Discovery and analysis of a potential blind geothermal system in southern Gabbs Valley, western Nevada
The southern Gabbs Valley geothermal prospect is a blind thermal anomaly located 5 km north of the Gabbs Valley Range and ~15 km southeast of the Don A. Campbell geothermal power plant in west-central Nevada. The discovery of this blind thermal anomaly was initiated from the development of a detailed geothermal potential map covering 96,000 km2 of the Great Basin region. This map synthesized about 9 geologic and geophysical parameters and showed high geothermal potential in southern Gabbs Valley. Subsequent geologic reconnaissance identified areas of favorable structure for hosting a blind geothermal system. Areas displaying complex fault relationships were then targeted for further exploration utilizing a shallow 2-meter thermal survey. The first 2-meter survey incorporated 60 data points in the basin, with one anomalously high temperature point located in the southern portion of the basin. Water samples were taken from the Diamond A ranch 6 km northwest of the thermal anomaly. These samples yielded a geothermometer of 130-140°C. Additional shallow temperature survey work has been completed constraining the extent of the thermal anomaly and establishing a 7 km2 area with elevated 2-meter temperatures. Subsurface data generated from a new gravity survey show that the 2-meter thermal anomaly corresponds to a significant gravity gradient that probably reflects a subsurface fault and possible fault intersection. Exploration of the system is ongoing, and further detailed mapping of bedrock and Quaternary exposures in the area will aid in understanding the structural controls of this potential geothermal system. The integration of geochemical, geophysical, and geologic datasets in this area will elucidate the probability of a commercial-grade geothermal system and produce a conceptual model to be used in the selection of possible drill targets.