Seasat synthetic aperture radar ( SAR) response to lowland vegetation types in eastern Maryland and Virginia
M. D. Krohn, N.M. Milton, D. B. Segal
1983, Journal of Geophysical Research - Oceans (88) 1937-1952
Examination of SEASAT SAR images of eastern Maryland and Virginia reveals botanical distinctions between vegetated lowland areas and adjacent upland areas. Radar returns from the lowland areas can be either brighter or darker than returns from the upland forests. Scattering models and scatterometer measurements predict an increase of 6 dB...
40Ar/39Ar and U-Th-Pb dating of separated clasts from the Abee E4 chondrite
D.D. Bogard, D.M. Unruh, M. Tatsumoto
1983, Earth and Planetary Science Letters (62) 132-146
Determinations of40Ar/39Ar and U-Th-Pb are reported for three clasts from the Abee (E4) enstatite chondrite, which has been the object of extensive consortium investigations. The clasts give40Ar/39Ar plateau ages and/or maximum ages of 4.5 Gy, whereas two of the clasts give...
Liquefaction sites, Imperial Valley, California.
T. L. Youd, M.J. Bennett
1983, Journal of Geotechnical Engineering (109) 440-457
Sands that did and did not liquefy at two sites during the 1979 Imperial Valley, Calif., earthquake (ML = 6.6) are identified and their properties evaluated. SPT tests were used to evaluate liquefaction susceptibility. Loose fine sands in an abandoned channel liquefied and produced sand boils, ground fissures, and a...
Influence of time on metamorphism of sedimentary organic matter in liquid-dominated geothermal systems, western North America
C.E. Barker
1983, Geology (11) 384-388
Temperature (T in °C) and mean vitrinite reflectance (Rm in %) of sedimentary organic matter samples from six liquid-dominated geothermal systems plot about a line approximated by a regression equation of the form Rm = 0.435 exp 0.00683T. The reflectance data from these systems are strongly temperature-dependent,...
Objective procedures for lineament enhancement and extraction
G. K. Moore, F. A. Waltz
1983, Photogrammetric Engineering and Remote Sensing (49) 641-647
A longterm research goal at EROS Data Center is to develop automated, objective procedures for lineament mapping. In support of this goal, a five-step digital convolution procedure has been used to produce directionally enhanced images, which contain few artifacts and little noise. The main limitation of this procedure is that...
Storm-controlled oblique dunes of the Oregon coast
R. E. Hunter, B. M. Richmond, T. R. Alpha
1983, Geological Society of America Bulletin (94) 1450-1465
The large (mean height 25 m, spacing 300 m), relatively straight-crested dunes of the central Oregon coast migrate an average of 3.8 m/yr toward an azimuth of 26°. The dunes are transverse to the strong, south-southwesterly winter storm winds that are responsible for...
Stability of streams and lakes on Mars
M. H. Carr
1983, Icarus (56) 476-495
Under present climatic conditions streams and lakes on Mars will freeze. Freezing is slow and would have a negligible effect in impeding flow of the large floods that are believed to have eroded the outflow channels. Valley networks are more difficult...
Geochemistry of diverse basalt types from Loihi Seamount, Hawaii: Petrogenetic implications
F.A. Frey, D.A. Clague
1983, Earth and Planetary Science Letters (66) 337-355
The wide variety of basalt types, tholeiitic to basanite, dredged from Loihi Seamount have minor and trace element abundances that are characteristic of subaerial Hawaiian basalts, thereby confirming that Loihi Seamount is a manifestation of the Hawaiian “hot spot”. Within the Loihi sample suite there are well-defined positive correlations among...
Scoresum - A technique for displaying and evaluating multi-element geochemical information, with examples of its use in regional mineral assessment programs
M.A. Chaffee
1983, Journal of Geochemical Exploration (19) 361-381
A technique called SCORESUM was developed to display a maximum of multi-element geochemical information on a minimum number of maps for mineral assessment purposes. The technique can be done manually for a small analytical data set or can be done with a computer for a large data set. SCORESUM...
A strategy for mineral and energy resource independence
W. D. Carter
1983, Advances in Space Research (3) 223-236
Data acquired by Landsats 1, 2, and 3, are beginning to provide the information on which an improved mineral and energy resource exploration strategy can be based. Landsat 4 is expected to augment this capability with its higher resolution (30 m) and additional spectral bands in the Thematic Mapper (TM)...
Development of reaction models for ground-water systems
Niel Plummer, D.L. Parkhurst, D.C. Thorstenson
1983, Geochimica et Cosmochimica Acta (47) 665-685
Methods are described for developing geochemical reaction models from the observed chemical compositions of ground water along a hydrologic flow path. The roles of thermodynamic speciation programs, mass balance calculations, and reaction-path simulations in developing and testing reaction models are contrasted. Electron transfer is included in the mass balance equations...
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...
Quaternary geology of the Rhode Island inner shelf
S. W. Needell, C. J. O’Hara, H.J. Knebel
1983, Marine Geology (53) 41-53
Five sedimentary units and three erosional unconformities identified in high-resolution seismic-reflection profiles reveal the stratigraphic framework and Quaternary history of the inner continental shelf south of Narragansett Bay, Rhode Island. Late Tertiary to early Pleistocene rivers eroded the pre-Mesozoic bedrock and the Upper Cretaceous to lower Tertiary coastal plain and...
