Publications

The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private...

From May 2008 to September 2009, the U.S. Geological Survey (USGS) collected data from more than 660 gravity stations, 100 line-km of truck-towed magnetometer traverses, and 260 physical-property sites in the vicinity of Blue Mountain and Pumpernickel Valley, northern Nevada (fig. 1). Gravity, magnetic, and physical-property data were collected to study regional crustal structures as an...

Mineral resource assessments represent a synthesis of available information to estimate the location, quality, and quantity of undiscovered mineral resources in the upper part of the Earth’s crust. This report presents a probabilistic mineral resource assessment of undiscovered sandstone copper deposits within the late Paleozoic Chu-Sarysu Basin in central Kazakhstan by the U.S...

A rich chiton assemblage consisting of more than 15,000 valves (shell plates) was collected by George P. Kanakoff (1897–1973) from Pliocene exposures of the San Diego Formation just north of the U.S./Mexican border. The assemblage includes 16 extant species, three extinct species (Callistochiton sphaerae n. sp., Lepidozona kanakoffi n. sp., and Amicula solivaga n. sp.), and three...

The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private...

The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private...

Ore formation at the Spar Lake red bed-associated strata-bound Cu deposit took place across a mixing and reaction zone between a hot oxidized metals-transporting brine and a reservoir of “sour” (H2S-bearing) natural gas trapped in the host sandstones. Fluid inclusion volatile analyses have very high CH4 concentrations (≥1 mol % in most samples), and a sample from the fringe of the...

Chromite ((Mg, Fe++)(Cr, Al, Fe+++)2O4) is the only source for the metallic element chromium, which is used in the metallurgical, chemical, and refractory industries. Podiform chromite deposits are small magmatic chromite bodies formed in the ultramafic section of an ophiolite complex in the oceanic crust. These deposits have been found in midoceanic ridge, off-ridge, and suprasubduction...

The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private...

The surface and subsurface geology, hydrothermal alteration, and mineralogy of the Handcart Gulch area was studied using map and drill core data as part of a multidisciplinary approach to understand the hydrology and affects of geology on acid-rock drainage in a mineralized alpine watershed. Handcart Gulch was the locus of intense hydrothermal alteration that affected an area of nearly 3...

The Cedars ultramafic mass is a mantle fragment that consists of partially serpentinized spinel harzburgite and dunite. Compositional layering and a chromite lineation define a penetrative metamorphic foliation that almost certainly formed in the upper mantle. Although detailed petrofabric and mineral chemistry are presently lacking, it seems reasonable that the Cedars peridotite...

Human occupation in Grand Canyon, Arizona, dates from at least 11,000 years before present to the modern era. For most of this period, the only evidence of human occupation in this iconic landscape is provided by archeological sites. Because of the dynamic nature of this environment, many archeological sites are subject to relatively rapid topographic change. Quantifying the extent...