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Page 2838, results 70926 - 70950

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Origin of minerals in joint and cleat systems of the Pottsville Formation, Black Warrior basin, Alabama: Implications for coalbed methane generation and production
Janet K. Pitman, J.C. Pashin, J. R. Hatch, M. B. Goldhaber
2003, American Association of Petroleum Geologists Bulletin (87) 713-731
Coalbed methane is produced from naturally fractured strata in the lower Pennsylvanian Pottsville Formation in the eastern part of the Black Warrior basin, Alabama. Major fracture systems include orthogonal fractures, which consist of systematic joints in siliciclastic strata and face...
Constraints on the composition of ore fluids and implications for mineralising events at the Cleo gold deposit, Eastern Goldfields Province, Western Australia
S.M. Brown, C. A. Johnson, R.J. Watling, W. R. Premo
2003, Australian Journal of Earth Sciences (50) 19-38
The Cleo gold deposit, 55 km south of Laverton in the Eastern Goldfields Province of Western Australia, is characterised by banded iron-formation (BIF)-hosted ore zones in the gently dipping Sunrise Shear Zone and high-grade vein-hosted ore in the Western Lodes. There is evidence that gold mineralisation in the Western Lodes...
Kinetic dissolution of carbonates and Mn oxides in acidic water: Measurement of in situ field rates and reactive transport modeling
J. G. Brown, P. D. Glynn
2003, Applied Geochemistry (18) 1225-1239
The kinetics of carbonate and Mn oxide dissolution under acidic conditions were examined through the in situ exposure of pure phase samples to acidic ground water in Pinal Creek Basin, Arizona. The average long-term calculated in situ dissolution rates for calcite and dolomite were 1.65??10-7 and 3.64??10-10 mmol/(cm2 s), respectively,...
Time-lapse video sysem used to study nesting Gyrfalcons
Travis Booms, Mark R. Fuller
2003, Journal of Field Ornithology (74) 416-422
We used solar-powered time-lapse video photography to document nesting Gyrfalcon (Falco rusticolus) food habits in central West Greenland from May to July in 2000 and 2001. We collected 2677.25 h of videotape from three nests, representing 94, 87, and 49% of the nestling period at each nest....
Heat flow and brine generation following the Chesapeake Bay bolide impact
W. Sanford
2003, Conference Paper, Journal of Geochemical Exploration
Calculations indicate that the impact of an asteroid or comet on the Atlantic Coastal Plain 35 million years ago created subsequent hydrothermal activity and conditions suitable for phase separation and the creation of the brine observed in the groundwater at the site today. A calculation of groundwater velocity using Darcy's...
Application of adaptive cluster sampling to low-density populations of freshwater mussels
D. R. Smith, R.F. Villella, D. P. Lemarie
2003, Environmental and Ecological Statistics (10) 7-15
Freshwater mussels appear to be promising candidates for adaptive cluster sampling because they are benthic macroinvertebrates that cluster spatially and are frequently found at low densities. We applied adaptive cluster sampling to estimate density of freshwater mussels at 24 sites along the Cacapon River, WV, where a preliminary timed search...
Structural localization and origin of compartmentalized fluid flow, Comstock lode, Virginia City, Nevada
B. R. Berger, J.V. Tingley, L.J. Drew
2003, Economic Geology (98) 387-408
Bonanza-grade orebodies in epithermal-style mineral deposits characteristically occur as discrete zones within spatially more extensive fault and/or fracture systems. Empirically, the segregation of such systems into compartments of higher and lower permeability appears to be a key process necessary for high-grade ore formation and, most commonly, it is such concentrations...
Evolution of CAM and C4 carbon-concentrating mechanisms
Jon E. Keeley, Philip W. Rundel
2003, International Journal of Plant Sciences (164) 555-577
Mechanisms for concentrating carbon around the Rubisco enzyme, which drives the carbon-reducing steps in photosynthesis, are widespread in plants; in vascular plants they are known as crassulacean acid metabolism (CAM) and C4 photosynthesis. CAM is common in desert succulents, tropical epiphytes, and aquatic plants and is characterized by nighttime fixation...
