Transformation microstructures in pyrolite under stress: Implications for anisotropy in subducting slabs below the 660 km discontinuity

Gay, Jeffrey-Phillip; Ledoux, Estelle; Krug, Matthias; Chantel, Julien; Pakhomova, Anna; Liermann, Hanns-Peter; Sanchez-Valle, Carmen; Merkel, Sébastien

Type de document :

Article dans une revue scientifique: Article original

DOI :

10.1016/j.epsl.2023.118015

URL permanente :

http://hdl.handle.net/20.500.12210/79130

Titre :

Transformation microstructures in pyrolite under stress: Implications for anisotropy in subducting slabs below the 660 km discontinuity

Auteur(s) :

Gay, Jeffrey-Phillip [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Ledoux, Estelle [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Krug, Matthias [Auteur]
Westfälische Wilhelms-Universität Münster = University of Münster [WWU]
Chantel, Julien [Auteur]

Unité Matériaux et Transformations - UMR 8207 [UMET]
Pakhomova, Anna [Auteur]
Deutsches Elektronen-Synchrotron [Hamburg] [DESY]
Liermann, Hanns-Peter [Auteur]
Deutsches Elektronen-Synchrotron [Hamburg] [DESY]
Sanchez-Valle, Carmen [Auteur]
Westfälische Wilhelms-Universität Münster = University of Münster [WWU]
Merkel, Sébastien [Auteur]

Unité Matériaux et Transformations - UMR 8207 [UMET]

Titre de la revue :

Earth and Planetary Science Letters

Numéro :

604

Pagination :

118015

Éditeur :

Elsevier BV

Date de publication :

2023-02-15

ISSN :

0012-821X

Mot(s)-clé(s) en anglais :

pyrolite
phase transformation
texture
seismic anisotropy
multigrain X-ray diffraction
660 km discontinuity

Discipline(s) HAL :

Chimie/Matériaux
Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Physique [physics]/Physique [physics]/Géophysique [physics.geo-ph]
Physique [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Sciences de la Terre

Résumé en anglais : [en]

The ‘660’ discontinuity is often associated with a phase transitions in pyrolite at about 24 GPa. There are ubiquitous reports of seismic anisotropy below the ‘660’ which are difficult to explain from a mineralogical point ...
Lire la suite >The ‘660’ discontinuity is often associated with a phase transitions in pyrolite at about 24 GPa. There are ubiquitous reports of seismic anisotropy below the ‘660’ which are difficult to explain from a mineralogical point of view. In this study, we implement multigrain crystallography X-ray diffraction in the laser-heated diamond anvil cell in order to track microstructures induced by phase transitions at the pressure and temperature conditions of the discontinuity. Before the onset of transformation, garnet is isotropic with ringwoodite displaying a weak 001 texture. After the transformation, bridgmanite displays strong 001 transformation textures which we attribute to growth under stress. Davemaoite exhibits weak maxima in 101 and 111 orientations with ferropericlase displaying no texture. The results are used to model anisotropy in a subducting slab, with a prediction of no anisotropy above the ‘660’ and up to 1.28% (0.08 km/s) shear wave splitting below the ‘660’. In addition, we predict for horizontally traveling waves and near-vertical subduction and in the case a slab impinging below the boundary layer.Lire moins >

Langue :

Anglais

Comité de lecture :

Oui

Audience :

Internationale

Vulgarisation :

Non

Références liée(s) :

http://hdl.handle.net/20.500.12210/79413

Projet Européen :

Convenient Access to Light Sources Open to Innovation, Science and to the World