A Map Of Geothermal Potential For The Great Basin, Usa- Recognition Of Multiple Geothermal Environments

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Conference Paper: A Map Of Geothermal Potential For The Great Basin, Usa- Recognition Of Multiple Geothermal Environments

Abstract
A 1:1,000,000 scale geothermal favorability map of the Great Basin is currently being published through the Nevada Bureau of Mines and Geology (NBMG) and is now available at the web site (http://www.unr.edu/geothermal/geothermal_gis2. htm) of the Great Basin Center for Geothermal Energy (GBCGE). This map allows for separate assessment of the potential for magmatically heated and extensional-type geothermal systems. Added to the map are temperature gradient wells from the Southern Methodist Laboratory (SMU) and United States Geological Survey (USGS) databases, thermal springs and wells from the Geo-Heat Center-compiled geochemical database, and Quaternary faults from the USGS Quaternary Fault and Fold Database. A background 200-meter-resolution shaded digital topographic map provides reference for location. Logistic regression was used to calculate a scaled favorability index on the map for extensional-type geothermal systems based on data input from maps of 1) horizontal gravity gradient, 2) horizontal topographic gradient, 3) crustal dilation as measured by GPS stations, 4) crustal extension calculated from slip rates along Quaternary faults, 5) temperature gradient in the upper crust, and 6) the number, magnitude, and distance to historic earthquakes. These input 'evidence' maps were chosen in part for their ability to model geothermal potential independently of groundwater characteristics and lithologic permeabilities that influence the ability of hot springs or fumaroles to form. Coefficients for the favorability index were calculated outside of known regional aquifers and then used to predict favorability in the aquifer areas to assess the extent to which regional aquifers may be concealing geothermal activity. The results indicate that known geothermal systems ≤ 150°C are underrepresented in areas underlain by regional aquifers, in essence confirming that these regions are either concealing geothermal systems or are under-explored relative to their non-aquifer counterparts. The factors controlling the location of extensional geothermal systems appear to change somewhat across the Great Basin. In the westernmost Great Basin (Walker Lane), geothermal systems are associated with higher earthquakes frequencies than in regions to the east, where steep gravity and topographic gradients are more diagnostic. These differences likely reflect a change in the character of active crustal tectonics across the basin, from relatively strike-slip dominant in the west, where pull-apart basins exist, to more purely extensional in the central and eastern portions in the basin





Authors
 
Mark Coolbaugh, Richard Zehner, Corne Kreemer, David Blackwell and Gary Oppliger






Published
 : GRC, 2005



DOI 
Not Provided
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Citation

Mark Coolbaugh,Richard Zehner,Corne Kreemer,David Blackwell,Gary Oppliger. 2005. A Map Of Geothermal Potential For The Great Basin, Usa- Recognition Of Multiple Geothermal Environments. In: (!) ; (!) ; (!) . (!) : GRC; p.

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Related Geothermal Exploration Activities
Activities (8)


Areas (4)
  1. Central Nevada Seismic Zone Geothermal Region

  2. Northern Basin and Range Geothermal Region

  3. Northwest Basin and Range Geothermal Region

  4. Walker-Lane Transition Zone Geothermal Region
Regions (0)