New maps of Federal coal
R. G. Wayland
1981, Geological Society of America Bulletin (92) 542-550
Compilation and analysis of publicly available data on Federal coal are resulting in voluminous map sets showing coal isopachs, structure contours, and overburden isopachs on each known minable coal bed. As of the spring of 1981, there are available from the U.S. Geological...
Rates and possible causes of neotectonic vertical crustal movements of the emerged southeastern United States Atlantic coastal plain
T. M. Cronin
1981, Geological Society of America Bulletin (92) 812-833
Emerged Pliocene and Pleistocene shorelines and associated marine deposits were used to determine the magnitude and rate of vertical crustal movement during the past 3 m.y. in the United States Atlantic Coastal Plain of South and North Carolina. On the basis of a...
An alternative model for the development of the allochthonous southern Appalachian Piedmont
E-An Zen
1981, American Journal of Science (281) 1153-1163
No abstract available....
Sr isotopic tracer study of the Samail ophiolite, Oman
M. A. Lanphere, R. G. Coleman, C.A. Hopson
1981, Journal of Geophysical Research Solid Earth (86) 2709-2720
We have measured Rb and Sr concentrations and Sr isotopic compositions in 41 whole-rock samples and 12 mineral separates from units of the Samail ophiolite, including peridotite, gabbro, plagiogranite, diabase dikes, and gabbro and websterite dikes within the metamorphic peridotite. Ten samples of cumulate gabbro from the Wadir Kadir section...
A stochastic fault model. 2. Time-dependent case
D.J. Andrews
1981, Journal of Geophysical Research Solid Earth (86) 10821-10834
A random model of fault motion in an earthquake is formulated by assuming that the slip velocity is a random function of position and time truncated at zero, so that it does not have negative values. This random function is chosen to be self-affine; that is, on change of length...
Radial outflow and unsteady retreat of late Wisconsin to early Holocene icecap in the northern Long Range upland, Newfoundland
R. B. Waitt Jr.
1981, Geological Society of America Bulletin (92) 834-838
A swampy very low-relief drift terrain along the medial zone of the northern Long Range Mountains passes outward into fresh glacially eroded bed rock of low to moderate relief. Striations, crescentic gouges, lunate fractures, streamlined stoss-and-ice surfaces, erratics, and other evidence in the...
Grazing intensity effects on the breeding avifauna of North Dakota native grasslands
H.A. Kantrud
1981, Canadian Field-Naturalist (95) 404-417
A breeding bird census and plant survey was conducted on 180 samples of lightly, moderately, and heavily grazed and hayed native grasslands in North Dakota in 1974. The ten most important cover plants on each of eight major physiographic landforms in three of the four regions (the Agassiz Lake Plain...
An interpretation of episodic slip on the Calaveras fault near Hollister, California
J. O. Langbein
1981, Journal of Geophysical Research Solid Earth (86) 4941-4948
Data from a precision multi-wavelength distance measuring (MWDM) instrument, located near Hollister, California, have been analyzed in terms of strike-slip faulting in the region covered by the network. Four episodes of deformation that are readily identifiable in the MWDM data for the year following September 1975 can be modeled as...
Stable isotope systematics in mesozoic granites of Central and Northern California and Southwestern Oregon
U. Masi, J. R. O’Neil, R. W. Kistler
1981, Contributions to Mineralogy and Petrology (76) 116-126
18O, D, and H2O+ contents were measured for whole-rock specimens of granitoid rocks from 131 localitics in California and southwestern Oregon. With 41 new determinations in the Klamath Mountains and Sierra Nevada, initial strontium isotope ratios are known for 104 of these samples. Large variations in ??18O (5.5 to 12.4),...
