R3: High-pressure science and deep Earth’s material

[R3-06] Hydrogen and aluminum depletion in bridgmanite coexisting with high-pressure hydrous phases and its geodynamical implications

*Eiji Ohtani¹, Takayuki Ishii² (1. Tohoku Univ. Sci., 2. Center for High Pressure Science and Technology Advanced Research)

Keywords:bridgmanite, hydrous phase δ, hydrous phase D, phase relation, lower mantle

We clarified the partitioning of aluminum and hydrogen between bridgmanite and hydrous minerals. We observed alumina depletion in bridgmanite under the wet conditions. Bridgmanite contains undetectable water, showing strong hydrogen partitioning into hydrous phases. Depletion of alumina in bridgmanite changes the phase relations in hydrated slabs, i.e., the pressures of the garnet-bridgmanite. The dry nature of bridgmanite coexisting with hydrous phases suggests that bridgmanite cannot be the water reservoir in the lower mantle.