Geothermal resources of the western arm of the Black Rock Desert, northwestern Nevada: Part II, aqueous geochemistry and hydrology

The western arm of the Black Rock Desert, Nevada, includes several distinct hydrothermal systems, some of which exceed 150 C and may exceed 200 C at depth, determined on the basis of chemical geothermometry. The cation composition of the thermal water appears to be controlled by aluminosilicate minerals that are common in other active geothermal systems. Estimates of the equilibrium temperatures at which some mineral pairs are stable, when compared with the more commonly applied geothermometer estimates, indicate that thermodynamic data may be useful for estimating deep aquifer temperatures. Thermal water at Great Boiling and Mud Springs, which has a chloride concentration of about 2,000 mg/L and a total dissolved-solids concentration of 4 ,500 mg/L, appears to have been affected by shallow evapotranspiration in an adjacent playa prior to deep circulation. This model of recharge within the basin floor is distinctly different from models proposed for most other geothermal systems in the northern Great Basin.