Structure of the Hawaiian Mantle Plume: Geochemical-Isotopic Mapping Using Post-Shield Lavas

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The geochemistry of Hawaiian lavas provides clues about the nature of the deep mantle. This project will use geochemical measurements on post-shield, and late-shield lavas of the islands of Hawaii and Maui, along with both selected offshore samples and samples of core from the shield of Kilauea volcano, to complete a geochemical-isotopic "map" of the magma-producing region of the Hawaiian mantle plume. The data will be integrated with fluid dynamical models of the flow, temperature structure and melting in the plume to evaluate the properties of the lower mantle plume source, and the nature of plume flow beneath the lithosphere. The primary geochemical characterization will be for the isotope ratios of Sr, Nd, Hf, Os, Pb, O, and He. Intellectual merit: The proposed research will contribute to our understanding of fundamental aspects of planetary processes and volcanology, and will combine geochemistry, petrology, and fluid dynamics. The U-Th-He method will be evaluated for application to volcanic rocks for the first time. The PI has 28 years of experience in isotope geochemical research, has an extensive publication record, trained more than twenty Ph.D. students who have gone on to successful careers in academia, government, and private industry, and has experience with research on Hawaiian isotope geochemistry and dynamics. Broader Impacts: The results will have broad impacts for geophysics, planetary science, and the origin and behavior of volcanoes. The multidisciplinary aspects of the project provide a rich venue for advanced earth science education and technical training. The funding will help support a research facility that, in the previous 15 years has benefited 22 graduate students (9 women) 8 postdoctoral fellows (4 women), plus more than 20 visitors, undergraduates and collaborators.