Torsion of a cylinder of partially molten rock with a spherical inclusion: Theory and simulation

Alisic, Laura and Rhebergen, Sander and Rudge, John F. and Katz, Richard F. and Wells, Garth N. (2016) Torsion of a cylinder of partially molten rock with a spherical inclusion: Theory and simulation. Geochemistry, Geophysics, Geosystems, 17 (1). pp. 143-161. ISSN 1525-2027 DOI https://doi.org/10.1002/2015GC006061

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Abstract

The processes that are involved in migration and extraction of melt from the mantle are not yet fully understood. Gaining a better understanding of material properties of partially molten rock could help shed light on the behavior of melt on larger scales in the mantle. In this study, we simulate three-dimensional torsional deformation of a partially molten rock that contains a rigid, spherical inclusion. We compare the computed porosity patterns to those found in recent laboratory experiments. The laboratory experiments show emergence of melt-rich bands throughout the rock sample, and pressure shadows around the inclusion. The numerical model displays similar melt-rich bands only for a small bulk-to-shear-viscosity ratio (five or less). The results are consistent with earlier two-dimensional numerical simulations; however, we show that it is easier to form melt-rich bands in three dimensions compared to two. The addition of strain-rate dependence of the viscosity causes a distinct change in the shape of pressure shadows around the inclusion. This change in shape presents an opportunity for experimentalists to identify the strain-rate dependence and therefore the dominant deformation mechanism in torsion experiments with inclusions.

Item Type:	Article
Uncontrolled Keywords:	2015AREP; IA69
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics 08 - Green Open Access
Journal or Publication Title:	Geochemistry, Geophysics, Geosystems
Volume:	17
Page Range:	pp. 143-161
Identification Number:	https://doi.org/10.1002/2015GC006061
Depositing User:	Sarah Humbert
Date Deposited:	12 Apr 2017 22:06
Last Modified:	12 Apr 2017 22:06
URI:	http://eprints.esc.cam.ac.uk/id/eprint/3924

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