Publications

The U.S. Geological Survey collaborated with the China Geological Survey to conduct a mineral-resource assessment of resources in porphyry copper deposits on the Tibetan Plateau in western China. This area hosts several very large porphyry deposits, exemplified by the Yulong and Qulong deposits, each containing at least 7,000,000 metric tons (t) of copper. However, large parts of the...

Gold- and iron sulfide-bearing deposits of the southeastern United States have distinctive mineralogical and geochemical features that provide a basis for constructing models of ore genesis for exploration and assessment of gold resources. The largest (historic) deposits, in approximate million ounces of gold (Moz Au), include those in the Haile (~ 4.2 Moz Au), Ridgeway (~1.5 Moz Au)...

This study presents geostatistical simulations of coal-quality parameters, major oxides and trace metals for an area covering roughly 812 km2 of the Blue Gem coal bed in southeastern Kentucky, USA. The Blue Gem, characterized by low ash yield and low sulfur content, is an important economic resource. Past studies have characterized the Blue Gem's geochemistry, palynology and petrography...

Mercury is a toxic pollutant. In its elemental form, gaseous mercury has a long residence time in the atmosphere, up to a year, allowing it to be transported long distances from emission sources. Mercury can be emitted from natural sources such as volcanoes, or from anthropogenic sources, such as coal-fired powerplants. In addition, all sources of mercury on the Earth's surface can re...

A new descriptive stratiform chromite deposit model was prepared which will provide a framework for understanding the characteristics of stratiform chromite deposits worldwide. Previous stratiform chromite deposit models developed by the U.S. Geological Survey (USGS) have been referred to as Bushveld chromium, because the Bushveld Complex in South Africa is the only stratified, mafic...

An analysis of the amount and location of undiscovered mineral resources that are likely to be economically recoverable is important for assessing the long-term adequacy and availability of mineral supplies. This requires an economic evaluation of estimates of undiscovered resources generated by traditional resource assessments (Singer and Menzie, 2010). In this study, simplified...

The 2007 Energy Independence and Security Act (Public Law 110-140) directs the U.S. Geological Survey (USGS) to conduct a national assessment of potential geologic storage resources for carbon dioxide (CO2). The methodology used for the national CO2 assessment is non-economic and intended to be used at regional to subbasinal scales. This report identifies and contains geologic...

We describe evidence of biogenicity in the morphology and carbon content of well-preserved, Neoarchean samples of banded iron formation (BIF) from Carajás, Brazil. Silica-rich BIF layers contain translucent ellipsoidal or trapezoidal structures (∼5–10 μm diameter) composed of silica, hematite, and kerogen, which are arranged in larger ring-like forms (rosettes). Stable carbon isotope...

This report presents ten storage assessment units (SAUs) within the Powder River Basin of Wyoming, Montana, South Dakota, and Nebraska. The Powder River Basin contains a thick succession of sedimentary rocks that accumulated steadily throughout much of the Phanerozoic, and at least three stratigraphic packages contain strata that are suitable for CO2 storage. Pennsylvanian through...

The Middle Eocene Claiborne Group was assessed using established U.S. Geological Survey (USGS) assessment methodology for undiscovered conventional hydrocarbon resources as part of the 2007 USGS assessment of Paleogene-Neogene strata of the United States part of the Gulf of Mexico Basin including onshore and State waters. The assessed area is within the Upper Jurassic-Cretaceous-Tertiary...

Detailed and reconnaissance field mapping and the results of geochemical and mineralogical analyses of outcrop samples indicate that the Devonian shales of the Broadtop Synclinorium from central Virginia to southern Pennsylvania have an organic content sufficiently high and a thermal maturity sufficiently moderate to be considered for a shale gas play. The organically rich Middle...

The Cook Inlet-Susitna region of south-central Alaska contains large quantities of gas-bearing coal of Tertiary age. The U.S. Geological Survey in 2011 completed an assessment of undiscovered, technically recoverable coal-bed gas resources underlying the Cook Inlet-Susitna region based on the total petroleum system (TPS) concept. The Cook Inlet Coal-Bed Gas TPS covers about 9,600,000...