STABILITY ANALYSIS OF A PRESSURE-SOLUTION SURFACE

We present a linear stability analysis of a dissolution surface subjec ted to non-hydrostatic stress. A sinusoidal perturbation is imposed on an initially flat solid/fluid interface, and the consequent changes i n elastic strain energy and surface energy are calculated. Our results demonstrate that if the far-field lateral stresses are either greater , or much smaller than the fluid pressure, the perturbed configuration has a lower strain energy than the initial one. For wavelengths great er than a critical wavelength this energy decrease may be large enough to offset the increased surface energy. Under these conditions, the p erturbation grows unstably. If these conditions are not met, the surfa ce becomes flat. The growth rate and wavelength of the maximally unsta ble mode depend on the mechanism of matter transport. We conclude that the instability discussed in this paper may account for the formation of stylolites and other pressure-resolution phenomena, such as roughe ning of grain contacts.