Comparing olivine single crystal and polycrystal rheology: evidence for supplementary accommodation mechanisms at grain boundaries - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2013

Comparing olivine single crystal and polycrystal rheology: evidence for supplementary accommodation mechanisms at grain boundaries

Résumé

Rheology in the Earth’s upper-mantle is mostly constrained by the plastic properties of olivine. Over recent years, several groups have been carrying out deformation experiments on single crystals and polycrystals of olivine at upper mantle pressure (P) and temperature (T). Yet, the rheology of olivine at mantle conditions is still not well constrained. We carried out deformation experiments on San Carlos olivine polycrystals, at P and T ranging from 3 to 8 GPa and 1373 to 1673 K, respectively, and at strain rates ranging from 10-6 to 10-4 s-1, using the D-DIA apparatus installed at the NSLS X17B2 beamline (NY, USA). The deformation rates of the polycrystals are compared to those of single crystals oriented along the soft orientations [110]c, [011]c, [101]c which activate the easiest slip systems (Raterron et al., 2012). This comparison suggests that, in olivine polycrystals deforming in the dislocation creep regime, other relaxation mechanisms need to be considered to account for the observed polycrystal strain rates. This highlights the importance of supplementary mechanisms, such as those occurring at grain boundaries, to properly model olivine aggregates plasticity.
Fichier non déposé

Dates et versions

hal-01168183 , version 1 (25-06-2015)

Identifiants

  • HAL Id : hal-01168183 , version 1

Citer

Caroline Bollinger, Sébastien Merkel, Paul Raterron, Olivier Castelnau, Fabrice Detrez. Comparing olivine single crystal and polycrystal rheology: evidence for supplementary accommodation mechanisms at grain boundaries. American Geophysical Union fall meeting, Dec 2013, San Francisco, United States. ⟨hal-01168183⟩
136 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More