Publications
Filter Total Items: 7240
Spatial and temporal geochemical trends in the hydrothermal system of Yellowstone National Park: Inferences from river solute fluxes
We present and analyze a chemical dataset that includes the concentrations and fluxes of HCO3−, SO42−, Cl−, and F− in the major rivers draining Yellowstone National Park (YNP) for the 2002–2004 water years (1 October 2001 – 30 September 2004). The total (molar) flux in all rivers decreases in the following order, HCO3− > Cl− > SO42− > F−, but each river is characterized by a distinct chemical comp
Authors
Shaul Hurwitz, Jacob B. Lowenstern, Henry Heasler
Shoreline change as a proxy for subaerial beach volume change
It is difficult and expensive to calculate changes in sediment volume for large sections of sandy beaches. Shoreline change could be a useful proxy for volume change because it can be collected quickly and relatively easily over long distances. In this paper, we summarize several studies that find a high correlation between shoreline change and subaerial volume change. We also examine three new da
Authors
Amy S. Farris, Jeffrey H. List
Characteristics of vesicomyid clams and their environment at the Blake Ridge cold seep, South Carolina, USA
Spatial distributions and patchiness of dominant megafaunal invertebrates in deep-sea seep environments may indicate heterogeneities in the flux of reduced chemical compounds. At the Blake Ridge seep off South Carolina, USA, the invertebrate assemblage includes dense populations of live vesicomyid clams (an undescribed species) as well as extensive clam shell beds (i.e. dead clams). In the present
Authors
Taylor P. Heyl, William P. Gilhooly, Randolph M. Chambers, George W. Gilchrist, Stephen A. Macko, Carolyn D. Ruppel, Cindy L. Van Dover
Preliminary analysis of the earthquake (MW 8.1) and tsunami of April 1, 2007, in the Solomon Islands, southwestern Pacific Ocean
On April 1, 2007, a destructive earthquake (Mw 8.1) and tsunami struck the central Solomon Islands arc in the southwestern Pacific Ocean. The earthquake had a thrust-fault focal mechanism and occurred at shallow depth (between 15 km and 25 km) beneath the island arc. The combined effects of the earthquake and tsunami caused dozens of fatalities and thousands remain without shelter. We present a pr
Authors
Michael A. Fisher, Eric L. Geist, Ray Sliter, Florence L. Wong, Carol Reiss, Dennis M. Mann
A multiple-approach radiometric age estimate for the Rotoiti and Earthquake Flat eruptions, New Zealand, with implications for the MIS 4/3 boundary
Pyroclastic fall deposits of the paired Rotoiti and Earthquake Flat eruptions from the Taupo Volcanic Zone (New Zealand) combine to form a widespread isochronous horizon over much of northern New Zealand and the southwest Pacific. This horizon is important for correlating climatic and environmental changes during the Last Glacial period, but has been the subject of numerous disparate age estimates
Authors
C. J. N. Wilson, D.A. Rhoades, M. A. Lanphere, A.T. Calvert, Bruce F. Houghton, S.D. Weaver, J. W. Cole
Meter-scale morphology of the north polar region of mars
Mars' north pole is covered by a dome of layered ice deposits. Detailed (∼30 centimeters per pixel) images of this region were obtained with the High-Resolution Imaging Science Experiment on board the Mars Reconnaissance Orbiter (MRO). Planum Boreum basal unit scarps reveal cross-bedding and show evidence for recent mass wasting, flow, and debris accumulation. The north polar layers themselves are
Authors
Kenneth E. Herkenhoff, S. Byrne, P.S. Russell, K.E. Fishbaugh, A. S. McEwen
Athabasca Valles, Mars: A lava-draped channel system
Athabasca Valles is a young outflow channel system on Mars that may have been carved by catastrophic water floods. However, images acquired by the High-Resolution Imaging Science Experiment camera onboard the Mars Reconnaissance Orbiter spacecraft reveal that Athabasca Valles is now entirely draped by a thin layer of solidified lava - the remnant of a once-swollen river of molten rock. The lava er
Authors
Windy L. Jaeger, Laszlo P. Keszthelyi, Alfred S. McEwen, Colin M. Dundas, Paul C. Russell
A closer look at water-related geologic activity on Mars
Water has supposedly marked the surface of Mars and produced characteristic landforms. To understand the history of water on Mars, we take a close look at key locations with the High-Resolution Imaging Science Experiment on board the Mars Reconnaissance Orbiter, reaching fine spatial scales of 25 to 32 centimeters per pixel. Boulders ranging up to ∼2 meters in diameter are ubiquitous in the middle
Authors
Alfred S. McEwen, C.J. Hansen, W.A. Delamere, E. M. Eliason, Kenneth E. Herkenhoff, Laszlo P. Keszthelyi, V. C. Gulick, Randolph L. Kirk, M. T. Mellon, J. A. Grant, N. Thomas, C.M. Weitz, S. W. Squyres, N.T. Bridges, S.L. Murchie, F. Seelos, K. Seelos, C.H. Okubo, M.P. Milazzo, L.L. Tornabene, W.L. Jaeger, S. Byrne, P.S. Russell, J.L. Griffes, S. Martinez-Alonso, A. Davatzes, F. C. Chuang, B.J. Thomson, K.E. Fishbaugh, C. M. Dundas, K.J. Kolb, M. E. Banks, J.J. Wray
Ecological observations on the colonial ascidian Didemnum sp. in a New England tide pool habitat
The colonial ascidian Didemnum sp. has colonized northwestern Atlantic coastal habitats from southern Long Island, New York, to Eastport, Maine. It is also present in offshore habitats of the Georges Bank fishing grounds. It threatens to alter fisheries habitats and shellfish aquacultures.
Observations in a tide pool at Sandwich, MA from December 2003 to February 2006 show that Didemnum sp. toler
Authors
P. C. Valentine, M.R. Carman, D.S. Blackwood, E.J. Heffron
An assessment of ichthyofaunal assemblages within the mangal of the Belize offshore cays
We assessed ichthyofaunal diversity within offshore mangrove cays in Belize during three, 2-wk surveys (2003, 2004, 2005). Nine sampling gears were deployed in pre-defined micro-habitats: fringe, transition, dwarf red mangrove, internal creeks, ponds, and sinkholes. Water quality data (temperature, salinity, DO) were taken during most collections. A total of 2586 gear sets was completed and 8131 i
Authors
D.S. Taylor, E.A. Reyier, C.C. McIvor, W.P. Davis
Altered mangrove wetlands as habitat for estuarine nekton: are dredged channels and tidal creeks equivalent?
Hasty decisions are often made regarding the restoration of "altered" habitats, when in fact the ecological value of these habitats may be comparable to natural ones. To assess the "value" of altered mangrove-lined habitats for nekton, we sampled for 1 yr within three Tampa Bay wetlands. Species composition, abundance, and spatial distribution of nekton assemblages in permanent subtidal portions o
Authors
Justin M. Krebs, Adam B. Brame, Carole C. McIvor
Coastal-change impacts during hurricane katrina: an overview
As part of an ongoing cooperative effort between USGS, NASA and USACE, the barrier islands within the right-front quadrant of Hurricane Katrina were surveyed with airborne lidar both before and after landfall. Dauphin Island, AL was located the farthest from landfall and wave runup intermittently overtopped its central and western sections. The Gulf-side of the island experienced severe erosion, l
Authors
Asbury Sallenger, C. Wayne Wright, Jeff Lillycrop