Oxidation of aromatic contaminants coupled to microbial iron reduction
Derek R. Lovley, M.J. Baedecker, D.J. Lonergan, I.M. Cozzarelli, Elizabeth J.P. Phillips, D. I. Siegel
1989, Nature (339) 297-300
THE contamination of sub-surface water supplies with aromatic compounds is a significant environmental concern1,2. As these contaminated sub-surface environments are generally anaerobic, the microbial oxidation of aromatic compounds coupled to nitrate reduction, sulphate reduction and methane production has been studied intensively1-7. In addition, geochemical evidence suggests that Fe(III) can be...
Data-collection program for Pamlico River Estuary model calibration and validation
Jerad D. Bales
1989, Conference Paper
An investigation is being conducted to collect and interpret continuous records relating to the flow characteristics of the Pamlico River Estuary, North Carolina, and to calibrate and validate a numerical model of estuarine hydrodynamics. The study reach is 50 kilometers long and ranges in width from 330 meters at the...
Moment-tensor solutions estimated using optimal filter theory: global seismicity, 1984-1987
S.A. Sipkin, R.E. Needham
1989, Physics of the Earth and Planetary Interiors (57) 233-259
Moment-tensor solutions, estimated using optimal filter theory, are listed for 426 moderate- to large-sized earthquakes occurring from 1984 to 1987. ?? 1989....
Adaptive modeling, identification, and control of dynamic structural systems. I. Theory
Erdal Safak
1989, Journal of Engineering Mechanics (115) 2386-2405
A concise review of the fheory of adaptive modeling, identification, and control of dynamic structural systems based on discrete‐time recordings is presented. Adaptive methods have four major advantages over the classical methods: (1) Removal of the noise from the signal is done over the whole frequency band; (2) time‐varying characteristics...
Solid-state 13C nuclear magnetic resonance studies of coalified gymnosperm xylem tissue from Australian brown coals
Patrick G. Hatcher, Harry E. Lerch, Anne L. Bates, T.V. Verheyen
1989, Organic Geochemistry (14) 145-155
We report here on the use of solid-state 13C nuclear magnetic resonance (NMR) spectroscopy to contrast the average chemical composition of modern degraded gymnosperm woods with fossil gymnosperm woods from Australian brown coals (Miocene). We first established the quantitative nature of the NMR techniques for these samples so that the conventional...
Mixing and residence times of stormwater runoff in a detection system
Edward H. Martin
1989, Conference Paper
Five tracer runs were performed on a detention pond and wetlands system to determine mixing and residence times in the system. The data indicate that at low discharges and with large amounts of storage, the pond is moderately mixed with residence times not much less than the theoretical maximum possible...
High-precision UPb ages of metamorphic rutile: Application to the cooling history of high-grade terranes
K. Mezger, G. N. Hanson, S.R. Bohlen
1989, Earth and Planetary Science Letters (96) 106-118
Metamorphic rutiles occurring in granulite and upper amphibolite facies metapelitic rocks of the Archean Pikwitonei granulite domain (Manitoba) and the Proterozoic Adirondack terrane (New York) give concordant and near concordant UPb ages. The Pb concentrations in rutile range from 2.85 to 168 ppm, U concentrations range...
Survey of three-dimensional numerical estuarine models
Ralph T. Cheng, Peter E. Smith
1989, Conference Paper
This paper surveys the existing 3-D estuarine hydrodynamic and solute transport models by a review of the commonly used assumptions and approximations, and by an examination of the methods of solution. The model formulations, methods of solution, and known applications are surveyed and summarized in tables. In conclusion, the authors...
Multiobjective sampling design for parameter estimation and model discrimination in groundwater solute transport
Debra S. Knopman, Clifford I. Voss
1989, Water Resources Research (25) 2245-2258
Sampling design for site characterization studies of solute transport in porous media is formulated as a multiobjective problem. Optimal design of a sampling network is a sequential process in which the next phase of sampling is designed on the basis of all available physical knowledge of the system. Three objectives...
