Boundary Nature of the DUPAL Anomaly in the South Atlantic

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The boundary between two major geochemical provinces in the earth's mantle lies in the South Atantic. The province centered over the Indian Ocean is referred as the DUPAL anomaly. This anomaly may be the result of contamination of the asthemosphere either by delamination of sub-continental lithosphere during the breakup and scatter of Gondwanaland or from the dispersal of mantle plumes of deeper origin within the Earth. This project will undertake a Nd-Sr-Pb isotope and trace element study of asalts from the South Atlantic seafloor to define in time and space the isotopic and geochemical nature of the DUPAL province in the South Atlantic. The principal investigator will further analyze his collection of South Atlantic basalts to obtain: Nd isotopic ratios on the same glass samples on which Pb,Sr, and He isotope data are already available, parent/daughter concentration ratios on the same glass samples, and Nd-Sr-Pb systematics on older basalts in order to document temporal mantle variations.