Flexural extension of the upper continental crust in collisional foredeeps
D. C. Bradley, W.S.F. Kidd
1991, Geological Society of America Bulletin (103) 1416-1438
Normal faults on the outer slopes of trenches and collisional foredeeps reveal that high-amplitude lithospheric flexure can result in inelastic extensional deformation of the convex side of a flexed plate. This process, which we call "flexural extension," differs fundamentally from rifting in that...
Changes in thermodynamic conditions of the Ahuachapán reservoir due to production and injection
B. Steingrimsson, Z. Aunzo, G.S. Bodvarsson, A. Truesdell, G. Cuellar, C. Escobar, A. Quintanilla
1991, Geothermics (20) 23-38
Since large-scale exploitation of the Ahuachapán reservoir began in 1975 large changes in the reservoir thermodynamic conditions have occurred. Drawdown of up to 15 bars and significant temperature changes have been observed in the wellfield. Temperatures have declined due to boiling in the reservoir in response to the pressure drawdown;...
Oxygen, hydrogen, and sulfur isotope studies in the Juneau gold belt, southeastern Alaska: Constraints on the origin of hydrothermal fluids
R.J. Goldfarb, R.J. Newberry, W.J. Pickthorn, C. A. Gent
1991, Economic Geology (86) 66-80
The delta 18 O values of gold-bearing quartz from the Juneau gold belt range from 15.2 to 20.8 per mil, indicating that ore fluid values ranged from 7.2 to 12.8 per mil at an estimated temperature of 300 degrees C. Hydrothermal micas from many of the deposits are characterized by delta D...
Alternative method to Mariotte reservoir system for maintaining constant hydraulic pressure
Falah Thamir
Anon, editor(s)
1991, Conference Paper, High Level Radioactive Waste Management
Several problems with the Mariotte reservoir system were discovered when it was used to apply a constant water pressure as a boundary condition for a prolonged period. The constant-pressure boundary condition is required for some laboratory experiments to study water flow through porous media. The observed problems were caused by...
A statistical approach to the interpretation of aliphatic hydrocarbon distributions in marine sediments
J. B. Rapp
1991, Chemical Geology (93) 163-177
Q-mode factor analysis was used to quantitate the distribution of the major aliphatic hydrocarbon (n-alkanes, pristane, phytane) systems in sediments from a variety of marine environments. The compositions of the pure end members of the systems were obtained from factor scores and the distribution of the systems within each sample...
Seasonal abundance and vertical distribution of capelin (Mallotus villosus) in relation to water temperature at a coastal site off eastern Newfoundland
David A. Methven, John F. Piatt
1991, ICES Journal of Marine Science (48) 187-193
The seasonal abundance and vertical distribution of capelin in relation to water temperature have been investigated by conducting repeated hydroacoustic surveys at a coastal site off eastern Newfoundland. Water temperatures were warmer in 1983 than in 1984 as indicated by the earlier appearance and greater depth of the seasonal thermocline....
Chemical equilibrium and mass balance relationships associated with the Long Valley hydrothermal system, California, U.S.A.
A. F. White, M. L. Peterson
1991, Journal of Volcanology and Geothermal Research (48) 283-302
Recent drilling and sampling of hydrothermal fluids from Long Valley permit an accurate characterization of chemical concentrations and equilibrium conditions in the hydrothermal reservoir. Hydrothermal fluids are thermodynamically saturated with secondary quartz, calcite, and pyrite but are in disequilibrium with respect to aqueous sulfide-sulfate speciation. Hydrothermal fluids are enriched in...
Comment on “Macrodispersion in sand-shale sequences” by A. J. Desbarats
Daniel J. Goode, Allen M. Shapiro
1991, Water Resources Research (27) 135-139
Desbarats [1990] used a particle-tracking scheme to investigate the physics of three-dimensional solute transport in aquifers composed of two porous media of different hydraulic conductivities. The spatially heterogeneous fluid velocity was assumed to be the only mechanism of solute...
