GEOCHEMICAL AND KINETIC EVOLUTION OF A KARST FLOW SYSTEM - LAUREL CREEK, WEST-VIRGINIA

An approach that couples flow rate measurement with mass balance calculations has been used to evaluate the geochemical evolution and kinetic behavior of Laurel Creek, West Virginia as it flows from a siliceous, noncarbonate caprock onto the Greenbrier Group Limestones, into and through the Laurel Creek-Cross Road Cave System, and out of the spring at the lower end of the system. At a discharge of 1.0 m3 s-1, the stream was calculated to be removing calcite from the aquifer by dissolution at a rate of 4.1 mg 1-1 hr-1, for a total removal of 46 kg CaCO3/hr. Laurel Creek remained undersaturated with respect to calcite throughout the entire reach studied. Comparison of calculated saturation states with laboratory based kinetic mechanism information provided by the work of Plummer et al. (1978) suggests that the elementary reaction that describes attack by carbonic acid dominates calcite dissolution within the main conduit portion of the flow system.