9633498 Jacobsen Title: Abundances of W and Mo in MORBs: characterization of the depleted mantle reservoir. The composition of the Earth's mantle is the consequence of core formation, of mantle melting and liquid magma eruption, and of subduction and recycling of crust back into the mantle. The low abundance of some elements in the mantle is explained by their high solubility in the core. Some elements prefer silicate minerals and therefore are found in the mantle. Some elements do not prefer metal or minerals and are therefore concentrated in liquid magmas. The metals tungsten (W) and molybdenum (Mo) behave like metal- lovers and like liquid-lovers so their concentration in the lavas may tell much about the timing of the formation or the core. These metals are in such low abundance, however, that few quality analyses exist. This project will measure W and Mo in ocean floor basalt to understand the segregation of the Earth's core, mantle, and crust.
