Discrim: a computer program using an interactive approach to dissect a mixture of normal or lognormal distributions
N.J. Bridges, R.B. McCammon
1980, Computers & Geosciences (6) 361-396
DISCRIM is an interactive computer graphics program that dissects mixtures of normal or lognormal distributions. The program was written in an effort to obtain a more satisfactory solution to the dissection problem than that offered by a graphical or numerical approach alone. It combines graphic and analytic techniques using a...
Petrology of Hualalai volcano, Hawaii: Implication for mantle composition
D.A. Clague, E.D. Jackson, T. L. Wright
1980, Bulletin Volcanologique (43) 641-656
Hualalai is one of five volcanoes whose eruptions built the island of Hawaii. The historic 1800-1801 flows and the analyzed prehistoric flows exposed at the surface are alkalic basalts except for a trachyte cone and flow at Puu Waawaa and a trachyte maar deposit near Waha Pele. The 1800-1801 eruption...
Opaque minerals as aids in distinguishing between source and sorting effects on beach sand mineralogy in southwestern Oregon
G. Luepke
1980, Journal of Sedimentary Petrology (50) 489-496
Both source area and wave sorting affect the heavy-mineral distributions of beach sands. Although source and sorting effects are difficult to distinguish, they can be separated on four Oregon beaches by studying the magnetic fraction of the sand. Prominent headlands bound the four...
Calculation of uncertainties of U-Pb isotope data
K.R. Ludwig
1980, Earth and Planetary Science Letters (46) 212-220
Equations are derived for the estimation of errors and error correlations for various types of U-Pb isotope data, taking into account ion-beam instabilities, run-to-run variability in mass-discrimination, uncertainties in Pb and U concentrations, and uncertainties in initial-Pb and blank-Pb amount and isotopic composition. Equations are also given for the calculation...
Radioactivity method
J. S. Duval
1980, Geophysics (45) 1690-1694
Radioactivity measurements have played an important role in geophysics since about 1935, and they have increased in importance to the present. The most important areas of application have been in petroleum and uranium exploration. Radioactivity measurements have proved useful in geologic mapping, as well as in specialized applications such as...
Distribution of Quaternary rhyolite domes of the Coso Range, California: implications for extent of the geothermal anomaly.
C. R. Bacon, W. A. Duffield
1980, Journal of Geophysical Research (85) 2425-2433
38 separate domes and flows of phenocryst-poor, high-silica rhyolite of similar major element chemical composition were erupted over the past 1My from vents arranged in a crudely S-shaped array atop a granitic horst in the Coso Range, California. Most of the extrusions are probably less than about 0.3My old. The...
Geothermal system at 21°N, East Pacific Rise: physical limits on geothermal fluid and role of adiabatic expansion
J. L. Bischoff
1980, Science (207) 1465-1469
Pressure-volume-temperature relations for water at the depth of the magma chamber at 21°N on the East Pacific Rise suggest that the maximum subsurface temperature of the geothermal fluid is about 420°C. Both the chemistry of the discharging fluid and thermal balance considerations indicate that the effective water/rock ratios in the...
Heat flow and energetics of the San Andreas fault zone
A.H. Lachenbruch, J.H. Sass
1980, Journal of Geophysical Research Solid Earth (85) 6185-6223
Approximately 100 heat flow measurements in the San Andreas fault zone indicate (1) there is no evidence for local factional heating of the main fault trace at any latitude over a 1000-km length from Cape Mendocino to San Bernardino, (2) average heat flow is high (∼2 HFU, ∼80 mW m−2)...
Paleoenvironment of the New Albany Shale Group ( Devonian- Mississippian) of Illinois
R.M. Cluff
1980, Journal of Sedimentary Petrology (50) 767-780
The distribution of lithofacies in the New Albany Shale Group of Illinois was determined by wave energy, bottom oxygenation, and bottom topography in a deep water stratified anoxic basin. A transect from the margin to the center of the Illinois Basin reveals a...
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...
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,...
The provenance of rutile.
E. R. Force
1980, Journal of Sedimentary Petrology (50) 485-488
Most coarse detrital rutile is derived from high-grade metamorphic rocks. Contrary to a conventional assumption, independent rutile grains are particularly rare in igneous rocks except alkalic rocks. The use of rutile in the ZTR (zircon-tourmaline-rutile) index of mineralogic maturity is only partially valid,...
