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: 1952
Opaline silica in young deposits on Mars Opaline silica in young deposits on Mars
High spatial and spectral resolution reflectance data acquired by the Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument reveal the presence of H2O- and SiOH-bearing phases on the Martian surface. The spectra are most consistent with opaline silica and glass altered to various degrees, confirming predictions based on geochemical...
Authors
Ralph E. Milliken, Gregg A. Swayze, Raymond E. Arvidson, Janice L Bishop, Roger N. Clark, Bethany L. Ehlmann, Robert O. Green, John P. Grotzinger, R.V. Morris, Scott L. Murchie, John F. Mustard, C. Weitz
Track of the Yellowstone hotspot: Young and ongoing geologic processes from the Snake River Plain to the Yellowstone Plateau and Tetons Track of the Yellowstone hotspot: Young and ongoing geologic processes from the Snake River Plain to the Yellowstone Plateau and Tetons
This field trip highlights various stages in the evolution of the Snake River Plain–Yellowstone Plateau bimodal volcanic province, and associated faulting and uplift, also known as the track of the Yellowstone hotspot. The 16 Ma Yellowstone hotspot track is one of the few places on Earth where time-transgressive processes on continental crust can be observed in the volcanic and tectonic...
Authors
Lisa A. Morgan, Kenneth L. Pierce, Pat Shanks
Axial high topography and partial melt in the crust and mantle beneath the western Galápagos Spreading Center Axial high topography and partial melt in the crust and mantle beneath the western Galápagos Spreading Center
The hot spot-influenced western Galápagos Spreading Center (GSC) has an axial topographic high that reaches heights of ∼700 m relative to seafloor depth ∼25 km from the axis. We investigate the cause of the unusual size of the axial high using a model that determines the flexural response to loads resulting from the thermal and magmatic structure of the lithosphere. The thermal structure...
Authors
Tanya M. Blacic, Garrett Ito, Anjana K. Shah, Juan Pablo Canales, Jian Lin
Evolution of Devonian carbonate-shelf margin, Nevada Evolution of Devonian carbonate-shelf margin, Nevada
The north-trending, 550-km-long Nevada segment of the Devonian carbonate-shelf margin, which fringed western North America, evidences the complex interaction of paleotectonics, eustasy, biotic changes, and bolide impact-related influences. Margin reconstruction is complicated by mid-Paleozoic to Paleogene compressional tectonics and younger extensional and strike-slip faulting. Reports...
Authors
J. R. Morrow, Charles Sandberg
Fluvial erosion and post-erosional processes on Titan Fluvial erosion and post-erosional processes on Titan
The surface of Titan has been revealed by Cassini observations in the infrared and radar wavelength ranges as well as locally by the Huygens lander instruments. Sand seas, recently discovered lakes, distinct landscapes and dendritic erosion patterns indicate dynamic surface processes. This study focus on erosional and depositional features that can be used to constrain the amount of...
Authors
R. Jaumann, R. H. Brown, K. Stephan, J. W. Barnes, L.A. Soderblom, Christophe Sotin, Stéphane Le Mouélic, R. N. Clark, J. Soderblom, B. J. Buratti, R. Wagner, T. B. McCord, S. Rodriguez, K. H. Baines, D. P. Cruikshank, P. D. Nicholson, C.A. Griffith, M. Langhans, R. D. Lorenz
Cathodoluminescence, laser ablasion inductively coupled plasma mass spectrometry, electron probe microanalysis and electron paramagnetic resonance analyses of natural sphalerite Cathodoluminescence, laser ablasion inductively coupled plasma mass spectrometry, electron probe microanalysis and electron paramagnetic resonance analyses of natural sphalerite
Natural sphalerite associated with copper, silver, lead-zinc, tin and tungsten deposits from various world-famous mineral deposits have been studied by cathodoluminescence (CL), laser ablasion inductively coupled plasma mass spectrometry (LA-ICP-MS), electron probe microanalysis (EPMA) and electron paramagnetic resonance (EPR) to determine the relationship between trace element type and...
Authors
M. Karakus, R.D. Hagni, A. Koenig, E. Ciftc
Boulder Creek: A stream ecosystem in an urban landscape Boulder Creek: A stream ecosystem in an urban landscape
The Boulder Creek Watershed, within the Front Range region of Colorado, is typical of many western watersheds because it is composed of a high-gradient upper reach mostly fed by snowmelt, a substantial change in gradient at the range front, and an urban corridor within the lower gradient section. A stream ecosystem within an urban landscape not only can provide water for municipal...
