Water Within The Earth

Water defines the entire biology and geology of Earth. The cycling of H2O at and near the surface, from the atmosphere, hydrosphere and biosphere, down to the crust and mantle governs the Earth's geodynamical and geochemical evolution. However, the distribution and amount of H2O in the mantle remains uncertain. In particular, water, or hydrogen, may be stored in solid minerals in the mantle, acting as a reservoir. Here we present spectroscopic data that we obtained by making Raman measurements up to 10 GPa using a diamond-anvil cell on a sample of silica glass (SiO2). This glass has very little hydrogen with approximately less than 10 parts per billion OH content. These data are compared to hydrated silica to understand the effect of water on the physical properties of silica, an important and abundant building block of the Earth.