Historical activity at Campi Flegrei caldera, southern Italy
J. Dvorak, P. Gasparini
1990, Earthquakes & Volcanoes (USGS) (22) 255-267
According to the biography of the 6th century Italian lawyer Antonion Castaldo, the swarm of earthquakes that had bothered the inhabitants of Pozzuoli and Naples all summer long ended abruptly on the eve of St. Michael (September 29) in the year 1538. Castaldo recalled that the end of this swarm...
Paleomagnetic rotations and the Cenozoic tectonics of the Cascade Arc, Washington, Oregon, and California
R.E. Wells
1990, Journal of Geophysical Research Solid Earth (95) 19409-19417
Paleomagnetic results from Cenozoic (62–12 Ma) volcanic rocks of the Cascade arc and adjacent areas indicate that moderate to large clockwise rotations are an important component of the tectonic history of the arc. Two mechanisms of rotation are suggested by the regional pattern of paleomagnetic rotations. The progressive increase in...
Magnetic forward models of Cement oil field, Oklahoma, based on rock magnetic, geochemical, and petrologic constraints
R. L. Reynolds, M. Webring, V. J. S. Grauch, M. Tuttle
1990, Geophysics (55) 344-353
Magnetic forward models of the Cement oil field, Oklahoma, were generated to assess the possibility that ferrimagnetic pyrrhotite related to hydrocarbon seepage in the upper 1 km of Permian strata contributes to aeromagnetic anomalies at Cement. Six bodies having different magnetizations were constructed for the magnetic models, based on geology...
The Taylor Creek Rhyolite of New Mexico: a rapidly emplaced field of lava domes and flows
W. A. Duffield, G. B. Dalrymple
1990, Bulletin of Volcanology (52) 475-487
The Tertiary Taylor Creek Rhyolite of southwest New Mexico comprises at least 20 lava domes and flows. Each of the lavas was erupted from its own vent, and the vents are distributed throughout a 20 km by 50 km area. The volume of the rhyolite and genetically associated pyroclastic deposits...
Regional vertical tectonic displacement of shorelines in south- central Alaska during and between great earthquakes
George Plafker
1990, Northwest Science (64) 250-258
Reviews the setting of the 1964 earthquake and the unprecedented tectonic deformation that accompanied it. Outlines research directed towards defining the deformation that occurs between great earthquakes (interseismic part of the seismic cycle) and the longterm history of deformation over repeated seismic cycles in the earthquake-affected region, emphasizing work in...
Molecular orbital (SCF-X-α-SW) theory of Fe2+-Mn3+, Fe3+-Mn2+, and Fe3+-Mn3+ charge transfer and magnetic exchange in oxides and silicates
David M. Sherman
1990, American Mineralogist (75) 256-261
Metal-metal charge-transfer and magnetic exchange interactions have important effects on the optical spectra, crystal chemistry, and physics of minerals. Previous molecular orbital calculations have provided insight on the nature of Fe2+-Fe3+ and Fe2+-Ti4+ charge-transfer transitions in oxides and silicates. In this work, spin-unrestricted molecular orbital calculations on (FeMnO10) clusters are...
Preparedness and mitigation paid off in the Loma Prieta Earthquake
R.K. Eisner
1990, Earthquakes & Volcanoes (USGS) (22) 201-203
Chronologic and isotopic framework for early Proterozoic crustal evolution in the eastern Mojave Desert region, SE California
J. L. Wooden, D. M. Miller
1990, Journal of Geophysical Research (95) 20133-20146
The Early Proterozoic geologic evolution of the eastern Mojave Desert region, as defined by characteristics of its supracrustal rocks, granitoids, metamorphism, structural history, and Pb and Nd isotopic signature, contrasts sharply with other Proterozoic provinces of the southwestern United States. The oldest supracrustal rocks of the Mojave Desert region contain...
High spectral resolution reflectance spectroscopy of minerals
R. N. Clark, T. V. V. King, M. Klejwa, Gregg A. Swayze, N. Vergo
1990, Journal of Geophysical Research Solid Earth (95) 12653-12680
The reflectance spectra of minerals are studied as a function of spectral resolution in the range from 0.2 to 3.0 μm. Selected absorption bands were studied at resolving powers (λ/Δλ) as high as 2240. At resolving powers of approximately 1000, many OH‐bearing minerals show diagnostic sharp absorptions at the resolution...
Age determinations and growth rates of Pacific ferromanganese deposits using strontium isotopes
B.L. Ingram, J.R. Hein, G. L. Farmer
1990, Geochimica et Cosmochimica Acta (54) 1709-1721
87Sr 86Sr ratios, trace element and REE compositions, and textural characteristics were determined for three hydrogenetic Fe-Mn crusts, one hydrothermal deposit, and two mixed hydrothermalhydrogenetic crusts from the Pacific. The Sr isotope data are compared to the Sr seawater curve for the Cenozoic to determine the ages and growth rates...
Fe(III)-reducing bacteria in deeply buried sediments of the Atlantic Coastal Plain
Derek R. Lovley, F. H. Chapelle, Elizabeth J.P. Phillips
1990, Geology (18) 954-957
The possibility that microorganisms are catalyzing the ongoing reduction of Fe(III) in the sediments of deep (20-250 m) aquifers was investigated. Acetate-oxidizing, Fe(III)-reducing bacteria were recovered from deep subsurface sediments, but only from sediments in which it appeared that Fe(III) reduction was the terminal electron-accepting process for oxidation of organic...
