Kinetics of Red Clay Bluff Dissolution in Western Lake Superior

The dissolution of red clay bluff samples from the southwestern Lake Superior shoreline area in Lake Superior water or deionized water is studied by following the aqueous concentrations of reactive silica over a three month period. The dissolution process is initially rapid, followed by a first-order dissolution process (k = 9.4 × 10^?7 sec^?1) up to about thirty days. After about 30 days, the rate of dissolution of the bluff material follows linear kinetics (k = 5.4 × 10^?8 mg SiO₂/gram of bluff per second).