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...
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...
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...
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...
Basement thrust sheets in the Clearwater orogenic zone, central Idaho and western Montana
B. Skipp
1987, Geology (15) 220-224
The Clearwater orogenic zone in central Idaho and western Montana contains at least two major northeast-directed Cordilleran thrust plates of Early Proterozoic metasedimentary and metaigneous rocks that overrode previously folded Middle Proterozoic rocks of the Belt basin in Cretaceous time. The northeastward migration...
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...
Source of lead and mineralizing brines for rossie-type Pb-Zn veins in the Frontenac axis area, New York ( USA).
Robert Ayuso, Nora K. Foley, C. Erwin Brown
1987, Economic Geology (82) 489-491
Veins composed mainly of calcite and some galena, sphalerite, fluorite, and other minerals are widespread in the Frontenac axis area of New York and Ontario. In New York, the veins (Fig. 1) occur mainly west and northwest of Gouverneur (Brown, 1983). The veins, mined in the 1800s for lead,...
Analysis of Shuttle Multispecral Infrared Radiometer measurements of the western Saudi Arabian shield.
Lawrence C. Rowan, Alexander F.H. Goetz, Elsa Abbott
1987, Geophysics (52) 907-923
During the November 12–14, 1981, mission of the space shuttle Columbia, the Shuttle Multispectral Infrared Radiometer (SMIRR) recorded radiances in ten channels along a 100 m wide groundtrack across the western Saudi Arabian shield. The ten channels are located in the 0.5 to 2.4 μm region, with five positioned between...
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...
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...
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...
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...
15N/14N variations in Cretaceous Atlantic sedimentary sequences: Implication for past changes in marine nitrogen biogeochemistry
G.H. Rau, M.A. Arthur, W.E. Dean
1987, Earth and Planetary Science Letters (82) 269-279
At two locations in the Atlantic Ocean (DSDP Sites 367 and 530) early to middle Cretaceous organic-carbon-rich beds (“black shales”) were found to have significantly lower δ15N values (lower15N/14N ratios) than adjacent organic-carbon-poor beds (white limestones or green claystones). While these lithologies are of marine origin, the black strata in...
Man-induced gradient adjustment of the South Fork Forked Deer River, west Tennessee
A. Simon, C. H. Robbins
1987, Environmental Geology and Water Sciences (9) 109-118
Channel modifications from 1968 to 1969 on the South Fork Forked Deer River in western Tennessee have caused upstream degradation, downstream aggradation, and bank failures along the altered channels, adjacent reaches, and tributaries. The result of these adjustments is a general decrease in gradient as the channel attempts to absorb...
The line integral approach to radarclinometry
R.L. Wildey
1987, Earth, Moon and Planets (38) 59-95
Radarclinometry, the invention of which has been previously reported, is a technique for deriving a topographic map from a single radar image by using the dependence upon terrain-surface orientation of the integrated signal of an individual image pixel. The radiometric calibration required for precise operation and testing does not yet...
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...
Heat capacity and thermodynamic properties of andradite garnet, Ca3Fe2Si3O12, between 10 and 1000 K and revised values for ΔfGom (298.15 K) of hedenbergite and wollastonite
Richard A. Robie, Zhao Bin, Bruce S. Hemingway, Mark D. Barton
1987, Geochimica et Cosmochimica Acta (51) 2219-2224
The heat capacity of synthetic andradite garnet (Ca3Fe2Si3O12) was measured between 9.6 and 365.5 K by cryogenic adiabatic calorimetry and from 340 to 990 K by differential scanning calorimetry. At 298.15 KCop,m and Som are 351.9 ± 0.7 and 316.4 ± 2.0 J/(mol·K), respectively. Andradite has a λ-peak in Cop,m with a maximum at...
Evolution, biogeography, and systematics of Puriana: evolution and speciation in Ostracoda, III.
T. M. Cronin
1987, Journal of Paleontology (61)
Three types of geographic isolation—land barriers, deep water barriers, and climatic barriers—resulted in three distinct evolutionary responses in Neogene and Quaternary species of the epineritic ostracode genus Puriana. Through systematic, paleobiogeographic, and morphologic study of several hundred fossil and Recent populations from the eastern Pacific, western Atlantic,...
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...
Climatic implications of alternating clay and carbonate formation in semiarid soils of South-Central Montana
M.C. Reheis
1987, Quaternary Research (27) 270-282
Evidence for climatic change is found in petrographic thin sections from soils formed on glaciofluvial deposits of Rock Creek and the lower Clarks Fork, Montana. These soils, presently in a semiarid climate, range from late Pliocene to Holocene in age, and have undergone periodic fluctuations in soil moisture caused by...
Turbidity as a control on phytoplankton biomass and productivity in estuaries
J. E. Cloern
1987, Continental Shelf Research (7) 1367-1381
In many coastal plain estuaries light attenuation by suspended sediments confines the photic zone to a small fraction of the water column, such that light limitation is a major control on phytoplankon production and turnover rate. For a variety of estuarine systems (e.g. San Francisco Bay, Puget Sound, Delaware Bay,...
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...
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...
Oxidized Nitrogen in Precipitation, Throughfall, and Streamfall from a Forested Watershed in Oklahoma
Stephen J. Lawrence, Parker J. Wigington Jr.
1987, Water Resources Bulletin (23) 1069-1076
Oxidized nitrogen (nitrite plus nitrate N) concentrations were measured from bulk precipitation, bulk throughfall, and screamflow in a 7. 86 hectare forested watershed in southeastern Oklahoma during the wet season from March through June 1983. Oxidized nitrogen inputs comparable to results of other studies were recorded during the 19 rainstorms...
Estimating generalized skew of the log-Pearson Type III distribution for annual peak floods in Illinois
Kevin A. Oberg, Dean M. Mades
1987, Water-Resources Investigations Report 86-4008
Four techniques for estimating generalized skew in Illinois were evaluated: (1) a generalized skew map of the US; (2) an isoline map; (3) a prediction equation; and (4) a regional-mean skew. Peak-flow records at 730 gaging stations having 10 or more annual peaks were selected for computing station skews. Station...
