Publications
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The ubiquitous nature of accessory calcite in granitoid rocks: Implications for weathering, solute evolution, and petrogenesis The ubiquitous nature of accessory calcite in granitoid rocks: Implications for weathering, solute evolution, and petrogenesis
Calcite is frequently cited as a source of excess Ca, Sr and alkalinity in solutes discharging from silicate terrains yet, no previous effort has been made to assess systematically the overall abundance, composition and petrogenesis of accessory calcite in granitoid rocks. This study addresses this issue by analyzing a worldwide distribution of more than 100 granitoid rocks. Calcite is...
Authors
A. F. White, M. S. Schulz, J. B. Lowenstern, D.V. Vivit, T.D. Bullen
Provenance and diagenesis of the evaporite-bearing Burns formation, Meridiani Planum, Mars Provenance and diagenesis of the evaporite-bearing Burns formation, Meridiani Planum, Mars
Impure reworked evaporitic sandstones, preserved on Meridiani Planum, Mars, are mixtures of roughly equal amounts of altered siliciclastic debris, of basaltic provenance (40 ± 10% by mass), and chemical constituents, dominated by evaporitic minerals (jarosite, Mg-, Ca-sulfates ± chlorides ± Fe-, Na-sulfates), hematite and possibly secondary silica (60 ± 10%). These chemical constituents...
Authors
S. M. McLennan, J.F. Bell, W. M. Calvin, P. R. Christensen, B. C. Clark, P.A. de Souza, J. Farmer, W. H. Farrand, D.A. Fike, Ralf Gellert, A. Ghosh, T.D. Glotch, J.P. Grotzinger, B. Hahn, Kenneth E. Herkenhoff, J.A. Hurowitz, J. R. Johnson, S.S. Johnson, B. Jolliff, G. Klingelhofer, A.H. Knoll, Z. Learner, M. C. Malin, H.Y. McSween, J. Pocock, S. W. Ruff, Laurence A. Soderblom, S. W. Squyres, N.J. Tosca, W.A. Watters, M.B. Wyatt, A. Yen
Volcán Popocatépetl, Mexico. Petrology, magma mixing, and immediate sources of volatiles for the 1994- Present eruption Volcán Popocatépetl, Mexico. Petrology, magma mixing, and immediate sources of volatiles for the 1994- Present eruption
Volcán Popocatépetl has been the site of voluminous degassing accompanied by minor eruptive activity from late 1994 until the time of writing (August 2002). This contribution presents petrological investigations of magma erupted in 1997 and 1998, including major-element and volatile (S, Cl, F, and H2O) data from glass inclusions and matrix glasses. Magma erupted from Popocatépetl is a...
Authors
J.B. Witter, V.C. Kress, C. G. Newhall
Decadal-scale change of infiltration characteristics of a tephra-mantled hillslope at Mount St Helens, Washington Decadal-scale change of infiltration characteristics of a tephra-mantled hillslope at Mount St Helens, Washington
The cataclysmic 1980 eruption of Mount St Helens radically reduced the infiltration characteristics of ∼60 000 ha of rugged terrain and dramatically altered landscape hydrology. Two decades of erosional, biogenic, cryogenic, and anthropogenic activity have modified the infiltration characteristics of much of that devastated landscape and modulated the hydrological impact of the eruption...
Authors
J. J. Major, T. Yamakoshi
Thermal infrared and visual observations of a water ice lag in the Mars southern summer Thermal infrared and visual observations of a water ice lag in the Mars southern summer
We present thermal infrared and visual evidence for the existence of water ice lags in the early southern summer. The observed H2O‐ice lags lay in and near a chasma and appears to survive between 6–8 sols past the sublimation of the CO2. Possible sources of the H2O that compose the lag are (1) atmospheric H2O that is incorporated into the seasonal cap during condensation, (2) cold...
Authors
Timothy N. Titus
Mars exploration rover geologic traverse by the spirit rover in the plains of Gusev crater, Mars Mars exploration rover geologic traverse by the spirit rover in the plains of Gusev crater, Mars
The Spirit rover completed a 2.5 km traverse across gently sloping plains on the floor of Gusev crater from its location on the outer rim of Bonneville crater to the lower slopes of the Columbia Hills, Mars. Using the Athena suite of instruments in a transect approach, a systematic series of overlapping panoramic mosaics, remote sensing observations, surface analyses, and trenching...
