Constraints were placed on the density of kimberlitic melts containing varying amounts of CO2 using high pressure sink/float experiments. The melt composition used was carefully selected and was prepared free of H2O and minor elements in order to focus on the effect of CO2. Experiments were run in graphite capsules over a pressure range of 4-10 GPa in a multi-anvil apparatus using Fo100 and Fo90 spheres as density markers. The compositions used contained 0, 3, 6, and 12 wt% CO2 and were derived from mixing the 0 and 12 wt% CO2 compositions together. Run products were analyzed with FTIR to confirm the presence of carbonate and lack of water and with EPMA to verify the composition. Carbon was quantified using the by difference method, but plans are in place to develop a method to quantify this element by EPMA. The density data places constraints on the location of the melt compression curves, and shows the melts to be eruptible from pressures below 9 GPa (10 GPa for the 6 wt% CO2 composition) on Earth. This data is also applicable to Venus, and all compositions are eruptible from up to 9 GPa according to current Venus mantle density models.
Earth and Planetary Sciences
Level of Degree
Department of Earth and Planetary Sciences
Agee, Carl B.
First Committee Member (Chair)
McCubbin, Francis M.
Second Committee Member
Fischer, Tobias P.
CO2, melt density, kimberlite, experimental petrology
Santos, Alison R.. "The effect of carbon dioxide on the density and compressibility of kimberlitic magma." (2012). https://digitalrepository.unm.edu/eps_etds/78