9304791 Getting The PIs will study the mechanisms and kinetic laws of the olivine-spinel transformation of the composition fayalite Fe2SiO4. This experimental program will exploit the unique capabilities of a gas piston-cylinder apparatus at the University of Colorado. This device offers extremely well known hydrostatic pressure in a range previously inaccessible. Differentia stresses can also be well characterized. The goal is to improve understanding of the processes of phase change in ferromagnesian minerals in subducting slabs and to develop greater insight into the physics of transformational faulting.