The metallogeny of Late Triassic rifting of the Alexander terrane in southeastern Alaska and northwestern British Columbia
C. D. Taylor, W. R. Premo, A. L. Meier, J.E. Taggart Jr.
2008, Conference Paper, Economic Geology
A belt of unusual volcanogenic massive sulfide (VMS) occurrences is located along the eastern margin of the Alexander terrane throughout southeastern Alaska and northwestern British Columbia and exhibits a range of characteristics consistent with a variety of syngenetic to epigenetic deposit types. Deposits within this belt include Greens Creek and...
Methyl tert-butyl ether (MTBE) in public and private wells in New Hampshire: Occurrence, factors, and possible implications
J. D. Ayotte, D.M. Argue, F.J. McGarry, J.R. Degnan, L. Hayes, S. M. Flanagan, D.R. Helsel
2008, Environmental Science & Technology (42) 677-684
Methyl tert-butyl ether (MTBE) concentrations ???0.2 ??g/L were found in samples of untreated water in 18% of public-supply wells (n = 284) and 9.1% of private domestic wells (n = 264) sampled in 2005 and 2006 in New Hampshire. In counties that used reformulated gasoline (RFG), MTBE occurred at or...
Restoring habitat permeability to roaded landscapes with isometrically-scaled wildlife crossings
J.A. Bissonette, W. Adair
2008, Biological Conservation (141) 482-488
Globally, human activities impact from one-third to one-half of the earth's land surface; a major component of development involves the construction of roads. In the US and Europe, road networks fragment normal animal movement patterns, reduce landscape permeability, and increase wildlife-vehicle collisions, often with serious wildlife population and human health...
Titan's inventory of organic surface materials
Ralph D. Lorenz, Karl L. Mitchell, Randolph L. Kirk, Alexander G. Hayes, Oded Aharonson, Howard A. Zebker, Philipe Paillou, Jani Radebaugh, Jonathan I. Lunine, Michael A. Janssen, Stephen D. Wall, Rosaly Lopes, Bryan Stiles, Steven J. Ostro, Giuseppe Mitri, Ellen R. Stofan
2008, Geophysical Research Letters (35)
Cassini RADAR observations now permit an initial assessment of the inventory of two classes, presumed to be organic, of Titan surface materials: polar lake liquids and equatorial dune sands. Several hundred lakes or seas have been observed, of which dozens are each estimated to contain more hydrocarbon liquid than the...
Storm-damaged saline-contaminated boreholes as a means of aquifer contamination
D.A. Carlson, T. P. Van Biersel, L.R. Milner
2008, Ground Water (46) 69-79
Saline water from a storm surge can flow down storm-damaged submerged water supply wells and contaminate boreholes and surrounding aquifers. Using data from conventional purging techniques, aquifer test response analysis, chemical analysis, and regression analysis of chloride/silica (Cl/Si) ratio, equations were derived to estimate the volume of saline water intrusion...
Multi-phase evolution of gnammas (weathering pits) in a Holocene deglacial granite landscape, Minnesota (USA)
D. Dominguez-Villar, C.E. Jennings
2008, Earth Surface Processes and Landforms (33) 165-177
The morphometry of 85 gnammas (weathering pits) from Big Stone County in western Minnesota allows the assessment of the relative ages of the gnamma population. The ratio between maximum and minimum depths is independent of the initial size of the cavity and only depends on the weathering evolution. Therefore, the...
Mapping invasive wetland plants in the Hudson River National Estuarine Research Reserve using quickbird satellite imagery
M. Laba, R. Downs, S. Smith, S. Welsh, C. Neider, S. White, M. Richmond, W. Philpot, P. Baveye
2008, Remote Sensing of Environment (112) 286-300
The National Estuarine Research Reserve (NERR) program is a nationally coordinated research and monitoring program that identifies and tracks changes in ecological resources of representative estuarine ecosystems and coastal watersheds. In recent years, attention has focused on using high spatial and spectral resolution satellite imagery to map and monitor wetland...
Food limitation leads to behavioral diversification and dietary specialization in sea otters
M. T. Tinker, G. Bentall, J. A. Estes
2008, Proceedings of the National Academy of Sciences of the United States of America (105) 560-565
Dietary diversity often varies inversely with prey resource abundance. This pattern, although typically measured at the population level, is usually assumed to also characterize the behavior of individual animals within the population. However, the pattern might also be produced by changes in the degree of variation among individuals. Here we...
