High-Pressure Synthesis, Synchrotron Single-Crystal XRD and Raman Spectroscopy of Synthetic K–Ba Minerals of Magnetoplumbite, Crichtonite and Hollandite Group Indicatory of Mantle Metasomatism

The paper summarizes the results of an experimental study of the formation of K–Ba high-Ti (and Cr) oxides synthesized in the chromite–rutile/ilmenite–K2CO3/BaCO3–H2O–CO2 systems at 1.8–5.0 GPa. Experiments confirm the conclusion that the formation of K–Ba high-Ti oxides characterizes the most advanced or repeated metasomatic stages in upper mantle peridotites, which lead first to the formation of simple Ti oxides and then to the formation of K–Ba high-Ti and Cr oxides. Relations between the oxides is a function of the activity of the K and Ba components in the fluid. The appearance of prideri... Mehr ...