Effects of Fluids and Chemical Environment
One major interest has been the effects of fluids, including both melt as well as water, on deformation. Earlier studies demonstrated the strong effect of confining pressure on hydrolytic weakening in quartz and feldspar, and recent buffered deformation experiments have identified the important variable as the water fugacity. Other recent experiments demonstrated stressinduced 'wetting' of finegrained feldspar aggregates, with a consequent switch in deformation mechanism from dislocation to diffusion creep. Recent experiments using a molten salt assembly demonstrate that water does not have an independent effect on the recrystallized grain size piezometer.
Tullis, J., Shelton, G.L., and Yund, R.A., 1979, Pressure dependence of rock strength: Implications for hydrolytic weakening: Bull. Mineral., 102, 110-114.
Tullis, J., and Yund, R.A., 1980, Hydrolytic weakening of experimentally deformed Westerly granite and Hale albite rock: J. Struc. Geol, 2, 439-451.
Kronenberg, A.K. and Tullis, J., 1984, Flow strengths of quartz aggregates: grain size and pressure effects due to hydrolytic weakening: J. Geophys. Res., 89, 42814297.
Tullis, J. and Yund, R.A., 1989, Hydrolytic weakening of quartz aggregates: The effects of water and pressure on recovery: Geophys. Res. Let., 16, 13431346.
Tullis, J., Yund, R.A. and Farver, J., 1996, Deformationenhanced fluid distribution in feldspar aggregates and implications for ductile shear zones. Geology, 24, 63-66.
Post, A., Tullis, J., and Yund, R.A., 1996, Effect of chemical environment on dislocation creep of quartzite. J. Geophys. Res.,101, 22,143-22,155.
Post, A.D. and Tullis, J., 1998, The rate of water penetration in experimentally deformed quartzite: implications for hydrolytic weakening. Tectonophysics, 295, 117138.
Stipp, M. and Tullis, J., 2006. The recrystallized grain size piezometer for quartz: effect of water, temperature and different recrystallization mechanisms. J. Geophys. Res., 111, B04201.
Chernak, L., Hirth, G., Silverstone, J., and Tullis, J., In Press, The effect of aqueous and carbonic fluids on the dislocation creep strength of quartz. J. Geophys. Res.
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