Seismograms offer insight into Oklahoma City bombing
T.L. Holzer, Joe B. Fletcher, G. S. Fuis, T. Ryberg, T.M. Brocher, C.M. Dietel
1996, Eos, Transactions, American Geophysical Union (77) 393-399
The terrorist bombing of the Alfred P. Murrah Federal Building in Oklahoma City on April 19, 1995, generated seismic waves that were recorded on two permanent seismographs about 7 and 26 km away from the bombing. The seismogram recorded at 26 km shows two low-frequency wave...
Timing of emplacement of the sapphire-bearing Yogo Dike, Little Belt Mountains, Montana
S. S. Harlan
1996, Economic Geology (91) 1159-1162
No abstract available....
Nitrate reduction in sediments of lowland tropical streams draining swamp forest in Costa Rica: An ecosystem perspective
J.H. Duff, C. M. Pringle, F.J. Triska
1996, Biogeochemistry (33) 179-196
Nitrate reduction and denitrification were measured in swamp forest streams draining lowland rain forest on Costa Rica's Atlantic slope foothills using the C2H2-block assay and sediment-water nutrient fluxes. Denitrification assays using the C2H2-block technique indicated that the full suite of denitrifying enzymes were present in the sediment but that only...
Contamination of Boston Harbor sediments by sewage: Assessment using molecular markers
R.P. Eganhouse, P.M. Sherblom
1996, ACS Division of Environmental Chemistry, Preprints (36) 189-191
[No abstract available]...
Simple method for the measurement of the hydrogenotrophic methanogenic activity of anaerobic sludges
J.D. Coates, M.F. Coughlan, E. Colleran
1996, Journal of Microbiological Methods (26) 237-246
The specific hydrogenotrophic activity of anaerobic sludges is usually assayed by gas chromatographic analysis for methane in the headspace of sealed test vials. Gas is sampled with a pressure lock syringe which allows quantification independent of the pressure prevailing in the vials. An alternative method was developed using pressure transducer...
Deep-sea ostracode shell chemistry (Mg:Ca ratios) and late Quaternary Arctic Ocean history
T. M. Cronin, Gary S. Dwyer, P.A. Baker, J. Rodriguez-Lazaro, W. M. Briggs Jr.
Andrews J.T.et al, editor(s)
1996, Geological Society Special Publication (111) 117-134
The magnesium:calcium (Mg:Ca) and strontium:calcium (Sr:Ca) ratios were investigated in shells of the benthic ostracode genus Krithe obtained from 64 core-tops from water depths of 73 to 4411 m in the Arctic Ocean and Nordic seas to determine the potential of ostracode shell chemistry for palaeoceanographic study. Shells from the...
Osmium isotopes and silver as tracers of anthropogenic metals in sediments from Massachusetts and Cape Cod bays
G.E. Ravizza, Michael H. Bothner
1996, Geochimica et Cosmochimica Acta (60) 2753-2763
High concentrations of osmium (Os) and silver (Ag) and low 187Os/186Os ratios in Boston sewage make these elements sensitive tracers of the influence of sewage on marine sediments in Massachusetts and Cape Cod bays. Pristine marine sediments have Ag concentrations more than 200 times lower than sewage sludge, Os concentrations...
Mechanism of formation of humus coatings on mineral surfaces 2. Attenuated total reflectance spectra of hydrophobic and hydrophilic fractions of organic acids from compost leachate on alumina
R.L. Wershaw, E.C. Llaguno, J.A. Leenheer, R.P. Sperline, Y. Song
1996, Colloids and Surfaces A: Physicochemical and Engineering Aspects (108) 199-211
Hydrophobic and hydrophilic fractions were isolated from a compost leachate. The adsorption isotherms of both fractions on alumina were measured by attenuated total reflectance infrared spectroscopy. The shapes of the adsorption isotherms of the two fractions were different. The isotherms for the hydrophilic fraction showed little change in surface excess...
Uranium adsorption on ferrihydrite - Effects of phosphate and humic acid
T.E. Payne, J.A. Davis, T.D. Waite
1996, Radiochimica Acta (74) 239-243
Uranium adsorption on ferrihydrite was studied as a function of pH in systems equilibrated with air, in the presence and absence of added phosphate and humic acid (HA). The objective was to determine the influence of PO43- and HA on...