Supra-subduction zone extensional magmatism in Vermont and adjacent Quebec: Implications for early Paleozoic Appalachian tectonics
J. Kim, R. Coish, M. Evans, G. Dick
2003, Geological Society of America Bulletin (115) 1552-1569
Metadiabasic intrusions of the Mount Norris Intrusive Suite occur in fault-bounded lithotectonic packages containing Stowe, Moretown, and Cram Hill Formation lithologies in the northern Vermont Rowe-Hawley belt, a proposed Ordovician arc-trench gap above an east-dipping subduction zone. Rocks of the Mount Norris Intrusive Suite are characteristically massive and weakly foliated,...
Temporal and spatial stability of red-tailed hawk territories in the Luquillo Experimental Forest, Puerto Rico
C. W. Boal, Hollice A. Snyder, Brent D. Bibles, T.S. Estabrook
2003, Journal of Raptor Research (37) 277-285
We mapped Red-tailed Hawk (Buteo jamaicensis) territories in the Luquillo Experimental Forest (LEF) of Puerto Rico in 1998. We combined our 1998 data with that collected during previous studies of Red-tailed Hawks in the LEF to examine population numbers and spatial stability of territorial boundaries over a 26-yr period. We...
The Tuscarora Au-Ag district: Eocene volcanic-hosted epithermal deposits in the Carlin gold region, Nevada
S.B. Castor, D.R. Boden, C.D. Henry, J. S. Cline, A. H. Hofstra, W. C. McIntosh, R. M. Tosdal, J.P. Wooden
2003, Economic Geology (98) 339-366
The Tuscarora mining district contains the oldest and the only productive Eocene epithermal deposits in Nevada. The district is a particularly clear example of association of low-sulfidation deposits with igneous activity and structure, and it is unusual in that it consists of two adjoining but physically and chemically distinct types...
Fish faunal resurgence in Lake Nabugabo, East Africa
L.J. Chapman, Colin A. Chapman, P. J. Schofield, J.P. Olowo, L.S. Kaufman, O. Seehausen, R. Ogutu-Ohwayo.
2003, Conservation Biology (17) 500-511
 In Lake Nabugabo, Uganda, a small satellite of the equatorial Lake Victoria, approximately 50% of the indigenous fish species disappeared from the open waters subsequent to establishment of the introduced predatory Nile perch (   Lates niloticus ). However, several of these species persisted in wetland refugia. Over the past decade, Nile perch...
A 38,000-year record of floods and debris flows in the Ilo region of southern Peru and its relation to El Niño events and great earthquakes
David K. Keefer, Michael E. Moseley, Susan D. deFrance
2003, Palaeogeography, Palaeoclimatology, Palaeoecology (194) 41-77
Previous work throughout the Ilo region of south coastal Peru has documented the existence of flood and debris-flow deposits produced by two El Niño events evidently much more severe than any in recent history. These two events have been dated to ca. AD 1300–1400 and AD 1607–08. The Late Pleistocene...
Protecting embryos from stress: Corticosterone effects and the corticosterone response to capture and confinement during pregnancy in a live-bearing lizard (Hoplodactylus maculatus)
A. Cree, C.L. Tyrrell, M.R. Preest, D. Thorburn, L.J. Guillette Jr.
2003, General and Comparative Endocrinology (134) 316-329
Hormones in the embryonic environment, including those of the hypothalamo-pituitary-adrenal (HPA) axis, have profound effects on development in eutherian mammals. However, little is known about their effects in reptiles that have independently evolved viviparity. We investigated whether exogenous corticosterone affected embryonic development in the viviparous gecko Hoplodactylus maculatus, and whether...
Deformation near the Casa Diablo geothermal well field and related processes Long Valley caldera, Eastern California, 1993-2000
J. F. Howle, J. O. Langbein, C. D. Farrar, S.K. Wilkinson
2003, Journal of Volcanology and Geothermal Research (127) 365-390
Regional first-order leveling lines, which extend from Lee Vining, CA, to Tom's Place, CA, have been surveyed periodically since 1957 by the U.S. Geological Survey (USGS), the National Geodetic Survey (NGS), and Caltrans. Two of the regional survey lines, or leveling networks, intersect at the Casa Diablo geothermal well field....
