Solution transport processes-- including pressure solution and crack healing--are important ways in which rocks may deform and change pore structure and connectivity. However, despite clear field evidence that solution-transfer deformation is widespread in the earth, major uncertainties remain in specifying the driving forces, the models, and the appropriate material constants. A detailed study will be made of the mechanisms and kinetics of pressure solution and crack healing under load in simple aqueous/quartz and brine/halite environments. Densification experiments on porous quartz aggregates will be continued. The evolution of grain size will be measured during the experiments. Permeability reduction experiments will be conducted on pre-cracked samples of Sioux quartzite. Finally, the permeability of a suite of rocks containing stylolites will be measured to begin an investigation of the correlation of permeability with localization of deformation. This work should significantly enhance our understanding of how permeability changes in the earth's crust.
