Dissolution and deposition in fractures

Fractures are relatively planar discontinuities in rocks induced by the huge internal stresses which are created by the slow but constant motions of the underground masses. Deposition and/or dissolution of a single solute in a single fracture is addressed in the limit where the geometrical changes are very slow compared with the average fluid velocity. The deposition or dissolution fluxes are calculated by means of an efficient finite-difference scheme. Examples of Gaussian and self-affine fractures which undergo dissolution and also successive cycles of deposition-dissolution are studied for four different values of the Peclet and the Peclet-Damkohler numbers. Some general trends are discussed. (C) 1997 Elsevier Science B.V.