Modelling the petrogenesis of high Rb/Sr silicic magmas
A. N. Halliday, J.P. Davidson, W. Hildreth, P. Holden
1991, Chemical Geology (92) 107-114
Rhyolites can be highly evolved with Sr contents as low as 0.1 ppm and Rb Sr > 2,000. In contrast, granite batholiths are commonly comprised of rocks with Rb Sr 100. Mass-balance modelling of source compositions, differentiation and contamination using the trace-element geochemistry of...
Mid-Paleozoic age of granitoids in enclaves within early Cretaceous granulites, Fiordland, southwest New Zealand
J.Y. Bradshaw, D.L. Kimbrough
1991, New Zealand Journal of Geology and Geophysics (34) 455-469
Orthogneisses of granite, quartz monzonite, monzonite, and tonalite, occur locally as isolated enclaves within the Early Cretaceous granulite terrain (Western Fiordland Orthogneiss - WFO). Discordant U-Pb zircon isotopic data (seven fractions) from four granitoid samples from enclaves at George Sound, define an upper intecept age of 341??34 Ma that is...
Pumping tests in non-uniform aquifers - The linear strip case
J.J. Butler Jr., W.Z. Liu
1991, Journal of Hydrology (128) 69-99
Many pumping tests are performed in geologic settings that can be conceptualized as a linear infinite strip of one material embedded in a matrix of differing flow properties. A semi-analytical solution is presented to aid the analysis of drawdown data obtained from pumping tests performed in settings that can be...
Radiometric dating of quaternary deposits and the hominid mandible of Lake Banyolas, Spain
R. Julia, J. L. Bischoff
1991, Journal of Archaeological Science (18) 707-722
We report results of U-series analyses of the travertine matrix surrounding the Banyolas mandible that indicate an age of 45??4 ka bp. The mandible, an archaic hominid fossil generally deemed of mid-Pleistocene age, was recovered from a travertine matrix in 1887. Similar analyses on 21 travertine samples from quarries near...
Geochronology and petrogenesis of MORB from the Juan de Fuca and Gorda ridges by 238U230Th disequilibrium
S.J. Goldstein, M.T. Murrell, D.R. Janecky, J.R. Delaney, D.A. Clague
1991, Earth and Planetary Science Letters (107) 25-41
A highly precise mass spectrometric method of analysis was used to determine238U234U230Th232Th in axial and off-axis basalt glasses from Juan de Fuca (JDF) and Gorda ridges. Initial 230Th activity excesses in the axial samples range from 3 to 38%,...
Wave groupiness variations in the nearshore
Jeffrey H. List
1991, Coastal Engineering (15) 475-496
This paper proposes a new definition of the groupiness factor, GF, based on the envelope of the incident-wave time series. It is shown that an envelope-based GF has several important advantages over the SIWEH-based groupiness factor, including objective criteria for determining the accuracy of the envelope function and well-defined numerical limits.Using this new GF,...
Methods of measuring pumpage through closed-conduit irrigation systems
L.C. Kjelstrom
1991, Journal of Irrigation and Drainage Engineering (117) 748-757
Methods of measuring volumes of water withdrawn from the Snake River and its tributaries and pumped through closed‐conduit irrigation systems were needed for equitable management of and resolution of conflicts over water use. On the basis of evaluations and field tests by researchers from the University of Idaho, Water Resources...
Effects of advanced wastewater treatment on the quality of White River, Indiana
Charles G. Crawford, David J. Wangsness
1991, Water Resources Bulletin (27) 769-779
In 1983, the City of Indianapolis, Indiana, completed construction of advanced wastewater treatment (AWT) systems to enlarge and upgrade its existing Belmont Road and Southport Road secondary treatment plants. A nonparametric statistical procedure, a modified form of the Wilcoxon-Mann-Whitney rank-sum test, was used to test for trends in water quality...
