Title: (soundbite only) Dynamics of chemical deterioration near the surface of rocks

Author (Talk): Daniel Reeves, MIT

Abstract:

When rocks are exposed to ambient fluids, such as groundwater, they develop a deteriorated layer near the rock surface. The formation of this so called “weathering rind” is a consequence of dissolution and precipitation of minerals within the rock occurring at the mineral-fluid interface within the pores. The speed at which the developed rind advances is controlled by both the kinetic reaction rates and the transport of ions away from the pore spaces into the outside fluid. We have developed conditional relationships to determine which process is limiting in a given system, and how those limitations evolve over time. Furthermore, we have explored how the weathering rate in diffusion limited systems depends on the geometry and size of the sample. The relationships we develop are consistent with field observations of weathering reported in the literature.