9316283 DePaolo The proposed research will develop and test a new approach to using isotopic variations in metamorphic rocks to measure bulk cation diffusivities, rates of metamorphic reactions, and durations of metamorphic conditions. The objective is to apply petrological and isotopic tools concurrently and complementarily. The research comprises two parts: (1) developing numerical codes to simulate one-dimensional isotopic redistribution in layered metamorphic rocks; the codes are used for generic experiments of isotope behavior, and for modelling in specific field situations, and (2) applying the exchange model to upper amphibolite facies, garnetiferous gneisses of the Tehachapi Mountains, southern California.
