Bias in ground-water data caused by well-bore flow in long-screen wells
P. E. Church, G.E. Granato
1996, Groundwater (34) 262-273
The results of a field experiment comparing water-quality constituents, specific conductance, geophysical measurements, and well-bore hydraulics in two long-screen wells and adjacent vertical clusters of short-screen wells show bias in ground-water data caused by well-bore flow in long-screen wells. The well screen acts as a...
Seismic reflection evidence against a shallow detachment beneath Yucca Mountain, Nevada
Thomas M. Brocher, W. Clay Hunter
1996, Conference Paper, High Level Radioactive Waste Management - Proceedings of the Annual International Conference
Intermediate-depth seismic reflection profile across Crater Flat and Yucca Mountain is obtained. The aim of the seismic profiling are discrimination the subsurface geometry of faults and imaging of the boundary between the pre-Tertiary sedimentary strata and the Miocene volcanic rocks of Yucca Mountain. Of major interest is the existence and...
The effect of iron content and dissolved O2 on dissolution rates of clinopyroxene at pH 5.8 and 25°C: Preliminary results
A.R. Hoch, M.M. Reddy, J.I. Drever
1996, Chemical Geology (132) 151-156
Dissolution experiments using augite (Mg0.87Ca0.85Fe0.19Na0.09Al0.03Si2O6) and diopside (Mg0.91Ca0.93Fe0.07Na0.03Al0.03Si2O6) were conducted in flow-through reactors (5-ml/h flow rate). A pH of 5.8 was maintained by bubbling pure CO2 through a solution of 0.01 M KHCO3 at 25°C. Two experiments were run for each pyroxene type. In one experiment dissolved O2 concentration in...
Bivalves and gastropods from the middle Campanian Anacacho limestone, South Central Texas
W.P. Elder
1996, Journal of Paleontology (70) 247-270
The Anacacho Limestone was deposited during the Campanian and represents two depositional intervals, one of early Campanian and one of middle Campanian age. These two intervals correspond to periods of major eustatic sea level rise. This study focuses on the molluscan paleontology of the middle Campanian interval in the eastern...
Covalent binding of aniline to humic substances. 2. 15N NMR studies of nucleophilic addition reactions
K. A. Thorn, P.J. Pettigrew, W.S. Goldenberg, E.J. Weber
1996, Environmental Science & Technology (30) 2764-2775
Aromatic amines are known to undergo covalent binding with humic substances in the environment. Although previous studies have examined reaction conditions and proposed mechanisms, there has been no direct spectroscopic evidence for the covalent binding of the amines to the functional groups in humic substances. In order to further elucidate...
Jellyfish Lake, Palau: Regeneration of C, N, Si, and P in anoxic marine lake sediments
W.B. Lyons, R.M. Lent, W. C. Burnett, P. Chin, W.M. Landing, W. H. Orem, J.M. McArthur
1996, Limnology and Oceanography (41) 1394-1403
Sediment cores from Jellyfish Lake were processed under an inert atmosphere and the pore waters extracted and analyzed for the following parameters: pH, titration alkalinity (TA), Cl-, H4SiO4, PO43-, NH4+, Ca2-, Mg2+, SO42-, and H2S. Additionally, in one set of pore-water samples (core 10), the ??13C of the ??CO2 was...
Rupture directivity and slip distribution of the M 4.3 foreshock to the 1992 Joshua Tree earthquake, Southern California
J. Mori
1996, Bulletin of the Seismological Society of America (86) 805-810
Details of the M 4.3 foreshock to the Joshua Tree earthquake were studied using P waves recorded on the Southern California Seismic Network and the Anza network. Deconvolution, using an M 2.4 event as an empirical Green's function, corrected for complicated path and site effects in the seismograms and produced...
Remote sensing of forest fire severity and vegetation recovery
J.D. White, K.C. Ryan, C.H. Key, S. W. Running
1996, International Journal of Wildland Fire (6) 125-136
Burned forested areas have patterns of varying burn severity as a consequence of various topographic, vegetation, and meteorological factors. These patterns are detected and mapped using satellite data. Other ecological information can be abstracted from satellite data regarding rates of recovery of vegetation foliage and variation of burn severity on...
