New experimental data and semi-empirical parameterization of H2O–CO2 solubility in mafic melts

摘要: Abstract We present here new experimental data on H 2 O–CO solubility in mafic melts with variable chemical compositions (alkali basalt, lamproite and kamafugite) that extend the existing database. show potassium calcium-rich can dissolve ∼1 wt% CO at 3500 bar (350 MPa) 1200 °C, whereas conventional models predict solubilities of 0.2–0.5 wt%, under similar P – T conditions. These data, together those literature, stress fundamental control melt composition solubility. a semi-empirical model for melts, which employs simplified concepts gas–melt thermodynamics coupled parameterization both structure silicate melt. The is calibrated selected database consisting 289 experiments 44 different compositions. Statistical analyses indicate that, therefore plays role strongly depends amount non-bridging oxygen per (NBO/O) melt, but nature cation bonded to NBO also critical. Alkalis (Na + K) result strong enhancement solubility, Ca has more moderate effect. Mg Fe have weakest effect Finally, we modelled water concluded O dissolution enhances most likely by triggering formation. In contrast agreement earlier findings, negligibly affected structure: it only shows weak correlation NBO/O.