9726264 Ripley This grant provides partial support to Indiana University for the costs of acquiring a stable isotope ratio mass spectrometer (SIRMS) with peripheral sample introduction and gas handling devices. The SIRMS will be dedicated to sulfur isotopic analyses, replacing the 19-yr. old Nuclide mass spectrometer currently operated at Indiana University. This new facility will be shared by researchers from Indiana-Bloomington, the University of Illinois at Champaign-Urbana and the University of Missouri- Columbia. State-of-the-art SIRMS allow analyses of much smaller gas samples (< 1 micromole) than currently possible on the Nuclide, thus greatly expanding the analytical possibilities for this regional group. This facility will provide data for a wide range of studies in economic geology, paleoceanography, biogeochemistry and sulfur isotope systematics. Specific studies will include sulfur isotopic investigations of the genesis of hydrothermal ore bodies within the Midcontinent Rift system, species specific sulfur isotopic analyses of organic compounds as proxies of diagenetic processes in anoxic marine sediments, characterization of the biogeochemical pathways of sulfur in Chesapeake Bay sediment pore-water systems, paleoenvironmental studies of pyrite formation in anoxic Black Sea sediments, and experimental studies of sulfur isotope fractionation in sulfosalt systems. ***
