Early evolution of the Bering Sea by collision of oceanic rises and North Pacific subduction zones
Z. Ben-Avraham, Alan K. Cooper
1981, GSA Bulletin (92) 485-495
Three major bathymetric features exist in the Bering Sea: Shirshov Ridge, Bowers Ridge, and Umnak Plateau. New refraction data over Umnak Plateau and previous geophysical data across Bowers Ridge indicate that a thickened welt of crustal material is present beneath both features. The crustal structure is transitional between oceanic and...
Biological and economic impact of stream alteration in the Virginia Piedmont
James B. Whelan
1981, FWS/OBS 81/33
A 31 month (September 1974 - March 1977) study was conducted on warmwater streams located in the Roanoke Creek watershed of the Piedmont Region of Virginia. The purpose of the study was to determine the effects of stream channelization on the aquatic/riparian wildlife resource and agricultural land-use patterns associated with...
Predictive models of macroinvertebrate density for use in instream flow studies and regulated flow management
J.A. Gore, R.D. Judy
1981, Canadian Journal of Fisheries and Aquatic Sciences (38)
No abstract available....
Results of a modeling workshop concerning resource development and management in Jackson Hole, Wyoming
A.K. Andrews, R.A. Ellison, David B. Hamilton, J. E. Roelle, P.J. McNamee
1981, Report
No abstract available....
Results of a modeling workshop concerning preservation and protection of wetlands in North Dakota
Austin K. Andrews, Gregor T. Auble, Richard A. Ellison, David B. Hamilton, James E. Roelle
1981, Report
In a recently signed letter, the Governor of North Dakota and the Assistant Secretary of the Interior for Fish and Wildlife and Parks charged a joint state-federal study group with examination of two separate questions: 1) mitigation for the Garrison Diversion Project; and 2) planning for long-range protection and preservation...
Results of a modeling workshop concerning acid precipitation
A.K. Andrews, R.A. Ellison, D. B. Hamilton, J. E. Roelle, D. Marmorek
1981, Report
No abstract available....
Ne matrix spectra of the sym-C6Br3F3+ radical cation
V.E. Bondybey, T.J. Sears, T.A. Miller, C. Vaughn, J.H. English, R.S. Shiley
1981, Chemical Physics (61) 9-16
The electronic absorption and laser excited, wavelength resolved fluorescence spectra of the title cation have been observed in solid Ne matrix and vibrationally analysed. The vibrational structure of the excited B2A2??? state shows close similarity to the parent compound. The X2E??? ground state structure is strongly perturbed and irregular owing...
Multiple asperity model for earthquake prediction
M. Wyss, A. C. Johnston, F. W. Klein
1981, Nature (289) 231-234
Large earthquakes often occur as multiple ruptures reflecting strong variations of stress level along faults. Dense instrument networks with which the volcano Kilauea is monitored provided detailed data on changes of seismic velocity, strain accumulation and earthquake occurrence rate before the 1975 Hawaii 7.2-mag earthquake. During the ???4 yr of...
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...
Satellite and field studies of man's impact on the surface in arid regions
Joseph Otterman
1981, Tellus, Series A: Dynamic Meteorology and Oceanography (33) 68-77
Models of the nadir reflectivity as a function of the fractional cover by plants or plant debris are presented and are applied to assessing the Negev vs Sinai differences and the sharp recovery (darkening) of the surface in a Sinai enclosure where anthropogenic pressures were stopped in 1974 by fencing...
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....
A review of regional mineral resource assessment methods
D.A. Singer, D.L. Mosier
1981, Economic Geology (76) 1006-1015
Over 100 papers on regional mineral resource assessment of nonfuels are classified according to method(s) used and form(s) of product in order to help identify possible methods for future assessments. Types of products that have been used include: tons of metal; tons of rock and associated grade; gross value; potential;...
Seismic amplitude anomalies associated with thick First Leo sandstone lenses, eastern Powder River basin, Wyoming
A. H. Balch, Myung W. Lee, J. J. Miller, R. T. Ryder
1981, Geophysics (46) 1519-1527
Several new discoveries of oil production in the Leo sandstone, an economic unit in the Pennsylvanian middle member of the Minnelusa formation, eastern Powder River basin, Wyoming-Nebraska-South Dakota, have renewed exploration interest in this area. Vertical seismic profiles (VSP) and model studies suggested that a measurable seismic amplitude anomaly is...
Sm-Nd systematics of a tonalitic augen gneiss and its constituent minerals from northern Michigan
K. Futa
1981, Geochimica et Cosmochimica Acta (45) 1245-1249
The Sm-Nd isotopic system of a tonalitic augen gneiss and its constituent minerals from northern Michigan was disturbed during metamorphism. Sm-Nd zircon ages are lower than the wholerock Sm-Nd model age. However, closely associated pairs of minerals (for example, sphene and biotite or apatite and plagioclase) retain their apparent metamorphic...
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...
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....
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...
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...
The Montenegro, Yugoslavia, earthquake of April 15, 1979: source orientation and strength
D.M. Boore, J.D. Sims, H. Kanamori, S. Harding
1981, Physics of the Earth and Planetary Interiors (27) 133-142
Long-period teleseismic P, S and Rayleigh waves and geologic considerations indicate that the Montenegro earthquake involved thrust faulting on a plane striking nearly parallel to the Adriatic coast and dipping ca. 15?? toward the Yugoslav mainland. There is some support from modeling of body waves recorded on long-period WWSSN instruments...
Northwest margin of California continental borderland: Marine geology and tectonic evolution
J.K. Crouch
1981, American Association of Petroleum Geologists Bulletin (65) 191-218
The northwest margin of the California continental borderland consists mainly of two northwest-trending pre-Neogene lithologic belts blanketed by Miocene and younger strata. These belts, which are lithologically and structurally correlated with the Franciscan Complex and Great Valley sequence of northern California, are interpreted to represent facies corresponding to the subduction...
Blast dynamics at Mount St Helens on 18 May 1980
S. W. Kieffer
1981, Nature (291) 568-570
At 8.32 a.m. on 18 May 1980, failure of the upper part of the north slope of Mount St Helens triggered a lateral eruption ('the blast') that devastated the conifer forests in a sector covering ???500 km2 north of the volcano. I present here a steady flow model for the...
Role of solute-transport models in the analysis of groundwater salinity problems in agricultural areas
Leonard F. Konikow
1981, Agricultural Water Management (4) 187-205
Undesirable salinity increases occur in both groundwater and surface water and are commonly related to agricultural practices. Groundwater recharge from precipitation or irrigation will transport and disperse residual salts concentrated by evapotranspiration, salts leached from soil and aquifer materials, as well as some dissolved fertilizers and pesticides. Where stream salinity...
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...
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),...
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...
