Can the earth be dated from decay of its magnetic field?.
G. B. Dalrymple
1983, Journal of Geological Education (31) 124-133
Thomas G. Barnes, Emeritus Professor of Physics at the University of Texas, El Paso, and a creationist, argues that the geomagnetic field was created by unknown processes at the time of creation of the earth and has been decaying irreversibly and exponentially, with a half-life of about 1400 years,...
Hashemite, Ba(Cr,S)O4, a new mineral from Jordan.
P. L. Hauff, E.E. Foord, S. Rosenblum
1983, American Mineralogist (68) 1223-1225
Hashemite, Ba(Cr,S)O4, the isostructural chromate analogue of baryte, has been found in west-central Jordan. It is associated with chromian ettringite, apatite and calcite in a phosphatic carbonate rock analogous to the Hatrurim formation in Israel. The mineral is orthorhombic, Pnma, with a 9.112(2), b 5.541(1), c 7.343(1) A, Z =...
Expendable bubble tiltmeter for geophysical monitoring
J.A. Westphal, M.A. Carr, W.F. Miller, D. Dzurisin
1983, Review of Scientific Instruments (54) 415-418
An unusually rugged highly sensitive and inexpensive bubble tiltmeter has been designed, tested, and built in quantity. These tiltmeters are presently used on two volcanoes and an Alaskan glacier, where they continuously monitor surface tilts of geological interest. This paper discusses the mechanical, thermal, and electric details of the meter,...
Location of internal hydrogen atoms in the paradodecatungstate polyanion by neutron diffraction
H. T. Evans Jr., E. Prince
1983, Journal of the American Chemical Society (105) 4838-4839
No abstract available....
Strangways Crater, Northern Territory, Australia: Siderophile element enrichment and lithophile element fractionation
J. W. Morgan, G.A. Wandless
1983, Journal of Geophysical Research Solid Earth (88) A819-A829
The Strangways Crater, Northern Territory, Australia (15°12′S, 133°35′E), has a central core, about 10 km in diameter, of shocked granitic gneiss and amphibolite, and some remnants of a melt rock sheet, surrounded by outer rings of quartzite and siltstone to a diameter of 20–25 km. Seven samples of melt rock...
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...
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...
Modeling of self-potential anomalies near vertical dikes
D.V. Fitterman
1983, Geophysics (48) 171-180
The self-potential (SP) Green's function for an outcropping vertical dike is derived from solutions for the dc resistivity problem for the same geometry. The Green's functions are numerically integrated over rectangular source regions on the contacts between the dike and the surrounding material to obtain the SP anomaly. The analysis...
Role of fluid mixing and fault-related sulfide in the origin of the Ray Point uranium district, south Texas
M. B. Goldhaber, R. L. Reynolds, R. O. Rye
1983, Economic Geology (78) 1043-1063
The Lamprecht and Felder deposits are roll-type deposits hosted by the Miocene Oakville Sandstone. Four distinct stages of FeS 2 mineral formation are recognized: (1) a generation of isotopically light (delta 34 S < -20 per mil) preore pyrite, (2) a generation of isotopically light (delta 34 S < -20 per mil) marcasite that formed mostly...
Geology of the head of Lydonia Canyon, U.S. Atlantic outer continental shelf
David C. Twichell
1983, Marine Geology (54) 91-108
The geology of the part of Lydonia Canyon shoreward of the continental shelf edge on the southern side of Georges Bank was mapped using high-resolution seismic-reflection and side-scan sonar techniques and surface sediment grab samples. The head of the canyon incises Pleistocene deltaic deposits and Miocene shallow marine strata. Medium...
An interpretation of carbon and sulfur relationships in Black Sea sediments as indicators of environments of deposition
J.S. Leventhal
1983, Geochimica et Cosmochimica Acta (47) 133-137
Syngenetic iron sulfides in sediments are formed from dissolved sulfide resulting from sulfate reduction and catabolism of organic matter by anaerobic bacteria. It has been shown that in recent marine sediments deposited below oxygenated waters there is a constant relationship between reduced sulfur and organic carbon which is generally independent...
Importance of the Lu-Hf isotopic system in studies of planetary chronology and chemical evolution
P. J. Patchett
1983, Geochimica et Cosmochimica Acta (47) 81-91
The 176Lu-176Hf isotope method and its applications in earth sciences are discussed. Greater fractionation of Lu/Hf than Sm/Nd in planetary magmatic processes makes 176Hf177Hf">176Hf177Hf a powerful geochemical tracer. In general, proportional variations of 176Hf177Hf"><span...
A teleseismic analysis of the New Brunswick earthquake of January 9, 1982
G. L. Choy, J. Boatwright, J. W. Dewey, S.A. Sipkin
1983, Journal of Geophysical Research Solid Earth (88) 2199-2212
The analysis of the New Brunswick earthquake of January 9, 1982, has important implications for the evaluation of seismic hazards in eastern North America. Although moderate in size (mb 5.7), it was well-recorded teleseismically. Source characteristics of this earthquake have been determined from analysis of data that were digitally recorded by...
