New Geologic Map—Bradys Geothermal Area, Churchill County
Preliminary Geologic Map of the Bradys Geothermal Area, Churchill County, Nevada
Authors: James E. Faulds, Alan R. Ramelli, Mark F. Coolbaugh, Nicholas H. Hinz, Larry J. Garside, and John H. Queen
Series: Open-File Report 2017-04
Format: plate: 51 x 39 inches, color, with cross sections; text: 6 pages, color
Free download/purchase: http://pubs.nbmg.unr.edu/Prel-geol-Bradys-geothermal-p/of2017-04.htm
The Bradys geothermal field lies in the northern Hot Springs Mountains ~80 km northeast of Reno in Churchill County, Nevada. The field has a reservoir temperature of 180-193°C at 1- to 2-km depth and currently supports a combined dual flash and binary geothermal power plant with a total installed capacity of 26 MWe, as well as a vegetable dehydration plant. The power plant has been in operation since 1992. The detailed geologic map and cross sections of the Bradys geothermal field illustrate the linkages between permeability and a complex structural setting dominated by a left step in a normal fault zone but also including several fault intersections within a broader accommodation zone. Seismic reflection data and re-logging of cuttings and core from 34 wells were incorporated into the cross sections. A previously published 1:24,000-scale geologic map of the Desert Peak quadrangle only included the easternmost part of the Bradys geothermal field. The purpose of this map is to show the entire geothermal field at a finer scale (1:12,000) sufficient to illustrate multiple geothermal features, such as the complex faulting, sinter, warm ground, and fumaroles. Unpublished versions of this map and cross sections have served as the foundation for previously published, 3D structural modeling and 3D gravity inversion of the Bradys geothermal field.
This project was supported by the U.S. Department of Energy, Ormat Technologies, Inc., and the U.S. Geological Survey STATEMAP Program.