Factors Affecting 14C Ages of Lacustrine Carbonates: Timing and Duration of the Last Highstand Lake in the Lahontan Basin
L. Benson
1993, Quaternary Research (39) 163-174
Two processes contribute to inaccurate 14C age estimates of carbonates precipitated within the Lahontan basin, NevadaCalifornia: low initial 14C/C ratios in lake water (reservoir effect) and addition of modern carbon to calcium carbonate after its precipitation. The mast reliable set of 14C ages on carbonates from elevations > 1310 m...
Using multisource data in global land-cover characterization: concepts, requirements, and methods
Jesslyn F. Brown, Thomas R. Loveland, James W. Merchant, Bradley C. Reed, Donald O. Ohlen
1993, Photogrammetric Engineering and Remote Sensing (59) 977-987
Global land-cover data are needed as baseline information for global change research. Multisource data, both coarse resolution satellite data and ancillary data, were used to produce a land-cover characteristics database for the conterqinous United States. Ancillary data, including elevation and ecological region data sets, were critical to the development, refinement, and...
Regional West Indian manatee 1992 Studbook
C.L. Salisbury, C.A. Beck
1993, Book
Abstract not supplied at this time...
Influence of seasonal climatic variability on shallow infiltration at Yucca Mountain
Joseph Hevesi, Alan L. Flint
1993, Conference Paper, High Level Radioactive Waste Management
To analyze infiltration and the redistribution of moisture in alluvial deposits at Yucca Mountain, water content profiles at a 13.5 m deep borehole were measured at monthly intervals using a neutron moisture probe. Increases in water content to a maximum depth of 1.8 m in response to winter season precipitation...
Variations in aqueous sulfate concentrations at Panola Mountain, Georgia
J. B. Shanley, N.E. Peters
1993, Journal of Hydrology (146) 361-382
Aqueous sulfate concentrations were measured in incident precipitation, canopy throughfall, stemflow, soil water, groundwater, and streamwater at three locations in a 41 ha forested watershed at Panola Mountain State Park in the Georgia Piedmont. To evaluate the variations in sulfate concentrations,...
Stratigraphic Context of Old Crow Tephra, Holitna Lowland, Interior Southwest Alaska
C. F. Waythomas, P.D. Lea, R.C. Walter
1993, Quaternary Research (40) 20-29
A thick deposit of Old Crow tephra was discovered in a bluff exposure along the middle Holitna River near the Kulukbuk Hills (61??20???N latitude, 157??10???W longitude) in interior southwest Alaska. This locality is the southwesternmost-known deposit of Old Crow tephra in Alaska. Thickness and grain-size data from this site support...
Deformation of the Wineglass Welded Tuff and the timing of caldera collapse at Crater Lake, Oregon
H. Kamata, K. Suzuki-Kamata, C. R. Bacon
1993, Journal of Volcanology and Geothermal Research (56) 253-265
Four types of deformation occur in the Wineglass Welded Tuff on the northeast caldera rim of Crater Lake: (a) vertical tension fractures; (b) ooze-outs of fiamme: (c) squeeze-outs of fiamme; and (d) horizontal pull-apart structures. The three types of plastic deformation (b-d) developed in the lower part of the Wineglass...
The deposit size frequency method for estimating undiscovered uranium deposits
R.B. McCammon, W.I. Finch
1993, Nonrenewable Resources (2) 106-112
The deposit size frequency (DSF) method has been developed as a generalization of the method that was used in the National Uranium Resource Evaluation (NURE) program to estimate the uranium endowment of the United States. The DSF method overcomes difficulties encountered during the NURE program when geologists were asked to...
Selective inhibition of ammonium oxidation and nitrification-linked N2O formation by methyl fluoride and dimethyl ether
L.G. Miller, M.D. Coutlakis, R.S. Oremland, B.B. Ward
1993, Applied and Environmental Microbiology (59) 2457-2464
Methyl fluoride (CH3F) and dimethyl ether (DME) inhibited nitrification in washed-cell suspensions of Nitrosomonas europaea and in a variety of oxygenated soils and sediments. Headspace additions of CH3F (10% [vol/vol]) and DME (25% [vol/vol]) fully inhibited NO2- and N2O production from NH4+ in incubations of N. europaea, while lower concentrations of these gases resulted in...