Authors
L.S. Crumpler, S. W. Squyres, R. E. Arvidson, J.F. Bell, D. Blaney, N.A. Cabrol, P. R. Christensen, D.J. DesMarais, J.D. Farmer, R. Fergason, M.P. Golombek, F.D. Grant, J. A. Grant, R. Greeley, B. Hahn, Kenneth E. Herkenhoff, J.A. Hurowitz, A.T. Knudson, G. A. Landis, R. Li, J. Maki, H.Y. McSween, D. W. Ming, J.E. Moersch, M.C. Payne, J.W. Rice, L. Richter, S. W. Ruff, M. Sims, S.D. Thompson, N. Tosca, A. Wang, P. Whelley, S.P. Wright, M.B. Wyatt
Physical and chemical properties of submarine basaltic rocks from the submarine flanks of the Hawaiian Islands Physical and chemical properties of submarine basaltic rocks from the submarine flanks of the Hawaiian Islands
To evaluate physical and chemical diversity in submarine basaltic rocks, approximately 280 deep submarine samples recovered by submersibles from the underwater flanks of the Hawaiian Islands were analyzed and compared. Based on observations from the submersibles and hand specimens, these samples were classified into three main occurrence types (lavas, coarse-grained volcaniclastic rocks...
Authors
Hisayoshi Yokose, Peter W. Lipman, Toshiya Kanamatsu
An efficient algorithm for double-difference tomography and location in heterogeneous media, with an application to the Kilauea volcano An efficient algorithm for double-difference tomography and location in heterogeneous media, with an application to the Kilauea volcano
Improving our understanding of crustal processes requires a better knowledge of the geometry and the position of geological bodies. In this study we have designed a method based upon double-difference relocation and tomography to image, as accurately as possible, a heterogeneous medium containing seismogenic objects. Our approach consisted not only of incorporating double difference in...
Authors
V. Monteiller, J.-L. Got, J. Virieux, P. Okubo
THEMIS VIS and IR observations of a high-altitude Martian dust devil THEMIS VIS and IR observations of a high-altitude Martian dust devil
The Mars Odyssey Thermal Emission Imaging System (THEMIS) imaged a Martian dust devil in both visible and thermal-infrared wavelengths on January 30, 2004. We believe this is the first documented infrared observation of an extraterrestrial dust devil, and the highest to be directly observed at more than 16 kilometers above the equatorial geoid of Mars. This dust devil measured over 700...
Authors
Glen Cushing, Timothy N. Titus, Phillip R. Christensen
Regulation of landslide motion by dilatancy and pore pressure feedback Regulation of landslide motion by dilatancy and pore pressure feedback
A new mathematical model clarifies how diverse styles and rates of landslide motion can result from regulation of Coulomb friction by dilation or contraction of water‐saturated basal shear zones. Normalization of the model equations shows that feedback due to coupling between landslide motion, shear zone volume change, and pore pressure change depends on a single dimensionless parameter...
Authors
R.M. Iverson
An assessment of volcanic threat and monitoring capabilities in the United States: Framework for a National Volcano Early Warning System An assessment of volcanic threat and monitoring capabilities in the United States: Framework for a National Volcano Early Warning System
Executive Summary NVEWS – a National Volcano Early Warning System – is being formulated by the Consortium of U.S. Volcano Observatories (CUSVO) to establish a proactive, fully integrated, national-scale monitoring effort that ensures the most threatening volcanoes in the United States are properly monitored in advance of the onset of unrest and at levels commensurate with the threats...
Authors
John W. Ewert, Marianne Guffanti, Thomas L. Murray
2004 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory 2004 volcanic activity in Alaska and Kamchatka: Summary of events and response of the Alaska Volcano Observatory
No abstract available.
Authors
Christina A. Neal, Robert G. McGimsey, Jim Dixon, Dmitry Melnikov