My area of research is experimental petrology, aimed at experimentally simulating conditions within the Earth in order to understand fundamental petrological and geochemical processes. One aspect of this has been the development of quantitative models to predict trace element partitioning between crystals and melts during igneous processes. This research uses high pressure-high temperature experiments in conjunction with microanalysis of mineral and melt phases and theory based on the elastic properties of the minerals.
A second major interest is the conditions under which the Earth and other terrestrial planets formed and differentiated into silicate crusts, silicate mantles and iron-rich metallic cores. This uses high pressure, high temperature experiments coupled to thermodynamic calculations and isotopic measurements of meteoritic and planetary materials. The experiments generate, for example, a small sample (10 mgm) in which a ball of metal has segregated from a metal-silicate mixture. We chemically analyse the different parts of sample in order to determine the partitioning of specific elements between metal and silicate under the physical conditions of interest. In this way we determine the extent to which elements enter the metal (siderophile character) or the silicate (lithophile). The experimental partitioning is then compared with that observed on the Earth (between core and mantle) in order to understand the core formation process.
Recently we have been studying the behaviour of moderately volatile elements (such as Pb, Bi, Sb) during planetary formation using a specially designed high temperature furnace in which the molten silicate is stirred at 1300 degrees. A final related arm of our research is to determine the behaviour of important volatile components in silicate melts. Current research centres on the halogens and sulphur.
