The thermal expansion of anhydrite to 1000° C
Howard T. Evans Jr.
1979, Physics and Chemistry of Minerals (4) 77-82
The thermal expansion of anhydrite, CaSO4, has been measured from 22° to 1,000° C by X-ray diffraction, using the Guinier-Lenné heating powder camera. The heating patterns were calibrated with Guinier-Hägg patterns at 25° C, using quartz as internal standard. Heating experiments were run on natural anhydrite (Bancroft, Ontario), which at...
Pattern drilling exploration: Optimum pattern types and hole spacings when searching for elliptical shaped targets
L.J. Drew
1979, Journal of the International Association for Mathematical Geology (11) 223-254
In this study the selection of the optimum type of drilling pattern to be used when exploring for elliptical shaped targets is examined. The rhombic pattern is optimal when the targets are known to have a preferred orientation. Situations can also be found where a rectangular pattern is as efficient...
Probability weighted moments: Definition and relation to parameters of several distributions expressable in inverse form
J. Arthur Greenwood, J. Maciunas Landwehr, N.C. Matalas, J.R. Wallis
1979, Water Resources Research (15) 1049-1054
Distributions whose inverse forms are explicitly defined, such as Tukey's lambda, may present problems in deriving their parameters by more conventional means. Probability weighted moments are introduced and shown to be potentially useful in expressing the parameters of these distributions....
Correlation of lunar far-side magnetized regions with ringed impact basins
K.A. Anderson, D.E. Wilhelms
1979, Earth and Planetary Science Letters (46) 107-112
By the method of electron reflection, we have identified seven well-defined magnetized regions in the equatorial belt of the lunar far side sampled by the Apollo 16 Particles and Fields subsatellite. Most of these surface magnetic fields lie within one basin...
Vesicularity and CO2 in mid-ocean ridge basalt
James G. Moore
1979, Nature (282) 250-253
Vesicles and included CO2 are enriched in deep-sea basalts that are also enriched in light rare earth and incompatible elements. This enrichment probably results from a unique deep mantle origin of such melts but may have been modified by CO2 bubbles rising in shallow magma chambers....
A review of recent activity in the United States.
H.L. Cannon, W.L. Petrie
1979, Philosophical Transactions of the Royal Society B: Biological Sciences (288) 137-149
Either an overabundance or a deficiency of trace metals in the food chain can ultimately affect adversely the health of livestock and man. Increasing interest in the United States in the distribution of metals in the environment and in metal pollutants has led to widespread interdisciplinary research sponsored by governmental,...
Origin of reverse-graded bedding in air-fall pumice, Coso Range, California
W. A. Duffield, C. R. Bacon, G.R. Roquemore
1979, Journal of Volcanology and Geothermal Research (5) 35-48
The origin of reverse grading in air-fall pyroclastic deposits has been ascribed to: (1) changing conditions at an erupting vent; (2) deposition in water; or (3) rolling of large clasts over smaller clasts on the surface of a steep slope. Structural features in a deposit of air-fall pumice lapilli in...
Four-dimensional modeling of recent vertical movements in the area of the southern California uplift
Petr Vanicek, Michael R. Elliot, Robert O. Castle
1979, Tectonophysics (52) 287-300
This paper describes an analytical technique that utilizes scattered geodetic relevelings and tide-gauge records to portray Recent vertical crustal movements that may have been characterized by spasmodic changes in velocity. The technique is based on the fitting of a time-varying algebraic surface of prescribed degree to the geodetic data treated...
Gases in steam from Cerro Prieto geothermal wells with a discussion of steam/gas ratio measurements
N.L. Nehring, L.J.J. Fausto
1979, Geothermics (8) 253-255
As part of a joint USGS-CFE geochemical study of Cerro Prieto, steam samples were collected for gas analyses in April, 1977. Analyses of the major gas components of the steam were made by wet chemistry (for H2O,CO2,H2S and NH3) and by gas chromatography (He,H2,Ar,O2,N2 and hydrocarbons). The hydrocarbon gases in...
Random crustal magnetization and its effect on coherence of short-wavelength marine magnetic anomalies
R.J. Blakely
1979, Earth and Planetary Science Letters (46) 43-48
Recent studies of DSDP samples from layer 2A of oceanic basement have found complex magnetic stratigraphies that seem incompatible with the frequent existence of linear short-wavelength anomalies caused by palaeomagnetic field behavior. Statistical models are developed for the lateral variation of...
Determination of the optimum-size californium-252 neutron source for borehole capture gamma-ray analysis
F. E. Senftle, R.J. Macy, J.L. Mikesell
1979, Nuclear Instruments and Methods (158) 293-302
The fast- and thermal-neutron fluence rates from a 3.7 ??g 252Cf neutron source in a simulated borehole have been measured as a function of the source-to-detector distance using air, water, coal, iron ore-concrete mix, and dry sand as borehole media. Gamma-ray intensity measurements were made for specific spectral lines at...
Measured crustal deformation in Imperial Valley, California
B. E. Lofgren
1979, Geothermics (8) 267-272
Precise geodetic surveys since 1972 indicate that significant vertical deformation of the land surface continues in Imperial Valley, California. Measured vertical changes as great as 3-5 cm per year indicate that two types of tectonic movement are occurring: (1) a downward regional tilt of the valley surface from the Mexican...
