Publications
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Robust 24 ± 6 ka 40Ar/39Ar age of a low-potassium tholeiitic basalt in the Lassen region of NE California Robust 24 ± 6 ka 40Ar/39Ar age of a low-potassium tholeiitic basalt in the Lassen region of NE California
40Ar/39Ar ages on the Hat Creek Basalt (HCB) and stratigraphically related lava flows show that latest Pleistocene tholeiitic basalt with very low K2O can be dated reliably. The HCB underlies ∼ 15 ka glacial gravel and overlies four andesite and basaltic andesite lava flows that yield 40Ar/39Ar ages of 38 ± 7 ka (Cinder Butte; 1.65% K2O), 46 ± 7 ka (Sugarloaf Peak; 1.85% K2O), 67 ± 4 ka...
Authors
Brent D. Turrin, L.J. Patrick Muffler, Michael A. Clynne, Duane E. Champion
A three-dimensional geophysical model of the crust in the Barents Sea region: Model construction and basement characterization A three-dimensional geophysical model of the crust in the Barents Sea region: Model construction and basement characterization
BARENTS50, a new 3-D geophysical model of the crust in the Barents Sea Region has been developed by the University of Oslo, NORSAR and the U.S. Geological Survey. The target region comprises northern Norway and Finland, parts of the Kola Peninsula and the East European lowlands. Novaya Zemlya, the Kara Sea and Franz-Josef Land terminate the region to the east, while the Norwegian...
Authors
O. Ritzmann, N. Maercklin, Faleide J. Inge, H. Bungum, Walter D. Mooney, Shane T. Detweiler
Probabilistic volcanic hazard and risk assessment Probabilistic volcanic hazard and risk assessment
[No abstract available]
Authors
W. Marzocchi, A. Neri, C. G. Newhall, P. Papale
Amplitude loss of sonic waveform due to source coupling to the medium Amplitude loss of sonic waveform due to source coupling to the medium
In contrast to hydrate-free sediments, sonic waveforms acquired in gas hydrate-bearing sediments indicate strong amplitude attenuation associated with a sonic velocity increase. The amplitude attenuation increase has been used to quantify pore-space hydrate content by attributing observed attenuation to the hydrate-bearing sediment's intrinsic attenuation. A second attenuation mechanism...
Authors
Myung W. Lee, William F. Waite
New estimates for Io eruption temperatures: Implications for the interior New estimates for Io eruption temperatures: Implications for the interior
The initial interpretation of Galileo data from Jupiter's moon, Io, suggested eruption temperatures ≥1600°C. Tidal heating models have difficulties explaining Io's prodigious heat flow if the mantle is >1300°C, although we suggest that temperatures up to ~1450°C may be possible. In general, Io eruption temperatures have been overestimated because the incorrect thermal model has been...
Authors
Laszlo P. Keszthelyi, Windy L. Jaeger, Moses P. Milazzo, Jani Radebaugh, Ashley G. Davies, Karl L. Mitchell
Airborne desert dust and aeromicrobiology over the Turkish Mediterranean coastline Airborne desert dust and aeromicrobiology over the Turkish Mediterranean coastline
Between 18 March and 27 October 2002, 220 air samples were collected on 209 of 224 calendar days, on top of a coastal atmospheric research tower in Erdemli, Turkey. The volume of air filtered for each sample was 340 liters. Two hundred fifty-seven bacterial and 2598 fungal colony forming units (CFU) were enumerated from the samples using a low-nutrient agar. Ground-based dust...
Authors
Dale W. Griffin, Nilgun Kubilay, Mustafa Kocak, Mike A. Gray, Timothy C. Borden, Eugene A. Shinn
1400 yr multiproxy record of climate variability from the northern Gulf of Mexico 1400 yr multiproxy record of climate variability from the northern Gulf of Mexico
A continuous decadal-scale resolution record of climate variability over the past 1400 yr in the northern Gulf of Mexico was constructed from a box core recovered in the Pigmy Basin, northern Gulf of Mexico. Proxies include paired analyses of Mg/Ca and δ18O in the white variety of the planktic foraminifer Globigerinoides ruber and relative abundance variations of G. sacculifer in the...
Authors
J.N. Richey, R.Z. Poore, B.P. Flower, T. M. Quinn
A simple model for the spatially-variable coastal response to hurricanes A simple model for the spatially-variable coastal response to hurricanes
The vulnerability of a beach to extreme coastal change during a hurricane can be estimated by comparing the relative elevations of storm-induced water levels to those of the dune or berm. A simple model that defines the coastal response based on these elevations was used to hindcast the potential impact regime along a 50-km stretch of the North Carolina coast to the landfalls of...
Authors
H.F. Stockdon, A. H. Sallenger, R.A. Holman, P.A. Howd
Mangrove removal in the belize cays: effects on mangrove-associated fish assemblages in the intertidal and subtidal Mangrove removal in the belize cays: effects on mangrove-associated fish assemblages in the intertidal and subtidal
We investigated the effects of mangrove cutting on fish assemblages in Twin Cays, Belize, in two habitat types. We conducted visual censuses at two sites in adjoining undisturbed/disturbed (30%–70% of shoreline fringe removed) sub-tidal fringing Rhizophora mangle Linnaeus, 1753. Observers recorded significantly more species and individuals in undisturbed sites, especially among smaller...
Authors
D.S. Taylor, E.A. Reyier, W.P. Davis, C.C. McIvor
Close temporal correspondence between geomagnetic anomalies and earthquakes during the 2002-2003 eruption of Etna volcano Close temporal correspondence between geomagnetic anomalies and earthquakes during the 2002-2003 eruption of Etna volcano
The early stages of the 2002-2003 lateral eruption at Mount Etna were accompanied by slow changes (over some hours) and some rapid step offsets in the local magnetic field. At five monitoring locations, the total magnetic field intensity has been measured using continuously operating Overhauser magnetometers at a sampling rate of 10 s. The very unique aspect of these observations is the...
Authors
G. Currenti, Negro C. Del, M. Johnston, Y. Sasai
A closer look at water-related geologic activity on Mars 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...
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 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...
Authors
P. C. Valentine, M.R. Carman, D.S. Blackwood, E.J. Heffron