The Origin and Evolution of Mantle Plumes

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9418398 White This is an analytical program that will produce a comprehensive data set on a number of key mantle plumes. This set will include radiogenic isotope ratios (Sr, Nd, and Pb), trace elements (Rb, Cs, Sr, Ba, rare earths, Y, Zr, Nb, Hf, Ta, U, Th, Pb, all the first transition metals, and possibly Li, Be, As, Mo, Tl, Sn, Sb, and W), stable isotope ratios of oxygen and boron, and major elements. The effort will focus on samples that have already been analyzed for a number of elements and isotopes; it is thus more an effort at complexing existing data sets rather than producing new ones. The analytical effort will be complimented by harvesting existing data from the literature, filtering it for quality, and creation of a n extensive geochemical database on oceanic island and island arc volcanics. From the resulting data set, an attempt will be made to answer the following questions: (1) What are the trace element and stable isotope characteristics of the 3 principal mantle plume classes? (2) What is the relative contribution of various sources in the geochemical evolution of mantle plume reservoirs? (3) What are the time scales upon which lithospheric recycling occurs? (4) In what proportions are the above materials present in plumes? (5) Can the existence of a common component in all plumes be verified?