Experimental study of the basalt–carbonate–H2O system at 4 GPa and 1100–1300°C: Origin of carbonatitic and high-K silicate magmas

Abstract

Generation of K-silicate and carbonatite melts by melting of carbonated eclogite has been studied experimentally under hydrous and dry conditions at 4 GPa and 1100–1300°C. At 1100°C, K-silicate melt appears first in equilibrium with Grt, Cpx, and Cb in the H2O-bearing system. At 1200–1250°C, the K-silicate melt coexists with a carbonatite melt and Cpx ± Grt ± Cb assemblage. A complete miscibility between the K-silicate and carbonatite melts with formation of supercritical silicate–carbonate fluid melt is observed at 1300°C.