Geothermometry, geochronology, and mass transfer associated with hydrothermal alteration of a rhyolitic hyaloclastite from Ponza Island, Italy
S. P. Altaner, R.F. Ylagan, S.M. Savin, J.L. Aronson, H. E. Belkin, A. Pozzuoli
2003, Geochimica et Cosmochimica Acta (67) 275-288
A rhyolitic hyaloclastite from Ponza Island, Italy, was hydrothermally altered, producing four distinct alteration zones based on X-ray diffraction mineralogy and field textures: (1) nonpervasive argillic zone; (2) propylitic zone; (3) silicic zone; and (4) sericitic zone. The unaltered hyaloclastite is volcanic breccia with clasts of vesiculated obsidian in a...
Chlorine-36 data at Yucca Mountain: Statistical tests of conceptual models for unsaturated-zone flow
K. Campbell, A. Wolfsberg, J. Fabryka-Martin, D. Sweetkind
2003, Journal of Contaminant Hydrology (62-63) 43-61
An extensive set of chlorine-36 (36Cl) data has been collected in the Exploratory Studies Facility (ESF), an 8-km-long tunnel at Yucca Mountain, Nevada, for the purpose of developing and testing conceptual models of flow and transport in the unsaturated zone (UZ) at this site. At several locations, the measured values...
Tracing the pathways of Neotropical migratory shorebirds using stable isotopes: A pilot study
A.H. Farmer, R. Rye, G. Landis, C. Bern, C. Kester, I. Ridley
2003, Isotopes in Environmental and Health Studies (39) 169-177
We evaluated the potential use of stable isotopes to establish linkages between the wintering grounds and the breeding grounds of the Pectoral Sandpiper (Calidris melanotos), the White-rumped Sandpiper (Calidris fuscicollis), the Baird's Sandpiper (Calidris bairdii), and other Neotropical migratory shorebird species (e.g., Tringa spp.). These species molt their flight feathers...
Designing mark-recapture studies to reduce effects of distance weighting on movement distance distributions of stream fishes
B. Albanese, P. L. Angermeier, C. Gowan
2003, Transactions of the American Fisheries Society (132) 925-939
Mark-recapture studies generate biased, or distance-weighted, movement data because short distances are sampled more frequently than long distances. Using models and field data, we determined how study design affects distance weighting and the movement distributions of stream fishes. We first modeled distance weighting as a function of recapture section length...
Basal metabolism of the black-footed ferret (Mustela nigripes) and the Siberian polecat (M. eversmannii)
L.A. Harrington, E. Biggins, A.W. Alldredge
2003, Journal of Mammalogy (84) 497-504
Black-footed ferrets (Mustela nigripes) and Siberian polecats (M. eversmannii) are medium-sized (about 1 kg) mustelids with similar ecological and morphological characteristics. We measured basal metabolic rates (BMR) for both species. In contrast with the commonly stated belief that mustelids have relatively high mass-specific BMR, neither the BMR of ferrets nor...
Goldquarryite, a new Cd-bearing phosphate mineral from the Gold Quarry mine, Eureka County, Nevada
Andrew C. Roberts, M. A. Cooper, Frank C. Hawthorne, Robert A. Gault, M.C. Jensen, E.E. Foord
2003, Mineralogical Record (34) 237-240
Goldquarryite, idealized formula CuCd2Al3(PO44F2(H2O)10(H2O 2, structure-derived formula (Cu0.70???0.30??1.00(Cd1.68Ca0.32??2.00Al3 (PO44F2(H2O)10[(H2O 1.60F0.40]??2.00, is triclinic, space group P1, with unit-cell parameters derived from crystal structure: a = 6.787(1), b = 9.082(2), c = 10.113(2) A??, ?? = 101.40(1)??, ?? = 104.27(1)??, ?? = 102.51(1)??, V = 568.7(3) A??3, a:b:c: = 0.7473:1:1.1135, Z =...