Implications of regional gravity for state of stress in the earth's crust and upper mantle
M. McNutt
1980, Journal of Geophysical Research Solid Earth (85) 6377-6396
Topography is maintained by stress differences within the earth. Depending on the distribution of the stress we classify the support as either local or regional compensation. In general, the stresses implied in a regional compensation scheme are an order of magnitude larger than those corresponding to local isostasy. Gravity anomalies,...
Geochemical exploration for uranium in playas
D. L. Leach, K.P. Puchlik, R.K. Glanzman
1980, Journal of Geochemical Exploration (13) 251-283
Playas and closed-basin lakes represent unique geochemical environments for the entrapment and concentration of mobile chemical elements. For this reason, playas may be considered as potentially favorable areas for the accumulation of uranium. We investigated playa sediments to determine their value as possible sample media for determining the presence...
Littoral transport in the surf zone elucidated by an Eulerian sediment tracer
D.B. Duane, W.R. James
1980, Journal of Sedimentary Petrology (50) 929-942
An Eulerian, or time integration, sand tracer experiment was designed and carried out in the surf zone near Pt. Mugu, California on April 19, 1972. Data indicate that conditions of stationarity and finite boundaries required for proper application of Eulerian tracer theory exist...
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...
Viruserkrankungen der Fische (Viral diseases of fishes)
W. Ahne, K. Wolf
H. H. Reichenbach-Klinke, editor(s)
1980, Book chapter, Krankheiten und Schadigungen der Fische (Diseases and Injuries of Fishes): 2nd Revised ed.
No abstract available at this time...
Growth rates of manganese nodules in Oneida Lake, New York
W.S. Moore, W.E. Dean, S. Krishnaswami, D.V. Borole
1980, Earth and Planetary Science Letters (46) 191-200
226Ra is used to document the growth histories of six manganese nodules from Oneida Lake, New York. Detailed sectioning and analysis reveal that there are discontinuous gradients in226Ra content in these samples. These gradients result from periods of rapid growth (>1...
Evolution of the continental margin of southern Spain and the Alboran Sea
William P. Dillon, James M. Robb, H. Gary Greene, Juan Carlos Lucena
1980, Marine Geology (36) 205-226
Seismic reflection profiles and magnetic intensity measurements were collected across the southern continental margin of Spain and the Alboran basin between Spain and Africa. Correlation of the distinct seismic stratigraphy observed in the profiles to stratigraphic information obtained from cores at Deep Sea Drilling Project site 121 allows effective dating...
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...
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...
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...
Speculations on processes responsible for mesoscale current lineations on the continental shelf, southern California
Herman A. Karl
1980, Marine Geology (34) M9-M18
A side-scan sonar survey of San Pedro shelf, California, reveals areas of mesoscale current lineations oriented approximately north-northeast in water depths of 20-25 m. Widths of sand ribbons range from 40 to 120 m and intervening erosional furrows, from 15 to 50 m. A conceptual model shows that the scale...
Radar, visual and thermal characteristics of Mars: Rough planar surfaces
G. G. Schaber
1980, Icarus (42) 159-184
High-resolution Viking Orbiter images (10 to 15 m/pixel) contain significant information on Martian surface roughness at 25- to 100-m lateral scales, whereas Earth-based radar observations of Mars are sensitive to roughness at lateral scales of 1 to 30 m, or more....
Geologic history of Grecian Rocks, Key Largo Coral Reef Marine Sanctuary.
E.A. Shinn
1980, Bulletin of Marine Science (30) 646-656
Two transects were drilled across the major ecologic zones of the c. 750 by 200 m reef, whose accumulation was controlled by a local Pleistocene topographic feature. The Reef is composed of 5 major ecologic zones: 1) a deep seaward rubble zone, 6-8 m depth; 2) a poorly developed spur...
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...
Degradation of the Hebgen Lake fault scarps of 1959
R.W. Wallace
1980, Geology (8) 225-229
Scarps produced during the Hebgen Lake earthquake of 1959 changed noticeably in 19 yr although they still appeared remarkably fresh in 1978. They have degraded much more rapidly than have those produced in 1915 and 1954 in Nevada, but a quasi-stable slope of...
