Chemical weathering in the Loch Vale Watershed, Rocky Mountain National Park, Colorado

Water Resources Research
By: , and 

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Abstract

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.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Chemical weathering in the Loch Vale Watershed, Rocky Mountain National Park, Colorado
Series title Water Resources Research
DOI 10.1029/WR026i012p02971
Volume 26
Issue 12
Year Published 1990
Language English
Publisher American Geophysical Union
Description 8 p.
First page 2971
Last page 2978
Country United States
State Colorado
Other Geospatial Rocky Mountain National Park