The structure of subtidal currents within and around Lydonia Canyon: Evidence for enhanced cross-shelf fluctuations over the mouth of the canyon
M. Noble, B. Butman
1989, Journal of Geophysical Research - Oceans (94) 8091-8110
Between October 1980 and April 1981, currents were measured within Lydonia Canyon and on the adjacent shelf and slope. The amplitude of the subtidal currents over the shelf and slope ranged between 10 and 30 cm s−1, but within the canyon, they were typically smaller than 5 cm s−1. The...
Speciation and equilibrium relations of soluble aluminum in a headwater stream at base flow and during rain events
Douglas A. Burns
1989, Water Resources Research (25) 1653-1665
In a small watershed in the Shenandoah National Park, Virginia, the short-term dynamics of soluble aluminum in stream water sampled during rain events differed significantly from stream water sampled during base flow conditions. Three fractions of dissolved aluminum were measured. The inorganic monomeric fraction made up approximately two thirds of...
The Relief Canyon gold deposit, Nevada: A mineralized solution breccia
A. R. Wallace
1989, Economic Geology (84) 279-290
The Relief Canyon gold deposit in the Humboldt Range of western Nevada is a low-grade, high-tonnage orebody of Tertiary or younger age. The host rocks include limestones of the Triassic Cane Spring Formation, which are overlain by shales of the Triassic Grass Valley Formation. The rocks were folded and metamorphosed...
Simulation of ground-water flow in coastal southern New Jersey
Frederick J. Spitz, Thomas H. Barringer
1989, Conference Paper, Coastal Zone: Proceedings of the Symposium on Coastal and Ocean Management
An increasing trend of shallow ground-water withdrawal over the first part of this century on the Cape May Peninsula of New Jersey has resulted in the intrusion of saltwater into the aquifers that comprise the shallow ground-water system. The U.S. Geological Survey has developed a mathematical model of the flow...
Pillow basalts of the Angayucham terrane: Oceanic plateau and island crust accreted to the Brooks Range
J.S. Pallister, J. R. Budahn, B.L. Murchey
1989, Journal of Geophysical Research Solid Earth (94) 15901-15923
The Angayucham Mountains (north margin of the Yukon-Koyukuk province) are made up of an imbricate stack of four to eight east-west trending, steeply dipping, fault slabs composed of Paleozoic (Devonian to Mississippean), Middle to Late Triassic, and Early Jurassic oceanic upper crustal rocks (pillow basalt, subordinate diabase, basaltic tuff, and...
Biogeography of marine podocopid Ostracodes in Micronesia
L.S. Weissleader, N.L. Gilinsky, R. M. Ross, T. M. Cronin
1989, Journal of Biogeography (16) 103-114
Shallow-water podocopic marine Ostracoda from Micronesian lagoons in the Marianas, Caroline, Marshall and Gilbert Islands in the western Pacific were analysed to establish their diversity and zoogeography within Micronesia and the taxonomic affinities with ostracodes from other tropical regions. Sixty-four bottom lagoonal sediment samples from twelve islands and atolls yielded...
Acceleration spectra for subduction zone earthquakes
J. Boatwright, G. L. Choy
1989, Journal of Geophysical Research Solid Earth (94) 15541-15553
We estimate the source spectra of shallow earthquakes from digital recordings of teleseismic P wave groups, that is, P + pP + sP, by making frequency dependent corrections for the attenuation and for the interference of the free surface. The correction for the interference of the free surface assumes that the earthquake radiates energy from a range...
Undiscovered lode tin resources of the Seward Peninsula, Alaska
B.L. Reed, W. D. Menzie, M. McDermott, D. H. Root, W. Scott, L.J. Drew
1989, Economic Geology (84) 1936-1947
The United States is a net importer of many important minerals, including tin. Consumption of primary tin in the United States is about 36,000 metric tons per year. Identified U.S. tin resources consist of about 40,000 metric tons. Although such figures provide insight about vulnerability to supply disruptions in the...