Solubility relations in the ternary system NaCl-CsCl-H2O at 1 atm. 1. Solubilities of halite from 20 to 100 °C
I.-M. Chou, R.D. Lee
1983, Journal of Chemical and Engineering Data (28) 390-393
Solubilities of halite in the ternary system NaCl-CsCl-H2O have been determined by the visual polythermal method at 1 atm from 20 to 100 °C along five constant CsCl/(CsCl + H2O) weight ratio lines. These five constant weight ratios are 0.1, 0.2, 0.3, 0.4, and 0.5. The maximum uncertainties in these...
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...
Distribution of mineral deposits in accreted terranes and cratonal rocks of western United States
J. P. Albers
1983, Canadian Journal of Earth Sciences (20) 1019-1029
The western margin of the conterminous United States, covering roughly 300 000 mi2 (777 000 km2), is an agglomeration of tectonostratigraphic terranes accreted to the North American craton mainly during Mesozoic time. The terranes represent a number of fundamental crustal types: oceanic crust, island-arc crust, mélange, various combinations of the preceding three, batholithic, miogeoclinal, and...
Statistical evaluation of oil and gas prospects in the outer continental shelf of the U.S. Gulf Coast
J.C. Davis, J.W. Harbaugh
1983, Journal of the International Association for Mathematical Geology (15) 217
Areas of the U.S. Gulf Coast, both onshore and offshore, are among the petroliferous regions of the United States. In offshore Louisiana and Texas, most oil and gas is associated with structurally controlled traps on the crest or flanks of domes created by the diapiric movement of salt. These structures...
The saltwater-freshwater interface in the Tertiary limestone aquifer, southeast Atlantic outer-continental shelf of the U.S.A.
R.H. Johnston
1983, Journal of Hydrology (61) 239-249
Hydrologic testing in an offshore oil well abandoned by Tenneco, Inc., determined the position of the saltwater-freshwater interface in Tertiary limestones underlying the Florida-Georgia continental shelf of the U.S.A. Previous drilling (JOIDES and U.S.G.S. AMCOR projects) established the existence of freshwater far offshore in this area. At the Tenneco well...
Determination of chloride in geological samples by ion chromatography
Stephen A. Wilson, Carol A. Gent
1983, Analytica Chimica Acta (148) 299-303
Samples of silicate rocks are prepared by sodium carbonate fusion and then treated by ion chromatography. The method was tested for geological standards with chloride concentration between 0.003 and 3%. Observed chloride concentrations comparedd favorably with literature values. The relative standard deviation and detection limit for the method were 8%...
Remote detection of metal anomalies on Pilot Mountain, Randolph County, North Carolina
N.M. Milton, W. Collins, Sheng-Huei Chang, R. G. Schmidt
1983, Economic Geology (78) 605-617
Pilot Mountain, a hydrothermally altered monadnock within the Carolina slate belt, contains areas of anomalously high amounts of Cu, Mo, and Sn in the soils. Leaves of canopy trees in the mineralized zone also contain more copper than trees in a nearby control area. Spectral data were processed using a...
Nd and Sr isotopic studies on cenozoic mafic lavas from West Antarctica: Another source for continental alkali basalts
K. Futa, W.E. Le Masurier
1983, Contributions to Mineralogy and Petrology (83) 38-44
The Nd and Sr isotopic ratios on a suite of continental alkali basalts from Marie Byrd Land, West Antarctica, define a change in the source over the range of K/Ar dates between 1 and 28 m.y. ago. The 87Sr/86Sr isotopic ratios (0.7026 to 0.7031) are unusually low for continental alkali...
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,...
Land-use planning: One geologist's viewpoint
E-An Zen
1983, Environmental Conservation (10) 97-104
Planning for the best use of land and its resources should take fully into consideration the long-term consequences of each type of use in order to stretch out most beneficially the well-being of society in the future, and to protect the integrity of the land and its...
Automated determination of bromide in waters by ion chromatography with an amperometric detector
G. S. Pyen, D. E. Erdmann
1983, Analytica Chimica Acta (149) 355-358
An automated ion chromatograph, including a program controller, an automatic sampler, an integrator, and an amperometric detector, was used to develop a procedure for the determination of bromide in rain water and many ground waters. Approximately 10 min is required to obtain a chromatogram. The detection limit for bromide is...
A short-pulse electromagnetic transponder for hole-to-hole use
David L. Wright, Raymond D. Watts, Erik Bramsoe
1983, IEEE Transactions on Geoscience and Remote Sensing (GE-22) 720-725
We have made hole-to-hole observations through nearly 20 m of granite using an electromagnetic transponder (an active reflector) in one borehole and a single-hole short-pulse radar in another. We found that the transponder is inexpensive, operationally simple, and effective in extending the capability of a short-pulse borehole radar system to...