Denitrification and nitrogen transport in a coastal aquifer receiving wastewater discharge
L.A. DeSimone, B.L. Howes
1996, Environmental Science & Technology (30) 1152-1162
Denitrification and nitrogen transport were quantified in a sandy glacial aquifer receiving wastewater from a septage-treatment facility on Cape Cod, MA. The resulting groundwater plume contained high concentrations of NO3- (32 mg of NL-1), total dissolved nitrogen (40.5 mg of N L-1), and dissolved organic carbon (1.9 mg of C...
Mineral nitrogen transformations in and under seasonal snow in a high-elevation catchment in the Rocky Mountains, United States
Mark W. Williams, Paul D. Brooks, Arvin Mosier, Kathy A. Tonnessen
1996, Water Resources Research (32) 3161-3171
In an effort to understand sources of nitrate (NO3−) in surface waters of high-elevation catchments, nitrogen (N) transformations in and under seasonal snow were investigated from 1993 to 1995 on Niwot Ridge, an alpine ecosystem at 3,500 m located in the Colorado Front Range of the Rocky Mountains. Ammonium (NH4+)...
Isolation of Geobacter species from diverse sedimentary environments
J.D. Coaxes, Elizabeth J.P. Phillips, D.J. Lonergan, H. Jenter, Derek R. Lovley
1996, Applied and Environmental Microbiology (62) 1531-1536
In an attempt to better understand the microorganisms responsible for Fe(III) reduction in sedimentary environments, Fe(III)-reducing microorganisms were enriched for and isolated from freshwater aquatic sediments, a pristine deep aquifer, and a petroleum-contaminated shallow aquifer. Enrichments were initiated with acetate or toluene as the electron donor and Fe(III) as the...
Bacterial dissimilatory reduction of arsenic(V) to arsenic(III) in anoxic sediments
P.R. Dowdle, A.M. Laverman, R.S. Oremland
1996, Applied and Environmental Microbiology (62) 1664-1669
Incubation of anoxic salt marsh sediment slurries with 10 mM As(V) resulted in the disappearance over time of the As(V) in conjunction with its recovery as As(III). No As(V) reduction to As(III) occurred in heat- sterilized or formalin-killed controls or in live sediments incubated in air. The rate of As(V)...
Source rock potential of middle Cretaceous rocks in southwestern Montana
T. S. Dyman, J. G. Palacas, R. G. Tysdal, W. J. Perry Jr., M. J. Pawlewicz
1996, American Association of Petroleum Geologists Bulletin (80) 1177-1184
The middle Cretaceous in southwestern Montana is composed of a marine and nonmarine succession of predominantly clastic rocks that were deposited along the western margin of the Western Interior Seaway. In places, middle Cretaceous rocks contain appreciable total organic carbon (TOC), such as 5.59% for the Mowry Shale and 8.11%...
Detailed observations of California foreshock sequences: Implications for the earthquake initiation process
D.A. Dodge, G. C. Beroza, W.L. Ellsworth
1996, Journal of Geophysical Research B: Solid Earth (101) 22371-22392
We find that foreshocks provide clear evidence for an extended nucleation process before some earthquakes. In this study, we examine in detail the evolution of six California foreshock sequences, the 1986 Mount Lewis (ML = 5.5), the 1986 Chalfant (ML = 6.4), the 1986 Stone Canyon (ML = 4.7), the 1990 Upland (ML =...
Hydrologic landscapes on the Delmarva Peninsula Part 1: Drainage basin type and base-flow chemistry
P. J. Phillips, L. J. Bachman
1996, Water Resources Bulletin (32) 767-778
The relation between landscape characteristics and water chemistry on the Delmarva Peninsula can be determined through a principal-component analysis of basin characteristics. Two basin types were defined by factor scores: (1) well-drained basins, characterized by combinations of a low percentage of forest cover, a low percentage of poorly drained soil,...
Tectonic model explaining divergent contraction directions along the Cascadia subduction margin, Washington
P. A. McCrory
1996, Geology (24) 929-932
Differential motion across the central Cascadia subduction boundary in Washington results in a complex pattern of folds and faults within the shelf and onshore parts of the accretionary margin. Faults and folds above a coastal, north-northwest–trending thrust system provide evidence of ongoing subduction-related...
