Structural Control of the Baltazor Hot Springs Geothermal System, Humboldt County, Nevada

Abstract

The Baltazor Hot Springs KGRA is centered on a low yield, sodium sulfate, 76-98°C/167-208°F hot springs, surrounded by small opaline sinter mounds and believed to be presently precipitating silica, thus suggesting a deep reservoir temperature of at least 180°C/365°F. The position of the springs, associated calcite-silica stockworks, and presumably a deep thermal reservoir at Baltazor, is clearly controlled by the intersection of a northeasterly trending Basin and Range fault trough with an older, northwest trending normal fault system. Of numerous exploration techniques applied at Baltazor, thermal gradient drilling, mapping of geology and alteration, geothermometry, detailed gravity and dipole-dipole resistivity have been most useful in appraising the geothermal resource potential. Baltazor is indicated by these techniques, and by probable active silica precipitation to remain an encouraging prospect. At least one deep drill hole is warranted. The target for this hole is a fracture controlled reservoir in Miocene volcanics and pre-Tertiary metamorphic rocks at depths greater than 2000 ft (610 m) beneath Baltazor Hot Springs.