Preliminary evaluation of effects of best management practices in the Black Earth Creek, Wisconsin, priority watershed
J.F. Walker, D.J. Graczyk
H. Olem, editor(s)
1993, Conference Paper, Water Science and Technology
Nonpoint-source contamination accounts for a substantial part of the water quality problems in many watersheds. The Wisconsin Nonpoint Source Water Pollution Abatement Program provides matching money for voluntary implementation of various best management practices (BMPs). The effectiveness of BMPs on a drainage-basin scale has not been adequately assessed in Wisconsin...
Epigenetic sulfide mineralization associated with Pennsylvanian paleokarst in eastern Iowa, U.S.A.
P.L. Garvin, Greg A. Ludvigson
1993, Chemical Geology (105) 271-290
Paleokarst-associated, sulfide-bearing mineral deposits are wide-spread in the Paleozoic carbonate rocks of eastern Iowa. Minerals occur in nodules enclosed in karst-filling mudstones, as sandstone cements, and as surface coatings on, and fracture fillings in, foundered carbonate rock clasts. Mineralogy and paragenetic sequence vary among the occurrences. Sulfur isotopic compositions exhibit...
Late Pleistocene Vertebrates and Other Fossils from Epiguruk, Northwestern Alaska
T. D. Hamilton, G.M. Ashley, K. M. Reed, C. E. Schweger
1993, Quaternary Research (39) 381-389
Sediments exposed at Epiguruk, a large cutbank on the Kobuk River about 170 km inland from Kotzebue Sound, record multiple episodes of glacial-age alluviation followed by interstadial downcutting and formation of paleosols. Vertebrate remains from Epiguruk include mammoth, bison, caribou, an equid, a canid, arctic ground squirrel, lemmings, and voles....
Radon anomalies on three kinds of faults in California
C.-Y. King, W. Zhang, B.-S. King
1993, Pure and Applied Geophysics PAGEOPH (141) 111-124
Radon emanation is known to be anomalously high along active faults in many parts of the world. We tested this relationship in California during July and early August 1992, using a portable radonmeter to conduct soil-air radon surveys at 5 sites across three kinds of faults: Creeping, locked, and freshly...
Factors controlling the geochemical evolution of fumarolic encrustations, Valley of Ten Thousand Smokes, Alaska
L.G. Kodosky, T. E. C. Keith
1993, Journal of Volcanology and Geothermal Research (55) 185-200
Factor and canonical correlation analysis of geochemical data from eight fossil fumaroles suggest that six major factors controlled the formation and evolution of fumarolic encrustations on the 1912 ash-flow sheet in the Valley of Ten Thousand Smokes (VTTS). The six-factor solution model explains a large proportion (low of 74% for...
Worldwide distribution of subaquatic gas hydrates
K.A. Kvenvolden, G.D. Ginsburg, V.A. Soloviev
1993, Geo-Marine Letters (13) 32-40
Sediments containing natural gas hydrates occur worldwide on continental and insular slopes and rises of active and passive margins, on continental shelves of polar regions, and in deep-water (> 300 m) environments of inland lakes and seas. The potential amount of methane in natural gas hydrates is enormous, with current...
Seismic response of eccentrically braced tall buildings
Mehmet Çelebi
1993, Journal of Structural Engineering (119) 1188-1205
Spectral analysis and system identification techniques are used to analyze a set of acceleration reponse records obtained during the Loma Prieta earthquake from the 47-story, moment-resisting framed and eccentrically braced Embarcadero Building (EMB). The EMB was constructed in 1979 based on the 1976 Uniform Building Code requirements and a design...
Actualistic models of mantle metasomatism documented in a composite xenolith from Dish Hill, California
J. E. Nielson, J. R. Budahn, D.M. Unruh, H. G. Wilshire
1993, Geochimica et Cosmochimica Acta (57) 105-121
Major and trace-element whole rock and mineral variations in composite hornblendite-peridotite xenolith Ba-2-1, from Dish Hill, CA, are due to a single event of metasomatism in the mantle. The hornblendite is the crystallized selvage of a dike conduit charged with incompatible-element-enriched hydrous mafic magma. The magma infiltrated the refractory peridotite...
