Heat flow in the Coso geothermal area, Inyo County, California
Journal Article: Heat flow in the Coso geothermal area, Inyo County, California
AbstractObvious surface manifestations of an anomalous concentration of geothermal resources at the Coso geothermal area, Inyo County, California, include fumarolic activity and associated hydrothermally altered rocks. Pleistocene volcanic rocks associated with the geothermal activity include 38 rhyolite domes occupying a north trending structural and topographic ridge and numerous basaltic cinder cones and lava flows partly surrounding its southern half. In an investigation of the thermal regime of this Basin and Range geothermal area, temperature measurements were made in 25 shallow and 1 intermediate depth borehole. Geothermal gradients ranged from 25.3 C/km to 906 C/km. The high gradients arise from convecting hot water and former convective transport of heat by dikes that fed the domes and flows. Thermal conductivity measurements were made on 312 samples from cores and drill cuttings. The actual process by which heat is transferred is rather complex; however, the heat flow determinations can be divided into two groups. The first group, less than 4.0 HFU, are indicative of regions with primarily conductive regimes, although deep-seated mass transfer is implied. The second group, greater than 4.0 HFU, are characteristics of regions with considerable convective heat transfer in the shallow subsurface. Heat transferred by convection of water would be rapidly exhausted if it were not intermittently supplied with heat energy from depth; therefore the heat flow data substantiate the concept that the surface hydrothermal activity and associated volcanic rocks are products of a long-lived magmatic system that has periodically erupted lava during the past 0.3--1.0 m.y. This magmatic system is the crustal heat source of the present-day Coso geothermal system (1 HFU=41.87 mW/m2).
- Combs and J.
- Published Journal
- Journal of Geophysical Research, 5/10/1980
- Not Provided
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Combs, J. . 5/10/1980. Heat flow in the Coso geothermal area, Inyo County, California. Journal of Geophysical Research. (!) .