Chemical Geology, 1989. Paper abstract bibtex
Studies of alkali-feldspar hydrolysis kinetics show that weathering rates innatural systems are up to three orders of magnitude slower than laborator yrates. The hypothesis is rejected that decelerated rates result from lower thermodynamic affinities for the hydrolysis reaction in natural systems than in laboratory systems. The chemical affinities for the feldspar hydrolysis reaction in two well-constrained natural systems are significantly higher than the threshold value at which affinity would exert detectable influences on the reaction rates. Differences in feldspar weathering rates between natural and laboratory systems are most likely due to a combination of experimental preparation artifacts, loss of reactive surface to the formation of etch pits innaturally weathered feldspars, and inhomogeneous access of reactive fluids to those surfaces.