Publications
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In situ evidence for an ancient aqueous environment at Meridiani Planum, Mars In situ evidence for an ancient aqueous environment at Meridiani Planum, Mars
Sedimentary rocks at Eagle crater in Meridiani Planum are composed of fine-grained siliciclastic materials derived from weathering of basaltic rocks, sulfate minerals (including magnesium sulfate and jarosite) that constitute several tens of percent of the rock by weight, and hematite. Cross-stratification observed in rock outcrops indicates eolian and aqueous transport. Diagenetic...
Authors
S. W. Squyres, J.P. Grotzinger, R. E. Arvidson, J.F. Bell, W. Calvin, P. R. Christensen, B. C. Clark, J.A. Crisp, W. H. Farrand, Kenneth E. Herkenhoff, J. R. Johnson, G. Klingelhofer, A.H. Knoll, S. M. McLennan, H.Y. McSween, R.V. Morris, J. W. Rice, R. Rieder, Laurence A. Soderblom
Basaltic rocks analyzed by the Spirit rover in Gusev crater Basaltic rocks analyzed by the Spirit rover in Gusev crater
The Spirit landing site in Gusev Crater on Mars contains dark, fine-grained, vesicular rocks interpreted as lavas. Pancam and Mini–Thermal Emission Spectrometer (Mini-TES) spectra suggest that all of these rocks are similar but have variable coatings and dust mantles. Magnified images of brushed and abraded rock surfaces show alteration rinds and veins. Rock interiors contain ≤25%...
Authors
H.Y. McSween, R. E. Arvidson, J.F. Bell, D. Blaney, N.A. Cabrol, P. R. Christensen, B. C. Clark, J.A. Crisp, L.S. Crumpler, D.J. Des Marias, J.D. Farmer, Ralf Gellert, A. Ghosh, S. Gorevan, T. Graff, J. Grant, L.A. Haskin, Kenneth E. Herkenhoff, J. R. Johnson, B.L. Jolliff, G. Klingelhoefer, A.T. Knudson, S. McLennan, K.A. Milam, J.E. Moersch, R.V. Morris, R. Rieder, S. W. Ruff, P.A. De Souza, S. W. Squyres, H. Wanke, A. Wang, M.B. Wyatt, A. Yen, J. Zipfel
Oxidized sulfur-rich mafic magma at Mount Pinatubo, Philippines Oxidized sulfur-rich mafic magma at Mount Pinatubo, Philippines
Basaltic fragments enclosed in andesitic dome lavas and pyroclastic flows erupted during the early stages of the 1991 eruption of Mount Pinatubo, Philippines, contain amphiboles that crystallized during the injection of mafic magma into a dacitic magma body. The amphiboles contain abundant melt inclusions, which recorded the mixing of andesitic melt in the mafic magma and rhyolitic melt...
Authors
J.C.M. de Hoog, K.H. Hattori, R. Hoblitt
Evidence for liquefaction identified in peeled slices of Holocene deposits along the Lower Columbia River, Washington Evidence for liquefaction identified in peeled slices of Holocene deposits along the Lower Columbia River, Washington
Peels made from 10 geoslices beneath a riverbank at Washington's Hunting Island, 45 km inland from the Pacific coast, aid in identifying sand that liquefied during prehistoric earthquakes of estimated magnitude 8-9 at the Cascadia subduction zone. Each slice was obtained by driving sheetpile and a shutter plate to depths of 6-8 m. The resulting sample, as long as 8 m, had a trapezoidal...
Authors
K. Takada, B.F. Atwater
Precise relocation of earthquakes following the 15 June 1991 eruption of Mount Pinatubo (Philippines) Precise relocation of earthquakes following the 15 June 1991 eruption of Mount Pinatubo (Philippines)
The 15 June 1991 climactic eruption of Mount Pinatubo (Philippines) was followed by intense seismicity that remained at a high level for several months. We located 10,839 events recorded between 1 July and mid-December 1991. In contrast to the preeruptive seismicity which was focused in two groups below the summit area, posteruptive events were widely distributed below and around the...
