New Mexico Geological Society Annual Spring Meeting — Abstracts

In Santa Rosa, NM there are several bodies of water known as sinkholes, fed by an artesian aquifer (the Permian Artesia Group). The sinkholes are perennial water sources that both host endemic species as well as provide water to the Pecos River. We examine ten locations, including four sinkholes, two Pecos River locations, one tributary to the Pecos River and three water wells to compare the different water chemistries and parameters to identify connections and processes occurring between the diverse water locations.

Data collected from the surface water and from wells are acquired by standard water sampling protocols. Samples that are collected from warm water vents at depths lower than 10 meters were taken using an original technique necessitated by the specific condition of the deep locations. We report temperature, pH, conductance, and major ion solute concentrations. All of the waters (sinkhole data (~18 °C, 7.3 pH, 3085µS); spring data (~18 °C, 5.7pH, 2530µS); Pecos River data (~17°C, 6.5pH, 2690 µS)) have a strong geochemical similarity to the regional aquifer (aquifer data (~18 °C, 6.8 pH, 2010 µS)). Additional effects on the waters include evaporation and mineral precipitation/dissolution. We use geochemical modelling codes to indicate the major ions composition and distribution as well as the saturation state with respect to minerals such as calcite and gypsum. The contribution of these artesian groundwater outflows is significant to the Pecos River, and take on additional importance given the projections of diminished stream flows in the future.