Sudden death at the end of the Mesozoic
C. Emiliani, E.B. Kraus, E.M. Shoemaker
1981, Earth and Planetary Science Letters (55) 317-334
A paleoecological analysis of the fossil record before and after the Cretaceous/Tertiary boundary indicates that the widespread extinctions and biological stresses around the boundary are best explained in terms of a sudden, significant, but short temperature rise. L. Alvarez and co-authors, having...
Sand waves on an epicontinental shelf: Northern Bering Sea
Michael E. Field, C. Hans Nelson, David A. Cacchione, David E. Drake
1981, Marine Geology (32) 233-258
Sand waves and current ripples occupy the crests and flanks of a series of large linear sand ridges (20 km × 5 km × 10 m high) lying in an open-marine setting in the northern Bering Sea. The sand wave area, which lies west of Seward Peninsula and southeast of...
A numerical inversion of the Laplace transform solution to radial dispersion in a porous medium
A.F. Moench, A. Ogata
1981, Water Resources Research (17) 250-252
A special form of the numerical inversion of the Laplace transform described by Stehfest (1970) is applied to the transformed solution of dispersion in a radial flow system in a porous medium. The inversion is extremely simple to use because the weighting coefficients depend only on the number of terms...
Estimation of surface temperature variations due to changes in sky and solar flux with elevation
S. Hummer-Miller
1981, Geophysical Research Letters (8) 595-598
Sky and solar radiance are of major importance in determining the ground temperature. Knowledge of their behavior is a fundamental part of surface temperature models. These two fluxes vary with elevation and this variation produces temperature changes. Therefore, when using thermal-property differences to discriminate geologic materials,...
Chemical composition, stratigraphy, and depositional environments of the Black River Group (Middle Ordovician), southwestern Ohio.
David A. Stith
1981, Geological Society of America Bulletin (92) 629-633
The chemical composition and stratigraphy of the Black River Group in southwestern Ohio were studied. Chemical analyses were done on two cores of the Black River from Adams and Brown Counties, Ohio. These studies show that substantial reserves of high-carbonate rock are present in the Black River at depths of...
Oxygen isotope thermometry of basic lavas and mantle nodules
T.K. Kyser, J. R. O’Neil, I. S. E. Carmichael
1981, Contributions to Mineralogy and Petrology (77) 11-23
Measurements have been made of the oxygen isotope and chemical composition of glass and phenocrysts in lavas and coexisting minerals in mantle nodules. Temperatures of formation of these assemblages have been estimated from various chemical thermometers and range from 855?? to 1,300?? C. The permil fractionations between coexisting orthopyroxene and...
Coincident sediment slump/clathrate complexes on the U.S. Atlantic continental slope
G. Carpenter
1981, Geo-Marine Letters (1) 29-32
High-resolution seismic reflection data recorded on the continental slope off the east coast of the United States have revealed instances of sediment mass movement (slumps) which appear to occur above clathrate accumulations. The slumping is believed to be related to the liberation of free gas by clathrate decomposition and consequent...
Heavy metals and manganese oxides in the genesee watershed, New York state: Effects of geology and land use
P.R. Whitney
1981, Journal of Geochemical Exploration (14) 95-117
Manganese oxide coatings on gravels from 255 sites on tributary streams in the Genesee River Watershed were analyzed for Mn, Fe, Zn, Cd, Co, Ni, Pb, and Cu. The results were compared with data on bedrock geology, surficial geology and land use, using factor analysis and stepwise multiple regression. All...
Depositional sequences in clastic continental slope deposits, Gulf of Mexico
A.H. Bouma
1981, Geo-Marine Letters (1) 115-121
Tertiary and Quaternary sediments, overlying diapiric older Tertiary shales and Louann Salt on the continental slope in the western Gulf of Mexico, show cyclicity based on seismic-reflection patterns. A set of indistinct parallel reflections or an acoustically semi-transparent zone, normally onlapping onto diapir flanks, alternates with a set of distinct...
