Chemical dynamics and weathering rates of a carbonate basin Bow River, southern Alberta

Discharge is the dominant control on the TDS load of the Bow River; TDS var ies inversely with discharge. Although discharge is the dominant control on concentration, the sources of ions in the river are atmospheric deposition and water/rock interaction. Atmospheric loading can be a significant sourc e of some ions in the pristine headwaters of the river (e.g., 50% of K, 17% of SO4, 16% of Cl). In terms of water/rock interaction, the input of ions to the river is largely controlled by dissolution of carbonate and evaporit e minerals. The chemical denudation rate for the Bow River at Banff is 678 kg/ha/a, or 1.50 x 10(8) kg of rock that is removed as dissolved load each year, in the low range for an alpine carbonate basin. An additional 11 kg/ha/a are remo ved as suspended load. A rock volume of 5.45 x 10(4) m(3) is carried by the Bow River from Banff National Park each year. (C) 1999 Elsevier Science Lt d. All rights reserved.