Sedimentary framework of the Potomac River estuary, Maryland
Harley J. Knebel, E. Ann Martin, J.L. Glenn, Sally W. Needell
1981, Geological Society of America Bulletin (92) 578-589
Analyses of seismic-reflection profiles, sediment cores, grab samples, and side-scan sonar records, along with previously collected borehole data, reveal the characteristics, distribution, and geologic history of the shallow strata beneath the Potomac River estuary. The lowermost strata are sediments of the Chesapeake Group (lower Miocene to lower Pleistocene) that crop...
Aeromagnetic and radio echo ice-sounding measurements over the Dufek intrusion, Antarctica
John C. Behrendt, D.J. Drewry, E. Jankowski, M. S. Grim
1981, Journal of Geophysical Research Solid Earth (86) 3014-3020
A combined aeromagnetic and radio echo ice-sounding survey (4200 km of traverse) made in 1978 in Antarctica over the Dufek layered mafic intrusion of Jurassic age suggests a minimum area of about 50,000 km2, making it comparable in size with the Bushveld Complex of Africa. Comparisons of the magnetic and...
Flow through fractures
C. E. Neuzil, James V. Tracy
1981, Water Resources Research (17) 191-199
Flow through fractures is often idealized as flow between two parallel plates (plane Poiseuille flow). The opening or aperture between parallel plates is unambiguous and its relation to flowrate is well known. However, fractures in rock have uneven walls and a variable aperture. A model for flow in a fracture...
Economics and coal resource appraisal: strippable coal in the Illinois Basin ( USA)
E. D. Attanasi, E.K. Green
1981, Southern Economic Journal (47) 742-752
Coal-resource appraisals generally describe the location and general characteristics of coal beds. Estimates are made of the average overburden depth (depth of the coal bed below the surface), bed thickness, and perhaps certain chemical properties of the coal [1]. Although such resource compilations represent an important initial step, neither they...
Dating of Archean basement in northeastern Wyoming and southern Montana.
Z. E. Peterman
1981, Geological Society of America Bulletin (92) 139-146
Rb-Sr whole-rock and U-Pb zircon ages of granite and gneiss cores from three deep drill holes extend known occurrences of Archean rocks in the subsurface of NE Wyoming and S Montanta. Rb-Sr and K- Ar mineral ages are discordant and reflect early or middle Proterozoic disturbance. Highly altered rocks occur...
Computer-assisted photogrammetric mapping systems for geologic studies-A progress report
C. L. Pillmore, K.S. Dueholm, H.S. Jepsen, C.H. Schuch
1981, Photogrammetria (36) 159-171
Photogrammetry has played an important role in geologic mapping for many years; however, only recently have attempts been made to automate mapping functions for geology. Computer-assisted photogrammetric mapping systems for geologic studies have been developed and are currently in use in offices of the Geological Survey of Greenland at Copenhagen,...
Geochemical evidence for modern sediment accumulation on the continental shelf off southern New England
Michael H. Bothner, E.C. Spiker, P. P. Johnson, R.R. Rendigs, P. J. Aruscavage
1981, Journal of Sedimentary Petrology (51) 281-292
An area of fine-grained sediment approximately 170 km x 74 km in size, located in water depths between 60 m and 150 m, south of Martha's Vineyard, Mass., is a site of modern sediment deposition. The 14C ages systematically increase with sediment depth from about 1,300 years B.P. at the...
First manned submersible dives on the East Pacific Rise at 21°N (project RITA): general results
Jean Francheteau, H.D. Needham, P. Choukroune, Tierre Juteau, M. Seguret, Richard D. Ballard, P.J. Fox, W. R. Normark, A. Carranza, D. Cordoba, J. Guerrero, C. Rangin
1981, Marine Geophysical Research (4) 345-379
A submersible study has been conducted in February–March 1978 at the axis of the East Pacific Rise near 21°N. The expedition CYAMEX, the first submersible program to be conducted on the East Pacific Rise, is part of the French-American-Mexican project RITA (Rivera-Tamayo), a 3-year study devoted to detailed geological and...
