In my research I use techniques of high pressure experimentation at pressures up to 25 GPa and temperatures up to 2000°C (piston-cylinder and multi-anvil apparatuses), coupled with synchrotron spectroscopy and quantitative microbeam analysis of experimental run products and natural samples, to investigate processes in the deep mantle and crust. Current major research interests include: the formation and evolution of carbonatites and their associated igneous and metasomatic rocks the fomation of critical metals deposits, including rare earth elements (REE) and niobium in carbonatites or tantalum in cassiterite associated with granitoid rocks the roles of volatiles components in the deep mantle in partial melting, leading to formation of large igneous provinces and other volcanism the petrology and geochemistry of the mantle lithosphere, including cratonic mantle lithosphere experimental calibration of diamond indicator minerals as geothermobarometers and oxybarometers for use in exploration for, and assessment of, the diamond potential of kimberlites the earth's deep carbon cycle including the fate of deeply subducted carbonate-bearing oceanic crust