The partial molar volume of carbon dioxide in peridotite partial melt at high pressure

The partial molar volume of CO2 (V¯CO2) in silicate melt was determined for a komatiite composition using high pressure sink/float experiments in a multi-anvil press. The density of the experimental melt at pressure was determined by observing sinking and floating of pure forsterite (Fo100) and forsterite (Fo90) buoyancy markers. Values for V¯CO2 were bracketed at 4.3 GPa (23.71 cm3/mol) and at 5.5 GPa (22.06 cm3/mol), normalized to 2123 K. Combining the current data with previous work we now more accurately constrain the compression curve of V¯CO2 over the pressure range of 1.0 × 10− 4 to 20 GPa. These data allow the calculation of density at pressure of carbonated silicate melts, such as kimberlite and silica undersaturated alkali basalts, and the determination of their buoyancy and eruptibility.

► We determined the partial molar volume of CO2 in peridotite partial melt. ► Values were bracketed at 4.3 GPa (23.71 cm3/mol) and 5.5 GPa (22.06 cm3/mol), at 2123 K. ► Data were combined with previous work to constrain the V¯CO2 compression curve to 20 GPa. ► With these data density of carbonated silicate melts can be calculated at pressure.