Measuring the performance of two stationary interrogation systems for detecting downstream and upstream movement of PIT-tagged salmonids
P.J. Connolly, I.G. Jezorek, K.D. Martens, E.F. Prentice
2008, North American Journal of Fisheries Management (28) 402-417
We tested the performance of two stationary interrogation systems designed for detecting the movement of fish with passive integrated transponder (PIT) tags. These systems allowed us to determine the direction of fish movement with high detection efficiency and high precision in a dynamic stream environment. We describe an indirect method...
A biodynamic understanding of dietborne metal uptake by a freshwater invertebrate
M.-N. Croteau, S. N. Luoma
2008, Environmental Science & Technology (42) 1801-1806
Aquatic organisms accumulate metals from dissolved and particulate phases. Dietborne metal uptake likely prevails in nature, but the physiological processes governing metal bioaccumulation from diet are not fully understood. We characterize dietborne copper, cadmium, and nickel uptake by a freshwater gastropod (Lymnaea stagnalis) both in terms of biodynamics and membrane...
HiRISE observations of fractured mounds: Possible Martian pingos
Colin M. Dundas, Michael T. Mellon, Alfred S. McEwen, Alexandra Lefort, Laszlo P. Keszthelyi, Nicolas Thomas
2008, Geophysical Research Letters (35)
Early images from the High Resolution Imaging Science Experiment (HiRISE) camera have revealed small fractured mounds in the Martian mid‐latitudes. HiRISE resolves fractures on the mound surfaces, indicating uplift, and shows that the mound surface material resembles that of the surrounding landscape. Analysis of Mars Orbiter Camera (MOC) images shows...
A comparative analysis of simulated and observed landslide locations triggered by Hurricane Camille in Nelson County, Virginia
M.M. Morrissey, G. F. Wieczorek, B. A. Morgan
2008, Hydrological Processes (22) 524-531
In 1969, Nelson County, Virginia received up to 71 cm of rain within 12 h starting at 7 p.m. on August 19. The total rainfall from the storm exceeded the 1000-year return period in the region. Several thousands of landslides were induced by rainfall associated with Hurricane Camille causing fatalities...
Sunlight, season, snowmelt, storm, and source affect E. coli populations in an artificially ponded stream
R.L. Whitman, K. Przybyla-Kelly, D.A. Shively, M.B. Nevers, M.N. Byappanahalli
2008, Science of the Total Environment (390) 448-455
Reducing fecal indicator bacteria, such as Escherichia coli (E. coli), in streams is important for many downstream areas. E. coli concentrations within streams may be reduced by intervening ponds or wetlands through a number of physical and biological means. A section of Dunes Creek, a small coastal stream of southern...
Are hotspots of evolutionary potential adequately protected in southern California?
Amy G. Vandergast, A.J. Bohonak, S.A. Hathaway, J. Boys, Robert N. Fisher
2008, Biological Conservation (141) 1648-1664
Reserves are often designed to protect rare habitats, or "typical" exemplars of ecoregions and geomorphic provinces. This approach focuses on current patterns of organismal and ecosystem-level biodiversity, but typically ignores the evolutionary processes that control the gain and loss of biodiversity at these and other levels (e.g., genetic, ecological). In...
Clarification and changes in Permian stratigraphic nomenclature in Kansas
R.S. Sawin, E. K. Franseen, R.R. West, Greg A. Ludvigson, W.L. Watney
2008, Current Research in Earth Sciences (254) 1-3
This paper outlines Permian nomenclature changes to Zeller (1968) that have been adopted by the Kansas Geological Survey. The Permian System/ Period, Cisuralian Series/Epoch, and Asselian Stage/Age are established at the base of the Bennett Shale Member of the Red Eagle Limestone. Series/epoch names Wolfcampian, Leonardian, and Guadalupian are retained...
SAGE celebrates 25 years of learning geophysics by doing geophysics
G.R. Jiracek, W.S. Baldridge, A.J. Sussman, S. Biehler, L.W. Braile, J.F. Ferguson, B.E. Gilpin, D.K. McPhee, L. Pellerin
2008, Leading Edge (Tulsa, OK) (27) 1340-1344
The increasing world demand and record-high costs for energy and mineral resources, along with the attendant environmental and climate concerns, have escalated the need for trained geophysicists to unprecedented levels. This is not only a national need; it's a critical global need. As Earth scientists and educators we must seriously...
