The carbon dioxide solubility in alkali basalts: an experimental study

Experiments were conducted to determine CO2 solubilities in alkali basalts from Vesuvius, Etna and Stromboli. The basaltic melts were equilibrated with nearly pure CO2 at 1200°C under oxidizing conditions, and at pressures ranging from 269 to 2060 bars. CO2 solubility was determined by FTIR measurements. The results show that alkalis have a strong effect on the CO2 solubility and confirm and refine the relationship between the compositional parameter Π devised by Dixon (1997) and the CO2 solubility. A general thermodynamic model for CO2 solubility in basaltic melts is defined for pressures up to 2 kbars. The new CO2 solubility model yields saturation pressures lower by as much as 50% relative to existing models when applied to volatile-rich alkali basalts.