This award provides partial funding for the acquisition of a mass spectrometer to be installed and operated in the Department of Geological Sciences at San Diego State University. The University is committed to providing the remaining funds needed. San Diego State University's Department of Geological Sciences has a strong training program for undergraduates and up to the master's level that includes practical work with advanced geochemical techniques. The Department also has made several recent appointments in isotope geochemistry (the PI and co-PI of this award), and the University has put considerable resources in establishing an Institute of Isotope Geochemistry. The research projects of the PI and co-PI are supported by NSF and other agencies and require the analytical capabilities of a modern mass spectrometer. The instrument will also be used in two laboratory courses open to undergraduate students (Isotope Geochemistry and Groundwater Geochemistry). This award is made under the auspices of the NSF program Research in Undergraduate Institutions.