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Page 4749, results 118701 - 118725

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Not all publications have extents, not all extents are completely accurate
Incorporation of prior information on parameters into nonlinear regression groundwater flow models: 2. Applications
Richard L. Cooley
1983, Water Resources Research (19) 662-676
This paper investigates factors influencing the degree of improvement in estimates of parameters of a nonlinear regression groundwater flow model by incorporating prior information of unknown reliability. Consideration of expected behavior of the regression solutions and results of a hypothetical modeling problem lead to several general conclusions. First, if the...
Use of multispectral scanner images for assessment of hydrothermal alteration in the Marysvale, Utah, mining area.
M. H. Podwysocki, D. B. Segal, M. J. Abrams
1983, Economic Geology (78) 675-687
Airborne multispectral scanner. A color composite image was constructed using the following spectral band ratios: 1.6/2.2 mu m, 1.6/0.48 mu m, and 0.67/1.0 mu m. The color ratio composite successfully distinguished most types of altered rocks from unaltered rocks; further division of altered rocks into ferric oxide-rich and -poor types....
EFFICIENT TRANSFER OF DATA BETWEEN MAPS OF DIFFERENT PROJECTIONS.
John P. Snyder
1983, Conference Paper, Technical Papers of the American Congress of Surveying and Mapping
There are several ways to transfer data from an existing map to another map by computer. If the projection and parameters of both maps are known, analytic formulas may be used to convert rectangular coordinates of the first map to latitude and longitude and then to rectangular coordinates of the...
A reexamination of the effects of adsorbates on the Raman spectrum of gibbsite
K.W. Cunningham, M. C. Goldberg
1983, Soil Science (136) 102-110
Previous workers have attributed substantial changes in the Raman intensities of the OH stretching bands in solid, powdered gibbsite of surface area 10 m2/g to surface interactions with the adsorbates 093Ca2+,HxPO43x- and SiO2.xH2O. These changes apparently resulted from an unsatisfactory Raman measurement procedure as a re-examination using an internal intensity...
SPONTANEOUS COAL COMBUSTION; MECHANISMS AND PREDICTION.
James R. Herring, Fredrick J. Rich
1983, Conference Paper
Spontaneous ignition and combustion of coal is a major problem to the coal mining, shipping, and use industries; unintentional combustion causes loss of the resource as well as jeopardy to life and property. The hazard to life is especially acute in the case of underground coal mine fires that start...
The past is the key to the future
B. R. Doe
1983, Geochimica et Cosmochimica Acta (47) 1341-1354
A new major frontier of geological research, which was initiated in the 1970's, involves predicting future geologic trends or events through study of the present and past, rather than trying to understand the past, often using what one knows about the present. Like most scientific frontiers, this one began from...
Quaternary geology of the Rhode Island inner shelf
S. W. Needell, C. J. O’Hara, H.J. Knebel
1983, Marine Geology (53) 41-53
Five sedimentary units and three erosional unconformities identified in high-resolution seismic-reflection profiles reveal the stratigraphic framework and Quaternary history of the inner continental shelf south of Narragansett Bay, Rhode Island. Late Tertiary to early Pleistocene rivers eroded the pre-Mesozoic bedrock and the Upper Cretaceous to lower Tertiary coastal plain and...
Scoresum - A technique for displaying and evaluating multi-element geochemical information, with examples of its use in regional mineral assessment programs
M.A. Chaffee
1983, Journal of Geochemical Exploration (19) 361-381
A technique called SCORESUM was developed to display a maximum of multi-element geochemical information on a minimum number of maps for mineral assessment purposes. The technique can be done manually for a small analytical data set or can be done with a computer for a large data set. SCORESUM...
Conjunctive use of groundwater and surface water for irrigated agriculture: Risk aversion
John D. Bredehoeft, Richard A. Young
1983, Water Resources Research (19) 1111-1121
In examining the South Platte system in Colorado where surface water and groundwater are used conjunctively for irrigation, we find the actual installed well capacity is approximately sufficient to irrigate the entire area. This would appear to be an overinvestment in well capacity. In this paper we examine to what...
Analysis of spurious oscillation modes for the shallow water and Navier-Stokes equations
Roy A. Walters, G. F. Carey
1983, Computers and Fluids (11) 51-68
The origin and nature of spurious oscillation modes that appear in mixed finite element methods are examined. In particular, the shallow water equations are considered and a modal analysis for the one-dimensional problem is developed. From the resulting dispersion relations we find that the spurious modes in elevation are associated...
40Ar/39Ar and U-Th-Pb dating of separated clasts from the Abee E4 chondrite
D.D. Bogard, D.M. Unruh, M. Tatsumoto
1983, Earth and Planetary Science Letters (62) 132-146
Determinations of40Ar/39Ar and U-Th-Pb are reported for three clasts from the Abee (E4) enstatite chondrite, which has been the object of extensive consortium investigations. The clasts give40Ar/39Ar plateau ages and/or maximum ages of 4.5 Gy, whereas two of the clasts give...
Orickite and coyoteite, two new sulfide minerals from Coyote Peak, Humboldt County, California.
Richard C. Erd, G.K. Czamanske
1983, American Mineralogist (68) 245-254
Minute quantities of orickite and coyoteite occur with rare alkali iron sulphides in a mafic alkalic diatreme near Orick, Humboldt County. Orickite, NaxKyCu0.95Fe1.06zH2O (x,y < 0.03, z < 0.5), is hexagonal, a 3.695, c 6.16 A, D 4.212 g/cm3, Z = 4. The strongest XRD reflections are 3.08(100), 3.20(90), 2.84(60),...