Dynamic rupture modeling with laboratory-derived constitutive relations
P. G. Okubo
1989, Journal of Geophysical Research Solid Earth (94) 12321-12335
A laboratory-derived state variable friction constitutive relation is used in the numerical simulation of the dynamic growth of an in-plane or mode II shear crack. According to this formulation, originally presented by J. H. Dieterich, frictional resistance varies with the logarithm of the slip rate and with the logarithm of...
Hydraulic analysis of the Schoharie Creek bridge
David C. Froehlich, Roy E. Trent
1989, Conference Paper
Ten people died on April 5, 1987 as a result of the collapse of two spans of a New York State Thruway bridge into the floodwaters of Schoharie Creek. The cause of the bridge failure was determined to be scour of bed material from under the foundations of piers supporting...
Petrologic evolution of divergent peralkaline magmas from the Silent Canyon caldera complex, southwestern Nevada volcanic field
D.A. Sawyer, K. A. Sargent
1989, Journal of Geophysical Research Solid Earth (94) 6021-6040
The Silent Canyon volcanic center consists of a buried Miocene peralkaline caldera complex and outlying peralkaline lava domes. Its location has been corroborated by geophysical data and more than 50 drill holes. Two widespread ash flow sheets, the Tub Spring and overlying Grouse Canyon members of the Miocene Belted Range...
A terracing operator for physical property mapping with potential field data
L. Cordell, A. E. McCafferty
1989, Geophysics (54) 621-634
The terracing operator works iteratively on gravity or magnetic data, using the sense of the measured field's local curvature, to produce a field comprised of uniform domains separated by abrupt domain boundaries. The result is crudely proportional to a physical-property function defined in one (profile case) or two (map case)...
The chemical structure of highly aromatic humic acids in three volcanic ash soils as determined by dipolar dephasing NMR studies
Patrick G. Hatcher, M. Schnitzer, A. M. Vassallo, M. A. Wilson
1989, Geochimica et Cosmochimica Acta (53) 125-130
Dipolar dephasing 13C NMR studies of three highly aromatic humic acids, one from a modern soil and two from paleosols, have permitted the determination of the degree of aromatic substitution. From these data and the normal solid-state 13C NMR data we have been able to develop a model for the average chemical...
Interrelationships among hydrologic-budget components of a northern Wisconsin seepage lake and implications for acid-deposition modeling
Dennis A. Wentz, William J. Rose
1989, Archives of Environmental Contamination and Toxicology (18) 147-155
Components of the hydrologic budget for a northern Wisconsin seepage lake were analyzed by applying correlation and regression techniques to monthly data. Analyses for the 1981–83 water years revealed a statistically significant, direct relationship between storage change and precipitation-evaporation balance. Ground-water outflow was negatively correlated with ground-water inflow, and this...
Influence of coupling of sorption and photosynthetic processes on trace element cycles in natural waters
C. C. Fuller, J.A. Davis
1989, Nature (340) 52-57
Chemical and biological processes have important roles in the transport and cycling of trace elements in natural waters, but their complex interactions are often not well understood. Trace-element concentrations may, for example, be controlled by adsorption-desorption reactions at mineral surfaces, with the equilibrium strongly influenced by pH. Variations in pH...
Thermal stresses due to cooling of a viscoelastic oceanic lithosphere
R.P. Denlinger, W. Z. Savage
1989, Journal of Geophysical Research Solid Earth (94) 744-752
Theories based upon thermal contraction of cooling oceanic lithosphere provide a successful basis for correlating seafloor bathymetry and heat flow. The horizontal components of the contraction of the lithosphere as it cools potentially give rise to large thermal stresses. Current methods to calculate these stresses assume that on the time...
