Laser-excited fluorescence of rare earth elements in fluorite: Initial observations with a laser Raman microprobe
R.C. Burruss, T.G. Ging, R. G. Eppinger, a.M. Samson
1992, Geochimica et Cosmochimica Acta (56) 2713-2723
Fluorescence emission spectra of three samples of fluorite containing 226–867 ppm total rare earth elements (REE) were excited by visible and ultraviolet wavelength lines of an argon ion laser and recorded with a Raman microprobe spectrometer system. Narrow emission lines (< 1 nm) due to 4f-4f electron transitions in individual...
Experiments with central-limit properties of spatial samples from locally covariant random fields
T. H. Barringer, T. E. Smith
1992, Regional Science and Urban Economics (22) 387-403
When spatial samples are statistically dependent, the classical estimator of sample-mean standard deviation is well known to be inconsistent. For locally dependent samples, however, consistent estimators of sample-mean standard deviation can be constructed. The present paper investigates the sampling properties of one such estimator, designated as the tau estimator of sample-mean standard...
Quantitative assessment of future development of cooper/silver resources in the Kootenai National Forest, Idaho/Montana: Part I-Estimation of the copper and silver endowments
G.T. Spanski
1992, Nonrenewable Resources (1) 163-183
Faced with an ever-increasing diversity of demand for the use of public lands, managers and planners are turning more often to a multiple-use approach to meet those demands. This approach requires the uses to be mutually compatible and to utilize the more valuable attributes or resource values of the land....
Reconnaissance exploration geochemistry in the central Brooks Range, northern Alaska: Implications for exploration of sediment-hosted zinc-lead-silver deposits
K.D. Kelley, D. L. Kelley
1992, Journal of Geochemical Exploration (42) 273-300
A reconnaissance geochemical survey was conducted in the southern Killik River quadrangle, central Brooks Range, northern Alaska. The Brooks Range lies within the zone of continuous permafrost which may partially inhibit chemical weathering and oxidation. The minus 30-mesh and nonmagnetic heavy-mineral...
Evidence from Cd/Ca ratios in foraminifera for greater upwelling off California 4,000 years ago
A. VanGeen, N. Luoma, C. C. Fuller, R. Anima, H.E. Clifton, S. Trumbore
1992, Nature (358) 54-56
UPWELLING of nutrient-rich Pacific deep water along the North American west coast is ultimately driven by the temperature difference between air masses over land and over the ocean. The intensity of upwelling, and biological production in the region, could therefore be affected by anthropogenic climate change. Examination of the geological...
Sources of nitrogen and phosphorus to Northern San Francisco Bay
S.W. Hager, L. E. Schemel
1992, Estuaries (15) 40-52
We studied nutrient sources to the Sacramento River and Suisun Bay (northern San Francisco Bay) and the influence which these sources have on the distributions of dissolved inorganic nitrogen (DIN) and dissolved reactive phosphorus (DRP) in the river and bay. We found that agricultural return flow drains and a...
Biological diversity of a temporary pond herpetofauna in north Florida sandhills
C.K. Dodd Jr.
1992, Biodiversity and Conservation (1) 125-142
From 1985 through 1990, the herpetofauna of a temporary pond in an uplands longleaf pine sandhills community in north-central Florida was monitored. A drift fence completely encircled the pond. Animals were captured in pitfall traps and marked as they entered and exited the pond basin. I captured 16 155 individuals...
Transfer of computer software technology through workshops: The case of fish bioenergetics modeling
Barry L. Johnson
1992, Fisheries (17) 114-118
I recommend a three-part program to promote the availability and use of computer software packages to fishery managers and researchers. The three-part approach consists of journal articles that announce new technologies, technical reports that serve as user's guides, and hands-on workshops that provide direct instruction to new users. Workshops, which...
