This three-year award supports U.S.-France cooperative research in mantle geochemistry between Gordon Brown and Jonathan Stebbins of Stanford University and George Calas and Francis Taulelle of the University of Paris VI and VII respectively. They will study silicate liquids at high temperatures and pressures and trace elements in silicate minerals. Drs. Brown and Calas bring to this collaboration their innovative methods in synchrotron based X-ray absorption. This is complemented by Stebbins and Taulelle's work in high temperature and pressure NMR (Nuclear Magnetic Resonance) spectroscopy. The project will benefit from access to advanced facilities at Stanford and in Paris. The project will provide new information on the bonding of silicate liquids (melts) under simulated upper mantle conditions and the structural role of transition metals in silicate minerals. The results will advance our understanding of the structure- property relationships of these silicate liquids at high temperatures and pressures. Detailed knowledge of the structure-property relationships of these liquids and the melting phase, will be vital for understanding the dynamic processes, structure and compositional zoning within the Earth and other planets.
