Preliminary Summary of Water Resource Investigations during 2012 at Timpanogos Cave National Monument, Utah

This manuscript considers the hydrology and geochemistry of water resources within Timpanogos Cave National Monument in American Fork, Utah. In particular, data are presented for five cave pools within the Monument and the American Fork River that flows through the Monument. Two independent dye trace attempts in this study have not established a connection between the surface near the canyon rim at the south border of the Monument and the cave pools or the river. Ion chemistry of the pools reveals elevated sulfate concentrations. Analysis of sulfate and other reaction products suggests the possibility of combined carbonic and sulfuric acids as speleogenetic agents. Enrichment of 13C in dissolved inorganic carbon above expected values provides initial support of this hypothesis. The enrichment of sulfate in the cave pools when coupled with higher concentrations of fluorine, suggest increased interaction with bedrock influenced in the past by hydrothermal activity. This is especially relevant in pools with muted water-level fluctuations during the course of the study. Other pools have greater water-level variation and unexpectedly have a very consistent chemical composition. One hypothesis is that the source waters for the pools with stable geochemical character are from the talus near the canyon rim. Evidence from the stable isotopes of oxygen and hydrogen within water samples support this hypothesis— cave pools with constant water levels are more enriched in heavier isotopes and thus derived from lower elevations compared to cave pools with variable water level and depletion in the heavier isotopes