New hydrologic instrumentation in the U.S. Geological Survey
V.J. Latkovich, W.G. Shope
Sodhi Devinder S., editor(s)
1991, Conference Paper, Cold Regions Engineering
New water-level sensing and recording instrumentation is being used by the U.S. Geological Survey for monitoring water levels, stream velocities, and water-quality characteristics. Several of these instruments are briefly described. The Basic Data Recorder (BDR) is an electronic data logger, that interfaces to sensor systems through a serial-digital interface standard...
Changes in the nearshore and offshore zooplankton communities in Lake Ontario: 1981-88
Ora E. Johannsson, Edward L. Mills, Robert O’Gorman
1991, Canadian Journal of Fisheries and Aquatic Sciences (48) 1546-1557
We examined trends and factors influencing changes in nearshore and offshore zooplankton abundance and composition in Lake Ontario between 1981 and 1988. In the nearshore (southshore and eastern basin), zooplankton abundance decreased and shifts occurred in the relative abundances of Bosmina longirostris and Daphnia retrocurva (eastern basin) and Daphnia retrocurva...
Late Neogene marine Ostracoda from Tjornes, Iceland
T. M. Cronin
1991, Journal of Paleontology (65) 767-794
On the western side of the Tjörnes Peninsula in northern Iceland exposures of fossiliferous marine sediments, basalts, and glacial tills record the climatic history of this region of the North Atlantic Ocean. Seventy-five marine ostracode species were recovered from the Pliocene Tjörnes sediments and Quaternary sediments known...
Using larval fish abundance in the St. Clair and Detroit Rivers to predict year-class strength of forage fish in Lakes Huron and Erie
Charles O. Hatcher, Robert T. Nester, Kenneth M. Muth
1991, Journal of Great Lakes Research (17) 74-84
Larval fish samples were collected in plankton tow nets in spring and summer, 1977–1978 and 1983–1984, in the St. Clair and Detroit rivers which are part of the connecting waterway between Lakes Huron and Erie. Larvae abundance of the major forage fish in the rivers are compared with their year-class...
Roles of predation, food, and temperature in structuring the epilimnetic zooplankton populations in Lake Ontario, 1981-1986
Ora E. Johannsson, Robert O’Gorman
1991, Transactions of the American Fisheries Society (120) 193-208
We sampled phytoplankton, zooplankton, and alewives Alosa pseudoharengus and measured water temperature in Lake Ontario during 1981–1986. Through the use of general linear regression models we then sought evidence of control of the eplimnetic zooplankton community (mid-July to mid-October) by producers, consumers, and temperature. Our measures of the zooplankton community...
Intrusion of horizontal dikes: tectonic significance of Middle Proterozoic diabase sheets widespread in the upper crust of the southwestern United States
K. A. Howard
1991, Journal of Geophysical Research (96) 12461-12478
Initially horizontal sheet intrusions of Middle Proterozoic diabase are abundant in a region 650 by 300 km across in Arizona and California. The diabase forms discordant sheets in basement granite and gneiss and sills in overlying shelf sedimentary sequences. Massive granite is the most common...
Genesis and continuity of quaternary sand and gravel in glacigenic sediment at a proposed low-level radioactive waste disposal site in east-central Illinois
K. G. Troost, B. Brandon Curry
1991, Environmental Geology and Water Sciences (18) 159-170
The Illinois Department of Nuclear Safety has characterized the Martinsville Alternative Site (MAS) for a proposed low-level radioactive waste disposal facility. The MAS is located in east-central Illinois approximately 1.6 km (1 mi) north of the city of Martinsville. Geologic investigation of the 5.5-km2 (1380-acre) site revealed a sequence of...
Regional assessment of nonpoint-source pesticide residues in ground water, San Joaquin Valley, California
Joseph L. Domagalski, N. M. Dubrovsky
1991, Water-Resources Investigations Report 91-4027
No abstract available....
