Ore Metals in Magmatic Systems

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"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Intellectual Merit: The proposed research is designed to fill critical gaps in our knowledge concerning the magmatic partitioning of selected elements among sulfides, Fe-(Cu)-S-O melts, and selected oxides and silicates. These elements fall into two important groups found in magmatic-hydrothermal ore deposits: the Mo-W group, and the Cu-Ag-Au group. This project builds on previous work on the experimental determination of the mineral/melt partition coefficients of many ore and related elements in felsic melt - vapor - brine - oxide - pyrrhotite systems by studying the partitioning of Mo, W, Ag and Au among melts, sulfides, oxides, and silicate minerals under well specified, low-variance conditions. In detail, this work involves: [1] Comprehensive evaluation of the effects of sulfur and oxygen fugacity on ore metal partitioning among magmatic phases; [2] LA-ICP-MS analysis of selected elements (many of which were difficult to study in the past); and [3] Expand the range of mineral/melt pairs to be investigated to include rock-forming silicates. New and previously collected partitioning data will be used to quantitatively evaluate competing hypotheses regarding magmatic processes that contribute to ore metal diversity in magmatic-hydrothermal deposits. Important parameters needed for such models are estimates of the proportion of metals lost to crystallization before magmas reach shallow crustal depths.Broader Impacts: Beyond the collection of important data on ore metal partitioning, and the fundamentals of their redistribution in the crust, these data will also serve as a basis for the construction of exploration models for porphyry deposits. The research group has an excellent track record of involving a mix of high school, undergraduate, masters and doctoral students in active research. All graduate students are involved in undergraduate teaching. Additionally, faculty and students participate in, and highlight their research in Maryland Day (held in April each year); the campus attracts an average of some 70,000 visitors for this event. Furthermore, the PIs actively participate in outreach in a variety of formats (science lectures in a retirement community and a church group; Partners in Education Program (PEP) sponsored by GSA; training for the Ranger Interpreter Program in Yosemite National Park for the National Park Service; visits to local Maryland elementary schools as part of the earth science curriculum; and lectures to local gem and lapidary societies).