This award provides one-half the funding required to purchase a gas source mass spectrometer. The instrument will be installed and operated by Department of Geological Sciences at the University of Michigan. Research in progress and planned in the Department of Geological Sciences requires many thousands of stable isotope analyses of natural and synthetic materials per year. Emphasis has been, and will continue to be, placed on microsampling techniques including the use of laser ablation methods. Research projects for which the spectrometer is needed include: 1) the isotope geochemistry of alunite, a mineral found in association with precious metal deposits, 2) oxygen isotope fractionation during the bacterial synthesis of apatite, useful for studies in paleothermometry of the oceans, 3) a study of the stable isotope composition of clay minerals at the Cretaceous-Tertiary boundary (an enrichment factor in the heavy oxygen-18 isotope could point to a glassy precursor for the clay which, in turn, would be related to the major bolide impact that has been hypothesized as the cause of the mysterious mass extinctions of living forms that occurred at the time).//
