| Title | Hyperspectral, Shallow Temperature, and Gravity Surveys: A Roundup of Recent Exploration Activity at Silver Peak, Alum, and Columbus Salt Marsh, Esmeralda County, Nevada |
|---|---|
| Authors | Kratt, Christopher |
| Year | 2011 |
| Conference | Geothermal Resources Council Transactions |
| Keywords | Alum; Columbus Salt Marsh; Silver Peak; Clayton Valley; Shallow temperature; Hyperspectral; Remote sensing; Gravity; Buddingtonite |
| Abstract | We used shallow temperature surveys and hyperspectral mineral mapping to explore the Alum and Silver Peak geothermal prospects located in Esmeralda County, Nevada. In addition, we conducted a gravity survey at the Columbus Salt Marsh (southwest) geothermal prospect. Analysis of the hyperspectral data identified alunite, buddingtonite, kaolinite, syngenite and gypsum. Shallow temperature surveys at Alum and Silver Peak potentially indicate the orientations of structures that control upwelling zones. The highest 2 m temperature recorded at Silver Peak is approximately 6 °C above background and located on the playa ~1 km to the north of town and less than 500 m from the range front. The Silver Peak shallow temperature anomaly parallels the range front to the north for at least 4 km and extends ~2 km across the playa. At Alum, the highest shallow temperature is approximately 4°C above background, and the anomalous zone suggests upwelling for at least 3 km along a NE-striking horsetail segment of the Lone Mountain fault. The gravity survey was conducted in the southwest corner of Columbus Salt Marsh and centered on a shallow temperature anomaly identified in 2009. Our results showed the shallow temperature anomaly is situated in a saddle between two gravity highs. Gravity contours indicate the shallow temperature anomaly may be located in the hanging wall along a NE-striking fault; however, modeled two-dimensional gravity cross-sections do not support significant vertical displacement. It remains unclear if the shallow anomaly is a result of direct upwelling or lateral outflow. The results and data presented herein provide guides for expanded geothermal exploration at Alum and Silver Peak. Moreover, the gravity and shallow temperature surveys contribute to refinements in conceptual models of the geothermal systems at all three study area locations. |