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

The partial molar volume of CO2 ( V ¯ C O 2 ) 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 ¯ C O 2 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 ¯ C O 2 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.