Titre :

Phase Change of Pyrolitic Material: In-situ Transformation of Ringwoodite to Bridgmanite at 660 km Conditions

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]

Unité Matériaux et Transformations - UMR 8207 [UMET]
Pakhomova, Anna [Auteur]
Deutsches Elektronen-Synchrotron [Zeuthen] [DESY]
Kupenko, Ilya [Auteur]

Chantel, Julien [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Sanchez-Valle, Carmen [Auteur]

Merkel, Sébastien [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]

Titre de la manifestation scientifique :

EMPG (Experimental Mineralogy, Petrology and Geochemistry)

Ville :

Potsdam

Pays :

Allemagne

Date de début de la manifestation scientifique :

2021-03-03

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]

It has long been known that phase transitions have contributed to seismic reflections in the mantle. These transitions are caused by pressure and temperature variations. More specifically, at the 660 km discontinuity, phase ...
Lire la suite >It has long been known that phase transitions have contributed to seismic reflections in the mantle. These transitions are caused by pressure and temperature variations. More specifically, at the 660 km discontinuity, phase transitions in pyrolitic composition samples, where ringwoodite and majoritic garnet decompose to form bridgmanite and ferropericlase, have been observed. Transformations at the 660 km discontinuity are not martensitic due to chemical variations within the material. Questions remain on the microstructures obtained after the phase transition. Are there preferred orientation within individual phases after the synthesis? Do grain sizes change during this transition? Better understanding the microstructures induced by phase transformations will give better insight to seismic anisotropy shortly after the discontinuity, the observed seismic reflection and its overall effect on mantle dynamics. Determining transformation microstructures at 660 km conditions will hence lead to a better understanding of the Earth’s mantle. By implementing synchroton multigrain x-ray diffraction in a laser heated diamond anvil cell, we are able to track individual grains, their crystal structure, and orientations, while being compressed in-situ at pressures ranging from 18-55 GPa and temperatures of ~1800K. Using this experimental approach, we can then use obtained transformation textures to refine current seismic models to better understand observable anisotropies and reflections at conditions relevant to the 660 km discontinuity.Lire moins >

Langue :

Anglais

Audience :

Internationale

Vulgarisation :

Non

Projet ANR :

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

Établissement(s) :

Université de Lille
CNRS
INRA
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Équipe(s) de recherche :

Matériaux Terrestres et Planétaires

Date de dépôt :

2021-03-09T14:22:29Z
2021-03-09T17:10:03Z