Selenium source identification and biogeochemical processes controlling selenium in surface water and biota, Kendrick Reclamation Project, Wyoming, U.S.A.
D. L. Naftz, R.B. See, P. Ramirez
1993, Applied Geochemistry (8) 115-126
The major tributaries draining the Kendrick Reclamation Project (KRP) account for an average of 52% of the total Se load measured in the North Platte River downstream from Casper, Wyoming. The Casper Creek drainage basin contributed the largest Se load of...
A rainfall intensity-duration threshold for landslides in a humid- tropical environment, Puerto Rico
M. C. Larsen, A. Simon
1993, Geografiska Annaler, Series A (75 A) 13-23
Landslides are triggered by factors such as heavy rainfall, seismic activity, and construction on hillslopes. The leading cause of landslides in Puerto Rico is intense and/or prolonged rainfall. A rainfall threshold for rainfall-triggered landsliding is delimited by 256 storms that occurred between 1959 and 1991 in the central mountains of...
Relict colluvial boulder deposits as paleoclimatic indicators in the Yucca Mountain region, southern Nevada
J.W. Whitney, C.D. Harrington
1993, Geological Society of America Bulletin (105) 1008-1018
Early to middle Pleistocene boulder deposits are common features on southern Nevada hillslopes. These darkly varnished, ancient colluvial deposits stand but in stark contrast to the underlying light-colored bedrock of volcanic tuffs, and they serve as minor divides between drainage channels on modern hillslopes. To demonstrate the antiquity of these...
A sampling method for conducting relocation studies with freshwater mussels
D. L. Waller, J.J. Rach, W.G. Cope, J.A. Luoma
1993, Journal of Freshwater Ecology (8) 397-399
Low recovery of transplanted mussels often prevents accurate estimates of survival. We developed a method that provided a high recovery of transplanted mussels and allowed for a reliable assessment of mortality.A 3 × 3 m polyvinyl chloride (PVC) pipe grid was secured to the sediment with iron reinforcing bars....
Reproductive characteristics of a population of the washboard mussel Megalonaias nervosa (Rafinesque 1820) in the upper Mississippi River
C.A. Woody, L. Holland-Bartels
1993, Journal of Freshwater Ecology (8) 57-66
We examined monthly and age-specific gametogenic development of the washboard mussel, Megalonaias nervosa, from April 1986 to March 1987 in navigation Pool 10 of the upper Mississippi River. We found M. nervosa to be a late tachytictic breeder. Female marsupia contained eggs or glochidia primarily from August (17°C) through October (9°C)....
Fingerprinting the K/T impact site and determining the time of impact by UPb dating of single shocked zircons from distal ejecta
T.E. Krogh, S.L. Kamo, B.F. Bohor
1993, Earth and Planetary Science Letters (119) 425-429
UPb isotopic dating of single 1–3 μg zircons from K/T distal ejecta from a site in the Raton Basin, Colorado provides a powerful new tool with which to determine both the time of the impact event and...
Evaluation of the energy budget method of determining evaporation at Williams Lake, Minnesota, using alternative instrumentation and study approaches
D.O. Rosenberry, A.M. Sturrock, T. C. Winter
1993, Water Resources Research (29) 2473-2483
Best estimates of evaporation at Williams Lake, north central Minnesota, were determined by the energy budget method using optimum sensors and optimum placement of sensors. These best estimates are compared with estimates derived from using substitute data to determine the effect of using less accurate sensors, simpler methods, or remotely...
Geophysical investigations of the tectonic boundary between East and West Antarctica
Uri S. ten Brink, S. Bannister, B. C. Beaudoin, T.A. Stern
1993, Science (261) 45-50
The Transantarctic Mountains (TAM), which separate the West Antarctic rift system from the stable shield of East Antarctica, are the largest mountains developed adjacent to a rift. The cause of uplift of mountains bordering rifts is poorly understood. One notion based on observations of troughs next to many uplifted blocks...
