Evaluation of the Geothermal Reservoir Associated with Auburn and Johnson Hot Springs, Upper Star Valley, Wyoming

Abstract

Auburn and Johnson Hot Springs are part of a low to moderate temperature geothermal rescue in western Wyoming. The thermal water is sodium chloride in character, with a dissolved solids content ranging form 5250 to 5962 ppm, and nearly neutral pH. Comparison with other thermal waters from Alpine and Heise Hot Springs, which occur from 45 to 115 km north along the same structural trend, shows them to be chemically very similar and suggests that the mechanisms for generation of these thermal waters are similar. The predicted subsurface temperature and depth of circulation for the thermal waters are on the order of 92°C and 2600m, respectively. Other sodium chloride waters flow as cold springs from the halite bearing Preuss sandstone just south of the area. These waters, which range in dissolved solids concept from 672 to 270000ppm, are chemically distinct from the thermal waters and do not appear to have had a thermal origin.