Fractionation of carbon and hydrogen isotopes by methane-oxidizing bacteria
D.D. Coleman, J.B. Risatti, M. Schoell
1981, Geochimica et Cosmochimica Acta (45) 1033-1037
Carbon isotopic analysis of methane has become a popular technique in the exploration for oil and gas because it can be used to differentiate between thermogenic and microbial gas and can sometimes be used for gas-source rock correlations. Methane-oxidizing bacteria, however,...
Geology and geochemistry of gas-charged sediment on Kodiak Shelf, Alaska
M. A. Hampton, K.A. Kvenvolden
1981, Geo-Marine Letters (1) 141-147
Methane concentrations in some sediment cores from the Kodiak Shelf and adjacent continental slope increase with depth by three or four orders of magnitude and exceed the solubility in water at ambient conditions. Acoustic anomalies in seismic-reflection records imply that methane-rich sediment is widespread. Molecular composition of hydrocarbon gases and...
Geochemical evidence for modern sediment accumulation on the continental shelf off southern New England
Michael H. Bothner, E.C. Spiker, P. P. Johnson, R.R. Rendigs, P. J. Aruscavage
1981, Journal of Sedimentary Petrology (51) 281-292
An area of fine-grained sediment approximately 170 km x 74 km in size, located in water depths between 60 m and 150 m, south of Martha's Vineyard, Mass., is a site of modern sediment deposition. The 14C ages systematically increase with sediment depth from about 1,300 years B.P. at the...
On the use of the nephelometer in estuarine waters
A. Eaton, V. Grant, O. Bricker, D. Wells
1981, Estuaries (4) 379-384
A study of the problems encountered in nephelometric determinations of suspended sediment loads in the Chesapeake Bay estuary has led to development of a technique which uses nephelometer readings as a guide for sampling at vertical profiles in an estuary. This permits optimum sampling for concentration profiles and allows one...
Geodetic strain measurements in Washington
J.C. Savage, M. Lisowski, W.H. Prescott
1981, Journal of Geophysical Research Solid Earth (86) 4929-4940
Two new geodetic measurements of strain accumulation in the state of Washington for the interval 1972–1979 are reported. Near Seattle the average principal strain rates are 0.07 ± 0.03 μstrain/yr N 19°W and −0.13 ± 0.02 μstrain/yr N71°E, and near Richland (south central Washington) the average principal strain rates are...
A distribution-free alternative to least-squares regression and its application to Rb/Sr isochron calculations
R.G. Vugrinovich
1981, Journal of the International Association for Mathematical Geology (13) 443-454
A distribution-free estimator of the slope of a regression line is introduced. This estimator is designated Sm and is given by the median of the set of n(n - 1)/2 slope estimators, which may be calculated by inserting pairs of points (Xi, Yi)and (Xj, Yj)into the slope formula Si =...
The origin and isotopic composition of dissolved sulfide in groundwater from carbonate aquifers in Florida and Texas
R. O. Rye, W. Back, B.B. Hanshaw, C.T. Rightmire, F. J. Pearson Jr.
1981, Geochimica et Cosmochimica Acta (45) 1941-1950
The δ34S values of dissolved sulfide and the sulfur isotope fractionations between dissolved sulfide and sulfate species in Floridan ground water generally correlate with dissolved sulfate concentrations which are related to flow patterns and residence time within the aquifer. The dissolved sulfide derives from the slow in situ biogenic reduction of sulfate dissolved from...
Late Cenzoic rhyolites from the Kern Plateau, southern Sierra Nevada, California.
C. R. Bacon, W. A. Duffield
1981, American Journal of Science (281) 1-34
Four late Cenozoic rhyolite domes lie atop the Kern Plateau, 30 to 40km S-SE of Mount Whitney. K-Ar and 40Ar/39Ar dating shows that Monache, Templeton, and Little Templeton Mountains are all about 2.4Ma old; a small dome nearby is approx 0.2Ma old. The three older rhyolites have SiO2 = 73-74%...
