Uranium in big sagebrush from western U.S. and evidence of possible mineralization in the Owyhee mountains of Idaho
J. A. Erdman, G.H. Harrach
1981, Journal of Geochemical Exploration (14) 83-94
Two regional studies of big sagebrush (Artemisia tridentata), a widely distributed and dominant shrub in the western United States, have shown its responsiveness to known uranium mineralization in the Monument Hill and Pumpkin Buttes districts of the southern Powder River Basin, Wyoming, and the Uravan mineral belt area in southeastern...
Martian geology
M. H. Carr
1981, Nature (294) 307-308
[No abstract available]...
Reservoir properties of submarine- fan facies: Great Valley sequence, California
H. McLean
1981, Journal of Sedimentary Petrology (51) 865-872
Submarine-fan sandstones of the Great Valley sequence west of the Sacramento Valley, California, have low porosities and permeabilities (64 samples averaged 10.1% porosity and 0.87 millidarcies permeability). However, petrography and scanning electron microscope studies indicate that most sands in almost all submarine fan...
Systems for measuring thickness of temperate and polar ice from the ground or from the air.
R.D. Watts, D.L. Wright
1981, Journal of Glaciology (27) 459-469
Equipment has been designed and tested for ground-based and airborne sounding of temperate glaciers. The transmitter is a free-running pulse generator that uses avalanche-mode transistor breakdown to create high-voltage pulses. The transmit and receive antennas are resistively loaded dipoles; for the airborne system, a twin-lead transmit element...
Storm-built sand ridges on the Maryland inner shelf: a preliminary report
D.J.P. Swift, M.E. Field
1981, Geo-Marine Letters (1) 33-37
Several aspects of the Maryland ridge field are pertinent to the problem of ridge genesis in response to Holocene sea-level rise. There is a systematic morphologic change from shoreface ridges through nearshore ridges to offshore ridges, which reflects the changing hydraulic regime. Grain size is 90?? out of phase with...
Simplified method of deep-tow seismic profiling
James M. Robb, Richard E. Sylwester, Ronald Penton
1981, Geo-Marine Letters (1) 65-67
To improve resolution of seismic-reflection profiles in continental slope water depths of 900 to 1500 m, a single hydrophone was towed about 150 m off the bottom to receive reflected signals from a surface-towed sparker sound source. That deep-towed hydrophone data show that valleys which appear V-shaped in records from...
Thermal inertia mapping of Mars from 60°S to 60°N
Frank Don Palluconi, Hugh H. Kieffer
1981, Icarus (45) 415-426
Twenty-micrometer brightness temperatures are used to derive the thermal inertia for 81% of the Martian surface between latitudes ±60°. These data were acquired by the two Viking Infrared Thermal Mappers in 1977 and 1978 following the two global dust storms of 1977. The spatial resolution used is 2° in latitude...
Effects of the atmosphere on the detection of surface changes from Landsat multispectral scanner data
Joseph Otterman, Charles J. Robinove
1981, International Journal of Remote Sensing (2) 351-360
The atmospheric effects on radiometric data recorded in the Landsat multispectral scanner system (MSS) bands are compiled for cases of representative and ideal atmospheric conditions. The effects are expressed as a difference between the Earth's surface spectral reflectivity, a0, and the surface-atmosphere system spectral reflectivity, as, derived from the satellite...
Determination of organic-matter content of Appalachian Devonian shales from gamma-ray logs
James W. Schmoker
1981, American Association of Petroleum Geologists Bulletin (65) 1285-1298
The organic-matter content of the Devonian shale of the Appalachian basin is important for assessing natural-gas resources. In most of the western part of the Appalachian basin the organic-matter content of the Devonian shale can be estimated from gamma-ray wire-line logs. Organic-matter contents estimated using these logs are compared with...
Lu-Hf total-rock age for the Amîtsoq gneisses, West Greenland
H.S. Pettingill, P. J. Patchett
1981, Earth and Planetary Science Letters (55) 150-156
Lu-Hf total-rock data for the Amîtsoq gneisses of West Greenland yield an age of 3.55±0.22Gy(2σ), based on the decay constant λ176Lu=1.96×10−11y−1, and an initial176Hf/177Hf ratio of 0.280482±33. The result is in good agreement with Rb-Sr total-rock and U-Pb zircon ages. In spite of severe metamorphism of the area at 2.9...
A routine high-precision method for Lu-Hf isotope geochemistry and chronology
P. J. Patchett, M. Tatsumoto
1981, Contributions to Mineralogy and Petrology (75) 263-267
A method for chemical separation of Lu and Hf from rock, meteorite and mineral samples is described, together with a much improved mass spectrometric running technique for Hf. This allows (i) geo- and cosmochronology using the176Lu???176Hf+??- decay scheme, and (ii) geochemical studies of planetary processes in the earth and moon....
210Pb method for estimating the rate of carbonate sand sedimentation
Charles W. Holmes
1981, Geo-Marine Letters (1) 237-241
The plot of 210Pb activity against depth in carbonate sands on the Virgin Island Bank is a negative asymmetric hyperbolic curve. As depth increases, an initial rapid decrease in 210Pb activity caused by the decay of unsupported 210Pb and 226Ra is followed by increasing activity as a result of 210Pb...