Electric-field-ratio profiling at the Silsilah tin-bearing greisen deposit, Kingdom of Saudi Arabia
R.J. Kamilli, C.J. Zablocki
1993, Exploration and Mining Geology (2) 155-163
Buried, possibly mineralized granite cupolas at the Silsilah tin deposit in Saudi Arabia have been successfully located using a closely spaced electric-field-ratio profiling technique. In this study electrical fields at 27 and 270 Hz across grounded electrodes spaced 50m apart were measured along six traverses. The technique allowed the authors...
Short-term water and suspended-sediment fluctuations in a Louisiana marsh
John R. Dingler
1993, Conference Paper, Coastal Zone: Proceedings of the Symposium on Coastal and Ocean Management
To determine the timing of and driving forces for sediment suspension and deposition and the effect of impoundment, three self-recording instrument packages were deployed in a section of Louisiana marsh. Two of the packages went into an impoundment and one into an adjacent open, or control, area. A data logger...
The Mount Evans batholith in the Colorado Front Range: Revision of its age and reinterpretation of its structure
J. N. Aleinikoff, J. C. Reed Jr., E. Dewitt
1993, Geological Society of America Bulletin (105) 791-806
The Mount Evans batholith, in the central Front Range of Colorado, is composed of a main phase of massive to conspicuously foliated monzogranite and granodiorite and undeformed aplite and pegmatite. The Mount Evans batholith was previously considered to be part of the 1.7 Ga Routt Plutonic Suite. New U-Pb zircon...
Active volcanism beneath the West Antarctic ice sheet and implications for ice-sheet stability
D. D. Blankenship, R.E. Bell, S. M. Hodge, J. M. Brozena, John C. Behrendt, C. A. Finn
1993, Nature (361) 526-529
IT is widely understood that the collapse of the West Antarctic ice sheet (WAIS) would cause a global sea level rise of 6 m, yet there continues to be considerable debate about the detailed response of this ice sheet to climate change1-3. Because its bed is grounded well below sea...
Fishway use by white sturgeon to bypass mainstem Columbia River dams
Joe Warren, L.G. Beckman
R.C. Beamesderfer, A.A. Nigro, editor(s)
1993, Report, Status and Habitat Requirements of the White Sturgeon Populations in the Columbia River Downstream from McNary Dam Volume I, 1986-1992 Final Report
No abstract available. ...
U.S. Geological Survey bedload sampling policy
G. Douglas Glysson
1993, Conference Paper, Proceedings - National Conference on Hydraulic Engineering
During the late 1960's, the U.S. Geological Survey's (USGS) Water Resources Division (WRD) developed the Helley-Smith bedload sampler. Since then, the USGS and the Technical Committee of the Federal Interagency Subcommittee on Sedimentation (Technical Committee) have performed extensive flume and field studies concerning the calibration and use of bedload samplers....
Aspects of three-dimensional strain at the margin of the extensional orogen, Virgin River depression area, Nevada, Utah, and Arizona
R.E. Anderson, T. P. Barnhard
1993, Geological Society of America Bulletin (105) 1019-1052
The Virgin River depression and surrounding mountains are Neogene features that are partly contiguous with the little-strained rocks of the structural transition to the Colorado Plateau province. This contiguity makes the area ideally suited for evaluating the sense, magnitude, and kinematics of Neogene deformation. Analysis along the strain boundary shows...
Processes affecting coastal wetland loss in the Louisiana deltaic plain
S. Jeffress Williams, Shea Penland, Harry H. Roberts
1993, Conference Paper, Coastal Zone: Proceedings of the Symposium on Coastal and Ocean Management
Nowhere are the problems of coastal wetland loss more serious and dramatic than in the Mississippi River deltaic plain region of south-central Louisiana. In that area, rates of shoreline erosion of 20 m.yr and loss of land area of up to 75 km/yr result from a complex combination of natural...
