A New Gold Pan for the West: Discovering Blind Geothermal Systems with Shallow Temperature Surveys

Abstract

The use of rapidly deployable 2-meter-deep shallow temperature surveys has led to the discovery of at least two blind geothermal systems in Nevada, USA and has helped to define the spatial extent of thermal anomalies at two other locations. At Teels Marsh, two shallow temperature anomalies with a combined strike length of almost 4 km were identified adjacent to a Quaternary fault on the west side of the playa. At Rhodes Marsh, a thermal anomaly at least 5 km long was located adjacent to outcrops of opalized sands. Shallow temperature data at Tungsten Mountain help to define the spatial extent of a thermal anomaly more than 5 km long that partially coincides with gold exploration holes that intersected hot water and steam. Similarly, a broad temperature anomaly was identified in Gabbs Alkali Flat whose geothermal origin is corroborated by a well temperature of 82º C measured at a depth of 317 feet. These successes clearly suggest that if shallow temperature surveys were used more widely in the Great Basin, many additional blind geothermal systems would be found. The Great Basin is well suited for the application of this technique because low precipitation limits the ability of shallow cold groundwater to conceal the upward propagation of conductive heat from deeper thermal aquifers.