Seismic gaps and source zones of recent large earthquakes in coastal Peru
J. W. Dewey, W. Spence
1979, Pure and Applied Geophysics PAGEOPH (117) 1148-1171
The earthquakes of central coastal Peru occur principally in two distinct zones of shallow earthquake activity that are inland of and parallel to the axis of the Peru Trench. The interface-thrust (IT) zone includes the great thrust-fault earthquakes of 17 October 1966 and 3 October 1974. The coastal-plate interior (CPI)...
A review of numerical simulation of hydrothermal systems
J.W. Mercer, C.R. Faust
1979, Hydrological Sciences Bulletin (24) 335-344
Many advances in simulating single and two-phase fluid flow and heat transport in porous media have recently been made in conjunction with geothermal energy research. These numerical models reproduce system thermal and pressure behaviour and can be used for heat-transport problems other than those associated with geothermal energy development, such...
An evaluation of the zircon method of isotopic dating in the Southern Arabian Craton
J.A. Cooper, J. S. Stacey, D.G. Stoeser, R.J. Fleck
1979, Contributions to Mineralogy and Petrology (68) 429-439
A zircon study has been made on eleven samples of igneous rocks from the Saudi Arabian Craton. Ages of sized and magnetic fractions of zircon concentrates show variable degrees of discordance which seem to result from a very young disturbance that produces linear arrays in the Concordia plot. Model age...
Sewage contamination in the New York Bight. Coprostanol as an indicator
Patrick G. Hatcher, P.A. McGillivary
1979, Environmental Science & Technology (13) 1225-1229
No abstract available....
Preliminary geological mapping of Io
H. Masursky, G. G. Schaber, L.A. Soderblom, R.G. Strom
1979, Nature (280) 725-729
Terrain units and their global distribution on Io are summarised. A map of the complex region of Io is also presented. ?? 1979 Nature Publishing Group....
Massive deep-sea sulphide ore deposits discovered on the East Pacific Rise
Jean Francheteau, H.D. Needham, P. Choukroune, Tierre Juteau, M. Seguret, Richard D. Ballard, P.J. Fox, William Normark, A. Carranza, D. Cordoba, J. Guerrero, C. Rangin, H. Bougault, P. Cambon, R. Hekinian
1979, Nature (277) 523-528
Massive ore-grade zinc, copper and iron sulphide deposits have been found at the axis of the East Pacific Rise. Although their presence on the deep ocean-floor had been predicted there was no supporting observational evidence. The East Pacific Rise deposits represent a modern analogue of Cyprus-type sulphide ores associated with...
Black shale - Its deposition and diagenesis.
H. A. Tourtelot
1979, Clays and Clay Minerals (27) 313-321
Black shale is a dark-colored mudrock containing organic matter that may have generated hydrocarbons in the subsurface or that may yield hydrocarbons by pyrolysis. Many black shale units are enriched in metals severalfold above expected amounts in ordinary shale. Some black shale units have served as host rocks for syngenetic...
Trace element and strontium isotope characteristics of volcanic rocks from Isla Tortuga: A young seamount in the Gulf of California
Rodey Batiza, K. Futa, C. E. Hedge
1979, Earth and Planetary Science Letters (43) 269-278
Isla Tortuga is a small isolated central volcano which is located near an actively spreading trough in the Gulf of California. The basalt lavas from Tortuga which have the highest Mg/Fe and Ni contents have trace element abundances and ratios and87Sr/86Sr...
Regional and local networks of horizontal control, Cerro Prieto geothermal area
B.L. Massey
1979, Geothermics (8) 275-281
The Cerro Prieto geothermal area in the Mexicali Valley 30 km southeast of Mexicali, Baja California, is probably deforming due to (1) the extraction of large volumes of steam and hot water, and (2) active tectonism. Two networks of precise horizontal control were established in Mexicali Valley by the U.S....
Application of a new Raman microprobe spectrometer to nondestructive analysis of sulfate and other ions in individual phases in fluid inclusions in minerals
G.J. Rosasco, E. Roedder
1979, Geochimica et Cosmochimica Acta (43) 1907-1915
Rosascoet al. (1975), reported the first successful application of laser-excited Raman spectroscopy for the identification and nondestructive partial analysis of individual solid, liquid, and gaseous phases in selected fluid inclusions. We report here the results of the application of a new instrument, based on back-scattering, that eliminates many of...
Improved signal discrimination in tectonomagnetism: Discovery of a volcanomagnetic effect at Kilauea, Hawaii
P.M. Davis, F.D. Stacey, C.J. Zablocki, J.V. Olson
1979, Physics of the Earth and Planetary Interiors (19) 331-336
Cancellation of extraterrestrial magnetic disturbances by taking simple differences between total field readings at spaced stations is imperfect. It is shown that improvement is possible when three component observatory data are available from a single station in the general, but not necessarily immediate, vicinity of an array of total field...
Recent developments in uranium exploration using the U.S. Geological Survey's mobile helium detector
G.M. Reimer, E.H. Denton, I. Friedman, J. K. Otton
1979, Journal of Geochemical Exploration (11) 1-12
A mobile mass spectrometer to measure He concentrations has been developed by the U.S. Geological Survey. This instrument has been tested in areas of known uranium deposits, and He anomalies have been found in both soil gas and water. A gas sample is collected in a hypodermic syringe, injected into...
Aquifer coefficients determined from multiple well effects, Fernandina Beach, Florida
C.B. Bentley
1979, Groundwater (17) 525-531
On September 30, 1977, a large industrial plant in Fernandina Beach, Florida, shut down six artesian wells that had been pumping continuously for several weeks from the Floridan aquifer. Two wells continued pumping until November 20, 1977, at which time the shutdown wells were restarted....
