Hydrogen in Lower Mantle Minerals

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Liquid water is essential to life, and the search for habitable planets within our solar system and elsewhere in the galaxy has come down to a search for planets on which liquid water can exist. Earth is a water planet, but how the Earth acquired its water is a subject of extensive debate, measurement, experiment, and theoretical calculation. We do not even have a solid constraint on how much water the Earth has, because the components of water, atoms of hydrogen and oxygen, are incorporated into the solid silicate minerals of the interior, and this water can be exchanged with the surface reservoir over the long stretch of geologic time. This is an experimental research project to measure the solubility of hydrogen in the solid, oxygen-based silicate minerals of the deep interior of the Earth in order to place some constraint on how much hydrogen the planet can harbor in this region which constitutes more than half the mass of the planet. This is a project to synthesize and characterize hydrous magnesium silicate and oxide phases thought to be stable in the lower transition zone and lower mantle at depths of 600 to 2900 km. The work is to be conducted in collaboration with scientists principally in Germany, but also in other EU countries and Japan. Synthesized high pressure minerals will be analyzed for crystal structure, chemical composition and hydrogen content. Measurements of elasticity will be made in order to constrain the effect of hydration on seismic velocity. The data obtained should permit a greater understanding of the crucial role of hydrogen in mantle dynamics and further constrain the amounts of hydrogen that may be stored in planetary interiors.