Pleistocene slope instability of gas hydrate-laden sediment on the Beaufort Sea margin
R. E. Kayen, H.J. Lee
1991, Marine Geotechnology (10) 125-141
In oceanic areas underlain by sediment with gas hydrate, reduction of sea level initiates disassociation along the base of the gas hydrate, which, in turn, causes the release of large volumes of gas into the sediment and creates excess pore-fluid pressures and reduced slope stability. Fluid diffusion properties dominate the...
Lg and Rg waves on the California regional networks from the December 23, 1985 Nahanni earthquake
L. A. Wald, T. H. Heaton
1991, Journal of Geophysical Research (96) 12099-12125
We investigate Lg and Rg propagation in California using the central and southern California regional networks. Approximately 550 stations constitute these two short-period networks providing a dense coverage of almost the entire state. The waveforms recorded from the December 23, 1985, Nahanni, Canada, earthquake are used to construct three...
Birds of the Kilbuck and Ahklun mountain region, Alaska
Margaret R. Petersen, Douglas N. Weir, Matthew H. Dick
1991, Report
Between 1952 and 1988, we studied the abundance, distribution, occurrence, and habitats used by birds in the northwest portion of Bristol Bay and the adjacent Kilbuck and Ahklun mountains. In the 809 days we were present, we conducted 53 studies or surveys of birds in the region. We gathered...
A microcomputer program for energy assessment and aggregation using the triangular probability distribution
R. A. Crovelli, R.H. Balay
1991, Computers & Geosciences (17) 197-225
A general risk-analysis method was developed for petroleum-resource assessment and other applications. The triangular probability distribution is used as a model with an analytic aggregation methodology based on probability theory rather than Monte-Carlo simulation. Among the advantages of the analytic method are its computational speed and flexibility, and the saving...
Examination of micrinite concentrates from the Cannel City coal bed of eastern Kentucky: Proposed mechanism of formation
D.N. Taulbee, J.C. Hower, S.F. Greb
1991, Organic Geochemistry (17) 557-565
A high volatile B, micrinite-rich bituminous coal from Morgan County, Kentucky, was crushed and screened to −100 mesh, demineralized and subjected to density gradient centrifugation (DGC). In an initial density separation, micrinite concentration was increased from 52 vol% in the demineralized coal to a maximum of 67% in the 1.25–1.26...
Release of 226Ra from uranium mill tailings by microbial Fe(III) reduction
E. R. Landa, Elizabeth J.P. Phillips, Derek R. Lovley
1991, Applied Geochemistry (6) 647-652
Uranium mill tailings were anaerobically incubated in the presence of H2 with Alteromonas putrefaciens, a bacterium known to couple the oxidation of H2 and organic compounds to the reduction of Fe(III) oxides. There was a direct correlation between the extent of Fe(III) reduction and...
Data standardization. The key to effective management
C. Russell Wagner
1991, Conference Paper, ASTM Special Technical Publication
Effective management of the nation's water resources is dependent upon accurate and consistent hydrologic information. Before the emergence of environmental concerns in the 1960's, most hydrologic information was collected by the U.S. Geological Survey and other Federal agencies that used fairly consistent methods and equipment. In the past quarter century,...
UDATE1: A computer program for the calculation of uranium-series isotopic ages
R.J. Rosenbauer
1991, Computers & Geosciences (17) 45-75
UDATE1 is a FORTRAN-77 program with an interface for an Apple Macintosh computer that calculates isotope activities from measured count rates to date geologic materials by uranium-series disequilibria. Dates on pure samples can be determined directly by the accumulation of 230Th from 234U and of 231Pa from 235U. Dates for...
Use of the Priestley-Taylor evaporation equation for soil water limited conditions in a small forest clearcut
Alan L. Flint, S.W. Childs
1991, Agricultural and Forest Meteorology (56) 247-260
The Priestley-Taylor equation, a simplification of the Penman equation, was used to allow calculations of evapotranspiration under conditions where soil water supply limits evapotranspiration. The Priestley-Taylor coefficient, α, was calculated to incorporate an exponential decrease in evapotranspiration as soil water content decreases. The method is appropriate for use when detailed...
