Partial melting in the Earth’s mantle is the only recognizable process that has generated continents, shallow-and-deep ocean floors, atmosphere, and hydrosphere. Voluminous basaltic magmas erupt at mid-oceanic ridges (mid-ocean ridge basalts, MORB) as a consequence of mantle upwelling beneath spreading plates. Volumetrically less significant are magmatic eruptions at oceanic 'hot-spot' locations such as Hawaii and Iceland (ocean-island basalts, OIB). Because of geochemistry, MORB and OIB carry important information about the chemical and physical properties/dynamics of the mantle. The basis of this proposal is to experimentally determine high pressure-temperature melting phase relations along two critical regions of the melting curve, plagioclase-spinel lherzolite and spinel-garnet lherzolite transitions. Such phase diagrams, which are essential for our understanding of how melting occurs inside our planet, are currently absent. A piston-cylinder press will be used for the experiments at 0.7-1.4 GPa and 2.3-3.0 GPa. An electron microprobe will be used to analyse composition of experimental run products. Completion of the project will provide a unique opportunity to place solid constraints on very important issues about magma generation in the upper mantle. Proposed work will for the first time make a serious attempt toward putting fundamental constraints on the very important issue of temperatures in the Earth’s mantle. Hence, such data will tell us how hot the upper mantle is, which has further significant consequences toward mantle convection and mantle dynamics. The applicant has excellent background in experimental and theoretical petrology. The present CIG proposal is a perfect launching pad for young scientists like me who want to make Europe their base of scientific work. Further, CIG is a very good program since it is open to nationals of countries outside Europe, but who have a foothold here, and bring-in their own expertise to European Science.