Growth, Dissolution and Pattern Formation in Geosystems

Growth and dissolution processes are of fundamental importance in any geological system, and they occur both near and far away from thermodynamic equilibrium. Familiar examples include the relatively slow growth of faceted mineral crystals, the much more rapid growth of dendritic snow crystals, and the formation of irregular and even spongy mineral grains during weathering near the earth’s surface. Growth and dissolution kinetics are controlled by processes taking place at atomic and molecular scales. However, these processes may affect the patterns that form on a much larger scale in geosysterns through the coupling with transport and/or deformation processes (Barber and Meredith, 1990; Lichtner et al., 1996). Numerous well known patterns that arise through nonlinear couplings between these processes include complex intracrystalline mineral zonation, banded or spotted rocks or polycrystalline aggregates, symplectites and other mineral intergrowths, stylolites and pressure solution seams and reaction front instabilities. These patterns represent the fingerprints of irreversible processes that may leave behind considerable information and memory about important geological processes that took place in the past.