Geothermal Exploration using AVIRIS Remote Sensing Data over Fish Lake Valley, NV

Authors: Littlefield, Elizabeth; Clavin, Wendy
Keywords: Fish Lake Valley; Nevada; Remote sensing; AVIRIS; Geothermal
Conference: Geothermal Resources Council Transactions Session: Exploration; Remote sensing; Sinter; Hydrothermal alteration
Year: 2010 Language: English
Geo Location:
Abstract: Fish Lake Valley, in Esmeralda County, Nevada, sits at the southern end of the Mina Deflection where the very active Death Valley-Furnace Creek-Fish Lake Valley fault system makes a right step to transfer slip northward into the Walker Lane. Northern Fish Lake Valley has been pulling part since ca. 6 Ma, primarily along the Emigrant Peak normal fault zone (Stockli et al., 2003). Elevated tectonic activity in Fish Lake Valley suggests there may be increased fracture permeability to facilitate the flow of thermal water. The Fish Lake Valley geothermal prospect is located at the base of the Volcanic Hills, in central northern Fish Lake Valley. Drilling in the region has revealed anomalously high temperatures at depth, but the geothermal system is not yet understood. Geothermal surface expression is limited to localized deposits of siliceous sinter and travertine that occur along a fault. The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) instrument acquired hyperspectral data over northern Fish Lake Valley in March 2003. The AVIRIS sensor is maintained by the Jet Propulsion Laboratory and collects data in 224 wavelengths from the visible to shortwave infrared (0.4 to 2.5 ?m) at 2 m spatial resolution. The data set covers the Fish Lake Valley prospect and the Silver Peak Range foothills, which are bounded by the Emigrant Peak fault zone. Past studies have successfully used remote sensing data to map hydrothermal alteration as minerals display characteristic spectral signatures. Remote sensing studies compliment traditional field mapping, often identifying alteration minerals that are not obvious in the field. Remote sensing is used to classify mineralogy across very large geographic areas, in this case, ~190 km2. The AVIRIS data were processed using statistical and subjective methods to identify hydrothermal alteration minerals including opal, kaolinite, montmorillonite, muscovite, clinochlore, hematite, calcite and borates. Mineral distribution was compared to existing geologic maps, including a surficial geology map by Reheis and Block (2007). We identify previously unmapped deposits of siliceous sinter and several locations with abundant hydrothermal clays that appear to be fault-controlled.
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