The PI will continue quantitative deformation experiments on carefully chosen structural analogues of deep mantle phases and to perform parallel qualitative deformation experiments on silicates of mantle composition. The analogue experiments will be performed in Griggs-type apparatus at relatively low pressures. The mantle silicate experiments will be performed at pressures of 14-25 GPa in a multianvil apparatus. Comparison of the deformation mechanisms activated in the silicates with those activated in the analogues will provide constraints on the reliability of extrapolation to mantle conditions of measurements made on the analogues.