Measurement and interpretation of low levels of dissolved oxygen in ground water
A. F. White, M. L. Peterson, R.D. Solbau
1990, Groundwater (28) 584-590
A Rhodazine-D colorimetric technique was adapted to measure low-level dissolved oxygen concentrations in ground water. Prepared samples containing between 0 and 8.0 μmoles · 1-1 dissolved oxygen in equilibrium with known gas mixtures produced linear spectrophotometric absorbance with a lower detection limit of 0.2 μmoles ·...
Transformation of Monoaromatic hydrocarbons to organic acids in anoxic groundwater environment
I.M. Cozzarelli, R.P. Eganhouse, M.J. Baedecker
1990, Environmental Geology and Water Sciences (16) 135-141
The transformation of benzene and a series of alkylbenzenes was studied in anoxic groundwater of a shallow glacial-outwash aquifer near Bemidji, Minnesota, U.S.A. Monoaromatic hydrocarbons, the most water-soluble components of crude oil, were transported downgradient of an oil spill, forming a plume of contaminated groundwater. Organic acids that were not...
The relation of catastrophic flooding of Mangala Valles, Mars, to faulting of Memnonia Fossae and Tharsis volcanism
K. L. Tanaka, M. G. Chapman
1990, Journal of Geophysical Research Solid Earth (95) 14315-14323
Detailed stratigraphic relations indicate two coeval periods of catastrophic flooding and Tharsis centered faulting (producing Memnonia Fossae) in the Mangala Valles region of Mars. Major sequences of lava flows of the Tharsis Montes Formation and local, lobate plains flows were erupted during and between these channeling and faulting episodes. First,...
Spatial resolution requirements for automated cartographic road extraction
S. Benjamin, L. Gaydos
1990, Photogrammetric Engineering and Remote Sensing (56) 93-100
Ground resolution requirements for detection and extraction of road locations in a digitized large-scale photographic database were investigated. A color infrared photograph of Sunnyvale, California was scanned, registered to a map grid, and spatially degraded to 1- to 5-metre resolution pixels. Road locations in each data set were extracted using...
Particle velocity interpolation in block-centered finite difference groundwater flow models
Daniel J. Goode
1990, Water Resources Research (26) 925-940
A block-centered, finite difference model of two-dimensional groundwater flow yields velocity values at the midpoints of interfaces between adjacent blocks. Method of characteristics, random walk and particle-tracking models of solute transport require velocities at arbitrary particle locations within the finite difference grid. Particle path lines and travel times are sensitive...
Young volcanic deposits in the Valles Marineris, Mars?
Baerbel K. Lucchitta
1990, Icarus (86) 476-509
A study of the interior deposits of the central Valles Marineris has led to the discovery of a sequence of deposits that cover the chasma floors and range in thickness from that of thin dust to several kilometers. The emplacement of the deposits was the last major event in the...
Multiple gas analyses using a mobile mass spectrometer
J. H. McCarthy Jr., R. C. Bigelow
1990, Journal of Geochemical Exploration (38) 233-245
A truck-mounted mass-spectrometer gas analyzer is described and field examples of its use are given. This unit provides a gas analyzer that can be used in the field to rapidly analyze a large number of gases. It has enabled us to...
Determination of total tin in silicate rocks by graphite furnace atomic absorption spectrometry
H.N. Elsheimer, T. L. Fries
1990, Analytica Chimica Acta (239) 145-149
A method is described for the determination of total tin in silicate rocks utilizing a graphite furnace atomic absorption spectrometer with a stabilized-temperature platform furnace and Zeeman-effect background correction. The sample is decomposed by lithium metaborate fusion (3 + 1) in graphite crucibles with the melt being dissolved in 7.5%...
Determination of trace concentrations of volatile organic compounds in ground water using closed-loop stripping, Edwards aquifer, Texas
P.M. Buszka, S.D. Zaugg, M.G. Werner
1990, Bulletin of Environmental Contamination and Toxicology (45) 507-515
No abstract available....
Carbon speciation and surface tension of fog
P. D. Capel, R. Gunde, F. Zurcher, W. Giger
1990, Environmental Science & Technology (24) 722-727
No abstract available....
Peridinialean dinoflagellate plate patterns, labels and homologies
Lucy E. Edwards
1990, Review of Palaeobotany and Palynology (65) 293-303
Tabulation patterns for peridinialean dinoflagellate thecae and cysts have been traditionally expressed using a plate labelling system described by C.A. Kofoid in the early 1900's. This system can obscure dinoflagellate plate homologies and has not always been strictly applied. The plate-labelling system presented here introduces new series labels but incorporates...
Temporal and spatial variations in the solute content of an alpine stream, Colorado Front Range
N. Caine, E.M. Thurman
1990, Geomorphology (4) 55-72
Seven years of discharge and water quality records define temporal and spatial patterns of solute movement in a Colorado alpine stream system. Dissolved solids concentrations are low, generally less than 30 mg 1−1 and occasionally less than 3 mg 1−1 at the highest elevations....
Conductivity and transit time estimates of a soil liner
I.G. Krapac, K. Cartwright, S.V. Panno, B.R. Hensel, K.H. Rehfeldt, B.L. Herzog
1990, Conference Paper
A field-scale soil linear was built to assess the feasibilty of constructing a liner to meet the saturated hydraulic conductivity requirement of the U.S. EPA (i.e., less than 1 ?? 10-7 cm/s), and to determine the breakthrough and transit times of water and tracers through the liner. The liner, 8...
Effects of neck bands on the behavior of wintering greater white-fronted geese
Craig R. Ely
1990, Journal of Field Ornithology (61) 249-253
Activity budgets of adult Greater White-fronted Geese (Anser albifrons frontalis) with and without neck bands during the non-breeding season revealed that geese with neck bands spent more time preening than geese without neck bands while at foraging sites, but not while at roosting sites. Neck-banded and control geese spent equal...
