Special Section: Chapman Conference on Hydrogeochemical Responses of Forested Catchments
Chemical Weathering in the Loch Vale Watershed, Rocky Mountain National Park, Colorado
Article first published online: 9 JUL 2010
Copyright 1990 by the American Geophysical Union.
Water Resources Research
Volume 26, Issue 12, pages 2971–2978, December 1990
How to Cite
1990), Chemical Weathering in the Loch Vale Watershed, Rocky Mountain National Park, Colorado, Water Resour. Res., 26(12), 2971–2978, doi:10.1029/WR026i012p02971., , and (
- Issue published online: 9 JUL 2010
- Article first published online: 9 JUL 2010
- Manuscript Accepted: 3 JUL 1990
- Manuscript Received: 14 NOV 1989
Mineralogic, hydrologic, and geochemical data were used to determine the source of solutes to surface waters draining the Loch Vale Watershed (LVWS), an alpine-subalpine drainage located in the Front Range of Colorado. The flux of dissolved solids from LVWS is primarily controlled by interactions between snowmelt and materials derived from the local bedrock; the biomass has only a minor effect on solute budgets except for ammonium. LVWS is underlain by Precambrian granite and gneiss, the major minerals include quartz, microcline, plagioclase, biotite, and sillimanite. Small amounts of calcite were found along hydrothermally altered zones in the bedrock. Mass balance calculations indicate that the weathering of calcite contributes nearly 40% of the cations derived within the basin. The importance of calcite weathering in LVWS is a result of its chemical reactivity and the high rate of physical erosion in this alpine environment. The average cationic denudation rate in the drainage (390 eq/ha/yr) is similar to long-term rates in forested Adirondack watersheds (500–600 eq/ha/yr), but much lower than the average for the North American Continent (3800 eq/ha/yr). Surface waters in LVWS are susceptible to acidification should acid deposition from the atmosphere increase.