Title :

Shear wave velocities across the olivine – wadsleyite – ringwoodite transitions and sharpness of the 410 km seismic discontinuity

Author(s) :

Perrillat, Jean-Philippe [Auteur]
Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [LGL-TPE]
Tauzin, Benoît [Auteur]

Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [LGL-TPE]
Chantel, Julien [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Jonfal, Julie [Auteur]
Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [LGL-TPE]
Daniel, Isabelle [Auteur]
Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [LGL-TPE]
Jing, Zhicheng [Auteur]
Center for Advanced Radiation Sources [University of Chicago] [CARS]
Wang, Yanbin [Auteur]
Center for Advanced Radiation Sources [University of Chicago] [CARS]

Journal title :

Earth and Planetary Science Letters

Volume number :

593

Pages :

117690

Publisher :

Elsevier

Publication date :

2022-09-01

ISSN :

0012-821X

English keyword(s) :

olivine
wadsleyite
ringwoodite
kinetics
seismic discontinuity
Earth's mantle

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 seismic signature of the 410-km seismic discontinuity is generally attributed to the olivine to wadsleyite polymorphic transformation. However, apparent discrepancies exist between seismic and experimental observations. ...
Show more >The seismic signature of the 410-km seismic discontinuity is generally attributed to the olivine to wadsleyite polymorphic transformation. However, apparent discrepancies exist between seismic and experimental observations. Among those, the sharpness of the discontinuity as inferred from the reflectivity of seismic waves is difficult to reconcile with the gradual nature of the olivine to wadsleyite transformation predicted by phase equilibria. In this study, we explore the contribution of the phase transition kinetics to the sharpness of the discontinuity by performing X-ray diffraction and sound velocity measurements on (Mg,Fe)2SiO4 with an unprecedented time resolution as a function of the reaction progress. Our data document for the first time a transient velocity softening phenomenon and attenuation which we relate to the formation of a metastable spineloid phase. In the Earth's mantle this transformation mechanism would affect the elastic gradient within the olivine-wadsleyite two-phase loop, potentially creating a low-velocity layer; hence explaining the unique sharpness and reflectivity of the discontinuity.Show less >

Language :

Anglais

Audience :

Internationale

Popular science :

Non

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 :

2022-07-08T13:00:00Z
2022-07-11T07:52:57Z