Dynamics of Mojave Desert shrub assemblages in the Panamint Mountains, California.
Robert Webb, John W. Steiger, Raymond M. Turner
1987, Ecology (68) 478-490
We studied shrub communities in the Panamint Mountains of the Mojave Desert to determine whether vegetational changes after disturbance can be characterized as succession according to modern successional theory. We found, on a variety of disturbed and undisturbed sites, that the rate of change was a function of the type...
Columbia Glacier, Alaska: Changes in velocity 1977-1986
R. M. Krimmel, B. H. Vaughn
1987, Journal of Geophysical Research Solid Earth (92) 8961-8968
The Columbia Glacier, a grounded, iceberg-calving tidewater glacier near Valdez, Alaska, began to retreat about 1977. Drastic retreat occurred in 1984, and by early 1986, retreat amounted to 2 km. The glacier has thinned more than 100 m since 1974 at a point 4 km behind the 1974 terminus position....
36Cl: A tracer in groundwater in the aquia formation of Southern Maryland
C.B. Purdy, A.C. Mignerey, G.R. Helz, D.D. Drummond, P.W. Kubik, D. Elmore, T. Hemmick
1987, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms (29) 372-375
The Aquia Formation (Paleocene) of Southern Maryland, a marine unit consisting predominantly of quartz sands, but containing 20-40% glauconite, represents one of the many productive, heavily pumped aquifers of the Southeastern Coastal Plain. An unusually high 36Cl activity ( ~ 15 ?? modem water) measured in an outcrop sample is...
Isotopic composition of pyrite: Relationship to organic matter type and iron availability in some North American cretaceous shales
D. L. Gautier
1987, Chemical Geology: Isotope Geoscience Section (65) 293-303
The S isotope composition of pyrite in Cretaceous shales from the Western Interior of North America is related to organic C abundance, kerogen type and Fe availability. Both calcareous and noncalcareous rocks show a correlation between S and C, but noncalcareous...
Quaternary silicic pyroclastic deposits of Atitlán Caldera, Guatemala
William I. Rose Jr., Christopher G. Newhall, Theodore J. Bornhorst, Stephen Self
1987, Journal of Volcanology and Geothermal Research (33) 57-80
Atitlán caldera has been the site of several silicic eruptions within the last 150,000 years, following a period of basalt/andesite volcanism. The silicic volcanism began with 5–10 km3 of rhyodacites, erupted as plinian fall and pyroclastic flows, about 126,000 yr. B.P. At 85,000 yr. B.P. 270–280 km3 of compositionally distinct rhyolite was...
Structural reinterpretation of the Ajo mining district, Pima County, Arizona, based on paleomagnetic and geochronologic studies
J.T. Hagstrum, D. P. Cox, R. J. Miller
1987, Economic Geology (82) 1348-1361
The Ajo mining district of southern Arizona is divided into two main structural blocks by the Gibson Arroyo fault. The eastern Camelback Mountain block contains the Late Cretaceous-early Tertiary porphyry copper deposit which has been previously thought to be associated with the displaced apex of a large intrusion exposed by...
Lead poisoning in Canada geese on Plum Island, Massachusetts (USA)
R. M. Windingstad, L. S. Hinds III
1987, Journal of Wildlife Diseases (23) 438-442
During December 1983 and early January 1984, about 200 Canada geese (Branta canadensis) died of lead poisoning at Parker River National Wildlife Refuge on Plum Island, Massachusetts. In an effort to determine the source of lead, 100 bottom samples were taken from a refuge impoundment where much of the mortality/morbidity...
The mobilization of aluminum in a natural soil system: Effects of hydrologic pathways
Isabelle M. Cozzarelli, Janet S. Herman, Roderic A. Parnell Jr.
1987, Water Resources Research (23) 859-874
A two-component soil water flow model was used in conjunction with an equilibrium speciation model WATEQF to study aluminum mobility in soils of a forested watershed, White Oak Run, in the Shenandoah National Park, Virginia. Soil solution samples, taken from the O, E, B, C1, and C2horizons, were collected from...
