University [Utrecht]
Plümper, Oliver [Auteur]
Universiteit Utrecht / Utrecht University [Utrecht]

Journal title :

Journal of Geophysical Research : Solid Earth

Abbreviated title :

J Geophys Res Solid Earth

Volume number :

126

Pages :

e2020JB020626

Publisher :

American Geophysical Union (AGU)

Publication date :

2021-03-31

ISSN :

2169-9356

English keyword(s) :

carbonate deformation
calcite CPO
crystal plasticity
microstructures
recrystallization
seismic cycle

HAL domain(s) :

Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Planète et Univers [physics]/Sciences de la Terre

English abstract : [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 ...
Show more >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.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

Université de Lille
CNRS
INRA
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Plasticité

Submission date :

2021-06-17T12:43:47Z
2021-06-18T14:03:05Z