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U.S. Geological Survey
Open-File Report 00-188
Online version 1.0
This report is only available on the web

Aeromagnetic Survey of the Amargosa Desert, Nevada and California: A Tool for Understanding Near-Surface Geology and Hydrology

By Richard J. Blakely, Victoria E. Langenheim, David A. Ponce, and Gary L. Dixon


Photograph of the Amargosa Valley in western Nevada.
The Amargosa Valley is a high, cold desert in western Nevada and eastern California. Fractured and faulted carbonate bedrock underlying the region has developed an extensive hydraulic system over the last several scores of thousands of years that transfers snow melt water from the Spring Mountains near Las Vegas underground through solution channels first south, then west into Death Valley. USGS photograph by B.J. Andraski, 1999.


A high-resolution aeromagnetic survey of the Amargosa Desert and surrounding areas provides insights into the buried geology of this structurally complex region. The survey covers an area of approximately 7,700 km2 (2,970 mi2), extending from Beatty, Nevada, to south of Shoshone, California, and includes parts of the Nevada Test Site and Death Valley National Park. Aeromagnetic flight lines were oriented east-west, spaced 400 m (0.25 mi) apart, and flown at an altitude of 150 m (500 ft) above terrain, or as low as permitted by safety considerations. Characteristic magnetic anomalies occur over volcanic terranes, such as Yucca Mountain and the Greenwater Range, and over Proterozoic basement rocks, such as Bare Mountain and the Black Mountains. Linear magnetic anomalies caused by offsets of volcanic rocks permit detailed mapping of shallow faults in volcanic terranes. Of particular interest are subtle anomalies that overlie alluvial deposits at Devils Hole and Pahrump Valley. Alignments of springs along magnetic anomalies at these locales suggest that these anomalies are caused by faults that cut the alluvium, displace magnetic rocks at depth, and eventually influence ground-water flow. Linear magnetic anomalies over the Funeral Mountains appear to coincide with a prominent set of north-northeast-striking faults that cut the Precambrian Stirling Quartzite, rocks that are typically nonmagnetic. The position and orientation of these anomalies with respect to springs north of Furnace Creek suggest that the faults may act as conduits for the flow of water from the north into Death Valley, but the mineralogical cause of the anomalies is unknown.

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Download the aeromagnetic data for the Amargosa Desert (10.3 MB).

Note: The above link leads to a download area containing links to three ASCII files. Depending on your web browser, clicking on ASCII-data links may send the data to your display rather than to your hard drive. Do the following in order to force download to a hard drive:

For Macintosh users: click on the desired data file but hold the mouse button down for a moment to display a pop-up menu. Select "Save this link as..." (Netscape Navigator) or "Download Link to Disk" (Internet Explorer), then navigate to where you want the file to be saved.

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For questions about the scientific content of this report, please contact Rick Blakely

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Please send comments and suggestions, or report problems, to: Michael Diggles
Created: August 3, 2000 (cad)
Updated: January 17, 2008 (bwr, mfd) logo