Publications

This 2 1/2 day field trip will present an overview of a U.S. Geological Survey (USGS) project whose objective was to estimate pre-mining groundwater chemistry at the Questa molybdenum mine, New Mexico. Because of intense debate among stakeholders regarding pre-mining groundwater chemistry standards, the New Mexico Environment Department and Chevron Mining Inc. (formerly Molycorp) agreed...

We construct kinematic earthquake rupture models for a suite of 39 Mw 6.6-7.2 scenario earthquakes involving the Hayward, Calaveras, and Rodgers Creek faults. We use these rupture models in 3D ground-motion simulations as discussed in Part II (Aagaard et al., 2010) to provide detailed estimates of the shaking for each scenario. We employ both geophysical constraints and empirical...

The Columbia River Basalt Group (CRBG) eruptions have a well-defined relative magnetostratigraphy but have not been definitively correlated to the geomagnetic polarity time scale. 40Ar/39Ar ages are presented from lavas erupted in the R0 through N1magnetozones of the CRBG and in the transition between R0 and N0. Four ages from transitionally magnetized lava flows at Steens Mountain...

The Lake Mead fault system is a northeast-striking, 130-km-long zone of left-slip in the southeast Great Basin, active from before 16 Ma to Quaternary time. The northeast end of the Lake Mead fault system in the Virgin Mountains of southeast Nevada and northwest Arizona forms a partitioned strain field comprising kinematically linked northeast-striking left-lateral faults, north-striking...

We simulate long-period (T>1.0–2.0 s) and broadband (T>0.1 s) ground motions for 39 scenario earthquakes (Mw 6.7–7.2) involving the Hayward, Calaveras, and Rodgers Creek faults. For rupture on the Hayward fault, we consider the effects of creep on coseismic slip using two different approaches, both of which reduce the ground motions, compared with neglecting the influence of creep...

The article talks about perlite, which is a mineral used as an aggregate for lightweight construction products, filler for paints and horticultural soil blends. Perlite comes from viscous lava, mined and processed to produce lightweight material that competes with pumice, exfoliated vermiculite and expanded clay and shale. It is mined in about 35 countries that include Greece, Japan and...

The article discusses the properties and uses lead as a mineral resource. According to the author, lead is a corrosion-resistant, dense, ductile, and malleable blue-gray metal that has been used by humans for 5,000 years. Lead was first used in decorative, fixtures, roofs, pipes, and windows. The author says that lead is the fifth-most consumed metal based on tonnage after iron, aluminum...

Consumption, imports and domestic production of perlite in the United States continued to be severely affected by the multi-year downturn in construction activity and decreased consumer spending. The estimated amount of processed perlite sold or used from U.S. mines in 2009 fell to 380 kt (418,000 st), the lowest amount of domestic perlite sold or used since 1967.The U.S. consumption of...

The article reports on the global market performance of bauxite and alumina in 2009 and presents an outlook for their 2010 performance. There were only several U.S. states that could produce bauxite and bauxitic clays including Georgia, Arkansas, and Alabama. The prices for imported refractory-grade calcined bauxite ranged between 426 U.S. dollars and 554 dollars per ton.

Each chapter of the 2010 edition of the U.S. Geological Survey (USGS) Mineral Commodity Summaries (MCS) includes information on events, trends, and issues for each mineral commodity as well as discussions and tabular presentations on domestic industry structure, Government programs, tariffs, 5-year salient statistics, and world production and resources. The MCS is the earliest...

The planet's layers - particularly the earth's crust - provide many of life's essential building blocks.

From cow paths to freeways, we seldom appreciate what went into America's highway system.