Publications
Products (journal articles, reports, fact sheets) authored by current and past scientists are listed below. Please check the USGS Pubs Warehouse for other USGS publications.
Filter Total Items: 1829
Geologic setting of the Fortymile River area - Polyphase deformational history within part of the eastern Yukon-Tanana uplands of Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998
The Fortymile River area lies within the Yukon-Tanana lithotectonic terrane of east-central Alaska. This terrane is a mosaic of several lithotectonic assemblages, each with a coherent lithologic, metamorphic, and deformational history. Previous workers have shown that the Fortymile River area is underlain by rocks of the Seventymile, Taylor Mountain, and Nisutlin assemblages. The Taylor Mountain t
Authors
Warren C. Day, Bruce M. Gamble, Mitchell W. Henning, Bruce D. Smith
New geochronological evidence for the timing of early Tertiary ridge subduction in southern Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998
We present new U/Pb (monazite, zircon) and 40Ar/39Ar (biotite, amphibole) ages for 10 Tertiary plutons and dikes that intrude the Chugach–Prince William accretionary complex of southern Alaska. The Sanak pluton of Sanak Island yielded ages of 61.1±0.5 Ma (zircon) and 62.7±0.35 (biotite). The Shumagin pluton of Big Koniuji Island yielded a U/Pb zircon age of 61.1±0.3 Ma. Two biotite ages from the K
Authors
Dwight Bradley, Randall Parrish, William Clendenen, Daniel R. Lux, Paul W. Layer, Matthew Heizler, D. Thomas Donley
Paleozoic strata of the Dyckman Mountain area, northeastern Medfra quadrangle, Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998
Paleozoic rocks in the Dyckman Mountain area (northeastern Medfra quadrangle; Farewell terrane) include both shallowand deep-water lithologies deposited on and adjacent to a carbonate platform. Shallow-water strata, which were recognized by earlier workers but not previously studied in detail, consist of algal-laminated micrite and skeletal-peloidal wackestone, packstone, and lesser grainstone. Th
Authors
Julie A. Dumoulin, Dwight Bradley, Anita G. Harris
Aeromagnetic Survey of the Amargosa Desert, Nevada and California: A Tool for Understanding Near-Surface Geology and Hydrology
A high-resolution aeromagnetic survey of the Amargosa Desert and surrounding areas provides insights into the buried geology of this structurally complex region. The survey covers an area of approximately 7,700 km2 (2,970 mi2), extending from Beatty, Nevada, to south of Shoshone, California, and includes parts of the Nevada Test Site and Death Valley National Park. Aeromagnetic flight lines were o
Authors
Richard J. Blakely, Victoria E. Langenheim, David A. Ponce, Gary L. Dixon
Airborne geophysical surveys in the Boulder Watershed, Jefferson and Lewis and Clark Counties, Montana
INTRODUCTIONThree airborne geophysical surveys have been made in the Boulder watershed and adjacent areas (fig. 1). The objectives of the geophysical studies in the watershed is to map subsurface lithologic, structural and hydrologic features important in controlling possible ground water contamination from mining activities and to design remediation efforts. These studies are part of an abandoned
Authors
Bruce D. Smith, Victor Franklin Labson, Patricia L. Hill
Geochemical investigations and interim recommendations for priority abandoned mine sites on U.S.D.A. Forest Service lands, Mineral Creek watershed, San Juan County, Colorado
Field observations, sampling of mine dumps and mine drainage waters, and
laboratory studies of dump materials have been made at mining areas deemed to be on
public lands administered by the USDA Forest Service in the Mineral Creek watershed.
Results of chemical analyses of dump materials, leachates of those materials, and of
surface waters draining mines or dumps provide indications of where a
Authors
J. T. Nash
Lithology and aggregate quality attributes for the digital geologic map of Colorado
This geologic map was prepared as a part of a study of digital
methods and techniques as applied to complex geologic maps. The
geologic map was digitized from the original scribe sheets used to
prepare the published Geologic Map of Colorado (Tweto 1979).
Consequently the digital version is at 1:500,000 scale using the
Lambert Conformal Conic map projec
Authors
Daniel H. Knepper, Gregory N. Green, William H. Langer
A Study of Roman mining and metallurgy and their environmental consequences at Plasenzuela, Extremadura, Spain
No abstract available.
Authors
Robert G. Schmidt, Cathy M. Ager, Juan Gil Montes
Digital geologic map database of the Payette National Forest and vicinity, Idaho
The geology of the Payette National Forest and vicinity, Idaho (Fig. 1), was mapped and compiled by Karen Lund between 1992 and 1996. The geologic data for the digital map are from original mapping as well as compilation by Lund of numerous sources of published and unpublished geologic maps that are cited in the section 'Bibliography of Geologic Map Sources.' The geology was compiled onto 1:100,00
Authors
Karen Lund, P. D. Derkey, T. R. Brandt, J.R. Oblad
Future of gas hydrate research
Methane hydrates are ice‐like inclusion compounds, in which every volume of hydrate can contain as much as 180 volumes (STP) of gas.The amount of methane in natural gas hydrates is twice the total recoverable fossil fuel reserve. Because of their natural abundance in oceans and permafrost, hydrates have become an exciting national and international research issue. The movement of the gas and oil i
Authors
D.E. Sloan, P.G. Brewer, C. K. Paull, Timothy S. Collett, W. Steven Holbrook, Keith A. Kvenvolden
Potassium-calcium decay system
Potassium has three isotopes (see Potassium); potassium-40 ( 40K) is radioactive and decays to both calcium-40 ( 40Ca) and argon-40 ( 40Ar). The combined half-life of 40K is 1.25 billion years. The branched decay scheme of 40K is shown in Figure P33. It decays by β- decay to 40Ca and to 40Ar by both electron capture and positron decay (see Potassium-argon decay system). Although 89.52% of the deca
Authors
Brian D. Marshall