Titre :

Ultrasonic Velocity of Diopside Liquid at High Pressure and Temperature: Constraints on Velocity Reduction in the Upper Mantle Due to Partial Melts

Auteur(s) :

Xu, Man [Auteur]
Case Western Reserve University [Cleveland]
Jing, Zhicheng [Auteur]
Southern University of Science and Technology [SUSTech]
Case Western Reserve University [Cleveland]
Chantel, Julien [Auteur]
174496|||Unité Matériaux et Transformations - UMR 8207 [UMET]
Case Western Reserve University [Cleveland]
Jiang, Peng [Auteur]
Case Western Reserve University [Cleveland]
Yu, Tony [Auteur]
University of Chicago
Wang, Y. [Auteur]
University of Chicago

Titre de la revue :

Journal of Geophysical Research : Solid Earth

Numéro :

123

Pagination :

8676-8690

Date de publication :

2018-10

Discipline(s) HAL :

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

Résumé en anglais : [en]

Sound velocities of diopside liquid were determined at high pressures and temperatures up to 3.8 GPa and 2375 K, using the ultrasonic technique combined with synchrotron X-ray diffraction and imaging in a multianvil ...
Lire la suite >Sound velocities of diopside liquid were determined at high pressures and temperatures up to 3.8 GPa and 2375 K, using the ultrasonic technique combined with synchrotron X-ray diffraction and imaging in a multianvil apparatus. Our results show that the sound velocity increases with pressure but is nearly independent of temperature. Using a Monte Carlo approach, the measured high-pressure sound velocities combined with ambient-pressure density provide tight constraints for the equation of state of diopside liquid, with a best-fit adiabatic bulk modulus (KS) of 23.8 ± 0.4 GPa and its pressure derivative (KS') of 7.5 ± 0.5. The calculated adiabatic temperature and density profile of diopside liquid suggest that a melt layer with diopside composition in the upper mantle would be gravitationally unstable and start to crystallize from the bottom of the layer during cooling. By comparing our results with previous acoustic measurements on silicate glasses, we demonstrate the important differences in sound velocities between silicate liquids and glasses and conclude that silicate glasses may not work as a good analog material for studying the acoustic properties of silicate liquids, as measurements on unrelaxed glasses do not capture the entropic contribution to the compressional properties of liquids. We modeled velocity reductions due to partial melts in the upper mantle using our results and found that for a given velocity reduction, the deeper the low-velocity region, the larger the melt fraction is required. Using silicate glass data for such estimation would result in a significant underestimation of melt fractions at high pressures.Lire moins >

Langue :

Anglais

Audience :

Internationale

Vulgarisation :

Non

Établissement(s) :

Université de Lille
ENSCL
CNRS
INRA

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Équipe(s) de recherche :

Matériaux Terrestres et Planétaires

Date de dépôt :

2019-05-17T09:24:58Z
2023-11-15T15:45:15Z