ALVIN investigation of an active propagating rift system, Galapagos 95.5° W
R.N. Hey, J.M. Sinton, M.C. Kleinrock, R.N. Yonover, K.C. MacDonald, S.P. Miller, R. C. Searle, D.M. Christie, T.M. Atwater, Norman H. Sleep, H. Paul Johnson, C.A. Neal
1992, Marine Geophysical Research (14) 207-226
ALVIN investigations have defined the fine-scale structural and volcanic patterns produced by active rift and spreading center propagation and failure near 95.5° W on the Galapagos spreading center. Behind the initial lithospheric rifting, which is propagating nearly due west at about 50 km m.y.−1, a triangular block of preexisting...
Comparison of the effects of filtration and preservation methods on analyses for strontium-90 in ground water
L.L. Knobel, L. DeWayne Cecil, S.J. Wegner, L.L. Moore
1992, Environmental Monitoring and Assessment (20) 67-80
From 1952 to 1988, about 140 curies of strontium-90 were discharged in liquid waste to disposal ponds and wells at the INEL (Idaho National Engineering Laboratory). Water from four wells was sampled as part of the U.S. Geological Survey's quality-assurance program to evaluate the effects of filtration and preservation methods...
Selenium and other elements in freshwater fishes from the irrigated San Joaquin Valley, California
M. K. Saiki, M.R. Jennings, T.W. May
1992, Science of the Total Environment (126) 109-137
Arsenic (As), chromium (Cr), mercury (Hg), and selenium (Se) were measured in composite whole-body samples of five fishes — bluegill (Lepomis macrochirus), common carp (Cyprinus carpio), mosquitofish (Gambusia affinis), largemouth bass (Micropterus salmoides), and Sacramento blackfish (Orthodon microlepidotus) — from the San Joaquin River system to determine if concentrations were...
Demographic structure of California chaparral in the long-term absence of fire
Jon E. Keeley
1992, Journal of Vegetation Science (3) 79-90
Demographic structure of 12 chaparral sites unburned for 56 to 120 years was investigated. All sites were dominated by vigorous shrub populations and, although there was colonization by seedlings of woodland tree species in several stands, successional replacement of chaparral was not imminent. Although successional changes in community composition were...
Morphology of ruffe (Gymnocephalus cernuus) protolarvae from the St. Louis River, Lake Superior
John R. P. French III, Thomas A. Edsall
1992, Journal of Freshwater Ecology (7) 59-68
We describe hatching and the morphological and meristic characteristics of 2.5-5.6 mm long ruffe protolarvae (Gymnocephalus cernuus). Eggs and sperm from St. Louis River ruffe were mixed, producing fertilized eggs that were 0.9-1.2 mm in diameter. Newly hatched protolarvae were 2.5-3.2 mm long. They had 14-15 preanal...
Characteristics of a sandy depositional lobe on the outer Mississippi fan from SeaMARC IA sidescan sonar images
D.C. Twichell, W. C. Schwab, C.H. Nelson, Neil H. Kenyon, H.J. Lee
1992, Geology (20) 689-692
SeaMARC IA sidescan sonar images of the distal reaches of a depositional lobe on the Mississippi Fan show that channelized rather than unconfined transport was the dominant transport mechanism for coarse-grained sediment during the formation of this part of the deep-sea fan. Overbank...
Metallogeny of the midcontinent rift system of North America
S. W. Nicholson, W.F. Cannon, K. J. Schulz
1992, Precambrian Research (58) 355-386
The 1.1 Ga Midcontinent rift system of North America is one of the world's major continental rifts and hosts a variety of mineral deposits. The rocks and mineral deposits of this 2000 km long rift are exposed only in the Lake Superior region. In the Lake Superior region, the...
Geochemistry and origin of the Bald Knob manganese deposit, North Carolina
M.J.K. Flohr
1992, Economic Geology (87) 2023-2040
Geochemical and textural evidence for the submarine hydrothermal origin of the Bald Knob Mn deposit, North Carolina, is preserved in a mineralogically diverse suite of rocks that have experienced amphibolite facies metamorphism. Manganese- and Mn-Fe-rich lithologies have high Mn/Fe ratios and low concentrations of Ni, Cu, Zn, U, Th, and...