Magnetic signals from the core of the earth and secular variation
L.R. Alldredge
1981, Journal of Geophysical Research Solid Earth (86) 7957-7965
An oscillating, radial magnetic dipole source was assumed to exist in the core of the earth, 100 km beneath the core-mantle boundary. As an approximation, electromagnetic propagation was assumed in the core in lieu of hydromagnetic propagation, which could not be used because of unknown internal fields.Using Debye potentials, the...
Sand waves on an epicontinental shelf: Northern Bering Sea
Michael E. Field, C. Hans Nelson, David A. Cacchione, David E. Drake
1981, Marine Geology (32) 233-258
Sand waves and current ripples occupy the crests and flanks of a series of large linear sand ridges (20 km × 5 km × 10 m high) lying in an open-marine setting in the northern Bering Sea. The sand wave area, which lies west of Seward Peninsula and southeast of...
Petroleum geology of Cook Inlet basin: An exploration model
Leslie B. Magoon, George E. Claypool
1981, American Association of Petroleum Geologists Bulletin (65) 1043-1061
Oil exploration commenced onshore adjacent to lower Cook Inlet on the Iniskin Peninsula in 1900, shifted with considerable success to upper Cook Inlet from 1957 through 1965, then returned to lower Cook Inlet in 1977 with the COST well and Federal OCS sale. Lower Cook Inlet COST No. 1 well,...
Chemistry of rock-forming minerals of the Cretaceous-Paleocene batholith in southwestern Japan and implications for magma genesis
G.K. Czamanske, S. Ishihara, S.A. Atkin
1981, Journal of Geophysical Research Solid Earth (86) 10431-10469
Petrographic descriptions and electron microprobe analyses of minerals are presented for 35 specimens from seven suites chosen to examine the transition from magnetite series to ilmenite series granitoids along two transects across the Cretaceous-Paleocene Inner Zone batholith of southwestern Japan. Regularities in chemical compositions of amphiboles, biotites, and feldspars suggest...
A transient laboratory method for determining the hydraulic properties of 'tight' rocks-I. Theory
P. A. Hsieh, J.V. Tracy, C. E. Neuzil, J.D. Bredehoeft, Stephen E. Silliman
1981, International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts (18) 245-252
Transient pulse testing has been employed increasingly in the laboratory to measure the hydraulic properties of rock samples with low permeability. Several investigators have proposed a mathematical model in terms of an initial-boundary value problem to describe fluid flow in a transient pulse test. However, the solution of this problem...
The glass transition in basalt
M.P. Ryan, C.G. Sammis
1981, Journal of Geophysical Research Solid Earth (86) 9519-9535
The glass transition has been experimentally detected in basalt as (1) an increase in the aggregate linear thermal expansion coefficient αL, (2) an abrupt change in the temperature dependence of Young's modulus dE/dT, and (3) a change in stress relaxation behavior that effectively separates the T> TG and T < TG creep regimes. Transition temperatures determined by the...
Design of exploration and minerals-data-collection programs in developing areas
E. D. Attanasi
1981, Socio-Economic Planning Sciences (15) 347-352
This paper considers the practical problem of applying economic analysis to designing minerals exploration and data collection strategies for developing countries. Formal decision rules for the design of government exploration and minerals-data-collection programs are derived by using a minerals-industry planning model that has been extended to include an exploration function....
Crystal growth of calcite from calcium bicarbonate solutions at constant PCO2 and 25°C: a test of a calcite dissolution model
Michael M. Reddy, Niel Plummer, E. Busenberg
1981, Geochimica et Cosmochimica Acta (45) 1281-1289
A highly reproducible seeded growth technique was used to study calcite crystallization from calcium bicarbonate solutions at 25°C and fixed carbon dioxide partial pressures between 0.03 and 0.3 atm. The results are not consistent with empirical crystallization models that have successfully described calcite growth at low PCO2 (< 10−3 atm). Good agreement was...