Faulting in outer continental shelf of southern Bering Sea
James V. Gardner, Tracy L. Vallier
1981, American Association of Petroleum Geologists Bulletin (65) 1568-1573
Synthesis of more than 10 000 line-km of high-resolution seismic data indicates the distribution, types, and trends of faults present on the outer continental shelf of the southern Bering Sea. Faults are classified into three types as to whether they 1) offset the sea floor (surface fault), 2) show less...
Halogenated benzene radical cations and ground state degeneracy splitting by asymmetric substitution
V.E. Bondybey, C.R. Vaughn, T.A. Miller, J.H. English, R.H. Shiley
1981, Journal of Chemical Physics (74) 6584-6591
The absorption and laser induced fluorescence of several halogenated benzene radical cations were studied in solid Ne matrices. The spectra of 1,2,4-trifluorobenzene, l,3-dichloro-5-fluorobenzene, and l-chloro-3,5- difluorobenzene radical cations are observed and analyzed. Studies of fluorescence polarization and a photoselection technique were used to examine the splitting of the degeneracy of...
Origin and structural implications of upper Miocene rhyolites in Kingston Canyon, Piute County, Utah
P. D. Rowley, T. A. Steven, H. H. Mehnert
1981, Geological Society of America Bulletin (92) 590-602
Kingston Canyon is one of the deepest antecedent canyons in the High Plateaus subprovince of the Colorado Plateaus. Here the East Fork of the Sevier River flows westward transversely across the gently east tilted Sevier Plateau, which is developed on a basin-range fault...
Late Cenozoic stages and molluscan zones of the U.S. Middle Atlantic Coastal Plain
B. W. Blackwelder
1981, Journal of Paleontology, Supplement, Part II (55)
Pliocene to Holocene deposits of the U.S.Atlantic Coastal Plain from Maryland to Georgia are divided into four stages and four substages using molluscan biostratigraphic data. These divisions are the Wiltonian and Burwellian Stages (early Pliocene), Gouldian and Windyan Substages of the Colerainian Stage (late Pliocene to early Pleistocene), and Myrtlean...
Hydrologic testing of tight zones in southeastern New Mexico
K.F. Dennehy, P. A. Davis
1981, Groundwater (19) 482-489
Increased attention is being directed toward the investigation of tight zones in relation to the storage and disposal of hazardous wastes. Shut-in tests, slug tests, and pressure-slug tests are being used at the proposed Waste Isolation Pilot Plant site, located in southeastern New Mexico, to...
Preconsolidation stress of aquifer systems in areas of induced land subsidence
Thomas L. Holzer
1981, Water Resources Research (17) 693-704
Aquifer systems in the Eloy-Picacho area, Arizona, the Houston-Galveston area, Texas, and the Tulare-Wasco area and Santa Clara Valley, California, appear to have been overconsolidated by an amount that ranged approximately from 1.6 to 6.2 bars (16 to 63 m of water) before man began to withdraw groundwater from them....
Uranium in big sagebrush from western U.S. and evidence of possible mineralization in the Owyhee mountains of Idaho
J. A. Erdman, G.H. Harrach
1981, Journal of Geochemical Exploration (14) 83-94
Two regional studies of big sagebrush (Artemisia tridentata), a widely distributed and dominant shrub in the western United States, have shown its responsiveness to known uranium mineralization in the Monument Hill and Pumpkin Buttes districts of the southern Powder River Basin, Wyoming, and the Uravan mineral belt area in southeastern...
Arid land monitoring using Landsat albedo difference images
Charles J. Robinove, Pat S. Chavez Jr., Dale G. Gehring, Ralph Holmgren
1981, Remote Sensing of Environment (11) 133-156
The Landsat albedo, or percentage of incoming radiation reflected from the ground in the wavelength range of 0.5 [mu]m to 1.1 [mu]m, is calculated from an equation using the Landsat digital brightness values and solar irradiance values, and correcting for atmospheric scattering, multispectral scanner calibration, and sun angle. The albedo...
