This project represents a continuation of research previously supported by NSF grant EAR85-18138 concerning high-pressure experimental studies of the melting behavior and structure of quenched melts of Earth materials. Pressure-temperature conditions up to 300 kilobars and 6000 K are achieved by focussed laser heating of samples in a diamond-anvil high pressure cell. Sample temperatures are determined by continuous-spectrum analysis of thermal emissivity; pressure is determined by the ruby-fluorescence technique. Specific objectives of the project include completion of the determination of the melting curve of carbon at high pressure and initiation of melting studies of (mg,Fe)O and (Mg,Fe)SiO3 (perovskite). The results of these studies will provide important information on the behavior of quenched melts of Earth materials.
