This award provides half of the funding necessary to acquire equipment that will be part of a laser-assisted extraction system to be constructed by the PI at the University of Chicago. The university is committed to provide the additional funds required to make this acquisition possible. A total of one-month's summer salary for the PI is also provided for in this award. The system that will be constructed will be used to analyze oxygen isotopes in silicate and oxide minerals. Oxygen isotope data are important in reconstructing the thermal history of rocks formed in diverse geologic environments. After the equipment is on line the PI will evaluate systematically the reactivity of selected terrestrial and meteoritic minerals, compare the results of conventional and laser heating methods, compare the results of in situ laser ablation and micro-drilling, and study fluorination reaction mechanisms. After the systematic evaluation described above, this system will be applied in oxygen isotope studies of minerals where it is especially critical to determine chemical changes over very small distances.