Authors
J. Battaglia, C.H. Thurber, J.-L. Got, C.A. Rowe, R.A. White
Age of the Rockland tephra, western USA Age of the Rockland tephra, western USA
The age of the Rockland tephra, which includes an ash-flow tuff south and west of Lassen Peak in northern California and a widespread ash-fall deposit that produced a distinct stratigraphic marker in western North America, is constrained to 565,000 to 610,000 yr by 40Ar/39Ar and U–Pb dating. 40Ar/39Ar ages on plagioclase from pumice in the Rockland have a weighted mean age of 609,000 ±...
Authors
M. A. Lanphere, D.E. Champion, M.A. Clynne, J. B. Lowenstern, A.M. Sarna-Wojcicki, J. L. Wooden
Comparison of USGS and DLR topographic models of Comet Borrelly and photometric applications Comparison of USGS and DLR topographic models of Comet Borrelly and photometric applications
Stereo analysis of images obtained during the 2001 flyby of Comet Borrelly by NASA's Deep Space 1 (DS1) probe allows us to quantify the shape and photometric behavior of the nucleus. The shape is complex, with planar facets corresponding to the dark, mottled regions of the surface whereas the bright, smooth regions are convexly curved. The photometric as well as textural differences...
Authors
Randolph L. Kirk, Elpitha Howington-Kraus, Laurence A. Soderblom, Bernd Giese, Jurgen Oberst
Coastal vulnerability assessment of Cumberland Island National Seashore (CUIS) to sea-level rise Coastal vulnerability assessment of Cumberland Island National Seashore (CUIS) to sea-level rise
A coastal vulnerability index (CVI) was used to map the relative vulnerability of the coast to future sea-level rise within Cumberland Island National Seashore in Georgia. The CVI ranks the following in terms of their physical contribution to sea-level rise-related coastal change: geomorphology, regional coastal slope, rate of relative sea-level rise, historical shoreline change rates...
Authors
Elizabeth A. Pendleton, E. Robert Thieler, S. Jeffress Williams
Holocene reef accretion: southwest Molokai, Hawaii, U.S.A. Holocene reef accretion: southwest Molokai, Hawaii, U.S.A.
Two reef systems off south Molokai, Hale O Lono and Hikauhi (separated by only 10 km), show strong and fundamental differences in modern ecosystem structure and Holocene accretion history that reflect the influence of wave-induced near-bed shear stresses on reef development in Hawaii. Both sites are exposed to similar impacts from south, Kona, and trade-wind swell. However, the Hale O...
Authors
Mary S. Engels, Charles H. Fletcher, Michael E. Field, Curt D. Storlazzi, Eric E. Grossman, John J.B. Rooney, Christopher L. Conger, Craig Glenn
Shear- and compressional- wave velocity measurements from two 150-m-deep boreholes in Seattle, Washington, USA Shear- and compressional- wave velocity measurements from two 150-m-deep boreholes in Seattle, Washington, USA
No abstract available.
Authors
Jack K. Odum, William J. Stephenson, Kathy Goetz-Troost, David M. Worley, Arthur D. Frankel, Robert A. Williams, Jake Fryer
The role of water in gas hydrate dissociation The role of water in gas hydrate dissociation
When raised to temperatures above the ice melting point, gas hydrates release their gas in well-defined, reproducible events that occur within self-maintained temperature ranges slightly below the ice point. This behavior is observed for structure I (carbon dioxide, methane) and structure II gas hydrates (methane-ethane, and propane), including those formed with either H2O- or D2O-host...
Authors
S. Circone, L.A. Stern, S. H. Kirby
Surface changes on Io during the Galileo mission Surface changes on Io during the Galileo mission
A careful survey of Galileo SSI global monitoring images revealed more than 80 apparent surface changes that took place on Io during the 5 year period of observation, ranging from giant plume deposits to subtle changes in the color or albedo of Patera surfaces. Explosive volcanic activity was discovered at four previously unrecognized centers: an unnamed patera to the south of Karei that...
Authors
Paul E. Geissler, Alfred McEwen, Cynthia B. Phillips, Laszlo P. Keszthelyi, John Spencer