Titre :

Evidence of Dislocation Mixed Climb in Quartz From the Main Central and Moine Thrusts: An Electron Tomography Study

Auteur(s) :

Weidner, Timmo [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Mussi, Alexandre [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Castelnau, Olivier [Auteur]
Kronenberg, Andreas [Auteur]
Law, Richard [Auteur]
Cordier, Patrick [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207

Titre de la revue :

Journal of Geophysical Research : Solid Earth

Nom court de la revue :

JGR Solid Earth

Numéro :

129

Pagination :

e2024JB029083

Éditeur :

American Geophysical Union (AGU)

Date de publication :

2024-07-17

ISSN :

2169-9313

Discipline(s) HAL :

Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Planète et Univers [physics]/Sciences de la Terre
Planète et Univers [physics]/Sciences de la Terre/Géophysique [physics.geo-ph]
Physique [physics]/Mécanique [physics]/Mécanique des solides [physics.class-ph]

Résumé en anglais : [en]

In this study we apply electron tomography to characterize 3D dislocation microstructures in two quartz mylonite specimens from the Moine and Main Central Thrusts, both of which accommodated displacements by dislocation ...
Lire la suite >In this study we apply electron tomography to characterize 3D dislocation microstructures in two quartz mylonite specimens from the Moine and Main Central Thrusts, both of which accommodated displacements by dislocation creep in the presence of water. Both specimens show dislocation activity with dislocation densities of the order of 3–4 × 1012 m−2 and evidence of recovery from the presence of subgrain boundaries. ⟨a⟩ slip occurs predominantly on pyramidal and prismatic planes (⟨a⟩ basal glide is not active). [c] Glide is not significant. On the other hand, we observe a very high level of activation of ⟨c + a⟩ glide on the , , (n = 1,2) and even planes. Approximately 60% of all dislocations show evidence of climb with a predominance of mixed climb, a deformation mechanism characterized by dislocations moving in a plane intermediate between the glide and the climb planes. This atypical mode of deformation demonstrates comparable glide and climb efficiency under natural deformation conditions. It promotes dislocation glide in planes not expected for the quartz structure, probably by inhibiting lattice friction. Our quantitative characterization of the microstructure enables us to assess the strain that dislocations can generate. We show that glide systems indicated by the observed dislocations are sufficient to accommodate any arbitrary 3D strain by themselves. Although historically dislocation glide has been regarded as being primarily responsible for producing strain, activation of climb can also directly contribute to the finite strain. On the basis of this characterization, we propose a numerical modeling approach for attempting to characterize the local stress state that gave rise to the observed microstructure.Lire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Internationale

Vulgarisation :

Non

Projet Européen :

Rheology of Earth materials: closing the gap between TIMEscales in the laboratory and in the MANtle

Établissement(s) :

Université de Lille
CNRS
INRAE
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Équipe(s) de recherche :

Plasticité

Date de dépôt :

2024-07-18T07:39:09Z
2024-08-20T14:07:27Z