Modeling variability and trends in pesticide concentrations in streams
A. V. Vecchia, Jeffrey D. Martin, R. J. Gilliom
2008, Journal of the American Water Resources Association (44) 1308-1324
A parametric regression model was developed for assessing the variability and long-term trends in pesticide concentrations in streams. The dependent variable is the logarithm of pesticide concentration and the explanatory variables are a seasonal wave, which represents the seasonal variability of concentration in response to seasonal application rates; a streamflow...
Mesozoic non-marine petroleum source rocks determined by palynomorphs in the Tarim Basin, Xinjiang, northwestern China
D.-X. Jiang, Y.-D. Wang, E. I. Robbins, J. Wei, N. Tian
2008, Geological Magazine (145) 868-885
The Tarim Basin in Northwest China hosts petroleum reservoirs of Cambrian, Ordovician, Carboniferous, Triassic, Jurassic, Cretaceous and Tertiary ages. The sedimentary thickness in the basin reaches about 15 km and with an area of 560000 km2, the basin is expected to contain giant oil and gas fields. It is therefore...
Factors influencing nesting success of king eiders on northern Alaska's Coastal Plain
R.L. Bentzen, A.N. Powell, R.S. Suydam
2008, Journal of Wildlife Management (72) 1781-1789
King eider (Somateria spectabilis) populations have declined markedly in recent decades for unknown reasons. Nest survival is one component of recruitment, and a female's chance of reproductive success increases with her ability to choose an appropriate nesting strategy. We estimated variation in daily nest survival of king eiders at 2...
Thermal and energetic constraints on ectotherm abundance: A global test using lizards
L.B. Buckley, G.H. Rodda, W. Jetz
2008, Ecology (89) 48-55
Population densities of birds and mammals have been shown to decrease with body mass at approximately the same rate as metabolic rates increase, indicating that energetic needs constrain endotherm population densities. In ectotherms, the exponential increase of metabolic rate with body temperature suggests that environmental temperature may additionally constrain population...
The role of shear and tensile failure in dynamically triggered landslides
T.L. Gipprich, R.K. Snieder, R.W. Jibson, W. Kimman
2008, Geophysical Journal International (172) 770-778
Dynamic stresses generated by earthquakes can trigger landslides. Current methods of landslide analysis such as pseudo-static analysis and Newmark's method focus on the effects of earthquake accelerations on the landslide mass to characterize dynamic landslide behaviour. One limitation of these methods is their use Mohr-Coulomb failure criteria, which only accounts...
Modeled tephra ages from lake sediments, base of Redoubt Volcano, Alaska
C.J. Schiff, D. S. Kaufman, K.L. Wallace, A. Werner, T.-L. Ku, T.A. Brown
2008, Quaternary Geochronology (3) 56-67
A 5.6-m-long lake sediment core from Bear Lake, Alaska, located 22 km southeast of Redoubt Volcano, contains 67 tephra layers deposited over the last 8750 cal yr, comprising 15% of the total thickness of recovered sediment. Using 12 AMS 14C ages, along with the 137Cs and 210Pb activities of recent...
Effects of grade control structures on the macroinvertebrate assemblage of an agriculturally impacted stream
M.E. Litvan, T.W. Stewart, C.L. Pierce, C.J. Larson
2008, River Research and Applications (24) 218-233
Nearly 400 rock rip-rap grade control structures (hereafter GCS) were recently placed in streams of western Iowa, USA to reduce streambank erosion and protect bridge infrastructure and farmland. In this region, streams are characterized by channelized reaches, highly incised banks and silt and sand substrates that normally support low macroinvertebrate...
Trace element emissions from spontaneous combustion of gob piles in coal mines, Shanxi, China
Y. Zhao, Jiahua Zhang, C. L. Chou, Y. Li, Z. Wang, Y. Ge, C. Zheng
2008, International Journal of Coal Geology (73) 52-62
The emissions of potentially hazardous trace elements from spontaneous combustion of gob piles from coal mining in Shanxi Province, China, have been studied. More than ninety samples of solid waste from gob piles in Shanxi were collected and the contents of twenty potentially hazardous trace elements (Be, F, V, Cr,...
An exact solution for ideal dam-break floods on steep slopes
C. Ancey, Richard M. Iverson, M. Rentschler, Roger P. Denlinger
2008, Water Resources Research (44)
The shallow‐water equations are used to model the flow resulting from the sudden release of a finite volume of frictionless, incompressible fluid down a uniform slope of arbitrary inclination. The hodograph transformation and Riemann's method make it possible to transform the governing equations into a linear system and then deduce...
