GEOCHEMISTRY OF CAVE POOLS CONNECTED TO AN ALPINE EPIKARST AQUIFER—TIMPANOGOS CAVE NATIONAL MONUMENT, UTAH
Synthesis of the data demonstrates a range of patterns among the sites. For example, CS is the most enriched in TDS (av. 389 mg/L) consistent with a diffuse water source and a longer interaction time with the bedrock. In contrast, AFR has lower TDS (av. 273 mg/L) reflecting meteoric water and snow melt as a major contributor. HC has the most consistent geochemistry and the highest calcium concentrations (av. 82 mg/L) among the sites suggestive of piston flow through the overlying talus.
Calcium saturation indices (SI) are generally positive for all the sites including AFR (SIAV = 0.83). Interestingly, HL and CS have the lowest SIAV, 0.25 and 0.31, respectively, but have the highest average Mg2+ concentrations suggesting greater interaction with dolomite. Mg2+/Ca2+ ratios support this hypothesis for HL. However, Mg2+/Ca2+ ratios are >1 for CS implying a removal of Ca2+ through calcite precipitation or an enrichment of Mg2+ from other sources. Observation of calcite rafts, the formation of which would lower the SI, is consistent with the first interpretation. Enrichment of F- in HL and CS, derived from the calcite veins in the Deseret Limestone of hydrothermal origin, is consistent with the second interpretation. Molar concentrations of reaction products in these cave pools suggest contributions of both carbonic and sulfuric acids to modern carbonate dissolution.