Authors
Philip L. Verplanck, Sheila F. Murphy, Peter W. Birkeland, Pitlick, Larry B. Barber, Travis S. Schmidt
Characterization of the shallow groundwater system in an alpine watershed: Handcart Gulch, Colorado, USA Characterization of the shallow groundwater system in an alpine watershed: Handcart Gulch, Colorado, USA
Water-table elevation measurements and aquifer parameter estimates are rare in alpine settings because few wells exist in these environments. Alpine groundwater systems may be a primary source of recharge to regional groundwater flow systems. Handcart Gulch is an alpine watershed in Colorado, USA comprised of highly fractured Proterozoic metamorphic and igneous rocks with wells completed...
Authors
Katherine G. Kahn, Shemin Ge, Jonathan S. Caine, A. Manning
Devonian brachiopods of southwesternmost laurentia: Biogeographic affinities and tectonic significance Devonian brachiopods of southwesternmost laurentia: Biogeographic affinities and tectonic significance
Three brachiopod faunas discussed herein record different depositional and tectonic settings along the southwestern margin of Laurentia (North America) during Devonian time. Depositional settings include inner continental shelf (Cerros de Los Murcielagos), medial continental shelf (Rancho Placeritos), and offshelf continental rise (Rancho Los Chinos). Ages of Devonian brachiopod faunas...
Authors
A. J. Boucot, Forrest G. Poole, R. Amaya-Martinez, A. G. Harris, Charles Sandberg, William R. Page
Phyllosilicate and sulfate-hematite deposits within Miyamoto crater in Southern Sinus Meridiani, Mars Phyllosilicate and sulfate-hematite deposits within Miyamoto crater in Southern Sinus Meridiani, Mars
Orbital topographic, image, and spectral data show that sulfate- and hematite-bearing plains deposits similar to those explored by the MER rover Opportunity unconformably overlie the northeastern portion of the 160 km in diameter Miyamoto crater. Crater floor materials exhumed to the west of the contact exhibit CRISM and OMEGA NIR spectral signatures consistent with the presence of Fe/Mg...
Authors
S.M. Wiseman, R. E. Arvidson, J. C. Andrews-Hanna, R. N. Clark, N.L. Lanza, D. des Marais, G.A. Marzo, R.V. Morris, S.L. Murchie, Horton E. Newsom, E.Z. Noe Dobrea, A.M. Ollila, F. Poulet, T. L. Roush, F.P. Seelos, G.A. Swayze
Phyllosilicate diversity and past aqueous activity revealed at Mawrth Vallis, Mars Phyllosilicate diversity and past aqueous activity revealed at Mawrth Vallis, Mars
Observations by the Mars Reconnaissance Orbiter/Compact Reconnaissance Imaging Spectrometer for Mars in the Mawrth Vallis region show several phyllosilicate species, indicating a wide range of past aqueous activity. Iron/magnesium (Fe/Mg)-smectite is observed in light-toned outcrops that probably formed via aqueous alteration of basalt of the ancient cratered terrain. This unit is...
Authors
J.L. Bishop, E.Z.N. Dobrea, N.K. McKeown, M. Parente, B.L. Ehlmann, J.R. Michalski, R.E. Milliken, F. Poulet, G.A. Swayze, J.F. Mustard, S.L. Murchie, J.-P. Bibring
Hydrated silicate minerals on Mars observed by the Mars Reconnaissance Orbiter CRISM instrument Hydrated silicate minerals on Mars observed by the Mars Reconnaissance Orbiter CRISM instrument
Phyllosilicates, a class of hydrous mineral first definitively identified on Mars by the OMEGA (Observatoire pour la Mineralogie, L’Eau, les Glaces et l’Activitié) instrument1,2, preserve a record of the interaction of water with rocks on Mars. Global mapping showed that phyllosilicates are widespread but are apparently restricted to ancient terrains and a relatively narrow range of...
Authors
J.F. Mustard, S.L. Murchie, S.M. Pelkey, B.L. Ehlmann, R.E. Milliken, J. A. Grant, J.-P. Bibring, F. Poulet, J. Bishop, E. N. Dobrea, L. Roach, F. Seelos, R. E. Arvidson, S. Wiseman, R. Green, C. Hash, D. Humm, E. Malaret, J.A. McGovern, K. Seelos, T. Clancy, R. Clark, D. des Marais, N. Izenberg, A. Knudson, Y. Langevin, T. Martin, P. McGuire, Robert Morris, M. Robinson, T. Roush, M. Smith, G. Swayze, H. Taylor, T. Titus, M. Wolff