CSEDI Collaborative Research: A Coupled Geodynamic-Geochemical Study of the Hawaiian Plume

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EAR-0002629Donald J. Depaolo This CSEDI proposal will focus on developing a coupled geodynamic-geochemical model of the Hawaiian plume that will allow the investigators to address questions relating to the spatial and temporal variations in magma compositions. Chemical data available from studies in the Hawaiian island chain and from the Hawaiian Scientific Drilling Project (HSDP) drill core will provide constraints for this modeling. The project will focus on answering the question: ``Can the petrological, geochemical, and isotopic characteristics observed among the Hawaiian volcanoes be explained in terms of plume derived melts from a self-consistent geodynamic-geochemical model?''. In particular, the investigators will determine whether the compositional changes in magmas erupted along the island chain are consistent with our understanding of plume dynamics and mantle melting. During the one-year time frame of this proposal, the goals will be to couple the recently developed 3-D variable viscosity plume model of Ribe and Christensen (1999) with calculations of trace-element chemistry and uranium series disequilibria. They will also develop a new major-element parameterization specifically designed to address melting in the Hawaiian plume. The development of this model will be an ongoing project; the algorithm will be designed to be updated as new experimental data become available. By iteratively refining the plume model and calculations of magma chemistry, and by comparing the model computations to the observed magma compositions and eruption rates, this research will further our understanding of the dynamics of the mantle plume and determine the melting conditions in the mantle beneath the Hawaiian island chain.