Under this award, the PIs will continue an experimental study investigating the physical properties of partially molten peridotite under drained and undrained conditions. The goals of this work are to constrain the relation between deformation and melt migration in partially molten mafic rocks and to understand the physical mechanisms of the migration of melt in those rocks under varying conditions of temperature, stress, lithostatic pressure, magma pressure, strain rate and time. Initial experiments by the PIs indicate that the solid matrix and melt form a system whose mechanical properties strongly depend on the drainage conditions and external loading, and a rich variety of mechanical behavior is possible. A combination of experimental techniques will be used, including extraction of melt during isostatic loading, conventional triaxial mechanical experiments under drained and undrained conditions, and permeability measurements using the pulse decay and oscillating pore pressure techniques. The experiments will have two solid phases: pyroxene and olivine and melt contents down to <5%. Observations will be made with optical microscopes, SEM, and TEM. The study entailes graduate student involvement, and the results will be widely applicable in many sub fields of geoscience.