Diatom evidence on Wisconsin and Holocene events in the Bering Sea
C. Sancetta, S.W. Robinson
1983, Quaternary Research (20) 232-245
Previous work on surface (modern) sediments has defined diatom species which appear to be good indicators of various oceanographic/ecologic conditions in the North Pacific Ocean and marginal seas. Three long cores from the eastern and northern sides of the Aleutian Basin show changes in species assemblage which can be interpreted...
Speculation on martian north polar wind circulation and the resultant orientations of polar sand dunes
A. W. Ward, K.B. Doyle
1983, Icarus (55) 420-431
Dunes in the Martian north polar erg show two dominant orientations. When seen at frost cap minimum, dunes north of 80°N record east winds, dunes south of 80°N record west winds. Many of the transverse dunes are considered to be reversing...
Tin granites of Seward Peninsula, Alaska
T. Hudson, Joseph G. Arth
1983, Geological Society of America Bulletin (94) 768-790
Seven granite plutons, spatially and genetically related to tin metalization, are exposed in a 170-km-long belt across northwestern Seward Peninsula, Alaska. These plutons are cupolas and epizonal composite stocks that consist of several textural varieties of biotite granite, including medium- to coarse-grained seriate...
Simulation of solute transport in a mountain pool-and-riffle stream: A transient storage model
Kenneth E. Bencala, Roy A. Walters
1983, Water Resources Research (19) 718-724
The physical characteristics of mountain streams differ from the uniform and conceptually well- defined open channels for which the analysis of solute transport has been oriented in the past and is now well understood. These physical conditions significantly influence solute transport behavior, as demonstrated by a transient storage model simulation...
Statistical averaging of marine magnetic anomalies and the aging of oceanic crust
R.J. Blakely
1983, Journal of Geophysical Research Solid Earth (88) 2289-2296
Visual comparison of Mesozoic and Cenozoic magnetic anomalies in the North Pacific suggests that older anomalies contain less short-wavelength information than younger anomalies in this area. To test this observation, magnetic profiles from the North Pacific are examined from crust of three ages: 0–2.1, 29.3–33.1, and 64.9–70.3 m.y, B.P. For...
Rare-earth element geochemistry and the origin of andesites and basalts of the Taupo Volcanic Zone, New Zealand
J. W. Cole, K. V. Cashman, P.C. Rankin
1983, Chemical Geology (38) 255-274
Two types of basalt (a high-Al basalt associated with the rhyolitic centres north of Taupo and a "low-Al" basalt erupted from Red Crater, Tongariro Volcanic Centre) and five types of andesite (labradorite andesite, labradorite-pyroxene andesite, hornblende andesite, pyroxene low-Si andesite and olivine andesite/low-Si andesite) occur in the Taupo Volcanic Zone...
Incorporation of prior information on parameters into nonlinear regression groundwater flow models: 2. Applications
Richard L. Cooley
1983, Water Resources Research (19) 662-676
This paper investigates factors influencing the degree of improvement in estimates of parameters of a nonlinear regression groundwater flow model by incorporating prior information of unknown reliability. Consideration of expected behavior of the regression solutions and results of a hypothetical modeling problem lead to several general conclusions. First, if the...
Atomic-absorption determination of mercury in geological materials by flame and carbon-rod atomisation after solvent extraction and using co-extracted silver as a matrix modifier
R. F. Sanzolone, T. T. Chao
1983, The Analyst (108) 58-63
Based on modifications and expansion of the original Tindall's solvent extraction flame atomic-absorption procedure, an atomic-absorption spectrophotometric method has been developed for the determination of mercury in geological materials. The sample is digested with nitric and hydrochloric acids in a boiling water-bath. The solution is made ammoniacal and potassium iodide...
Relationship of two lacustrine ostracode species to solute composition and salinity: Implications for paleohydrochemistry ( Limnocythere sappaensis/staplini)
R. M. Forester
1983, Geology (11) 435-438
Nonmarine ostracode species are indicative of the physical and chemical nature of lacustrine environments. Although salinity has traditionally been regarded as one of the more important parameters that affect the occurrence patterns of lacustrine ostracodes, examination of the solute composition and salinities of...
Paleohydraulic reconstruction of flash- flood peaks from boulder deposits in the Colorado Front Range
J. E. Costa
1983, Geological Society of America Bulletin (94) 986-1004
Nine watersheds in the Colorado Front Range with steep bedrock channels were used to test the accuracy of paleohydraulic reconstruction of large flash floods using boulder deposits. The nine basins consist of eight small ungauged basins ranging in size from 1.6 to 29...
INTERACTIVE NAME PLACEMENT FOR PROVISIONAL MAPS.
Jeffrey L. Goldberg, Thomas C. Miller
1983, Conference Paper, Technical Papers of the American Congress of Surveying and Mapping
Computer generation and placement of map type has been refined into a production mode at Mid-Continent Mapping Center (MCMC) for USGS 1:24,000- and 1:25,000-scale Provisional maps. The map collar program is written in FORTRAN using batch processing that allows the program to work in the background....
Crustal structure of the northern mississippi embayment and a comparison with other continental rift zones
Walter D. Mooney, M.C. Andrews, A. Ginzburg, D.A. Peters, R. M. Hamilton
1983, Tectonophysics (94) 327-348
Previous geological and geophysical investigations have suggested that the Mississippi Embayment is the site of a Late Precambrian continental rift that was reactivated in the Mesozoic. New information on the deep structure of the northern Mississippi Embayment, gained through an extensive seismic refraction survey, supports a rifting hypothesis. The data...
