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Page 5073, results 126801 - 126825

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Morphology of Lonar Crater, India: Comparisons and implications
R.F. Fudali, D.J. Milton, K. Fredriksson, A. Dube
1980, The Moon and the Planets (23) 493-515
Lonar Crater is a young meteorite impact crater emplaced in Deccan basalt. Data from 5 drillholes, a gravity network, and field mapping are used to reconstruct its original dimensions, delineate the nature of the pre-impact target rocks, and interpret the emplacement mode of the ejecta. Our estimates of the pre-erosion...
Origin of gasoline-range hydrocarbons and their migration by solution in carbon dioxide in Norton basin, Alaska.
Keith A. Kvenvolden, George E. Claypool
1980, American Association of Petroleum Geologists Bulletin (64) 1078-1086
Carbon dioxide from a submarine seep in Norton Sound, Alaska, carries a minor component of gas- and gasoline-range hydrocarbons. The molecular and isotopic compositions of the hydrocarbon gases and the presence of gasoline-range hydrocarbons indicate that these molecules are derived from thermal alteration of marine and/or nonmarine organic matter buried...
Stable isotope and fluid inclusion studies of carbonate deposits from the Tolfa Mountains mining district (Latium, central Italy)
U. Masi, V. Ferrini, J. R. O’Neil, J. N. Batchelder
1980, Mineralium Deposita (15) 351-359
Carbon and oxygen isotope analyses were made of representative samples of calcite and quartz from the carbonate deposits in the Tolfa Mountains mining district. Measurements were also made of hydrogen isotope compositions, filling temperatures and salinities of fluid inclusions in these minerals. There are three stages of mineralization at Tolfa....
Sedimentary masses and concepts about tectonic processes at underthrust ocean margins
D.W. Scholl, Roland E. von Huene, T.L. Vallier, D. G. Howell
1980, Geology (8) 564-568
Tectonic processes associated with subduction of oceanic crust, but unrelated to the collision of thick crustal masses or microplates, are presumed by many geologists to significantly affect the formation and deformation of large sedimentary bodies at underthrust ocean margins. More geologists are familiar with the concept of subduction accretion, which describes...
Geophysical investigations in deep horizontal holes drilled ahead of tunnelling
R. D. Carroll, M.J. Cunningham
1980, International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts (17) 89-107
Deep horizontal drill holes have been used since 1967 by the Defense Nuclear Agency as a primary exploration tool for siting nuclear events in tunnels at the Nevada Test Site. The U.S. Geological Survey had developed geophysical logging techniques for obtaining resistivity and velocity in these holes, and to date...
Extraction and concentration of phenolic compounds from water and sediment
Marvin C. Goldberg, Eugene R. Weiner
1980, Analytica Chimica Acta (115) 373-378
Continuous liquid-liquid extractors are used to concentrate phenols at the ??g l-1 level from water into dichloromethane; this is followed by Kuderna-Danish evaporative concentration and gas chromatography. The procedure requires 5 h for 18 l of sample water. Overall concentration factors around 1000 are obtained. Overall concentration efficiencies vary from...
New evidence for magmatic intrusion beneath the Rio Grande rift, New Mexico
J.N. Towle
1980, Geological Society of America Bulletin (91) 626-630
An analysis of the geomagnetic variation field across the Rio Grande rift has identified two concentrations of telluric current flow beneath the rift caused by channeling of telluric currents in electrically conductive structures in the crust and upper mantle. A shallow conductor nearly...
The morphology of the Martian surface
M. H. Carr
1980, Space Science Reviews (25) 231-284
Most of the southern hemisphere of Mars is densely cratered and stands 1-3 km above the topographic datum. The northern hemisphere is more sparsely cratered and elevations are generally below the datum. A broad rise, the Tharsis bulge, centered at 14?? S, 101?? W, is 8000 km across and 10...
Stable isotope variations in the Quaternary epithermal calcite-fluorite deposit at Monte delle Fate near Cerveteri (Latium, central Italy)
U. Masi, J. R. O’Neil
1980, Mineralium Deposita (15) 41-45
Carbon, oxygen and hydrogen isotope variations have been measured in samples from the epithermal fluorite vein deposit at Monte delle Fate, Latium. The ranges in ?? 13C and ??18O of calcite are -1.3 to 3.4 and 9.5 to 17.3, respectively. ??D values of water extracted from fluid inclusions are -49...
Measurement of irrigated acreage in Western Kansas from LANDSAT images
K.M. Keene, C.D. Conley
1980, Environmental Geology (3) 107-116
In the past four decades, irrigated acreage in western Kansas has increased rapidly. Optimum utilization of vital groundwater supplies requires implementation of long-term water-management programs. One important variable in such programs is up-to-date information on acreage under irrigation. Conventional ground survey methods of estimating irrigated acreage are too slow to...
Comparison of three techniques for the determination of uranium and thorium in rocks
R. J. Hart, D.L. Reid, J. S. Stuckless, H.J. Welke
1980, Chemical Geology (29) 345-350
U and Th concentrations have been determined in a series of selected whole-rock samples, using three different techniques: neutron activation analysis (INAA), X-ray fluorescence spectrometry (XRF) and isotope dilution mass spectrometry (ID). The INAA technique yields U and Th data that are comparable with those obtained by ID over the...
