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: 1826
A 20-year record of water chemistry in an alpine setting, Mount Emmons, Colorado, USA
From 1997 to the present, the U.S. Geological Survey and other agencies have been collecting water samples for chemical analyses on Mount Emmons in central Colorado, USA. The geology of Mount Emmons is dominated by Upper Cretaceous to Paleogene sediments of marine to continental origin, with felsic intrusive rocks interrupting the sedimentary block. Extensive sulphide-rich alteration accompanied t
Authors
Richard Wanty, Andrew H. Manning, Michaela Johnson, Philip Verplanck
Geological and geophysical data for a three-dimensional view—Inside the San Juan and Silverton Calderas, Southern Rocky Mountains Volcanic Field, Silverton, Colorado
IntroductionThe San Juan-Silverton caldera complex located near Silverton, Colorado, in the Southern Rocky Mountains volcanic field is an ideal natural laboratory for furthering the understanding of shallow-to-deep volcanic-related mineral systems. Recent advances in geophysical data processing and three-dimensional (3D) model construction will help to characterize shallow properties important for
Authors
Douglas B. Yager, Eric D. Anderson, Maria Deszcz-Pan, Brian D. Rodriguez, Bruce D. Smith
Petrology of volcanic rocks associated with silver-gold (Ag-Au) epithermal deposits in the Tonopah, Divide, and Goldfield Mining Districts, Nevada
Miocene calc-alkaline volcanic rocks, part of the southern segment of the ancestral Cascades magmatic arc, are spatially, temporally, and likely genetically associated with precious metal epithermal deposits in the Tonopah, Divide, and Goldfield Districts of west-central Nevada. In the Tonopah mining district, volcanic rocks include the Mizpah Trachyte, Fraction Tuff, and Oddie Rhyolite; in the Di
Authors
Edward A. du Bray, David John, Joseph Colgan, Peter G. Vikre, Michael A. Cosca, Leah E. Morgan
Explosive summit collapse of Kīlauea Volcano in 1924 preceded by a decade of crustal contamination and anomalous Pb isotope ratios
A geochemical time-series analysis of lavas from frequently active basaltic volcanoes has the potential to reveal the enigmatic mantle controls on volcanic behavior and hazards. In May 1924, the century-long lava lake within Halemaʻumaʻu pit crater at the summit of Kīlauea Volcano drained and the floor of Halemaʻumaʻu collapsed, triggering ∼3 weeks of phreatic explosions due to the interaction of
Authors
Aaron Pietruszka, Daniel E. Heaton, Michael O Garcia, Jared P. Marske
Ross Ice Shelf response to climate driven by the tectonic imprint on seafloor bathymetry
Ocean melting has thinned Antarctica's ice shelves at an increasing rate over the past two decades, leading to loss of grounded ice. The Ross Ice Shelf is currently close to steady state but geological records indicate that it can disintegrate rapidly, which would accelerate grounded ice loss from catchments equivalent to 11.6 m of global sea level rise. Here, we use data from the ROSETTA-Ice air
Authors
K J Tinto, L Padman, C S Siddoway, M.R. Springer, H.A. Fricker, I. Das, F. Caratori Tontini, D.F. Porter, N.P. Frearson, S. J. Howard, M.R. Siegfried, C. Mosbeux, M.K. Becker, C. Bertinato, A. Boghosian, N. Brady, Bethany L. Burton, W. Chu, S.I. Cordero, T. Dhakal, L. Dong, C.D. Gustafson, S. Keeshin, C. Locke, A. Lockett, G. O'Brien, J.J. Spergel, S.E. Starke, M. Tankersley, M. Wearing, R. E. Bell
Petrographic, geochemical, and geochronologic data for cenozoic volcanic rocks of the Tonopah, Divide, and Goldfield Mining Districts, Nevada
The purpose of this report is to summarize geochemical, petrographic, and geochronologic data for samples, principally those of unmineralized Tertiary volcanic rocks, from the Tonopah, Divide, and Goldfield mining districts of west-central Nevada (fig. 1). Much of the data presented here for the Tonopah and Divide districts are for samples collected by Bonham and Garside (1979) during geologic map
Authors
Edward A. du Bray, David John, Peter G. Vikre, Joseph Colgan, Michael A. Cosca, Leah E. Morgan, Robert J. Fleck, Wayne R. Premo, Christopher S. Holm-Denoma
Inversion of airborne EM data with an explicit choice of prior model
Inversion of airborne electromagnetic (AEM) data is an under-determined inverse problem, in that infinitely many resistivity models exist that will be able to explain the observed data, within measurement errors. Therefore, additional information or constraints must be taken into account to solve the inverse problem. In deterministic approaches, the goal is to locate one optimal model that can be
Authors
Thomas Mejer Hansen, Burke J. Minsley
Revisiting Herto: New evidence of Homo sapiens from Ethiopia
Localities in the radiometrically dated Upper Herto Member of Ethiopia’s Bouri Formation continue to produce new data that complement and extend initial reports of fossils and artifacts published in 2003. Results of these revisits are reported here and include the in situ recovery of artifacts from the same sediments containing hominid fossils. We evaluate the absolute and relative temporal placem
Authors
Yonatan Sahle, Yonas Beyene, Alban Defleur, Berhane Asfaw, Giday WoldeGabriel, William K Hart, Leah E. Morgan, Paul R. Renne, Joshua Carlson, Tim D White
Distributed fault slip in the eastern California shear zone: Adding pieces to the puzzle near Barstow, California
We investigate the dextral Lockhart and Mt. General faults, which are among four active structures in the northwestern portion of the eastern California shear zone (ECSZ). Early mapping depicts the Lockhart and Mt. General faults as discontinuous fault traces that continue northwest of the Lenwood Fault. Recent work indicates that the Lenwood Fault slips at ~0.2-1.0 mm/yr over the past ~8 ka and 0
Authors
Elizabeth K. Haddon, David M. Miller, Victoria Langenheim, Shannon A. Mahan
Geochemical and mineralogical maps, with interpretation, for soils of the conterminous United States
Between 2007 and 2013, the U.S. Geological Survey conducted a low-density (1 site per 1,600 square kilometers, 4,857 sites) geochemical and mineralogical survey of soils in the conterminous United States. The sampling protocol for the national-scale survey included, at each site, a sample from a depth of 0 to 5 centimeters, a composite of the soil A horizon, and a deeper sample from the soil C hor
Authors
David B. Smith, Federico Solano, Laurel G. Woodruff, William F. Cannon, Karl J. Ellefsen
Comment on “Particle fluxes in groundwater change subsurface rock chemistry over geologic time”
Over the last decade, studies at the Shale Hills Critical Zone Observatory (Shale Hills) have greatly expanded knowledge of weathering in previously understudied, shale-mantled terrains, as well as Earth's Critical Zone as a whole. Among the many discoveries made was the importance of redistribution and losses of micron-sized particles during development of shale-derived soils. A geochemical finge
Authors
Carleton R. Bern, Tiffany Yesavage
Calcrete uranium deposits in the Southern High Plains, USA
The Southern High Plains (SHP) is a new and emerging U.S. uranium province. Here, uranyl vanadates form deposits in Pliocene to Pleistocene sandstone, dolomite, and limestone. Fifteen calcrete uranium occurrences are identified; two of these, the Buzzard Draw and Sulfur Springs Draw deposits, have combined in-place resources estimated at about 4 million pounds of U3O8. Ore minerals carnotite and f
Authors
Susan Hall, Bradley S. Van Gosen, James B. Paces, Robert A. Zielinski