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...
Fluxes of metals to a manganese nodule: Radiochemical, chemical, structural, and mineralogical studies
W.S. Moore, T.-L. Ku, J.D. Macdougall, V.M. Burns, R. Burns, J. Dymond, M.W. Lyle, D.Z. Piper
1981, Earth and Planetary Science Letters (52) 151-171
Fluxes of metals to the top and bottom surfaces of a manganese nodule were determined by combining radiochemical (230Th,231Pa,232Th,238U,234U) and detailed chemical data. The top of the nodule had been growing in its collected orientation at 4.7 mm Myr−1 for at least...
Geographic distribution and dispersal of normapolles genera in North America
R.H. Tschudy
1981, Review of Palaeobotany and Palynology (35) 283-314
Normapolles pollen have been found in North America in Cretaceous and Lower Tertiary rocks from the eastern Atlantic Seaboard, the Mississippi embayment region and from the states and provinces from western North America as far north as the District of Mackenzie, Northwest Territories. Previous postulates relating to the Normapolles floral...
Discrimination of a chestnut-oak forest unit for geologic mapping by means of a principal component enhancement of Landsat multispectral scanner data
M. D. Krohn, N.M. Milton, D. Segal, A. Enland
1981, Geophysical Research Letters (8) 151-154
A principal component image enhancement has been effective in applying Landsat data to geologic mapping in a heavily forested area of eastern Virginia. A chestnut-oak forest unit, which occurs on metavolcanic rocks and some metaclastic rocks in the western Piedmont and on highly weathered upland...
Objectives, accomplishments, and future plans of IGCP project 143, remote sensing and mineral exploration
W. D. Carter, L. C. Rowan
1981, Advances in Space Research (1) 227-236
The International Geological Correlation Programme (IGCP) is a worldwide cooperative research programme that began in 1974 under the auspices of the International Union of Geological Sciences. Because of the global availability of Earth resources data collected by satellites and the great interest among geologists in taking advantage of these new...
Estimating usable resources from historical industry data
S.M. Cargill, D. H. Root, E. H. Bailey
1981, Economic Geology (76) 1081-1095
Historical production statistics are used to predict the quantity of remaining usable resources. The commodities considered are mercury, copper and its byproducts gold and silver, and petroleum; the production and discovery data are for the United States. The results of the study indicate that the cumulative return per unit of...
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...
Seismic evidence for an extensive gas-bearing layer at shallow depth, offshore from Prudhoe Bay, Alaska
G. Boucher, E. Reimnitz, E. Kempema
1981, Cold Regions Science and Technology (4) 63-71
High-resolution seismic reflection data, recorded offshore from Prudhoe Bay, Alaska, were processed digitally to determine the reflectivity structure of the uppermost layers of the seafloor. A prominent reflector, found at 27 m below the mud line (water depths 7-9 m), has a negative reflection coefficient greater than 0.5. The large...
A five-collector system for the simultaneous measurement of argon isotope ratios in a static mass spectrometer
J. S. Stacey, N.D. Sherrill, G. B. Dalrymple, M. A. Lanphere, N.V. Carpenter
1981, International Journal of Mass Spectrometry and Ion Physics (39) 167-180
A system is described that utilizes five separate Faraday-cup collector assemblies, aligned along the focal plane of a mass spectrometer, to collect simultaneous argon ion beams at masses 36–40. Each collector has its own electrometer amplifier and analog-to-digital measuring channel, the outputs of which are processed by a minicomputer that...
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...
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...
Identification of kaolins and associated minerals in altered volcanic rocks by infrared spectroscopy
Graham R. Hunt, Robert B. Halley
1981, Clays and Clay Minerals (29) 76-78
Mid-infrared spectroscopy (2.5-50 /µm) has been extensively used to identify and characterize clays and associated minerals in rocks and soils, with particular emphasis on the 3-, 10-, and 20-/µm regions (Farmer and Russell, 1967; Farmer, 1968; White, 1971; Van der Marel and Beutelspacher, 1976). However, application of mid-infrared spectroscopy in...
