9725672 Smyth This project will investigate the structures and elastic constants of H-bearing silicate minerals at high pressure in order to assess the possibility that the mantle of Earth may contain a reservoir of H2O as hydroxyl equivalent to many times the volume of the hydrosphere. PI will measure the compressibilities and determine the structures of several hydrous and nominally anhydrous silicate phases, including wadsleyite, majoritic garnet, ringwoodite, phengitic muscovite, chlorite and humites at pressure. These minerals are likely H-bearing constituents of subducting slabs, the upper mantle and/or the transition zone. The determination of their bulk moduli and structures at pressure may allow constraints to be place on the amount of H2O that can be transported to and reside in the minerals of the upper mantle and transition zone.
