Mechanism of molybdenum removal from the sea and its concentration in black shales: EXAFS evidence
G.R. Helz, C.V. Miller, J.M. Charnock, J.F.W. Mosselmans, R.A.D. Pattrick, C.D. Garner, D.J. Vaughan
1996, Geochimica et Cosmochimica Acta (60) 3631-3642
Molybdenum K-edge EXAFS (extended X-ray absorption fine structure) spectra yield new structural information about the chemical environment of Mo in high-Mo black shales and sediments. Two spectral types are found. The less common one, associated with Mo ores developed in shale in China, is that of a MoS2 phase, possibly...
Paleomagnetism of the Mississippi Valley-type Zn-Pb deposits of the Silesian-Cracow area, Poland
David T. A. Symons, D. F. Sangster, D. L. Leach
1996, Prace - Panstwowego Instytutu Geologicznego (154) 157-161
Paleomagnetic analysis of zinc-lead ore and host rocks from 35 sites in three mines and several quarries was completed using alternating field and thermal step demagnetization and saturation isothermal remanent magnetization methods. Paleomagnetic conglomerate, breccia and fold tests were used to test for remanence stability. Most limestone and dolostone sites...
Two-dimensional advective transport in ground-water flow parameter estimation
E.R. Anderman, M. C. Hill, E. P. Poeter
1996, Ground Water (34) 1001-1009
Nonlinear regression is useful in ground-water flow parameter estimation, but problems of parameter insensitivity and correlation often exist given commonly available hydraulic-head and head-dependent flow (for example, stream and lake gain or loss) observations. To address this problem, advective-transport observations are added to the ground-water flow, parameter-estimation model MODFLOWP using...
Analysis of nitrate in near-surface aquifers in the midcontinental United States: An application of the inverse hyperbolic sine Tobit model
Steven T. Yen, Shiping Liu, Dana W. Kolpin
1996, Water Resources Research (32) 3003-3011
A nonnormal and heteroscedastic Tobit model is used to determine the primary factors that affect nitrate concentrations in near-surface aquifers, using data from the U.S. Geological Survey collected in 1991. Both normality and homoscedasticity of errors are rejected, justifying the use of a nonnormal and heteroscedastic model. The following factors...
The alteration of rhyolite in CO2 charged water at 200 and 350°C: The unreactivity of CO2 at higher temperature
James L. Bischoff, Robert J. Rosenbauer
1996, Geochimica et Cosmochimica Acta (60) 3859-3867
Geochemical and hydrologic modeling indicates that geothermal waters in the T > 270°C reservoirs beneath Yellowstone National Park have HCO3 ≪ Cl and contrast with waters in reservoirs at lower temperatures which attain HCO3 about equal to Cl. Experiments reacting rhyolite with 0.5 molal solutions of CO2 at 200°...
Geochemistry of aquatic humic substances in the Lake Fryxell basin, Antarctica
G. Aiken, D. McKnight, R. Harnish, R. Wershaw
1996, Biogeochemistry (34) 157-188
Dissolved organic carbon (DOC) in Lake Fryxell, 10 streams flowing into the lake, and the moat surrounding the lake was studied to determine the influence of sources and biogeochemical processes on its distribution and chemical nature. Lake Fryxell is an amictic, permanently ice-covered lake in the McMurdo Dry Valleys which...
Remote mineralogic and lithologic mapping of the Ice River alkaline complex, British Columbia, Canada, using AVIRIS data
T. L. Bowers, L. C. Rowan
1996, Photogrammetric Engineering and Remote Sensing (62) 1379-1385
The Ice River Alkaline Complex is a late Paleozoic intrusion of mafic alkaline rocks, syenite, and carbonatite exposed in southeastern British Columbia, Canada. The complex intrudes Cambrian and Ordovician shales, slates, and limestones of the Chancellor and Ottertail Formations and the McKay Group. We examined the alkaline complex and adjacent...
A Generalized Approach for the Interpretation of Geophysical Well Logs in Ground-Water Studies:Theory and Application
Frederick L. Paillet, R.E. Crowder
1996, Ground Water (34) 883-898
Quantitative analysis of geophysical logs in ground-water studies often involves at least as broad a range of applications and variation in lithology as is typically encountered in petroleum exploration, making such logs difficult to calibrate and complicating inversion problem formulation. At the same time, data inversion and analysis depend on...
