Earth Mantle Rheology Inferred from Homogenization Theories
TypeChapitres d'ouvrages scientifiques
The Earth’s upper mantle is known to exhibit elastic anisotropy, which is commonly attributed to the presence of Lattice Preferred Orientations (LPO). Such anisotropy is revealed in recordings of seismic waves that travel through the mantle with speeds that depend on propagation and/or polarization direction. The development of LPO is due to the plastic deformation of mantle minerals associated with large-scale convective flow. Both olivine and pyroxene crystals exhibit an orthorhombic structure and have only a few slip systems available for dislocation creep. This leads to very high viscoplastic anisotropy at the grain scale, so that an upper mantle region with strong seismic anisotropy (i.e., pronounced LPO) may also exhibit a large effective viscoplastic anisotropy which may manifest itself as differences in effective viscosities of up to one or two orders of magnitude depending on the loading direction. This may have a large influence on the flow in (at least) some regions of the mantle [CHR 87], as was also shown for the flow of ice in ice sheets [MAN 97], but the topic has received little attention [BLA 07]. The key of this issue is to understand the link between single crystal rheology, microstructure (in particular LPO) and associated polycrystal behavior, e.g. as attempted for polar ices [CAS 08b].
Files in this item
Showing items related by title, author, creator and subject.
Full-field vs. homogenization methods to predict microstructure-property relations for polycrystalline materials LEBENSOHN, Ricardo A.; PONTE CASTAÑEDA, Pedro; BRENNER, Rénald; CASTELNAU, Olivier (Springer, 2011)In this chapter, we review two recently proposed methodologies, based on crystal plasticity, for the prediction of microstructure-property relations in polycrystalline aggregates. The first, known as the second-order ...
BORNERT, M; BRENNER, R.; CASTELNAU, Olivier; PONTE CASTANEDA, P.; SUQUET, Pierre (Elsevier, 2012)La Mécanique des Matériaux a connu, en France et dans le monde, un développement spectaculaire au cours des dernières décennies, rendu à la fois nécessaire par les besoins d’innovation et de sûreté de secteurs industriels ...
LEBENSOHN, Ricardo A.; HARTLEY, Craig S.; TOMÉ, Carlson N.; CASTELNAU, Olivier (TAYLOR & FRANCIS, 2010)This paper presents a crystallographically-based constitutive model of a single crystal deforming by climb and glide. The proposed constitutive law is an extension of the rate-sensitivity approach for single crystal ...
MONTAGNAT, Maurine; CASTELNAU, Olivier; BONS, P.D; FARIA, S.H; GAGLIARDINI, O; GILLET-CHAULET, F; GRENNERAT, Fanny; GRIERA, A; LEBENSOHN, R.A.; MOULINEC, Hervé; ROESSIGER, J.; SUQUET, Pierre (ELSEVIER, 2013)Understanding the flow of ice in glaciers and polar ice sheets is of increasing relevance in a time of potentially significant climate change. The flow of ice has hitherto received relatively little attention from the ...
ROBACH, Odile; KIRCHLECHNER, Christoph; MICHA, Jean Sébastien; ULRICH, M. Olivier; BIQUARD, Xavier; GEAYMOND, M. Olivier; CASTELNAU, Olivier; BORNERT, Michel; PETIT, Johann; BERVEILLER, Sophie; SICARDY, Olivier; VILLANOVA, Julie; RIEUTORD, François (mperial College Press, 2014)This book highlights emerging diffraction studies of strain and dislocation gradients with mesoscale resolution, which is currently a focus of research at laboratories around the world. While ensemble-average diffraction ...