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

Alisic, L and Rhebergen, S and Rudge, JF and Katz, RF and Wells, GN (2015) Torsion of a cylinder of partially molten rock with a spherical inclusion: Theory and simulation. Geochemistry, Geophysics, Geosystems, 17. pp. 143-161.

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© 2015. American Geophysical Union. All Rights Reserved. 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. Key Points: Evolution of partially molten rock under torsion is simulated in 3-D Melt-rich bands only form near inclusion at small bulk-to-shear-viscosity ratios Strain-rate dependence affects shape of pressure shadows near the inclusion.

Item Type: Article
Divisions: Div C > Applied Mechanics
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:40
Last Modified: 21 Jun 2018 02:39