Use of temperature surveys at a depth of 1 meter in geothermal exploration in Nevada

Abstract

Temperature surveys at a depth of 1 m in the Soda Lakes and Upsal Hogback areas of the western Carson Desert, Nevada, had varying degrees of success in delineating temperature and heatflow anomalies at greater depths. Optimum results were obtained in a detailed survey of a small area near a fumarole and an abandoned steam well in the Soda Lakes area. At this location steam occurs above the water table and the unconfined water is at the boiling temperature at depths of only a few meters; also temperatures and heat flows are far above background values. Somewhat more equivocal results were obtained in surveys of a larger surrounding area in which the temperature range at 1 m was smaller than immediately adjacent to the fumarole and steam well, and in which perturbing effects of geologic, topographic, hydrologic, and other factors not related directly to geothermal heat flow are locally significant. Poorest results were obtained in surveys of the Upsal Hogback area, where temperature of the thermal water leaking into shallow aquifers is much less than that in the Soda Lakes area, the range in temperature at a depth of 1 m is correspondingly smaller, and the variability of the geology,more » topography, depth to the water table, and other perturbing factors is greater than that in the Soda Lakes area.« less