Geophysical and geochemical observations provide insights into the physical and chemical states of the Earth's interior. However, only by comparing mineral physics data (physical properties) with geophysical (seismological) observations can we disentangle the thermal state of the deep Earth from its chemistry. Conventionally, as a first order approximation, the Earth's mantle is thought to be composed of a homogenous pyrolite. However, the distinct trace element signatures in mid ocean ridge and ocean island basalts reveal the heterogeneity in the Earth's mantle. Although the scale of the heterogeneity is unknown, it is likely that large regions of the mantle are composed of a depleted harzburgite and enriched crustal fractions. We have limited knowledge of the thermodynamics and physical properties of mineral phases in these subducted crusts at high pressures.
In this proposal, the PI intends to use first principles calculations to investigate how chemistry influences crystal structure, energetics, and elasticity of aluminous mineral phases which are likely to be stabilized in deeply subducted oceanic and continental crusts. He will also investigate the energetics of hydrogen incorporation within these aluminous phases. The results will be relevant for geophysics, mineral-physics, geodynamics, petrology, and geochemistry sub disciplines. The PI will also train undergraduate student/s in Solid Earth Geosciences/Mineral Physics.
