GEOCHEMISTRY OF THERMAL WATERS IN NEVADA (2002-2003)

There are approximately 1000 thermal springs in Nevada for which a location is known (Nevada Bureau of Mines and Geology, Map 141, June 2003), but for which there are no available temperature (or chemical) measurements. Although many of these sites are within known geothermal areas and are located near springs for which temperature and/or geochemical data are available for one of the springs, many of these sites are not so located and require evaluation before the geothermal potential of the area can be assessed. In order to begin filling in data gaps, water sampling commenced in 2002 when over 70 analyses were obtained from springs with previously limited or poor water chemistry data. Relatively little was known of many of the sites sampled, and most areas are characterized by relatively low discharge springs.

A preliminary evaluation of geothermometer temperatures indicates most of the areas have relatively low geothermal potential, however, possible mixing and re-equilibration at lower, near surface temperatures has yet to be evaluated at the sites. At most of the sites, the waters are not fully equilibrated (i.e., Giggenbach, 1988), and hence, the Na-K-Ca geothermometer may not be appropriate. Of the sites not previously identified as having high geothermal potential, the following have the highest potential for electrical power production (based on chalcedony geothermometer temperatures, which should provide a conservative estimate): Hot Creek Canyon Area (136ºC; T7 and 8N, R49 and 50E), Buffalo Valley (130ºC; T29N, R41E), Pumpernickel Valley (Tipton Ranch; 125ºC; T33N, R40E), and Smith Creek Valley (119ºC; T16N, R39E). One sample from Smith Creek Valley was apparently a fully-equilibrated water and its Na-K-Ca geothermometer temperature indicates 141ºC, suggesting that additional attention should be given to this area.