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...
Volcanic rocks cored on hess rise, Western Pacific Ocean
T.L. Vallier, K.E. Windom, K.E. Seifert, Jorn Thiede
1980, Nature (286) 48-50
Large aseismic rises and plateaus in the western Pacific include the Ontong-Java Plateau, Magellan Rise, Shatsky Rise, Mid-Pacific Mountains, and Hess Rise. These are relatively old features that rise above surrounding sea floors as bathymetric highs. Thick sequences of carbonate sediments overlie, what are believed to be, Upper Jurassic and...
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...
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...
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...
Regional tilt patterns of Late Cenozoic basin-range fault blocks, western United States.
John H. Stewart
1980, Geological Society of America Bulletin (91) 460-464
The pattern of tilt domains is characterized by transverse zones or boundaries, parallel to the extension direction, and by antiformal (tilts away from) and synformal (tilts toward) boundaries at right angles to the extension direction. Tilting of ranges averages about 15o to 20o in Nevada and Utah and indicates extension...
Emission spectra of the cations of some fluoro-substituted phenols in the gaseous phase
John Paul Maier, O. Marthaler, Manijeh Mohraz, R.H. Shiley
1980, Journal of Electron Spectroscopy and Related Phenomena (19) 11-20
Emission spectra of the cations of 2,5- and 3,5-difluorophenol, of 2,3,4- and 2,4,5-trifluorophenol, of 2,3,5,6-tetrafluorophenol and of 2,3,4,5,6-pentafluorophenol have been obtained in the gas phase using low-energy electron beam excitation. The band systems are assigned to the B̃(π−1) → X̃(π−1) electronic transitions of these cations by reference to photoelectron spectroscopic data. The...
Crude oil degradation as an explanation of the depth rule
L.C. Price
1980, Chemical Geology (28) 1-30
Previous studies of crude oil degradation by water washing and bacterial attack have documented the operation of these processes in many different petroleum basins of the world. Crude oil degradation substantially alters the chemical and physical makeup of a crude oil, changing a light paraffinic low-S "mature" crude to a...
Comparison of bed form variance spectra within a meander bend during flood and average discharge
R.A. Levey, B. Kjerfve, R.T. Getzen
1980, Journal of Sedimentary Petrology (50) 149-155
Time series analysis of streambed elevation in a meander bend along the Congaree River was used to determine the changes in bed form population succeeding a 16-year flood event. Bed forms observed during the flood event had a significantly greater total height variance...
An econometric model of the U.S. secondary copper industry: Recycling versus disposal
M.E. Slade
1980, Journal of Environmental Economics and Management (7) 123-141
In this paper, a theoretical model of secondary recovery is developed that integrates microeconomic theories of production and cost with a dynamic model of scrap generation and accumulation. The model equations are estimated for the U.S. secondary copper industry and used to assess the impacts that various policies and future...
Asymmetric measures of association, closed data, and multivariate analysis
M. Hohn, E.B. Nuhfer
1980, Journal of the International Association for Mathematical Geology (12) 235-246
The association between constant-sum variables Xiand Xjexpressed as percentages can be calculated as a product-moment correlation between Xiand Xj/(100 - Xi) and a correlation between Xjand Xi/(100 - Xj). An asymmetric, square matrix may be formed from these coefficients, and multivariate analysis performed by two methods: singular value decomposition and...
Declination and inclination errors in experimentally deposited specularite-bearing sand
S.L. Bressler, D. P. Elston
1980, Earth and Planetary Science Letters (48) 227-232
Naturally disaggregated specularite-bearing sandstone from the Triassic Moenkopi Formation, artificially deposited in controlled magnetic fields of ∼5 × 10−2 mT, acquires a stable remanent magnetization that has systematic errors in inclination and declination. Inclinations about 12° shallower than the applied fields are...
Compositional controls on spinel clouding and garnet formation in plagioclase of olivine metagabbros, Adirondack Mountains, New York
J. M. McLelland, P.R. Whitney
1980, Contributions to Mineralogy and Petrology (73) 243-251
Olivine metagabbros from the Adirondacks usually contain both clear and spinel-clouded plagioclase, as well as garnet. The latter occurs primarily as the outer rim of coronas surrounding olivine and pyroxene, and less commonly as lamellae or isolated grains within plagioclase. The formation of garnet and metamorphic spinel is dependent upon...