Paint chip poisoning of Laysan albatross at Midway Atoll
L. Sileo, S.I. Fefer
1987, Journal of Wildlife Diseases (23) 432-437
Epizootic mortality occurred in Laysan albatross (Diomedea immutabilis) fledgings at Midway Atoll in 1983. Heavy metal toxicity from ingestion of weathered paint chips was one of the causes. Sick albatrosses were unable to retract their wings, causing a 'droop-wing' appearance. Five normal and 12 droop-winged fledglings were captured, killed, and...
Modes of development of slope canyons and their relation to channel and levee features on the Ebro sediment apron, off-shore northeastern Spain
S. O'Connell, William B. F. Ryan, W. R. Normark
1987, Marine and Petroleum Geology (4)
Six submarine slope canyons in an area of the northwestern Mediterranean, offshore from the Ebro River and Delta, were surveyed with bathymetric swathmapping (SeaBeam) and mid-range side-looking sonar (SeaMARC I). All of the canyons have slightly winding paths with concave-upwards gradients that are relatively steep shallower than 1,200 m. Two...
Sources and flux of natural gases from Mono Lake, California
Ronald S. Oremland, L.G. Miller, Michael J. Whiticar
1987, Geochimica et Cosmochimica Acta (51) 2915-2929
The ability to identify a formation mechanism for natural gas in a particular environment requires consideration of several geochemical factors when there are multiple sources present. Four primary sources of methane have been identified in Mono Lake. Two of these sources were associated with numerous natural gas seeps which...
Role of pressure in smectite dehydration: Effects on geopressure and smectite-to-illite transformation
Virginia Colten-Bradley
1987, American Association of Petroleum Geologists Bulletin (71) 1414-1427
Evaluation of the effect of pressure on the temperature of interlayer water loss (dehydration) by smectites under diagenetic conditions indicates that smectites are stable as hydrated phases in the deep subsurface. Hydraulic and differential pressure conditions affect dehydration differently. Smectites under hydraulic pressure conditions, such as in the pores of...
Analysis of broadband seismograms from selected IASPEI events
G. L. Choy, E.R. Engdahl
1987, Physics of the Earth and Planetary Interiors (47) 80-92
Broadband seismograms of body waves that are flat to displacement and velocity in the frequency range from 0.01 to 5.0 Hz can now be routinely obtained for most earthquakes of magnitude greater than about 5.5. These records are obtained either directly or through multichannel deconvolution of waveforms from digitally recording...
The crustal structure of the axis of the Great Valley, California, from seismic refraction measurements
W.S. Holbrook, Walter D. Mooney
1987, Tectonophysics (140) 49-63
In 1982 the U.S. Geological Survey collected six seismic refraction profiles in the Great Valley of California: three axial profiles with a maximum shot-to-receiver offset of 160 km, and three shorter profiles perpendicular to the valley axis. This paper presents the results of two-dimensional raytracing and synthetic seismogram modeling of...
Estimating threshold values for the land disposal of organic solvent-contaminated wastes
William R. Roy, R. A. Griffin
1987, Journal of Hazardous Materials (15) 365-376
This paper describes conceptual and mathematical modeling approaches to evaluate environmentally suitable waste management practices that prevent ground water pollution from landfill disposal of solid wastes contaminated with organic solvents. Threshold values for disposal of solid wastes contaminated with acetone, nitrobenzene, chlorobenzene, and carbon tetrachloride were estimated using a disposal...
Analysis of the U.S. geological survey streamgaging network
A. G. Scott
1987, Water Science and Technology (19) 31-42
This paper summarizes the results from the first 3 years of a 5-year cost-effectiveness study of the U.S. Geological Survey streamgaging network. The objective of the study is to define and document the most cost-effective means of furnishing streamflow information. In the first step of this study, data uses were...
