Title :

Periclase deforms more slowly than bridgmanite under mantle conditions

Author(s) :

Cordier, Patrick [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Gouriet, Karine [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Weidner, Timmo [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207
Van Orman, James [Auteur]
Case Western Reserve University [Cleveland]
Castelnau, Olivier [Auteur]
Jackson, Jennifer M. [Auteur]
California Institute of Technology [CALTECH]
Carrez, Philippe [Auteur]
Unité Matériaux et Transformations (UMET) - UMR 8207

Journal title :

Nature

Abbreviated title :

Nature

Volume number :

613

Pages :

303-307

Publisher :

Springer Science and Business Media LLC

Publication date :

2023-01-11

ISSN :

0028-0836

HAL domain(s) :

Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Planète et Univers [physics]/Sciences de la Terre

English abstract : [en]

Transport of heat from the interior of the Earth drives convection in the mantle, which involves the deformation of solid rocks over billions of years. The lower mantle of the Earth is mostly composed of iron-bearing ...
Show more >Transport of heat from the interior of the Earth drives convection in the mantle, which involves the deformation of solid rocks over billions of years. The lower mantle of the Earth is mostly composed of iron-bearing bridgmanite MgSiO3 and approximately 25% volume periclase MgO (also with some iron). It is commonly accepted that ferropericlase is weaker than bridgmanite1. Considerable progress has been made in recent years to study assemblages representative of the lower mantle under the relevant pressure and temperature conditions2,3. However, the natural strain rates are 8 to 10 orders of magnitude lower than in the laboratory, and are still inaccessible to us. Once the deformation mechanisms of rocks and their constituent minerals have been identified, it is possible to overcome this limitation thanks to multiscale numerical modelling, and to determine rheological properties for inaccessible strain rates. In this work we use 2.5-dimensional dislocation dynamics to model the low-stress creep of MgO periclase at lower mantle pressures and temperatures. We show that periclase deforms very slowly under these conditions, in particular, much more slowly than bridgmanite deforming by pure climb creep. This is due to slow diffusion of oxygen in periclase under pressure. In the assemblage, this secondary phase hardly participates in the deformation, so that the rheology of the lower mantle is very well described by that of bridgmanite. Our results show that drastic changes in deformation mechanisms can occur as a function of the strain rate.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

European Project :

Rheology of Earth materials: closing the gap between TIMEscales in the laboratory and in the MANtle

Administrative institution(s) :

Université de Lille
CNRS
INRAE
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Plasticité

Submission date :

2023-01-13T11:47:00Z
2023-01-13T12:15:27Z
2023-01-16T09:59:09Z
2023-01-18T09:31:28Z
2023-01-18T10:10:43Z