Analysis of the mobility of far reaching debris flows on the Mississippi Fan, Gulf of Mexico
J. Locat, H. J. Lee, H.C. Nelson, W. C. Schwab, D.C. Twichell
Kaare Senneset, editor(s)
1996, Conference Paper, Landslides: Proceedings of the seventh international symposium on landslides (Volume 1: Assessment and management of landslide risks and hazards)
No abstract available....
Quantitative investigations of the Missouri gravity low: A possible expression of a large, Late Precambrian batholith intersecting the New Madrid seismic zone
T.G. Hildenbrand, A. Griscom, W. R. Van Schmus, W.D. Stuart
1996, Journal of Geophysical Research B: Solid Earth (101) 21921-21942
Analysis of gravity and magnetic anomaly data helps characterize the geometry and physical properties of the source of the Missouri gravity low, an important cratonic feature of substantial width (about 125 km) and length (> 600 km). Filtered anomaly maps show that this prominent feature extends NW from the Reelfoot...
Low-velocity fault-zone guided waves: Numerical investigations of trapping efficiency
Y.-G. Li, J.E. Vidale
1996, Bulletin of the Seismological Society of America (86) 371-378
Recent observations have shown that shear waves trapped within low-velocity fault zones may be the most sensitive measure of fault-zone structure (Li et al., 1994a, 1994b). Finite-difference simulations demonstrate the effects of several types of complexity on observations of fault-zone trapped waves. Overlying sediments...
Climatic control of nitrate loss from forested watersheds in the northeast United States
M.J. Mitchell, C. T. Driscoll, J. S. Kahl, G.E. Likens, Peter S. Murdoch, L.H. Pardo
1996, Environmental Science & Technology (30) 2609-2612
Increased losses of nitrate from watersheds may accelerate the depletion of nutrient cations and affect the acidification and trophic status of surface waters. Patterns of nitrate concentrations and losses were evaluated in four forested watersheds (East Bear Brook Watershed, Lead Mountain, ME; Watershed 6, Hubbard Brook Experimental Forest, White Mountains,...
Diatoms as an aid in identifying late-holocene tsunami deposits
E. Hemphill-Haley
1996, Holocene (6) 439-448
Diatoms (Bacillariophyta) help identify the onshore deposits of tsunamis from earthquakes on the Cascadia subduction zone along the Pacific coast of Oregon, Washington, and British Columbia, and on faults high in the North American plate in the Puget Sound area of Washington. At the Copalis River, Washington, diatom analyses suggest...
Silurian sequence stratigraphy in the North American craton, Great Lakes area
R.H. Shaver
Witzke B.J., editor(s)
1996, Paleozoic sequence stratigraphy: views from the North American craton 193-202
A notable circumstance of late Early through Late Silurian sedimentation on the Great Lakes area craton is that at least two and possibly three cycles of third-order duration (if eustatically considered) are recognized in basin and shallow-platform settings alike. Both virtually pure and siliciclastic-rich carbonate rocks exist in parts of...
Chemistry and potential mutagenicity of humic substances in waters from different watersheds in Britain and Ireland
B.E. Watt, Ronald L. Malcolm, M.H.B. Hayes, N.W.E. Clark, J.K. Chipman
1996, Water Research (30) 1502-1516
Humic substances are amorphous organic macromolecules responsible for the hue of natural waters. They are also known to be precursors of mutagens formed on chlorination prior to distribution of drinking water. In this study humic substances from the waters of primary streams, from major rivers, and from reservoirs were isolated...
Processes affecting the fate of monoaromatic hydrocarbons in an aquifer contaminated by crude oil
R.P. Eganhouse, T.F. Dorsey, C.S. Phinney, A.M. Westcott
1996, Environmental Science & Technology (30) 3304-3312
Crude oil spilled from a subsurface pipeline in north-central Minnesota has dissolved in the groundwater, resulting in the formation of a plume of aliphatic, aromatic, and alicyclic hydrocarbons. Comparison of paired oil and groundwater samples collected along the central axis of the residual oil body shows that the trailing edge...