Coastal lava flows from Mauna Loa and Hualalai volcanoes, Kona, Hawaii
James G. Moore, D. Clague
1987, Bulletin of Volcanology (49) 752-764
A major carbonate reef which drowned 13 ka is now submerged 150 m below sea level on the west coast of the island of Hawaii. A 25-km span of this reef was investigated using the submersible Makali'i. The reef occurs on the flanks of two active volcanoes, Mauna Loa and...
Valles Marineris, Mars: Wet debris flows and ground ice
Baerbel K. Lucchitta
1987, Icarus (72) 411-429
Detailed study of the Valles Marineris equatorial troughs suggests that the landslides in that area contained water and probably were gigantic wet debris flows: one landslide complex generated a channel that has several bends and extends for 250 km. Further support for water or ice in debris masses includes rounded...
Kinetics and mechanisms of iron sulfide reductions in hydrogen and in carbon monoxide
T. Wiltowski, C.C. Hinckley, Gerard V. Smith, T. Nishizawa, Mykola Saporoschenko, R.H. Shiley, J.R. Webster
1987, Journal of Solid State Chemistry (71) 95-102
The reduction of iron sulfides by hydrogen and by carbon monoxide has been studied using plug flow and thermogravimetric methods. The reactions were studied in the 523–723°K temperature range and were found to be first-order processes. Plug flow studies were used to correlate reaction rates between pyrite and the gases...
Theoretical analysis of the transient pressure response from a constant flow rate hydraulic conductivity test
Roger H. Morin, Harold W. Olsen
1987, Water Resources Research (23) 1461-1470
Incorporating a flow pump into a conventional triaxial laboratory system allows fluid to be supplied to or withdrawn from the base of a sediment sample at small and constant rates. An initial transient record of hydraulic head versus time is observed which eventually stabilizes to a constant steady state gradient...
Recent geologic history of lake Atitlán, a caldera lake in western Guatemala
C. G. Newhall, C. K. Paull, J.P. Bradbury, A. Higuera-Gundy, L.J. Poppe, S. Self, Sharpless N. Bonar, J. Ziagos
1987, Journal of Volcanology and Geothermal Research (33) 81-107
Lake Atitlán, a caldera lake in western Guatemala, was investigated for evidence of recent volcanic and tectonic activity. No vents, faults, or folds are apparent on high-resolution seismic reflection profiles of lake sediment, representing at least 17,500 years and probably more than 35,000 years of deposition. Three post-caldera stratovolcanoes...
Ecological aspects of microorganisms inhabiting uranium mill tailings
C.L. Miller, E. R. Landa, D.M. Updegraff
1987, Microbial Ecology (14) 141-155
Numbers and types of microorganisms in uranium mill tailings were determined using culturing techniques. Arthrobacter were found to be the predominant microorganism inhabiting the sandy tailings, whereas Bacillus and fungi predominated in the slime tailings. Sulfate-reducing bacteria, capable of leaching radium, were isolated in low numbers from tailings samples but...
Design of a spatial data structure using the relational normal forms
Jan W. van Roessel
1987, International Journal of Geographical Information Systems (1) 33-50
In previous work, a relational data structure aimed at the exchange of spatial data between systems was developed. As this data structure was relational it was of first normal form, but compliance with the higher normal forms was not investigated. Recently, a new procedural method for composing fully normalized data...
ECONOMICS AND THE SEARCH FOR OFFSHORE HEAVY MINERAL DEPOSITS.
E. D. Attanasi, J.H. DeYoung Jr.
1987, Marine Mining (6) 323-337
This paper examines the relative importance, in terms of a deposit's commercial status, of physical characteristics of onshore titanium-bearing heavy-mineral placer deposits, and applies these findings to the search for and evaluation of offshore deposits. Results obtained by applying statistical discriminant analysis show that the characteristics most useful for predicting...
Slab pull and the seismotectonics of subducting lithosphere
William Spence
1987, Reviews of Geophysics (25) 55-69
This synthesis links many seismic and tectonic processes at subduction zones, including great subduction earthquakes, to the sinking of subducted plate. Earthquake data and tectonic modeling for subduction zones indicate that the slab pull force is much larger than the ridge push force. Interactions between the forces that drive and...