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...
Hydrogeology of the Hawaii Scientific Drilling Project borehole KP-1 2. Groundwater geochemistry and regional flow patterns
D. M. Thomas, Frederick L. Paillet, M.E. Conrad
1996, Journal of Geophysical Research B: Solid Earth (101) 11683-11694
A series of downhole and surface water samples were taken from the 1‐km‐deep KP‐1 borehole located on the eastern flank of the island of Hawaii. Early samples from depths of more than 700 m showed salinities nearly equivalent to seawater but having anomalous cation concentrations that are...
Simulation of temporal changes in rainfall-runoff characteristics, Coon Creek basin, Wisconsin
W.R. Krug
1996, Water Resources Bulletin (32) 745-752
Stream flow for 67 years was simulated for Coon Creek at Coon Valley, Wisconsin, for three conditions in the drainage basin: (1) conditions in the 1930s; (2) conditions in the 1970s, excluding flood-detention reservoirs; and (3) conditions in the 1970s, including flood-detention reservoirs. These simulations showed that the changes in...
Imaging the San Andreas fault with explosion and earthquake sources
C. Thurber, S. Roecker, W. Lutter, W. Ellsworth
1996, Eos, Transactions, American Geophysical Union (77) 45-48
Mounting evidence suggests that fault zone heterogeneity may play a crucial role in the localization of rupture in earthquakes [Aki, 1995]. The heterogeneity can take several forms: spatial variations in physical properties (elastic properties, pore fluid pressure, etc.) or complexity in the fault surface (bends, offsets, etc.). High-resolution, three-dimensional models...
Amplitude blanking in seismic profiles from Lake Baikal
Myung W. Lee, Warren F. Agena, D. R. Hutchinson
1996, Marine and Petroleum Geology (13) 549-563
Imaging of the deepest sedimentary section in Lake Baikal using multichannel seismic profiling was hampered by amplitude blanking that is regionally extensive, is associated with water depths greater than about 900 m and occurs at sub-bottom depths of 1-2 km in association with the first water-bottom multiple. Application of a...
Upscaled soil-water retention using van Genuchten's function
T.R. Green, J.E. Constantz, D.L. Freyberg
1996, Journal of Hydrologic Engineering (1) 123-130
Soils are often layered at scales smaller than the block size used in numerical and conceptual models of variably saturated flow. Consequently, the small-scale variability in water content within each block must be homogenized (upscaled). Laboratory results have shown that a linear volume average (LVA) of water content at a...
The reversibility of virus attachment to mineral surfaces
J.P. Loveland, J. N. Ryan, G.L. Amy, R.W. Harvey
1996, Colloids and Surfaces A: Physicochemical and Engineering Aspects (107) 205-221
Virus transport through groundwater is limited by attachment to mineral surfaces and inactivation. Current virus transport models do not consider the implications of the reversibility of virus attachment to minerals. To explore the reversibility of virus attachment to mineral surfaces, we attached PRD1, a bacteriophage considered to be a good...
Calculation of earthquake rupture histories using a hybrid global search algorithm: Application to the 1992 Landers, California, earthquake
S. Hartzell, P. Liu
1996, Physics of the Earth and Planetary Interiors (95) 79-99
A method is presented for the simultaneous calculation of slip amplitudes and rupture times for a finite fault using a hybrid global search algorithm. The method we use combines simulated annealing with the downhill simplex method to produce a more efficient search algorithm then either of the two constituent parts....
Character, paleoenvironment, rate of accumulation, and evidence for seismic triggering of Holocene turbidites, Canada Abyssal Plain, Arctic Ocean
A. Grantz, R. L. Phillips, M. W. Mullen, S. W. Starratt, Glenn A. Jones, A.S. Naidu, B. P. Finney
1996, Marine Geology (133) 51-73
Four box cores and one piston core show that Holocene sedimentation on the southern Canada Abyssal Plain for the last 8010 ± 120 yr has consisted of a continuing rain of pelagic organic and ice-rafted clastic sediment with a net accumulation rate during...
