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: 1814
Detection of crystalline hematite mineralization on Mars by the Thermal Emission Spectrometer: evidence for near-surface water
The Thermal Emission Spectrometer (TES) instrument on the Mars Global Surveyor (MGS) mission has discovered a remarkable accumulation of crystalline hematite (α-Fe2O3) that covers an area with very sharp boundaries approximately 350 by 350–750 km in size centered near 2°S latitude between 0° and 5°W longitude (Sinus Meridiani). Crystalline hematite is uniquely identified by the presence of fundame
Authors
P. R. Christensen, J. L. Bandfield, R. N. Clark, K.S. Edgett, V.E. Hamilton, T. Hoefen, H. H. Kieffer, R.O. Kuzmin, M. D. Lane, M. C. Malin, R.V. Morris, J.C. Pearl, R. Pearson, T. L. Roush, S. W. Ruff, M. D. Smith
Environmental geochemistry at the global scale
Land degradation and pollution caused by population pressure and economic development pose a threat to the sustainability of the Earth's surface, especially in tropical regions where a long history of chemical weathering has made the surface environment particularly fragile. Systematic baseline geochemical data provide a means of monitoring the state of the environment and identifying problem area
Authors
J. Plant, D. Smith, B. Smith, L. Williams
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
Yellowstone plume head: Postulated tectonic relations to the Vancouver Slab, continental boundaries, and climate
No abstract available.
Authors
Kenneth Lee Pierce, Lisa A. Morgan, Richard W. Saltus
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
Dating methods
One of the greatest contributions of geochemistry to man's knowledge of the Earth and solar system has been the development and application of chemical and isotopic techniques used to measure the passage of time. Rates of geologic processes, rates of biological evolution, and contemporaneity of past events all depend on accurate ages of geologic materials. Many geochemical methods have been used t
Authors
Brian D. Marshall