Circum-arctic plate accretion - Isolating part of a pacific plate to form the nucleus of the Arctic Basin
M. Churkin Jr., J.H. Trexler Jr.
1980, Earth and Planetary Science Letters (48) 356-362
A mosaic of large lithospheric plates rims the Arctic Ocean Basin, and foldbelts between these plates contain numerous allochthonous microplates. A new model for continental drift and microplate accretion proposes that prior to the late Mesozoic the Kula plate extended from...
Evolution of the continental margin of southern Spain and the Alboran Sea
William P. Dillon, James M. Robb, H. Gary Greene, Juan Carlos Lucena
1980, Marine Geology (36) 205-226
Seismic reflection profiles and magnetic intensity measurements were collected across the southern continental margin of Spain and the Alboran basin between Spain and Africa. Correlation of the distinct seismic stratigraphy observed in the profiles to stratigraphic information obtained from cores at Deep Sea Drilling Project site 121 allows effective dating...
Rare earth element distribution in some hydrothermal minerals: Evidence for crystallographic control
J. W. Morgan, G.A. Wandless
1980, Geochimica et Cosmochimica Acta (44) 973-980
Rare earth element (REE) abundances were measured by neutron activation analysis in anhydrite (CaSO4), barite (BaSO4), siderite (FeCO3) and galena (PbS). A simple crystal-chemical model qualitatively describes the relative affinities for REE substitution in anhydrite, barite, and siderite. When normalized to ‘crustal’ abundances (as an approximation to the hydrothermal fluid...
The frontal method in hydrodynamics simulations
Roy A. Walters
1980, Computers and Fluids (8) 265-272
The frontal solution method has proven to be an effective means of solving the matrix equations resulting from the application of the finite element method to a variety of problems. In this study, several versions of the frontal method were compared in efficiency for several hydrodynamics problems. Three basic modifications...
Rate of mercury loss from contaminated estuarine sediments
Michael H. Bothner, R.A. Jahnke, M. L. Peterson, R. Carpenter
1980, Geochimica et Cosmochimica Acta (44) 273-285
The concentration of mercury in contaminated estuarine sediments of Bellingham Bay, Washington was found to decrease with a half-time of about 1.3 yr after the primary anthropogenic source of mercury was removed. In situ measurements of the mercury flux from sediments, in both dissolved and volatile forms, could not account...
Computational methods for inverse problems in geophysics: Inversion of travel time observations
V. Pereyra, H.B. Keller, W.H.K. Lee
1980, Physics of the Earth and Planetary Interiors (21) 120-125
General ways of solving various inverse problems are studied for given travel time observations between sources and receivers. These problems are separated into three components: (a) the representation of the unknown quantities appearing in the model; (b) the nonlinear least-squares problem; (c) the direct, two-point ray-tracing problem used to compute...
Crystallization history of Kilauea Iki lava lake as seen in drill core recovered in 1967-1979
Rosalind Tuthill Helz
1980, Bulletin Volcanologique (43) 675-701
Kilauea Iki lava lake formed during the 1959 summit eruption, one of the most picritic eruptions of Kilauea Volcano in the twentieth century. Since 1959 the 110 to 122 m thick lake has cooled slowly, developing steadily thickening upper and lower crusts, with a lens of more molten lava in...
Kinetic model for the short-term dissolution of a rhyolitic glass
A. F. White, H.C. Claassen
1980, Chemical Geology (28) 91-109
Aqueous dissolution experiments with the vitric phase of a rhyolitic tuff were performed at 25??C and constant pH in the range 4.5-7.5. Results suggest interchange of aqueous hydrogen ions for cations situated both on the surface and within the glass. At time intervals from 24 to 900 hr., dissolution kinetics...
Mid- Tertiary climate of southeastern United States, the sporomorph evidence
N. O. Frederiksen
1980, Journal of Paleontology (54) 728-739
Climatic affinities of modern genera represented by late Eocene sporomorphs suggest that the climate of that time in southeastern United States was winter-dry tropical close to the Gulf of Mexico and marginal humid subtropical on the upper Coastal Plain. Lack of change of the sporomorph assemblages suggests that the climate...
Tertiary δ18O record and glacio-eustatic sea-level fluctuations
R.K. Matthews, R.Z. Poore
1980, Geology (8) 501-504
Previous interpretation of the Tertiary δ18O record of plaiiktic and benthic foraminifers has emphasized comparison to the modern ocean, assumed an ice-free world prior to middle Miocene time, and thereby calculated surprisingly cool temperatures for the tropical sea surface. We propose an alternative...
Comment on 'A reinterpretation of the linear heat flow and heat production relationship for the exponential model of the heat production in the crust' by R.N. Singh & J.G. Negi.
A.H. Lachenbruch
1980, Geophysical Journal of the Royal Astronomical Society (63) 791-795
In their recent paper, Singh & Negi, (This journal, 57, 741-744) contend that if thd slope of the empirical linear relation between heat flow and heat production is interpreted as the decay-length of an exponential depth-distribution of sources, a discrepancy rises, whereas if it is interpreted as the depth of...
Faulting caused by groundwater level declines, San Joaquin Valley, California
Thomas L. Holzer
1980, Water Resources Research (16) 1065-1070
Approximately 230 mm of aseismic vertical offset of the land surface across the Pond-Poso Creek fault in the San Joaquin Valley, California, probably is related to groundwater withdrawal for crop irrigation. The scarp is approximately 3.4 km long and occurs in an area where the land subsided more than 1.5...
