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Application of Geothermal Play Fairway Analysis to the Desert Queen Geothermal Prospect, Northern Hot Springs Mountains, Churchill County, Nevada
Date
2021Type
ThesisDepartment
Geology
Degree Level
Master's Degree
Abstract
This study utilized a multidisciplinary approach to assess geothermal potential at the Desert Queen geothermal area, a known blind geothermal system in western Nevada. Geothermal play fairway analysis was employed to vector into the most favorable areas for further exploration in the Desert Queen basin. This study hinged on decades of previous exploration work by synthesizing and expanding upon many existing datasets, including detailed geologic mapping, temperature gradient well data, 2 m temperature probe data, and multiple geophysical surveys. With the addition of new geologic and geophysical data, a comprehensive structural model was completed to elucidate the structural controls on geothermal activity. The motivation for applying the play fairway analysis methodology to the Desert Queen area was to further refine the method at a fine-scale in the middle to late stages of exploration.The Desert Queen area occupies the eastern portion of the northern Hot Springs Mountains adjacent to two power producing geothermal systems, Bradys and Desert Peak. The northern Hot Springs Mountains lie within the Basin and Range province directly northeast of the Walker Lane, where dextral shear diffuses into and enhances regional extension. The Desert Queen geothermal system appears to be controlled by the southward termination and horse-tailing of the Desert Queen fault zone, a major east-dipping normal fault, as well as a step over to a less prominent fault to the east, the Power Line fault. The termination and step over of the Desert Queen fault zone generated a zone of structural complexity marked by abundant closely spaced normal faults. Enhanced permeability induced by greater fracture density within this structurally complex area generated a favorable environment for geothermal activity.
Detailed geologic mapping, structural analysis, and geothermal play fairway analysis have resulted in the delineation of five favorable structural settings that potentially control geothermal activity in the area. Two of the favorable structural settings are hybrid overlap settings that are the most favorable based on multiple lines of evidence. Both hybrid settings are marked by a 2 m temperature anomaly that spatially coincides with the warmest temperature gradient wells. The hottest measured temperature within the Desert Queen basin (140°C) occurs in a well proximal to the eastern hybrid overlap between the Desert Queen fault – Power Line fault step over and the termination of the Power Line fault into the Desert Queen basin. The western hybrid overlap between the termination of the Desert Queen fault and the step over to the Power Line fault has moderate shallow temperatures but slightly higher play fairway favorability scores. Fluids may upwell in the vicinity of the western hybrid setting and flow up and out to the east-northeast. An alternative interpretation is that multiple upwellings occur at Desert Queen in the vicinity of both hybrid settings. This study indicates two promising areas to focus further exploration at Desert Queen. Additionally, the fine-scale, geothermal play fairway analysis has been shown to be an effective tool in middle to late stages of exploration.
Permanent link
http://hdl.handle.net/11714/8094Additional Information
Committee Member | Zuza, Andrew; Bassett, Scott |
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