Title :

In-situ study of microstructures induced by the olivine to wadsleyite transformation at conditions of the 410 km depth discontinuity

Author(s) :

Ledoux, Estelle [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Krug, Matthias [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Gay, Jeffrey-Phillip [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Chantel, Julien [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Hilairet, Nadege [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Bykov, Maxim [Auteur]
Bykova, Elena [Auteur]
Aprilis, Georgios [Auteur]
Svitlyk, Volodymyr [Auteur]
Garbarino, Gaston [Auteur]
Guignot, Nicolas [Auteur]
Sanchez-Valle, Carmen [Auteur]
Speziale, Sergio [Auteur]
Merkel, Sébastien [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207

Journal title :

American Mineralogist

Volume number :

108

Pages :

2283-2293

Publisher :

Mineralogical Society of America

Publication date :

2023-12-01

English abstract : [en]

The olivine-wadsleyite transformation is believed to occur at depths of about 410 km in the Earth, producing a major seismic discontinuity in this region of the Earth’s mantle. The mechanism of this phase transition controls ...
Show more >The olivine-wadsleyite transformation is believed to occur at depths of about 410 km in the Earth, producing a major seismic discontinuity in this region of the Earth’s mantle. The mechanism of this phase transition controls the microstructures of the newly nucleated wadsleyite, the major phase of the upper part of the mantle transition zone, and thus impacts seismic observations in the region. Here, we study the microstructures produced by the olivine-wadsleyite transformation using in situ laboratory experiments at pressures and temperatures relevant for the mantle transition zone. We transform pure olivine samples in laser-heated diamond-anvil cells at pressures ranging from 12.3 to 20.2 GPa and temperatures of 1400–1730 K. At different steps of the transformation we measure the orientation and size distribution of individual sample grains using multigrain crystallography at synchrotron radiation sources. We find that the olivine to wadsleyite transformation is incoherent at the conditions of the mantle transition zone, and is probably dominated by nucleation of wadsleyite at grain boundaries of the parent olivine. Thus, we expect that seismic anisotropy near 410 km would drop significantly due to the randomized lattice preferred orientation of newly nucleated wadsleyite induced by the incoherent transformation.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

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 :

2023-12-02T07:52:59Z