9418090 Veblen The proposed work will involve applications of transmission electron microscopy and ancillary techniques to problems important in the fields of petrology, geochemistry, geophysics, and environmental mineralogy. The underlying thread of the research is to understand the crystal chemistry of minerals and their reactions at the sub- nanometer scale. Topics to be explored include: in situ variable-temperature studies of the C2/c - P21/c phase transition in monoclinic pyroxene, the structural state of excess Ca in monoclinic pyroxenes, mixed layer illite- smectite and defect structures of mixed layer chlorites- serpentines, structural and chemical changes in thermally heated asbestos, time series studies of tremolite and other amphiboles during synthesis, quench products from high pressure DAC experiments of high-pressure peridotite, and mosaic-equilibrium domain size of layer silicates as a function of prograde, low temperature metamorphism.
