Argon behavior in basaltic melts in presence of a mixed H2O-CO2 fluid at upper mantle conditions

The behavior of argon in H2O-CO2 bearing basaltic melts was experimentally investigated in the pressure range 1-5 GPa and at temperatures between 1350 and 1600 °C. Our experimental data simulate the partitioning of argon between an Ar-H2O-CO2 bearing fluid and a silicate melt occurring during magma ascent and degassing. The experimental results show several features: