9305187 Mackwell Only from an understanding of the way in which hydrous species partition at upper mantle conditions will it be possible to interpret mechanical property measurements. This program will include static experiments on aggregates of mantle minerals under high pressure and temperature conditions, infrared measurements to characterize the partitioning of water-derived species between the phases, and Mossbauer spectroscopy measurements to monitor changes in the iron valence during uptake of water. This last technique is particularly important in that it may allow us to use iron ionic ratios and infrared spectroscopy on minerals exposed at the Earth's surface to infer water contents and water partitioning at depth. Finally, the inferred effects of this partitioning behavior will be investigated by performing deformation experiments on multiphase aggregates under wet conditions. ***
