9527009 Barton This collaborative project (NSF and industry) will yield a novel comparison of igneous-related mineralization across regions of contrasting characteristics. It provides an integrated approach to sorting our some of the major controls on igneous-related metallogenesis. These studies build on earlier NSF-sponsored research by the PIs. Industry funding/collaboration is in place for student and field support; NSF funds will be used primarily for geochemical, petrological, and geochronometric studies. Comparative studies will be conducted in three regions which have contrasting crustal compositions, igneous and tectonic histories, and metallogenic characteristics. These contrasts, when considered together, will provide tests of hypotheses that can not be evaluated in any local area. Overall, the PIs will develop the following topics: (1) characteristics of key districts, (2) magmatic compositional controls on mineralization, (3) crustal-scale controls on magmatism and metallogeny, and (4) secular variations reflecting preservation, exposure, and contrasting petrogenetic regimes. The goal of the coupled geochemical and field studies is to better understand the geology, geochemistry, and timing of representative magmatic-hydrothermal centers.