Channelizing Melt during Deformation of Partially Molten Rocks with Application to Mid-Ocean Ridges

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Under this award, the PI will investigate the physical mechanisms and geophysical implications of melt channelization that occurs during deformation of partially molten rocks. With experimental investigations of deformation-driven melt channelization, the boundary and thermodynamic conditions can be rigorously controlled and systematically varied, to study (i) the mechanism by which deformation drives melt segregation, (ii) the time and length scales appropriate for melt segregation to occur in nature, and (iii) the effects of deformation-driven melt segregation on viscosity, permeability and seismic structures. High-strain simple shear and torsional shear experiments will be carried out on samples of specific grain sizes, melt fractions, and melt compositions at controlled stresses and temperatures. Both the mechanical and the microstructural state of the samples will be quantified and correlated as they evolve with increasing strain and as functions of shear stress and compaction length. The rheological and microstructural, states will be quantified using a variety of proven techniques.