Publications

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This chapter reviews detection of materials on solid and liquid (lakes and ocean) surfaces in the solar system using ultraviolet to infrared spectroscopy from space, or near space (high altitude aircraft on the Earth), or in the case of remote objects, earth-based and earth-orbiting telescopes. Point spectrometers and imaging spectrometers have been probing the surfaces of our solar...

Geophysical methods provide valuable information about subsurface permafrost and its relation to dynamic hydrologic systems. Airborne electromagnetic data from interior Alaska are used to map the distribution of permafrost, geological features, surface water, and groundwater. To validate and gain further insight into these field datasets, we also explore the geophysical response to...

A prospectivity map for rare earth element (REE) mineralization at the Bokan Mountain peralkaline granite complex, Prince of Wales Island, southeastern Alaska, was calculated from high-resolution airborne gamma-ray data. The map displays areas with similar radioelement concentrations as those over the Dotson REE-vein-dike system, which is characterized by moderately high %K, eU, and eTh...

The Permian age Phosphoria Formation in southeastern Idaho and adjoining states represents possibly the largest marine phosphate deposit in the world. The Meade Peak Member, which contains the highest concentrations and amount of carbonate fluorapatite in the formation, was not significantly altered by mechanical reworking during deposition or subsequently by chemical weathering. Thus...

Mineral maps based on Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data were used to study late Miocene advanced argillic alteration at Cuprite, Nevada. Distributions of Fe-bearing minerals, clays, micas, sulfates, and carbonates were mapped using the Tetracorder spectral-shape matching system. The Al content of white micas increases toward altered areas and near intrusive...

Five magnetotelluric (MT) profiles have been acquired across the Cascadia subduction system and transformed using 2-D and 3-D nonlinear inversion to yield electrical resistivity cross sections to depths of ∼200 km. Distinct changes in plate coupling, subduction fluid evolution, and modes of arc magmatism along the length of Cascadia are clearly expressed in the resistivity structure...

This field guide covers geology across north-central Idaho from the Snake River in the west across the Bitterroot Mountains to the east to near Missoula, Montana. The regional geology includes a much-modified Mesozoic accretionary boundary along the western side of Idaho across which allochthonous Permian to Cretaceous arc complexes of the Blue Mountains province to the west are...

Future astrobiological missions to Mars are likely to emphasize the use of rovers with in situ petrologic capabilities for selecting the best samples at a site for in situ analysis with onboard lab instruments or for caching for potential return to Earth. Such observations are central to an understanding of the potential for past habitable conditions at a site and for identifying samples...

From December 2010 to January 2011, the U.S. Geological Survey conducted airborne electromagnetic and magnetic surveys of Leach Lake Basin within the National Training Center, Fort Irwin, California. These data were collected to characterize the subsurface and provide information needed to understand and manage groundwater resources within Fort Irwin. A resistivity stratigraphy was...

Saltwater intrusion in southern Florida poses a potential threat to the public drinking-water supply that is typically monitored using water samples and electromagnetic induction logs collected from a network of wells. Transient electromagnetic (TEM) soundings are a complementary addition to the monitoring program because of their ease of use, low cost, and ability to fill in data gaps...

In this chapter, the intent is to summarize the results of traditional stable isotope studies (mainly H, B, O, C, and S) that have greatly contributed to the understanding of ore-forming processes over the last 60 years and to provide an up-to-date assessment of the application of new nontraditional isotope systems (Fe, Cu, Zn, Se, Mo, Hg, and Tl).