The role of acoustic emission in the study of rock fracture
D. Lockner
1993, International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts (30) 883-899
The development of faults and shear fracture systems over a broad range of temperature and pressure and for a variety of rock types involves the growth and interaction of microcracks. Acoustic emission (AE), which is produced by rapid microcrack growth, is a ubiquitous phenomenon associated with brittle fracture and has...
Chronology, Eruption Duration, and Atmospheric Contribution of the Martian Volcano Apollinaris Patera
M.S. Robinson, P. J. Mouginis-Mark, J. R. Zimbelman, S.S.C. Wu, K.K. Ablin, A. E. Howington-Kraus
1993, Icarus (104) 301-323
Geologic mapping, thermal inertia measurements, and an analysis of the color (visual wavelengths) of the martian volcano Apollinaris Patera indicate the existence of two different surface materials, comprising an early, easily eroded edifice, and a more recent, competent fan on the southern flank. A chronology of six major events that...
Regional and economic geology of Pennsylvanian age coal beds of West Virginia
T.E. Repine Jr., B.M. Blake, K. C. Ashton, N. Fedorko III, A.F. Keiser, E.I. Loud, C.J. Smith, S. McClelland, G.H. McColloch
1993, International Journal of Coal Geology (23) 75-101
West Virginia is the only place in the United States where an entire section of Pennsylvanian age (Upper Carboniferous) strata can be seen. These strata occur within a wedge of rock that thins to the north and west from the southeastern...
Erosion response of a disturbed sagebrush steppe hillslope
B.F. Goff, G.C. Bent, G.E. Hart
1993, Journal of Environmental Quality (22) 698-709
Land management activities that disrupt surface vegetation cover pose a serious threat to the long-term stability of buried-waste sites located within the semiarid sagebrush (Artemisia tridentata Nutt.) steppe region of the northwestern USA. In this study, we evaluated the erosion response of a sagebrush hillslope subjected to...
Prediction by regression and intrarange data scatter in surface-process studies
T.J. Toy, W. R. Osterkamp, K.G. Renard
1993, Environmental Geology (22) 121-128
Modeling is a major component of contemporary earth science, and regression analysis occupies a central position in the parameterization, calibration, and validation of geomorphic and hydrologic models. Although this methodology can be used in many ways, we are primarily concerned with the prediction of values for one variable from another...
Volcanic eruption of the mid-ocean ridge along the East Pacific Rise crest at 9°45-52'N: direct submersible observations of seafloor phenomena associated with an eruption event in April, 1991
R.M. Haymon, D.J. Fornari, Karen L. Von Damm, M.D. Lilley, M.R. Perfit, J.M. Edmond, Wayne C. Shanks III, R.A. Lutz, J.M. Grebmeier, S. Carbotte, D. Wright, E. McLaughlin, M. Smith, N. Beedle, E. Olson
1993, Earth and Planetary Science Letters (119) 85-101
In April, 1991, we witnessed from the submersible Alvin a suite of previously undocumented seafloor phenomena accompanying an in-progress eruption of the mid-ocean ridge on the East Pacific Rise crest at 9°45′N–52′N. The volume of the eruption could not be precisely determined, although comparison of pre- and post-eruption SeaBeam...
The hydrothermal-convection systems of kilauea: an historical perspective
R. B. Moore, J. P. Kauahikaua
1993, Geothermics (22) 233-241
Kilauea is one of only two basaltic volcanoes in the world where geothermal power has been produced commercially. Little is known about the origin, size and longevity of its hydrothermal-convection systems. We review the history of scientific studies aimed at understanding these systems and describe their commercial development. Geothermal energy...
Alteration and geochemical zoning in Bodie Bluff, Bodie mining district, eastern California
P.A. Herrera, L.G. Closs, M.L. Silberman
1993, Journal of Geochemical Exploration (48) 259-275
Banded, epithermal quartz-adularia veins have produced about 1.5 million ounces of gold and 7 million ounces of silver from the Bodie mining district, eastern California. The veins cut dacitic lava flows, pyroclastic rocks and intrusions. Sinter boulders occur in a graben structure at the top of Bodie Bluff and fragments...