Use of forecasting signatures to help distinguish periodicity, randomness, and chaos in ripples and other spatial patterns
D. M. Rubin
1992, Chaos (2) 525-536
Forecasting of one-dimensional time series previously has been used to help distinguish periodicity, chaos, and noise. This paper presents two-dimensional generalizations for making such distinctions for spatial patterns. The techniques are evaluated using synthetic spatial patterns and then are applied to a natural example: ripples formed in sand by blowing...
Distribution and effects of shallow gas on bulk estuarine sediment properties
J. M. Hill, J.P. Halka, R. Conkwright, K. Koczot, S. Coleman
1992, Continental Shelf Research (12) 1219-1229
Gas bubble are present in sediments covering approximately 30% of the main stem of Chesapeake Bay, with bubbles occurring at the sediment-water interface in 18% of the main stem sediments. This biogenic gas is found either in the sediments in the lower salinity reaches of the Bay, or confined to...
Energy budgets and resistances to energy transport in sparsely vegetated rangeland
William D. Nichols
1992, Agricultural and Forest Meteorology (60) 221-247
Partitioning available energy between plants and bare soil in sparsely vegetated rangelands will allow hydrologists and others to gain a greater understanding of water use by native vegetation, especially phreatophytes. Standard methods of conducting energy budget studies result in measurements of latent and sensible heat fluxes above the plant canopy...
The effect of membrane filtration artifacts on dissolved trace element concentrations
A. J. Horowitz, K. A. Elrick, M.R. Colberg
1992, Water Research (26) 753-763
Among environment scientists, the current and almost universally accepted definition of dissolved constituents is an operational one only those materials which pass through a 0.45-??m membrane filter are considered to be dissolved. Detailed laboratory and field studies on Fe and Al indicate that a number of factors associated with filtration,...
An aeromagnetic survey over the northwestern Ross Ice Shelf and the McMurdo Sound area
Detlef Damaske, Uwe Meyer, Anne E. McCafferty, John Behrendt, Herbert Hoppe
1992, Polarforschung (60) 152-156
As part of the expedition GANOVEX VI 1990/91, the Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), the Alfred Wegener Institute for Polar and Marine Research (AWI), and the United States Geological Survey (USGS) carried out an airborne magnetic survey over the northwestern Ross Ice Shelf and McMurdo Sound between Ross Island,...
Lake acidity and mercury content of fish in Darwin National Reserve, Russia
Terry A. Haines, V. Komov, C. H. Jagoe
1992, Environmental Pollution (78) 107-112
Darwin National Reserve is a protected natural area on the north-west shore of the Rybinsk Reservoir, 350 km north of Moscow. In June 1989, six lakes in the Reserve and the reservoir were surveyed to assess lake acidity and the mercury content of perch, Perca fluviatilis. Five were seepage lakes...
Roosting behavior of premigratory Dunlins (Calidris alpina)
Colleen M. Handel, Robert E. Gill Jr.
1992, The Auk (109) 57-72
We studied roosting behavior of Dunlins (Calidris alpina) during late summer along the coast of the Yukon-Kuskokwim Delta, Alaska, in relation to tidal cycle, time of day, time of season, and occurrence of predators. Within Angyoyaravak Bay, peak populations of 70,000-100,000 Dunlins occur each year. The major diurnal roost sites...
Tensiometers: Theory, construction, and use
D.I. Stannard
1992, Geotechnical Testing Journal (15) 48-58
Standard tensiometers are used to measure matric potential as low as −870 cm of water in the unsaturated zone by creating a saturated hydraulic link between the soil water and a pressure sensor. The direction and, in some cases, quantity of water flux can be determined using multiple installations.A variety...
The use of tumors in wild populations of fish to assess ecosystem health
Paul C. Baumann
1992, Journal of Aquatic Ecosystem Health (1) 135-146
Evidence has linked toxicants in aquatic systems with cancer in fish and population level effects on species. Thus some types of tumors may be useful monitors of ecosystem health, at least as affected by genotoxins and promoters. However, tumors caused by purely genetic mechanisms or by virus would not be...