The atomic arrangement of iimoriite-(Y), Y2(SiO4)(CO3)
J.M. Hughes, E.E. Foord, J. Jai-Nhuknan, J.M. Bell
1996, Canadian Mineralogist (34) 817-820
Iimoriite-(Y) from Bokan Mountain, Prince of Wales Island, Alaska has been studied using single-crystal X-ray-diffraction techniques. The mineral, ideally Y2(SiO4)(CO3), crystallizes in space group P1, with a 6.5495(13), b 6.6291(14), c 6.4395(11)A??, ?? 116.364(15), ?? 92.556(15) and ?? 95.506(17)??. The atomic arrangement has been solved and refined to an R...
Recent volcanism in the Siqueiros transform fault: Picritic basalts and implications for MORB magma genesis
M.R. Perfit, D.J. Fornari, W.I. Ridley, P.D. Kirk, John F. Casey, K.A. Kastens, J.R. Reynolds, M. Edwards, D. Desonie, R. Shuster, S. Paradis
1996, Earth and Planetary Science Letters (141) 91-108
Small constructional volcanic landforms and very fresh-looking lava flows are present along one of the inferred active strike-slip faults that connect two small spreading centers (A and B) in the western portion of the Siqueiros transform domain. The most primitive lavas (picritic and olivine-phyric basalts), exclusively recovered from the young-looking...
A resource evaluation of the Bakken Formation (Upper Devonian and Lower Mississippian) continuous oil accumulation, Williston Basin, North Dakota and Montana
J. W. Schmoker
1996, Mountain Geologist (33) 1-10
The Upper Devonian and Lower Mississippian Bakken Formation in the United States portion of the Williston Basin is both the source and the reservoir for a continuous oil accumulation - in effect a single very large field - underlying approximately 17,800 mi2 (46,100 km2) of North Dakota and Montana. Within...
Earthquake mechanisms from linear-programming inversion of seismic-wave amplitude ratios
B.R. Julian, G.R. Foulger
1996, Bulletin of the Seismological Society of America (86) 972-980
The amplitudes of radiated seismic waves contain far more information about earthquake source mechanisms than do first-motion polarities, but amplitudes are severely distorted by the effects of heterogeneity in the Earth. This distortion can be reduced greatly by using the ratios of amplitudes...
Aquifer Response to Record Low Barometric Pressures in the Southeastern United States
J. E. Landmeyer
1996, Groundwater (34) 917-924
A late-winter cyclone classified as one of the most intense of the 20th century moved across the Southeastern states of Georgia and South Carolina and onto the Northeast during March 12–14, 1993. Record low barometric pressures were recorded in Augusta, Georgia (28.93 inches of...
Limestone characterization to model damage from acidic precipitation: Effect of pore structure on mass transfer
S.D. Leith, M.M. Reddy, W.F. Irez, M.J. Heymans
1996, Environmental Science & Technology (30) 2202-2210
The pore structure of Salem limestone is investigated, and conclusions regarding the effect of the pore geometry on modeling moisture and contaminant transport are discussed based on thin section petrography, scanning electron microscopy, mercury intrusion porosimetry, and nitrogen adsorption analyses. These investigations are compared to and shown to compliment permeability...
Residence time of water discharging from the Hanging Gardens of Zion Park
B. A. Kimball, P.K. Christensen
1996, Water Resources Bulletin (32) 531-540
The Hanging Gardens are a unique feature of Zion National Park. Knowledge of the source and residence time of water discharging from the Hanging Gardens is necessary to help preserve these features. Ground-water chemical and isotopic data distinguish the discharge from seeps and springs into two groups, one of low...
Identification of a new sulfonic acid metabolite of metolachlor in soil
D.S. Aga, E.M. Thurman, M.E. Yockel, L.R. Zimmerman, T.D. Williams
1996, Environmental Science & Technology (30) 592-597
An ethanesulfonic acid metabolite of metolachlor (metolachlor ESA) was identified in soil-sample extracts by negative-ion, fast-atom bombardment mass spectrometry (FAB-MS) and FAB tandem mass spectrometry (FAB-MS/MS). Production fragments from MS/MS analysis of the deprotonated molecular ion of metolachlor ESA in the soil extract can be reconciled with the structure of...