Radionuclides in ground water of the Carson River Basin, western Nevada and eastern California, U.S.A.
J. M. Thomas, A. H. Welch, M.S. Lico, J. L. Hughes, R. Whitney
1993, Applied Geochemistry (8) 447-471
Ground water is the main source of domestic and public supply in the Carson River Basin. Ground water originates as precipitation primarily in the Sierra Nevada in the western part of Carson and Eagle Valleys, and flows down gradient in the direction of the Carson River through Dayton and Churchill...
Bimodal Density Distribution of Cryptodome Dacite from the 1980 Eruption of Mount St. Helens, Washington
R. Hoblitt, R.S. Harmon
1993, Bulletin of Volcanology (55) 421-437
The explosion of a cryptodome at Mount St. Helens in 1980 produced two juvenile rock types that are derived from the same source magma. Their differences-color, texture and density-are due only to vesicularity differences. The vesicular gray dacite comprises bout 72% of the juvenile material; the black dacite comprises the...
Dissolved sulfides in the oxic water column of San Francisco Bay, California
J.S. Kuwabara, G.W. Luther
1993, Estuaries (16) 567-573
Trace contaminants enter major estuaries such as San Francisco Bay from a variety of point and nonpoint sources and may then be repartitioned between solid and aqueous phases or altered in chemical speciation. Chemical speciation affects the bioavailability of metals as well as organic ligands to planktonic and benthic organisms,...
Relationship of geological and geothermal field properties: Midcontinent area, USA, an example
A. Forster, D. F. Merriam, J.C. Brower
1993, Mathematical Geology (25) 937-947
Quantitative approaches to data analysis in the last decade have become important in basin modeling and mineral-resource estimation. The interrelation of geological, geophysical, geochemical, and geohydrological variables is important in adjusting a model to a real-world situation. Revealing the interdependences of variables can contribute in understanding the processes interacting in...
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...
Plasmid-mediated romet resistance of Edwardsiella ictaluri
C. E. Starliper, R.K. Cooper, E. B. Shotts Jr., P.W. Taylor
1993, Journal of Aquatic Animal Health (5) 1-8
Romet®, a potentiated sulfa drug composed of five parts sulfadimethoxine and one part ormetoprim, is used to treat channel catfish Ictalurus punctatus infected with Edwardsiella ictaluri, the causal agent of enteric septicemia of catfish (ESC). Recently, several Romet-resistant isolates of E. ictaluri were isolated from channel catfish that had died...
Comparison of plasmids isolated from Romet-30-resistant Edwardsiella ictaluri and tribrissen-resistant Escherichia coli
R.K. Cooper, C. E. Starliper, E. B. Shotts Jr., P.W. Taylor
1993, Journal of Aquatic Animal Health (5) 9-15
Edwardsiella ictaluri, the etiological agent of enteric septicemia of channel catfish (ESC) is the leading cause of bacterial disease in commercially raised channel catfish Ictalurus punctatus. The only drug approved by U.S. Food and Drug Administration for use against ESC is Romet-30. Recently, several isolates were...
Effects of one-year exposures to gas supersaturation on lake trout
W. F. Krise
1993, Progressive Fish-Culturist (55) 169-176
Lake trout (Salvelinus namaycush) were reared for 1 year in water with one of six levels of incoming differential gas pressure (▵P): 4, 17, 33, 43, 58, or 75 mm Hg. Growth and survival of fish were evaluated as measures of response to the potential long‐term stress of elevated dissolved...
Evaluation of the anesthetic metomidate for the handling and transport of juvenile American shad
R. M. Ross, T. W. H. Backman, R. M. Bennett
1993, Progressive Fish-Culturist (55) 236-243
Juvenile American shad (Alosa sapidissima) were exposed to three levels of metomidate (0.0 = control, 0.5, and 1.0 mg/L) and three types of sedation or handling (none, sedation only, and handling after sedation) to determine the efficacy and safety of the drug for use in transport and handling of this...