U-Pb ages of uraniferous opals and implications for the history of beryllium, fluorine, and uranium mineralization at Spor Mountain, Utah
K.R. Ludwig, D. A. Lindsey, R. A. Zielinski, K. R. Simmons
1980, Earth and Planetary Science Letters (46) 221-232
The U-Pb isotope systematics of uraniferous opals from Spor Mountain, Utah, were investigated to determine the suitability of such material for geochronologic purposes, and to estimate the timing of uranium and associated beryllium and fluorine mineralization. The results indicate that uraniferous...
Radiometric dating of sediments using fission tracks in conodonts
H.M. Sachs, M. Denkinger, C.L. Bennett, A. G. Harris
1980, Nature (288) 359-361
Conodonts are microfossils which are commonly found in marine rocks of Cambrian to Triassic age. Although their biological affinities are difficult to assess, conodonts are valuable stratigraphical indices for much of their geological range1. Recent work has also established that conodont colour alteration indices (CAI) are useful guides to diagenetic...
Clarification of the Hashin-Shtrikman bounds on the effective elastic moduli of polycrystals with hexagonal, trigonal, and tetragonal symmetries
J.P. Watt, L. Peselnick
1980, Journal of Applied Physics (51) 1525-1531
Bounds on the effective elastic moduli of randomly oriented aggregates of hexagonal, trigonal, and tetragonal crystals are derived using the variational principles of Hashin and Shtrikman. The bounds are considerably narrower than the widely used Voigt and Reuss bounds. The Voigt-Reuss-Hill average lies within the Hashin-Shtrikman bounds in nearly all...
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...
Aerial photography summary record system - five years later.
T.J. Lauterborn
1980, Photogrammetric Engineering and Remote Sensing (46) 1537-1539
Describes the APSRS, an automated information system for conventional aerial photography projects, established after the formation of the National Cartographic Information Center in the US Geological Survey in 1974. -after Author...
Hydrocarbon gas in sediment from the shelf, slope and basin of the Bering Sea.
K.A. Kvenvolden, G.D. Redden
1980, Geochimica et Cosmochimica Acta (44) 1145-1150
Methane, ethane, ethene, propane, propene, isobutane and n-butane are present in low concentrations in the top 2m of sediment. Methane is most abundant and its concentration increases with depth in the sediment. Ethane, ethene, propane and propene are present in almost all samples, but the concentrations of these gases are...
Circum-arctic plate accretion - Isolating part of a pacific plate to form the nucleus of the Arctic Basin
M. Churkin Jr., J.H. Trexler Jr.
1980, Earth and Planetary Science Letters (48) 356-362
A mosaic of large lithospheric plates rims the Arctic Ocean Basin, and foldbelts between these plates contain numerous allochthonous microplates. A new model for continental drift and microplate accretion proposes that prior to the late Mesozoic the Kula plate extended from...
Petroleum geology of Kodiak Shelf, Alaska.
Michael A. Fisher
1980, American Association of Petroleum Geologists Bulletin (64) 1140-1157
Organic geochemical data show that Cenozoic rocks on Kodiak Island, in Albatross basin, and under the continental slope generally contain less than 0.5 wt. % organic carbon. Moreover, kerogen from all rocks analyzed is predominantly (60 to 100%) herbaceous; woody and coaly kerogens are present in secondary (20 to 40%)...
Computer-composite mapping for geologists
J.N. van Driel
1980, Environmental Geology (3) 151-157
A computer program for overlaying maps has been tested and evaluated as a means for producing geologic derivative maps. Four maps of the Sugar House Quadrangle, Utah, were combined, using the Multi-Scale Data Analysis and Mapping Program, in a single composite map that shows the relative stability of the land...
Evaluation of organic matter, subsurface temperature and pressure with regard to gas generation in low-permeability Upper Cretaceous and Lower Tertiary sandstones in Pacific Creek area, Sublette and Sweetwater Counties, Wyoming.
B. E. Law, C. W. Spencer, N. H. Bostick
1980, Mountain Geologist (17) 23-35
The onset of overpressuring occurs at c.3,500 m, near the base of the U. Cretaceous Lance Formation. The development of overpressuring may involve several processes; however, interpretation of the available information indicates that active generation of large amounts of wet gas is one of the more important processes. The present...
