Experimental model for alkalic chloride-rich liquids in the upper mantle

In order to expand an applicability of a model for evolution of the alkalic chloride-rich liquids in the upper mantle additional runs in chloride-carbonate-silicate systems involving model silicate end-members were performed at 5 GPa. Results of experiments can be evaluated using the single scheme of phase relations. They show that interaction of the chloride-carbonate liquids with silicates produces a wide range of the chloride-rich carbonate-silicate melts, whose composition is determined by the chloride/carbonate ratio in the chloride-carbonate liquid and composition of the interacting silicate assemblage. The carbonate-silicate melts are immiscible with Si-Al-saturated chloride-carbonate melts. With decreasing temperature, evolution of both melts proceeds toward the homogeneous chloride-carbonate or carbonatitic liquid coexisting with silicates. Trends for melt evolution in the model systems closely reproduce the evolution of the carbonate-silicate and saline inclusions in kimberlitic diamonds. These trends suggest a diamond growth during cooling. In addition, experiments showed stronger effect of interaction of eclogite-related phases with the alkalic chloride-carbonate melts, in contrast to peridotite-related phases.