INSIGHTS INTO A COLD-WATER GEYSER USING TOTAL DISSOLVED GAS PRESSURE

Downhole total dissolved gas pressure (P_TDG) measurements were conducted to improve understanding of eruption dynamics in Crystal Geyser, a cold-water geyser in east-central Utah. Although this feature has been studied as an analog to understand modes of CO₂ leakage from anthropogenic carbon storage sites, comprehensive gas monitoring at this site is lacking. We measured P_TDG along with water pressure, temperature, and specific conductance every minute throughout four days of the eruption cycle, and collected water samples for major element chemistry and dissolved gas analysis. The current geyser cycle consists of three phases: a Recovery Phase, Minor Eruptions Phase, and Major Eruption Phase with distinct behavior during transitions between phases. Since dissolved gas was consistently comprised solely of CO_2­ gas, time series of P_TDG can be used to represent variations in the rate of CO₂ release. The combination of P_TDG measurements with standard geochemical techniques allowed us to determine that minor eruption dynamics are distinct from those of major eruptions, and to develop a new conceptual model for minor eruptions. With continued research and use of these techniques, we plan to fill current knowledge gaps and expand our model to include all phases of Crystal Geyser.