Title :

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

Author(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]

Journal title :

Earth and Planetary Science Letters

Volume number :

604

Pages :

118015

Publisher :

Elsevier BV

Publication date :

2023-02-15

ISSN :

0012-821X

English keyword(s) :

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

HAL domain(s) :

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

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

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

Related reference(s) :

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

European Project :

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

ANR Project :

Transformations de phase, microstructures, et leur signatures sismiques dans le manteau terrestre

Administrative institution(s) :

Université de Lille
CNRS
INRAE
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Matériaux Terrestres et Planétaires

Submission date :

2023-02-03T09:43:16Z
2023-02-08T13:51:16Z
2023-03-20T16:31:20Z