Mars and Earth: Comparison of cold-climate features
Baerbel K. Lucchitta
1981, Icarus (45) 264-303
On Earth, glacial and periglacial features are common in areas of cold climate. On Mars, the temperature of the present-day surface is appropriate for permafrost, and the presence of water is suspected from data relating to the outgassing of the planet, from remote-sensing measurements over the polar caps and elsewhere...
Experimental seawater-basalt interaction at 300°C, 500 bars, chemical exchange, secondary mineral formation and implications for the transport of heavy metals
W.E. Seyfried Jr., J. L. Bischoff
1981, Geochimica et Cosmochimica Acta (45) 135-147
Seawater and NaCl solutions were reacted with basalt (basalt glass and diabase) for several months at 300°C, 500 bars and a water/rock ratio of 10. During reaction, seawater was significantly modified, increasing in Ca, H2S, CO2. SiO2, K. Fe, Mn. Ba, Al and H+, and decreasing in Mg and...
Mars: Paleostratigraphic restoration of buried surfaces in Tharsis Montes
D. H. Scott, K. L. Tanaka
1981, Icarus (45) 304-319
Volcanism in the Tharsis province of Mars occurred in several different areas and was generally continuous without large time intervals between eruptive episodes. Major lava flow units are numerous and extensive, but relatively thin. In many places, impact craters on buried...
Tectonic setting for ophiolite obduction in Oman
R. G. Coleman
1981, Journal of Geophysical Research Solid Earth (86) 2497-2508
The Samail ophiolite is part of an elongate belt in the Middle East that forms an integral part of the Alpine mountain chains that make up the northern boundary of the Arabian-African plate. The Samail ophiolite represents a portion of the Tethyan ocean crust formed at a spreading center of...
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,...
Application of capillary gas chromatography mass spectrometry/computer techniques to synoptic survey of organic material in bed sediment
Thomas R. Steinheimer, Wilfred E. Pereira, Sharon M. Johnson
1981, Analytica Chimica Acta (129) 57-67
A bed sediment sample taken from an area impacted by heavy industrial activity was analyzed for organic compounds of environmental significance. Extraction was effected on a Soxhlet apparatus using a freeze-dried sample. The Soxhlet extract was fractionated by silica gel micro-column adsorption chromatography. Separation and identification of the organic compounds...
The late-Neoglacial histories of the Agassiz and Jackson glaciers, Glacier National Park, Montana.
P. E. Carrara, R. G. McGimsey
1981, Arctic and Alpine Research (13) 183-196
Twenty-one tree-ring stations, totaling 116 trees, were sampled at various localities within the forest trimlines fronting the Agassiz and Jackson glaciers, Glacier National Park, Montana. Tree ages within these zones became progressively younger from the region of the maximum late-Neoglacial position to the bases of the bedrock slopes on which...
Measurement and computation of bed-material discharge in a shallow sand-bed stream, Muddy Creek, Wyoming
E.D. Andrews
1981, Water Resources Research (17) 131-141
Both the measurement and computation of the bed-material discharge of a stream involve large uncertainties because of the difficulties in determining bedload discharge. Measurements of bedload discharge are rare and frequently of unknown accuracy because no bedload sampler has been extensively tested and calibrated over a wide range of hydraulic...
Did ice streams carve martian outflow channels?
Baerbel K. Lucchitta, D.M. Anderson, H. Shoji
1981, Nature (290) 759-763
Outflow channels on Mars1 are long sinuous linear depressions that occur mostly in the equatorial area (±30° lat.). They differ from small valley networks2 by being larger and arising full born from chaotic terrains. Outflow channels resemble terrestrial stream beds, and their origin has generally been attributed to water3–5 in catastrophic floods6,7 or mudflows8....
Magneto-stratigraphic studies in Neogene deposits of Taylor Valley and McMurdo Sound, Antarctica
D. P. Elston, S.L. Bressler
1981, Journal Royal Society New Zealand (11) 481-486
Magnetic polarity and susceptibility zonations obtained from drill cores have served to refine temporal correlations in glaciogenic sections cored in eastern Taylor Valley. The zonations have led to a better understanding of the glacial and structural history for an interval of time that extends from the late Miocene (about 7...
Ancient buried submarine trough, northwest Gulf of Mexico
H. L. Berryhill Jr.
1981, Geo-Marine Letters (1) 105-110
A large buried submarine trough crosses the seaward margin of the continental shelf off the southwest coast of Louisiana. Original length was about 90 km, and width at the shelf edge was 16 km. Maximum eroded depth may have been as much as 305 m. Seismic characteristics of the prograded...
Fission-track dating of apatite and zircon: An interlaboratory comparison
C. W. Naeser, R.A. Zimmermann, G. T. Cebula
1981, Nuclear Tracks (5) 65-72
Apatite and zircon separates from the Fish Canyon Tuff (K-Ar age, 27.9??0.7 Myr), San Juan Mtns., Colorado, have been given to over 50 laboratories for fission-track dating. Nineteen laboratories have reported fission-track ages that they have determined for apatites. Nine laboratories have reported their analysis of the zircons. The principal...
An assessment of the accuracy of the geodetic measurements that define the southern California uplift
R. K. Mark, J. C. Tinsley III, E. B. Newman, T.D. Gilmore, R. O. Castle
1981, Journal of Geophysical Research Solid Earth (86) 2783-2808
Examination of the charge that the geodetic measurements which define the southern California uplift are seriously flawed by height-dependent systematic errors indicates that this charge is unfounded. Our review of those factors designed to minimize the effects of rod error shows that systematic errors attributable to rod miscalibration are trivial...
