We propose to continue on several lines of research in which the laboratory is currently active, as follows: (1) Experimental determinations of oxygen isotope equilibrium constants using silicate-carbonate exchange techniques. (2) Oxygen isotope studies of eclogites. (3) Isotopic studies of Brazilian carbonatites. (4) origin of crustal rocks as seen in the Kohistan batholith. (5) Isotopic and trace- element studies of a natural analog of a nuclear waste repository. (6) Oxygen and silicon isotope variations in primitive and differentiated meteorites; trace-element studies in primitive achondrites. (7) Laboratory measurement of the kinetics of oxygen isotope exchange between gases and molten silicates for application to the origin of chondrules. (8) Investigation of H2O and CO2 in SNC meteorites for their relevance to planetary surface processes.