9304159 Halliday This award provides 45 percent of the funds required for the development of a mass spectrometer system that will combine a laser ablation sampling source with plasma ionization and a multi- collector magnetic sector mass spectrometer. The system will be developed to optimize analytical performance with respect to microanalytical spatial resolution as well as trace element and isotope sensitivity for a wide range of geological samples. It will be housed and operated in the Department of Geological Sciences at the University of Michigan. The University of Michigan is committed to providing the remaining funds needed to carry out this instrument development project. The instrument will extend existing capabilities for trace element and isotopic analysis and will be applied to research including the dating of microscopic fluid inclusions by the rubidium-strontium radioactive decay method, lutetium-hafnium isotope geochemistry of small samples, transition element geochemistry of terrestrial and extraterrestrial materials, and precise geochronology to determine the production rates of silicic magma. ***