Geochemical and hydrologic controls on the composition of surface water in a high‐elevation basin. Sierra Nevada, California

摘要: Hydrologic, mineralogic, and soil data are used to determine the sources geochemical controls on composition of surface water in Emerald Lake watershed (ELW), a high-altitude basin located southern Sierra Nevada. The solute stream waters at ELW can be divided into three periods: snowpack runoff, transition period summer as runoff decreases little precipitation occurs, low-flow from late through winter. Each has different waters. During -50% flow was direct return subsurface reservoirs. Hydrologic residence time maximum measured directly with 6LiBr tracer varied 9 20 h. Three independent measurements show that acidity neutralized by cation exchange soils talus. Discharge reservoirs primary source during when congruent stoichiometry plagioclase weathering. Processes occurring below zone exerted dominant low flow, preferential weathering anorthite component rock further kaolinite gibbsite.