Recovery of datable charcoal beneath young lavas: Lessons from Hawaii
J. P. Lockwood, P. W. Lipman
1980, Bulletin Volcanologique (43) 609-615
Field studies in Hawaii aimed at providing a radiocarbon-based chronology of prehistoric eruptive activity have led to a good understanding of the processes that govern the formation and preservation of charcoal beneath basaltic lava flows. Charcoal formation is a rate-dependent process controlled primarily by temperature and duration of heating, as...
Biogenic and thermogenic origins of natural gas in Cook Inlet basin, Alaska.
George E. Claypool, C. N. Threlkeld, L. B. Magoon
1980, American Association of Petroleum Geologists Bulletin (64) 1131-1139
Two types of natural gas occurrences are present in the Cook Inlet basin. The major reserves (1.8 × 1011m3) occur in shallow (less than 2,300 m), nonassociated dry gas fields that contain methane with ^dgr13C in the range of -63 to -56 per mil. These gas fields are in sandstones...
Arctic sea-ice variations from time-lapse passive microwave imagery
W. J. Campbell, R.O. Ramseier, H.J. Zwally, P. Gloersen
1980, Boundary-Layer Meteorology (18) 99-106
This paper presents: (1) a short historical review of the passive microwave research on sea ice which established the observational and theoretical base permitting the interpretation of the first passive microwave images of Earth obtained by the Nimbus-5 ESMR; (2) the construction of a time-lapse motion picture film of a...
Water resources of the People's Republic of China
N.C. Matalas, C.F. Nordin Jr.
1980, Eos, Transactions, American Geophysical Union (61) 891-901
At the invitation of the Society of Hydraulic Engineers of the People's Republic of China (PRC), a delegation of U.S. hydrologists and hydraulic engineers visited the PRC in the fall of 1978.* From discussions with officials of both the Society and the Ministry of Water Conservancy and Power (MWCP), and...
Debris-flow deposits of Early Miocene age, Deadman Stream, Marlborough, New Zealand.
D.W. Lewis, M.G. Laird, R.D. Powell
1980, Sedimentary Geology (27) 83-118
Detailed analysis is presented of a conformable succession of conglomerates and sandstones lying between massive marine mudstones. The coarse sediments reflect deposition by a spectrum of subaqueous debris-flow mechanisms during an early pulse of tectonism that ultimately resulted in Plio-Pleistocene eversion of the Kaikoura Mountains. Sparse pebbly mudstones and rare...
Quantile estimation with more or less floodlike distributions
J. Maciunas Landwehr, N.C. Matalas, J.R. Wallis
1980, Water Resources Research (16) 547-555
The desirable properties of an estimator relative to a hypothetical population may be irrelevant in practice unless the population at issue more or less resembles the hypothetical population. Evidence that floods are distributed with long, stretched upper tails suggests that use of the more common distributions results in a rather...
Ocean eddy structure by satellite radar altimetry required for iceberg towing
W. J. Campbell, R. E. Cheney, J. G. Marsh, N. M. Mognard
1980, Cold Regions Science and Technology (1) 211-221
Models for the towing of large tabular icebergs give towing speeds of 0.5 knots to 1.0 knots relative to the ambient near surface current. Recent oceanographic research indicates that the world oceans are not principally composed of large steady-state current systems, like the Gulf Stream, but that most of the...
Rate of mercury loss from contaminated estuarine sediments
Michael H. Bothner, R.A. Jahnke, M. L. Peterson, R. Carpenter
1980, Geochimica et Cosmochimica Acta (44) 273-285
The concentration of mercury in contaminated estuarine sediments of Bellingham Bay, Washington was found to decrease with a half-time of about 1.3 yr after the primary anthropogenic source of mercury was removed. In situ measurements of the mercury flux from sediments, in both dissolved and volatile forms, could not account...
Computational methods for inverse problems in geophysics: Inversion of travel time observations
V. Pereyra, H.B. Keller, W.H.K. Lee
1980, Physics of the Earth and Planetary Interiors (21) 120-125
General ways of solving various inverse problems are studied for given travel time observations between sources and receivers. These problems are separated into three components: (a) the representation of the unknown quantities appearing in the model; (b) the nonlinear least-squares problem; (c) the direct, two-point ray-tracing problem used to compute...
Gas and hydrogen isotopic analyses of volcanic eruption clouds in Guatemala sampled by aircraft
W.I. Rose Jr., R.D. Cadle, L.E. Heidt, I. Friedman, A.L. Lazrus, B.J. Huebert
1980, Journal of Volcanology and Geothermal Research (7) 1-10
Gas samples were collected by aircraft entering volcanic eruption clouds of three Guatemalan volcanoes. Gas chromatographic analyses show higher H2 and S gas contents in ash eruption clouds and lower H2 and S gases in vaporous gas plumes. H isotopic data demonstrate lighter isotopic distribution of water vapor in ash...
Secular, annual, and semiannual changes in the baseline level of the earth's magnetic field at North American locations
W.H. Campbell
1980, Journal of Geophysical Research Solid Earth (85) 6557-6571
Secular, annual, and semiannual changes were obtained from the midnight values of field on specially determined days of quiet magnetospheric conditions. From a selection of North American observatories the latitude variation of these changes was evaluated from 20° to 65°. Results for the active and quiet sun years (1958 and...
Treasures from the deep ( Metallic nodules).
D.Z. Piper
1980, Water Spectrum (13) 8-15
The composition, distribution, metric growth rates and variations in sea-floor metallic nodules are outlined and discussed The considerable age, slow accretion and relationship to underlying sediments are problems of origin which are yet to be solved and some speculative answers are discussed. Mining of the nodules is reviewed and its...