Ferromanganese crusts as indicators for paleoceanographic events in the NE Atlantic
A. Koschinsky, P. Halbach, J.R. Hein, A. Mangini
1996, Geologische Rundschau (85) 567-576
Hydrogenetic ferromanganese crusts reflect the chemical conditions of the sewater from which they formed. Fine-scale geochemical analysis of crust layers in combination with age determinations can therefore be used to investigate paleoceanographic changes which are recorded in geochemical gradients in the crusts. At Tropic seamount (off northwest Africa), uniform crust...
Incorporation of bacterial extracellular polysaccharide by black fly larvae (Simuliidae)
C. A. Couch, J.L. Meyer, R. O. Hall Jr.
1996, Journal of the North American Benthological Society (15) 289-299
Black fly larvae (Simulium) assimilated, with high efficiency (80-90%), bacterial extracellular polysaccharide (EPS) extracted from laboratory cultures of a pseudomonad isolated from the Ogeechee River. Incorporation was traced using <sup>13</sup>C-labelled EPS offered to larvae as a coating on a mixture of 1-μm...
Devonian conodont biochronology in geologic time calibration
Charles Sandberg, W. Ziegler
1996, Senckenbergiana Lethaea (76) 259-265
The conodont-based biochronology of the Devonian Period is calibrated herein on the basis of: (1) a recent, reliable radiometric dating (CLAQUE??-LONG et al. 1992) of a stratigraphic position just above the Devonian-Carboniferous boundary; and (2) new calculations of stage durations based on our estimates and those of a large number...
Simulating secondary succession of elk forage values in a managed forest landscape, western Washington
Kurt J. Jenkins, Edward E. Starkey
1996, Environmental Management (20) 715-724
Modern timber management practices often influence forage production for elk (Cervus elaphus) on broad temporal and spatial scales in forested landscapes. We incorporated site-specific information on postharvesting forest succession and forage characteristics in a simulation model to evaluate past and future influences of forest management practices on forage values for...
Shallow ground-water quality beneath a major urban center: Denver, Colorado, USA
B. W. Bruce, P.B. McMahon
1996, Journal of Hydrology (186) 129-151
A survey of the chemical quality of ground water in the unconsolidated alluvial aquifer beneath a major urban center (Denver, Colorado, USA) was performed in 1993 with the objective of characterizing the quality of shallow ground-water in the urban area and relating water quality to land use. Thirty randomly selected...
Non-double-couple earthquake mechanisms at the Geysers geothermal area, California
A. Ross, G.R. Foulger, B.R. Julian
1996, Geophysical Research Letters (23) 877-880
Inverting P- and S-wave polarities and P:SH amplitude ratios using linear programming methods suggests that about 20% of earthquakes at The Geysers geothermal area have significantly non-double-couple focal mechanisms, with explosive volumetric components as large as 33% of the seismic moment. This conclusion contrasts with those of earlier studies, which...
Late quaternary deltaic and carbonate sedimentation in the Gulf of Papua foreland basin: Response to sea-level change
P.T. Harris, C.B. Pattiaratchi, J.B. Keene, R.W. Dalrymple, J.V. Gardner, E.K. Baker, A.R. Cole, D. Mitchell, P. Gibbs, W.W. Schroeder
1996, Journal of Sedimentary Research (66) 801-819
The rivers that drain the wet, mountainous island of New Guinea discharge about 1.5 billion tonnes/yr of sediments into the adjacent seas, including the foreland basin between New Guinea and Australia. Despite this huge sediment input, there appears to have been only limited...
Writing user selectable data on the extended header of seismic recordings made on the Texas Instruments DFS-V
W.C. Robinson
1996, Marine Geology (135) 159-162
A circuit has been developed to allow the writing of up to 192 digits of user-selectable data on a portion of tape called extended header, which is always available for use before each DFS-V seismic record is written. Such data could include navigation information, air gun and streamer depth and...
Determination of nitroaromatic explosives and their degradation products in unsaturated-zone water samples by high-performance liquid chromatography with photodiode-array, mass spectrometric, and tandem mass spectrometric detection
Paul M. Gates, E. T. Furlong, T.F. Dorsey, M.R. Burkhardt
1996, TrAC - Trends in Analytical Chemistry (15) 319-325
Mass spectrometry and tandem mass spectrometry, coupled by a thermospray interface to a high-performance liguid chromatography system and equipped with a photodiode array detector, were used to determine the presence of nitroaromatic explosives and their degradation products in USA unsaturated-zone water samples. Using this approach, the lower limits of quantitation...
