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Page 1523, results 38051 - 38075

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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...
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,...
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...
The geology of the terrestrial planets.
M. H. Carr
1983, Reviews of Geophysics and Space Physics (21) 160-172
During the last four years our knowledge of the geology of the terrestrial planets has advanced rapidly. The advances are particularly noticeable for Venus and Mars. Improved understanding of Venus has come largely from the Pioneer Venus mission. The period was also one of almost continuous data gathering for Mars...
CHEMICAL STRUCTURES IN COAL: GEOCHEMICAL EVIDENCE FOR THE PRESENCE OF MIXED STRUCTURAL COMPONENTS.
Patrick G. Hatcher, Irving A. Breger, G.E. Maciel, N.M. Szeverenyi
1983, Conference Paper
The purpose of this paper is to summarize work on the chemical structural components of coal, comparing them with their possible plant precursors in modern peat. Solid-state **1**3C nuclear magnetic resonance (NMR), infrared spectroscopy (IR), elemental analysis and, in some cases, individual compound analyses formed the bases for these comparisons....
Landslide risk assessment
P. Lessing, C.P. Messina, R.F. Fonner
1983, Environmental Geology (5) 93-99
Landslide risk can be assessed by evaluating geological conditions associated with past events. A sample of 2,4 16 slides from urban areas in West Virginia, each with 12 associated geological factors, has been analyzed using SAS computer methods. In addition, selected data have been normalized to account for areal distribution...
VARIATIONS IN MINERAL MATTER CONTENT OF A PEAT DEPOSIT IN MAINE RESTING ON GLACIO-MARINE SEDIMENTS.
Cornelia C. Cameron, Paul Schruben
1983, Conference Paper, Los Alamos National Laboratory (Report) LA
The Great Heath, Washington County, Maine, is an excellent example of a multidomed ombrotrophic peatland resting on a gently undulating surface of glacio-marine sediments and towering above modern streams. A comprehensive study sponsored by the Geological Survey of Maine in cooperation with the U. S. Geological Survey included preparation of...
INTERACTIVE NAME PLACEMENT FOR PROVISIONAL MAPS.
Jeffrey L. Goldberg, Thomas C. Miller
1983, Conference Paper, Technical Papers of the American Congress of Surveying and Mapping
Computer generation and placement of map type has been refined into a production mode at Mid-Continent Mapping Center (MCMC) for USGS 1:24,000- and 1:25,000-scale Provisional maps. The map collar program is written in FORTRAN using batch processing that allows the program to work in the background....
Kinetic analysis of strontium and potassium sorption onto sands and gravels in a natural channel
Kenneth E. Bencala, Alan P. Jackman, Vance C. Kennedy, Ronald J. Avanzino, Gary W. Zellweger
1983, Water Resources Research (19) 725-731
A kinetic, first-order mass transfer model was used to describe the sorption of strontium onto sand- and gravel-sized streambed sediments. Rate parameters, empirically determined for strontium, allowed for the prediction of potassium sorption with moderate success. The model parameters varied significantly with particle size. The sorption data were collected during...
Mechanical and chemical compaction in fine-grained shallow-water limestones
E.A. Shinn, D.M. Robbin
1983, Journal of Sedimentary Petrology (53) 595-618
Artificial compaction of in-situ cores of sediments resulted in: 1) reduction of sediment thickness by 50 percent and more; 2) reduction of initial porosities of 65 to 75 percent to 35 to 45 percent; 3) creation of megascopic textures almost identical to many...
Noble gas systematics for coexisting glass and olivine crystals in basalts and dunite xenoliths from Loihi Seamount
I. Kaneoka, N. Takaoka, D.A. Clague
1983, Earth and Planetary Science Letters (66) 427-437
Noble gas isotopes including 3He/4He, 40Ar/36Ar and Xe isotope ratios were determined for coexisting glass and olivine crystals in tholeiitic and alkalic basalts and dunite xenoliths from Loihi Seamount.Glass and coexisting olivine crystals have similar 3He/4He ratios (2.8–3.4) × 10−5, 20 to 24 times the atmospheric ratio (RA), but different 40Ar/36Ar ratios (400–1000). Based...
Major and trace elements in Mahogany zone oil shale in two cores from the Green River Formation, piceance basin, Colorado
M. L. Tuttle, W.E. Dean, N. L. Parduhn
1983, Conference Paper, Preprints Symposia
The Parachute Creek Member of the lacustrine Green River Formation contains thick sequences of rich oil-shale. The richest sequence and the richest oil-shale bed occurring in the member are called the Mahogany zone and the Mahogany bed, respectively, and were deposited in ancient Lake Uinta. The name "Mahogany" is derived...
The use of MAGSAT data to determine secular variation
J.C. Cain, J. Frayser, L. Muth, D. Schmitz
1983, Journal of Geophysical Research Solid Earth (88) 5903-5910
A combined spatial and secular variation model of the geomagnetic field, labeled M061581, is derived from a selection of Magsat data. Secular variation (SV) data computed from linear fits to midnight hourly values from 19 magnetic observatories were also included in the analysis but were seen to have little effect...
Estimation of groundwater recharge parameters by time series analysis
Richard L. Naff, Allan L. Gutjahr
1983, Water Resources Research (19) 1531-1546
A model is proposed that relates water level fluctuations in a Dupuit aquifer to effective precipitaton at the top of the unsaturated zone. Effective precipitation, defined herein as that portion of precipitation which becomes recharge, is related to precipitation measured in a nearby gage by a two-parameter function. A second-order...
Statistical averaging of marine magnetic anomalies and the aging of oceanic crust
R.J. Blakely
1983, Journal of Geophysical Research Solid Earth (88) 2289-2296
Visual comparison of Mesozoic and Cenozoic magnetic anomalies in the North Pacific suggests that older anomalies contain less short-wavelength information than younger anomalies in this area. To test this observation, magnetic profiles from the North Pacific are examined from crust of three ages: 0–2.1, 29.3–33.1, and 64.9–70.3 m.y, B.P. For...
A review of distributed parameter groundwater management modeling methods
Steven M. Gorelick
1983, Water Resources Research (19) 305-319
Models which solve the governing groundwater flow or solute transport equations in conjunction with optimization techniques, such as linear and quadratic programing, are powerful aquifer management tools. Groundwater management models fall in two general categories: hydraulics or policy evaluation and water allocation. Groundwater hydraulic management models enable the determination of...
SHALLOW HYDROTHERMAL SYSTEM AT NEWBERRY VOLCANO, OREGON: A CONCEPTUAL MODEL.
Edward A. Sammel
1983, Conference Paper, Transactions - Geothermal Resources Council
Investigations at Newberry Volcano, Oregon, have resulted in a satisfactory account of the shallow hydrothermal system, but have not indicated the nature of a possible geothermal reservoir. Hot springs in the caldera probably represent the return of circulating meteoric water, warmed at shallow depths by high conductive heat flow and...
Birdseyes, fenestrae, shrinkage pores, and loferites: a reevaluation
E.A. Shinn
1983, Journal of Sedimentary Petrology (53) 619-628
Birdseyes, birdseye limestone, fenestrae, fenestral fabric, shrinkage pores, and loferites are considered similar or synonymous when occurring in lime mudstone or syndepositional dolomite, especially in association with mudcracks and stromatolites. Compaction experiments indicate, however, that without early cementation, these vugs can be obliterated,...