Tracing the Source of Shallow-water Contamination near a Leaky Fault System, Green River, Utah

The Crystal Geyser includes low-temperature CO2-rich saline water near the town of Green River, Utah. The high salinity of the water in the geyser area has been attributed to either the natural evolution of the aquifer water chemistry or from an upwelling deeper source. However, the composition of the deep fluids in the geyser area, aquifer recharge water, and baseline composition of water from outside the geyser area were lacking and no mechanism could be ruled out. The purpose of this study is to determine the source of fluid migration that has altered the chemical components of the shallow aquifers in the vicinity of the fault system associated with Crystal Geyser, Paradox Basin, Utah.
For this study, water, oil, and gas samples were collected from water wells and springs from the recharge area, from up-gradient and within the geyser area, and from hydrocarbon wells and seeps in and outside the geyser area. Using public databases, published sources, and additional analyses performed for this study, a shallow aquifer flow path and a baseline chemistry were established in the shallow aquifers outside the study area to show the evolution of this groundwater.as compared with the anomalously high saline geyser area. Aquifers were found to be enriched in dissolved ions by one or two orders of magnitude compared to the same aquifer units outside of the area. Chemical and isotopic tracers such as I, Br, Cl, δD, δ18O, and δ13C were used to confirm that the source of saline fluids is from depth but could not determine from which formation the source of upwelling occurred.
In addition, a study of the hydrocarbons within the geyser area showed that maturation in the area is lower than previous studies have suggested. Initial interest in the hydrocarbon stemmed from the presence of an oil seep that is located on one of the leaky faults. However, this oil was too biodegraded for comparison. A hydrocarbon study of the Greater Cisco Field, 65 kilometers east of the geyser area, shows that there is mixing of oil types that is occurring which supports previous studies of the area.