Is the extent of glaciation limited by marine gas-hydrates?
Charles K. Paull, William Ussler III, William P. Dillon
1991, Geophysical Research Letters (18) 432-434
Methane may have been released to the atmosphere during the Quaternary from Arctic shelf gas-hydrates as a result of thermal decomposition caused by climatic warming and rising sea-level; this release of methane (a greenhouse gas) may represent a positive feedback on global warming [Revelle, 1983; Kvenvolden, 1988a; Nisbet, 1990]. We...
Selenium and associated trace elements in soil, rock, water and streambed sediment of the proposed Sandstone Reservoir, south-central Wyoming
D. L. Naftz, C. S. Barclay
1991, Water-Resources Investigations Report 91-4000
No abstract available....
Influence of pycnocline topography and water-column structure on marine distributions of alcids (Aves: Alcidae) in Anadyr Strait, Northern Bering Sea, Alaska
J. Christopher Haney
1991, Marine Biology (110) 419-435
Systematic ship-board surveys were used to simultaneously record seabird abundances and resolve coarse-scale (3 to 10 km) horizontal and fine-scale (1 to 10 m) vertical variability in water-column structure and bathymetry for portions of the coastal zone in Anadyr Strait near western St. Lawrence Island, northern Bering Sea, Alaska, during...
Ground-water conditions in Amargosa Desert, Nevada-California, 1952-87
K. C. Kilroy
1991, Water-Resources Investigations Report 89-4101
No abstract available....
Response of Ned Wilson Lake watershed, Colorado, to changes in atmospheric deposition of sulfate
Donald H. Campbell, John T. Turk, Norman E. Spahr
1991, Water Resources Research (27) 2047-2060
The Ned Wilson Lake watershed responds directly and rapidly to changes in precipitation inputs of sulfate, which has important implications for effects of acid deposition on the aquatic system. Chemistry at three precipitation collection sites and three watershed sites (a pond, a lake, and a spring) has been monitored in...
Disturbance effects on aquatic vegetation in regulated and unregulated lakes in northern Minnesota
Douglas A. Wilcox, James E. Meeker
1991, Canadian Journal of Botany (69) 1542-1551
The effects of water-level regulation on aquatic macrophyte communities were investigated by comparing two regulated lakes in northern Minnesota with a nearby unregulated lake (Lac La Croix). Natural annual fluctuations of about 1.8 m were replaced with fluctuations of 1.1 m and 2.7 m in the regulated lakes, and the...
Seasonal patterns of prey availability and the foraging behavior of arctic foxes (Alopex lagopus) in a waterfowl nesting area
Alice Stickney
1991, Canadian Journal of Zoology (69) 2853-2859
The foraging behavior of arctic foxes was observed in a waterfowl nesting area on the Yukon–Kuskokwim Delta of Alaska in 1985–1986. Observations were made during peak fox activity from two towers, 3 m high, located in different community types. Data were collected continuously for individual foxes on specific activities, the community...
Mortality of seabirds in the Japanese land-based gillnet fishery for salmon
Anthony R. DeGange, Robert H. Day
1991, The Condor (93) 251-258
Mortality rates of seabirds in the Japanese land-based drift gillnet fishery for salmon were assessed from 413 gillnet sets made by Japanese research vessels in offshore areas used by the commercial fleet. Sixteen species of seabirds were recorded in nets. Shearwaters, primarily Short-tailed Shearwaters (Puffinus tenuirostris), and to a lesser...
Periphyton accumulation at remote reefs and shoals in Lake Superior
Thomas A. Edsall, Eugene F. Stoermer, John P. Kociolek
1991, Journal of Great Lakes Research (17) 412-418
Observations made from a submarine showed that the bed-rock surfaces at water depths of about 5 to 14 m on Stannard Rock and Superior Shoal in Lake Superior were covered with a dense, fleece-like blanket of periphyton. Examination of the periphyton revealed it consisted primarily of structurally complex, diverse, diatom...