Sources and magnitude of bias associated with determination of polychlorinated biphenyls in environmental samples
Robert P. Eganhouse, R. W. Gossett
1991, Analytical Chemistry (63) 2130-2137
Recently compiled data on the composition of commercial Aroclor mixtures and ECD (electron capture detector) response factors for all 209 PCB congeners are used to develop estimates of the bias associated with determination of polychlorinated blphenyis. During quantitation of multlcomponent peaks by congener-specific procedures error is introduced because of variable...
Seismicity and detection/location threshold in the southern Great Basin seismic network
J. Gomberg
1991, Journal of Geophysical Research (96) 16401-16414
A spatially varying model of the detection/location capabilities of the Southern Great Basin seismic network (SGBSN) has been derived that is based on simple empirical relations and statistics. This permits use of almost all the catalog data gathered; instead of ignoring data that are below...
Submarine processes of the middle Atlantic continental rise based on GLORIA imagery
J. S. Schlee, James M. Robb
1991, Geological Society of America Bulletin (103) 1090-1103
Approximately 6100 km of 3.5-kHz echo-sounding profiles was correlated with a GLORIA side-scan sonar image of the mid-Atlantic United States (34??N, 70??W) lower slope-upper continental rise. The image allows us to map the major erosional and depositional features and to identify major processes that have shaped the area. Interpretation of...
Employment of Gibbs-Donnan-based concepts for interpretation of the properties of linear polyelectrolyte solutions
J.A. Marinsky, M.M. Reddy
1991, Journal of Physical Chemistry (95) 10208-10214
Earlier research has shown that the acid dissociation and metal ion complexation equilibria of linear, weak-acid polyelectrolytes and their cross-linked gel analogues are similarly sensitive to the counterion concentration levels of their solutions. Gibbs-Donnan-based concepts, applicable to the gel, are equally applicable to the linear polyelectrolyte for the accommodation of...
High-energy carbonate-sand accumulation, the Quicksands, southwest Florida Keys
Eugene A. Shinn, Barbara H. Lidz, Charles W. Holmes
1991, Journal of Sedimentary Research (61) 861-862
High-resolution seismic-reflection profiles of the Quicksands, located along a broad ridge on the platform shelf west of Key West, Florida, indicate a significant deposit of non-oolitic carbonate sand occurs in a belt 47 km long by 28 km wide. The surface of the...
The high-pressure electronic structure of magnesiowustite (Mg, Fe)O: applications to the physics and chemistry of the lower mantle
David M. Sherman
1991, Journal of Geophysical Research (96) 14299-14312
The electronic structure of magnesiowustite is investigated using self-consistent field Xα scattered wave (SCF-Xα-SW) molecular orbital calculations on (FeO6)10− and (FeMg12O14)2− clusters. Calculated one-electron transition energies are used to interpret the optical spectrum of (Mg, Fe)O. The results are applied to the electrical and thermal conductivity of the lower...
Emulsification of hydrocarbons by subsurface bacteria
D.S. Francy, J. M. Thomas, R.L. Raymond, C.H. Ward
1991, Journal of Industrial Microbiology (8) 237-246
Biosurfactants have potential for use in enhancement of in situ biorestoration by increasing the bioavailability of contaminants. Microorganisms isolated from biostimulated, contaminated and uncontaminated zones at the site of an aviation fuel spill and hydrocarbon-degrading microorganisms isolated from sites contaminated with unleaded gasoline were examined for their abilities to emulsify...
Midwayan (Paleocene) pollen correlations in the eastern United States
N. O. Frederiksen
1991, Micropaleontology (37) 101-123
The Midwayan Stage of the eastern United States is divided into three new pollen zones, the Pseudoplicapollis serana, Tricolpites asper and Caryapollenites prodromus interval zones. Pollen data support the presence of an unconformity between the Rhems and Williamsburg Formations of South Carolina. The base of the Aquia Formation of Virginia...
