Constraints on Primordial Noble Gas Reservoir Deep in the Earth by High-Pressure and High-Temperature Experiments

Noble gas isotopes have been a strong argument for the presence of primordial reservoir in the mantle, which has been isolated from the mantle convection throughout the Earth's history. However, recent understanding of mantle dynamics has revealed difficulty with the isolation within the mantle. Alternatively the core is a promising candidate, validity of which depends on partition coefficient of noble gases between liquid iron-rich metal and silicate melt at condition of core segregation in the magma ocean. A few experiments showed that the core could hold primordial noble gases though there are several uncertainties possibly due to extreme noble gas concentrations. For a better understanding of the primordial noble gas reservoir, we are conducting new experiments to determine noble gas partition coefficients between molten metal and silicate.