United States Geological Survey

About: United States Geological Survey is a government organization based out in Reston, Virginia, United States. It is known for research contribution in the topics: Population & Groundwater. The organization has 17899 authors who have published 51097 publications receiving 2479125 citations. The organization is also known as: USGS & US Geological Survey.

Assessment of Undiscovered Oil and Gas in the Arctic

Abstract: Among the greatest uncertainties in future energy supply and a subject of considerable environmental concern is the amount of oil and gas yet to be found in the Arctic. By using a probabilistic geology-based methodology, the United States Geological Survey has assessed the area north of the Arctic Circle and concluded that about 30% of the world's undiscovered gas and 13% of the world's undiscovered oil may be found there, mostly offshore under less than 500 meters of water. Undiscovered natural gas is three times more abundant than oil in the Arctic and is largely concentrated in Russia. Oil resources, although important to the interests of Arctic countries, are probably not sufficient to substantially shift the current geographic pattern of world oil production.

Iron and Aluminum Hydroxysulfates from Acid Sulfate Waters

Abstract: Acid sulfate waters are produced mostly by the oxidation of common sulfide minerals such as pyrite, chalcopyrite, pyrrhotite, and marcasite in rocks, soils, sediments, and industrial wastes. This spontaneous process of mineral weathering plays a fundamental role in the supergene alteration of ore deposits, the formation of acid sulfate soils, and the mobilization and release of acidity and metals to surface and ground waters. The purely natural process of “acid rock drainage” is often intensified by human activities related to mining, mineral processing, construction, soil drainage, and dredging. Geochemical reaction rates are accelerated because physical disturbance gives greater exposure of mineral surfaces to air and water, and to microbes that catalyze the reaction process. Large quantities of reactive sulfides are also concentrated and exposed to air as a result of mining and mineral processing. Acid sulfate waters produce a number of fairly insoluble hydroxysulfate and oxyhydroxide minerals that precipitate during oxidation, hydrolysis, and neutralization. The objective of this chapter is to describe the formation, properties, fate, and environmental implications of the nano- to microphase hydroxy-sulfates of Fe and Al that are precipitated from acid sulfate waters. These minerals are commonly of poor crystallinity and difficult to characterize. Much remains to be learned about their occurrence, formation, and properties. ### Mine drainage The best known examples of acid sulfate waters are those released from mines where coal and metallic sulfide ores have been exploited (Ash et al. 1951, Barton 1978, Nordstrom 1982a, Rose and Cravotta 1998, Nordstrom and Alpers 1999). There may be as many as 500,000 inactive or abandoned mine sites in the United States alone (Lyon et al. 1993). Although most of these pose no immediate water-quality problem, Kleinmann (1989) estimated that about 19,300 km of streams and more than 72,000 ha of lakes and reservoirs have been …

Topographic Slope as a Proxy for Seismic Site Conditions and Amplification

Abstract: We describe a technique to derive first-order site condition maps directly from topographic data. For calibration, we use global 30 arc sec topographic data and V S 30 measurements (here V S 30 , refers to the average shear-velocity down to 30 m) aggregated from several studies in the U.S., as well as in Taiwan, Italy, and Australia. V S 30 values are correlated against topographic slope to develop two sets of parameters for deriving V S 30 : one for active tectonic regions where topographic relief is high, and one for stable shields where topography is more subdued. By taking the gradient of the topography and choosing ranges of slope that maximize the correlation with shallow shear-velocity observations, we can recover, to first order, many of the spatially varying features of sitecondition maps developed for California. Our site-condition map for the low-relief Mississippi Embayment also predicts the bulk of the V S 30 observations in that region despite rather low slope ranges. We find that maps derived from the slope of the topography is often well correlated with other independently-derived, regional-scale site-condition maps, but the latter maps vary in quality and continuity, and subsequently, also in their ability to match observed V S 30 measurements contained therein. Alternatively, the slope-based method provides a simple approach to uniform site condition mapping.

Character and Spatial Distribution of OH/H2O on the Surface of the Moon Seen by M3 on Chandrayaan-1

Abstract: The search for water on the surface of the anhydrous Moon had remained an unfulfilled quest for 40 years. However, the Moon Mineralogy Mapper (M 3 ) on Chandrayaan-1 has recently detected absorption features near 2.8 to 3.0 micrometers on the surface of the Moon. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. On the Moon, the feature is seen as a widely distributed absorption that appears strongest at cooler high latitudes and at several fresh feldspathic craters. The general lack of correlation of this feature in sunlit M 3 data with neutron spectrometer hydrogen abundance data suggests that the formation and retention of hydroxyl and water are ongoing surficial processes. Hydroxyl/water production processes may feed polar cold traps and make the lunar regolith a candidate source of volatiles for human exploration.