Rates of manganese oxidation in aqueous systems
J.D. Hem
1981, Geochimica et Cosmochimica Acta (45) 1369-1374
The rate of crystal growth of Mn3O4 (hausmannite) and βMnOOH (feitknechtite) in aerated aqueous manganous perchlorate systems, near 0.01 M in total manganese, was determined at pH levels ranging from 7.00 to 9.00 and at temperatures from 0.5 to 37.4°C. The process is autocatalytic, but becomes psuedo first-order in dissolved Mn2+ activity...
Stratigraphy of the Caloris basin, Mercury
J.F. McCauley, J. E. Guest, G. G. Schaber, N.J. Trask, R. Greeley
1981, Icarus (47) 184-202
Caloris basin, Mercury’s youngest large impact basin, is filled by volcanic plains that are spectrally distinct from surrounding material. Post-plains impact craters of a variety of sizes populate the basin interior, and the spectra of the material they have...
Back-extraction of trace elements from organometallic-halide extracts for determination by flameless atomic absorption spectrometry
J. Robert Clark, John G. Viets
1981, Analytical Chemistry (53) 65-70
The Methyl isobutyl ketone-Amine synerGistic Iodkte Complex (MAGIC) extraction system offers the advantage that a large number of trace elements can be rapidly determined with a single sample preparation procedure. However, many of the elements extracted by the MAGIC system form volatile organometallic halide salts when the organic extract is...
Correlation of natural gas content to iron species in the New Albany shale group
R.H. Shiley, R.M. Cluff, D. R. Dickerson, C.C. Hinckley, Gerard V. Smith, H. Twardowska, Mykola Saporoschenko
1981, Fuel (60) 732-738
Mössbauer parameters were obtained for four Illinois Basin shales and their corresponding < 2μm clay fractions from wells drilled through the New Albany Shale Group in Henderson, Tazewell, and Effingham counties in Illinois and Christian County in Kentucky. Off-gas analysis indicated that the Illinois cores were in an area of...
Gas hydrates (clathrates) causing pore-water freshening and oxygen isotope fractionation in deep-water sedimentary sections of terrigenous continental margins
R. Hesse, W.E. Harrison
1981, Earth and Planetary Science Letters (55) 453-462
The occurrence of gas hydrates in deep-water sections of the continental margins predicted from anomalous acoustic reflectors on seismic profiles has been confirmed by recent deep-sea drilling results. On the Pacific continental slope off Guatemala gas hydrates were brought up for...
Seawater sulfate reduction and sulfur isotope fractionation in basaltic systems: interaction of seawater with fayalite and magnetite at 200–350°C
Wayne C. Shanks III, James L. Bischoff, Robert J. Rosenbauer
1981, Geochimica et Cosmochimica Acta (45) 1977-1995
Sulfate reduction during seawater reaction with fayalite and with magnetite was rapid at 350°C, producing equilibrium assemblages of talc-pyrite-hematite-magnetite at low water/rock ratios and talc-pyrite-hematite-anhydrite at higher water/rock ratios. At 250°C, seawater reacting with fayalite produced detectable amounts of dissolved H2S, but extent of reaction of solid phases was...
Sudden death at the end of the Mesozoic
C. Emiliani, E.B. Kraus, E.M. Shoemaker
1981, Earth and Planetary Science Letters (55) 317-334
A paleoecological analysis of the fossil record before and after the Cretaceous/Tertiary boundary indicates that the widespread extinctions and biological stresses around the boundary are best explained in terms of a sudden, significant, but short temperature rise. L. Alvarez and co-authors, having...
Martian channels and valleys: Their characteristics, distribution, and age
M. H. Carr, G.D. Clow
1981, Icarus (48) 91-117
All Martian channels and valleys visible at a resolution of 125 to 300 meters between 65°N and 65°S were mapped at a scale of 1:5,000,000 and the maps then digitized. Correlations of valley presence with other surface features show that almost...
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...
The earliest seeds
W.H. Gillespie, G.W. Rothwell, S.E. Scheckler
1981, Nature (293) 462-464
Lagenostomalean-type seeds in bifurcating cupule systems have been discovered in the late Devonian Hampshire Formation of Randolph County, West Virginia, USA (Fig. 1). The associated megaflora, plants from coal balls, and vertebrate and invertebrate faunas demonstrate that the material is Famennian; the microflora indicates a more specific Fa2c age. Consequently,...
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...
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...
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...
