This award provides 42% of the funds needed to acquire a gas source stable isotope ratio mass spectrometer to be installed and operated in the Department of Geology at Washington State University. The University is committed to providing the remaining funds necessary for this acquisition. The instrument will be suitable for measuring the ratios of carbon and oxygen isotopes in carbon dioxide samples prepared from carbonate, silicate and oxide minerals, as well as the deuterium to hydrogen ratios in hydrogen gas samples prepared from water or mineral samples. It will be used primarily in studies of the role of fluid-rock interactions and fluid evolution in the production of vein deposits of economic value. The instrument will be made available for use by faculty and graduate students at Washington State University, The University of Idaho, and other regional research groups.