Distribution of modern benthic foraminifers on the New Jersey Outer Continental Shelf
C. Wylie Poag, H.J. Knebel, R. Todd
1980, Marine Micropaleontology (5) 43-69
We used samples from 21 stations within a 600 km2 area of the New Jersey Outer Continental Shelf to assess the effects of a hydrodynamic environment on the distribution and redistribution of benthic foraminifers. These samples show that, although the predominant genera (Elphidium, Cibicides, and Saccammina) are the same as...
On the extraction of directional sea-wave spectra from synthetic- aperture radar-signal arrays without matched filtering.
R.L. Wildey
1980, Modern Geology (7) 147-159
An economical method of digitally extracting sea-wave spectra from synthetic-aperture radar-signal records, which can be performed routinely in real or near-real time with the reception of telemetry from Seasat satellites, would be of value to a variety of scientific disciplines. This paper explores techniques for such data extraction and concludes...
Circular current loops, magnetic dipoles and spherical harmonic analysis.
L.R. Alldredge
1980, Journal of Geomagnetism & Geoelectricity (32) 357-364
Spherical harmonic analysis (SHA) is the most used method of describing the Earth's magnetic field, even though spherical harmonic coefficients (SHC) almost completely defy interpretation in terms of real sources. Some moderately successful efforts have been made to represent the field in terms of dipoles placed in the core in...
Supplementary modification and introduction of code numbers to the low-latitude coccolith biostratigraphic zonation (Bukry, 1973; 1975)
H. Okada, D. Bukry
1980, Marine Micropaleontology (5) 321-325
No abstract available. ...
Lithospheric loading by the 1896 Riku-u earthquake, northern Japan: Implications for plate flexure and asthenospheric rheology
W. Thatcher, T. Matsuda, T. Kato, J. B. Rundle
1980, Journal of Geophysical Research Solid Earth (85) 6429-6435
Under favorable circumstances the time-dependent aseismic deformation resulting from the loading of the lithosphere by the stress drop of large dip slip earthquakes can be used to determine both the effective elastic plate thickness and the asthenospheric viscosity. The deformation has several similarities with the deflection of the lithosphere by...
Evaluation of multispectral middle infrared aircraft images for lithologic mapping in the East Tintic Mountains, Utah
A.B. Kahle, L. C. Rowan
1980, Geology (8) 234-239
Six channels of multispectral middle infrared (8 to 14 μrn) aircraft scanner data were acquired over the East Tintic mining district, Utah. This area has high relief and moderate vegetation and consists mainly of Tertiary silicic igneous rocks and Paleozoic quartzite and carbonate...
The role of volatiles and lithology in the impact cratering process.
Kieffer S. Werner, C.H. Simonds
1980, Reviews of Geophysics and Space Physics (18) 143-181
A survey of published descriptions of 32 of the largest, least eroded terrestrial impact structures reveals that the amount of melt at craters in crystalline rocks is approximately 2 orders of magnitude greater than at craters in sedimentary rocks. In this paper we present a model for the impact process;...
The distribution and mobility of uranium in glassy and zeolitized tuff, Keg Mountain area, Utah, U.S.A.
R. A. Zielinski, D. A. Lindsey, J.N. Rosholt
1980, Chemical Geology (29) 139-162
The distribution and mobility of uranium in a diagenetically altered, 8 Ma old tuff in the Keg Mountain area, Utah, are modelled in this study. The modelling represents an improvement over similar earlier studies in that it: (1) considers a large number of samples (76) collected with good geologic control...
Tertiary climates and floristic relationships at high latitudes in the northern hemisphere
J. A. Wolfe
1980, Palaeogeography, Palaeoclimatology, Palaeoecology (30) 313-323
During the Paleocene and Eocene, climates were characterized by a low mean annual range of temperature (a maximum of 10-15??C), a moderate to high mean annual temperature (10-20??C), and abundant precipitation; strong broad-leaved evergreen vegetation extended to almost lat. 60??N during the Paleocene and to well above 61??N during the...
Influence of San Gabriel submarine canyon on narrow-shelf sediment dynamics, southern California
Herman A. Karl
1980, Marine Geology (34) 61-78
Variations in the concentration of total suspended particulate matter (TSM) collected 1 m above bottom, changes in vertical profiles of light transmission, and substrate textural patterns reveal a corridor for preferential sediment transport on San Pedro continental shelf, California. During the winter, this corridor, designated the preferential transport corridor (PTC),...
Modern and ancient submarine fans: Reply
William R. Normark
1980, American Association of Petroleum Geologists Bulletin (64) 1108-1112
No abstract available....
Transition of basaltic lava from pahoehoe to aa, Kilauea Volcano, Hawaii: Field observations and key factors
Donald W. Peterson, Robert I. Tilling
1980, Journal of Volcanology and Geothermal Research (7) 271-293
Nearly all Hawaiian basaltic lava erupts as pahoehoe, and some changes to aa during flowage and cooling; factors governing the transition involve certain critical relations between viscosity and rate of shear strain. If the lava slows, cools, and stops in direct response to concomitant increase in viscosity before these critical...
Ice-sheet glaciation of the Puget lowland, Washington, during the Vashon Stade (late Pleistocene)
R.M. Thorson
1980, Quaternary Research (13) 303-321
During the Vashon Stade of the Fraser Glaciation, about 15,000–13,000 yr B.P., a lobe of the Cordilleran Ice Sheet occupied the Puget lowland of western Washington. At its maximum extent about 14,000 yr ago, the ice sheet extended across the Puget lowland between the Cascade Range and Olympic Mountains and...