Thermal and mass implications of magmatic evolution in the Lassen volcanic region, California, and minimum constraints on basalt influx to the lower crust
M. Guffanti, M.A. Clynne, L.J.P. Muffler
1996, Journal of Geophysical Research B: Solid Earth (101) 3003-3013
We have analyzed the heat and mass demands of a petrologic model of basalt-driven magmatic evolution in which variously fractionated mafic magmas mix with silicic partial melts of the lower crust. We have formulated steady state heat budgets for two volcanically distinct areas in the Lassen region: the large, late...
Uranium-series disequilibrium, sedimentation, diatom frustules, and paleoclimate change in Lake Baikal
D.N. Edgington, J. A. Robbins, Steven M. Colman, K.A. Orlandini, M.-P. Gustin
1996, Earth and Planetary Science Letters (142) 29-42
The large volume of water, approximately one-fifth of the total surface fresh water on the planet, contained in Lake Baikal in southeastern Siberia is distinguished by having a relatively high concentration of uranium (ca. 2 nM), and, together with the surface...
Lower and lower Middle Pennsylvanian fluvial to estuarine deposition, central Appalachian basin: Effects of eustasy, tectonics, and climate
S.F. Greb, D.R. Chesnut Jr.
1996, Geological Society of America Bulletin (108) 303-317
Interpretations of Pennsylvanian sedimentation and peat accumulation commonly use examples from the Appalachian basin because of the excellent outcrops and large reserve of coal (>100 billion metric tons) in the region. Particularly controversial is the origin of Lower and lower Middle Pennsylvanian quartzose sandstones; beach-barrier, marine-bar, tidal-strait, and fluvial models...
Groundwater inflow measurements in wetland systems
Randy J. Hunt, David P. Krabbenhoft, Mary P. Anderson
1996, Water Resources Research (32) 495-507
Our current understanding of wetlands is insufficient to assess the effects of past and future wetland loss. While knowledge of wetland hydrology is crucial, groundwater flows are often neglected or uncertain. In this paper, groundwater inflows were estimated in wetlands in southwestern Wisconsin using traditional Darcy's law calculations and three...
Mauna Loa lava accumulation rates at the Hilo drill site: Formation of lava deltas during a period of declining overall volcanic growth
P. W. Lipman, J.G. Moore
1996, Journal of Geophysical Research B: Solid Earth (101) 11631-11641
Accumulation rates for lava flows erupted from Mauna Loa, as sampled in the uppermost 280 m of the Hilo drill hole, vary widely for short time intervals (several thousand years), but overall are broadly similar to those documented elsewhere on this volcano since 100 ka. Thickness variations and accumulation rates...
Isotopic evolution of Mauna Kea volcano: Results from the initial phase of the Hawaii Scientific Drilling Project
J.C. Lassiter, D.J. DePaolo, M. Tatsumoto
1996, Journal of Geophysical Research B: Solid Earth (101) 11769-11780
We have examined the Sr, Nd, and Pb isotopic compositions of Mauna Kea lavas recovered by the first drilling phase of the Hawaii Scientific Drilling Project. These lavas, which range in age from ∼200 to 400 ka, provide a detailed record of chemical and isotopic changes in basalt composition during...
Origin and depositional environment of clastic deposits in the Hilo drill hole, Hawaii
M.H. Beeson, D.A. Clague, J. P. Lockwood
1996, Journal of Geophysical Research B: Solid Earth (101) 11617-11629
Volcaniclastic units cored at depths of about 87, 164, 178, 226, and 246 m below sea level and carbonate units located between depths of 27 and 53 m below sea level in the Hilo drill core were found to be deposited at or near sea level. Four of these units...
Mount St. Augustine volcano fumarole wall rock alteration: Mineralogy, zoning, composition and numerical models of its formation process
A. Getahun, M.H. Reed, R. Symonds
1996, Journal of Volcanology and Geothermal Research (71) 73-107
Intensely altered wall rock was collected from high-temperature (640 °C) and low-temperature (375 °C) vents at Augustine volcano in July 1989. The high-temperature altered rock exhibits distinct mineral zoning differentiated by color bands. In order of decreasing temperature, the color bands and their mineral assemblages are: (a) white to grey...