Iron disulfide minerals and the genesis of roll-type uranium deposits
R. L. Reynolds, M. B. Goldhaber
1983, Economic Geology (78) 105-120
FeS 2 minerals in host rocks for deposits that contain fossil vegetal (organic) matter differ in abundance, distribution, texture, and sulfur isotopic ratios from FeS 2 minerals in host rocks for deposits that do not contain fossil vegetal matter. In three South Texas deposits lacking such organic matter, preore FeS 2 is dominantly euhedral pyrite which...
RECENT DEVELOPMENTS ON THE ORIGIN OF MINERAL MATTER IN COAL.
C. B. Cecil, R.W. Stanton, F.T. Dulong, L.P. Ruppert
1983, Conference Paper
This study attempts to quantify some of the various origins of mineral matter. Data developed for the Upper Freeport coal bed indicates that mineral matter other than pyrite and calcite is primarily derived from the vegetal matter that ultimately became coal. Cathodoluminesence was used to verify that the quartz in...
COORDINATION OF DIGITAL CARTOGRAPHY IN THE FEDERAL GOVERNMENT.
K. Eric Anderson, Peter F. Bermel
1983, Conference Paper, Technical Papers of the American Congress of Surveying and Mapping
The development and application of digital cartographic data bases are significant and important activities in the Federal Government. Increasingly, digital spatial data are being used for computer-based analyses in support of management decisions on land, forests, minerals, and energy....
Two classes of volcanic plumes on Io
A. S. McEwen, L.A. Soderblom
1983, Icarus (55) 191-217
Comparison of Voyager 1 and Voyager 2 images of the south polar region of Io has revealed that a major volcanic eruption occured there during the period between the two spacecraft encounters. An annular deposit ∼1400 km in diameter formed around the Aten Patera caldera (311°W, 48°S), the floor of...
Helium isotopic variations in volcanic rocks from Loihi Seamount and the Island of Hawaii
M.D. Kurz, W.J. Jenkins, S.R. Hart, David Clague
1983, Earth and Planetary Science Letters (66) 388-406
Helium isotopic ratios ranging from 20 to 32 times the atmospheric 3He 4He(RA) have been observed in a suite of 15 basaltic glasses from the Loihi Seamount. These ratios, which are up to four times higher than those of MORB glasses and more than twice those of nearby Kilauea,...
Distribution, abundance and carbon isotopic composition of gaseous hydrocarbons in Big Soda Lake, Nevada: An alkaline, meromictic lake
R.S. Oremland, D.J. Des Marais
1983, Geochimica et Cosmochimica Acta (47) 2107-2114
Distribution and isotopic composition (δ13C) of low molecular weight hydrocarbon gases were studied in Big Soda Lake (depth = 64 m), an alkaline, meromictic lake with permanently anoxic bottom waters. Methane increased with depth in the anoxic mixolimnion (depth = 20–35 m), reached uniform concentrations (55 μM/l) in the monimolimnion...
Plutonic rocks of Jurassic age in the Alaska-Aleutian Range batholith: Ghemical variation and polarity
B.I. Reed, A.T. Miesch, M. A. Lanphere
1983, Geological Society of America Bulletin (94) 1232-1240
Plutonic rocks of Jurassic age exposed on the eastern, or Pacific, side of the Alaska–Aleutian Range batholith represent the roots of a magmatic arc generally considered to have been generated in response to northwest-directed subduction. These rocks form a compositionally continuous calc-alkaline suite...
Hydrothermal alteration of graywacke and basalt by 4 m NaCl
R.J. Rosenbauer, J. L. Bischoff, A. S. Radtke
1983, Economic Geology (78) 1701-1710
Separate experiments at 350 degrees C and 500 bars at a rock/fluid ratio of 1/10. Illite, dolomite, and quartz amounting to 67 percent of the original graywacke, were converted to albite and smectite. The rock gained Na and released Ca, K, heavy metals, and CO 2 to solution. In sharp contrast, the...
Explosive activity associated with the growth of volcanic domes
C. G. Newhall, W.G. Melson
1983, Journal of Volcanology and Geothermal Research (17) 111-131
Domes offer unique opportunities to measure or infer the characteristics of magmas that, at domes and elsewhere, control explosive activity. A review of explosive activity associated with historical dome growth shows that: 1. (1) explosive activity has occurred in close association with nearly all historical dome growth; 2. (2) whole-rock...
Old Crow tephra: A new late Pleistocene stratigraphic marker across north-central Alaska and western Yukon Territory
J.A. Westgate, T. D. Hamilton, M.P. Gorton
1983, Quaternary Research (19) 38-54
Old Crow tephra is the first extensive Pleistocene tephra unit to be documented in the northwestern part of North America. It has a calc-alkaline dacitic composition with abundant pyroxene, plagioclase, and FeTi oxides, and minor hornblende, biotite, apatite, and zircon. Thin, clear, bubble-wall fragments are the dominant type of glass...
Laboratory investigations of steam flow in a porous medium
W.N. Herkelrath, A.F. Moench, II C. F. O’Neal C. F.
1983, Water Resources Research (19) 931-937
Experiments were carried out in the laboratory to test a theory of transient flow of pure steam in a uniform porous medium. This theory is used in modeling pressure transient behavior in vapor dominated geothermal systems. Transient, superheated steam flow experiments were run by bringing a cylinder of porous material...