Mechanical and chemical denudation of drainage areas

The considerable tectonic activity which occurred in the present geologic epoch probably furnishes the reason for the lack of extensive formation of structural eluvium in Siberia and the Black Sea area, the authors suggest. In the more than 70 rivers surveyed in this study if was found that the predominant chemical elements dissolved in the water were readily soluble ones, with little silica as a rule. A striking fact is that the chemical weathering index decreases, while the modulus of solid runoff increases, the more rugged the relief.--AGI Staff.