Northern East Pacific Rise: Magnetic anomaly and bathymetric framework
Kim D. Klitgord, Jacqueline Mammerickx
1982, Journal of Geophysical Research B: Solid Earth (87) 6725-6750
The oceanic crust in the eastern Pacific between 7°N and 30°N and east of 127°W contains a fairly complete history of the spreading centers associated with the East Pacific Rise since 25 m.y. B.P. (late Oligocene). In this paper, we have summarized the seafloor spreading magnetic-anomaly data and the bathymetric...
Sedimentation, metamorphism and tectonic accretion of the Franciscan assemblage of northern California
M. Clark Blake Jr., A. S. Jayko, D. G. Howell
1982, Book chapter, Geological Society, London, Special Publications
Miocene actinommid Radiolaria from the equatorial Pacific
J. R. Blueford
1982, Micropaleontology (28) 189-213
Actinommids (spumellarian Radiolaria) are a group of microfossils in which taxonomy and phylogeny hitherto have been based on features of morphology that change with the growth of individuals. To make Miocene actinommids from the equatorial Pacific useful in biostratigraphy, paleocenography, and paleoecology, ontogenetically invariant morphological features can be analyzed by...
Use of packrat middens to determine rates of cliff retreat in the eastern Grand Canyon, Arizona
Kenneth L. Cole, Larry Mayer
1982, Geology (10) 597-599
Packrat midden data can be used to calculate rates of cliff retreat by relating midden age to the distance between cliff face and midden. Regression analysis using 14 radiocarbon-dated packrat deposits from the Mississippian Redwall Limestone in the eastern Grand Canyon suggests that the Redwall has been retreating at an...
Paleoenvironment and age of kaolin deposits in the Andersonville district, Georgia
Harland E. Cofer, Norman O. Frederiksen
1982, Conference Paper, Proceedings: Second Symposium on the Geology of the Southeastern Coastal Plain
The kaolin deposits of the Andersonville district of Georgia are thick and relatively pure; they grade laterally and vertically into sandy kaolin and sand. The sedimentological and mineralogical character of the clay and the enclosing sand suggests deposition in a marine shallow-water to estuarine environment. Palynomorph and invertebrate fossil assemblages...
Kinematic evolution of the junction of the San Andreas, Garlock, and Big Pine faults, California
Robert G. Bohannon, David G. Howell
1982, Geology (10) 358-363
If the San Andreas fault with about 300 km of right slip, the Carlock fault with about 60 km of left slip, and the Big Pine fault with about 15 km of left slip are considered to have been contemporaneously active, a space problem at their high-angle junctions becomes apparent....
The Yellowstone-Snake River Plain seismic profiling experiment: Crustal structure of the Eastern Snake River Plain
L.W. Braile, R. B. Smith, J. Ansorge, M.R. Baker, M.A. Sparlin, C. Prodehl, M.M. Schilly, J. H. Healy, Mueller, K.H. Olsen
1982, Journal of Geophysical Research B: Solid Earth (87) 2597-2609
Seismic refraction profiles recorded along the eastern Snake River Plain (ESRP) in southeastern Idaho during the 1978 Yellowstone-Snake River Plain cooperative seismic profiling experiment are interpreted to infer the crustal velocity and attenuation (Q-1) structure of the ESRP. Travel-time and synthetic seismogram modeling of a 250 km reversed refraction profile...
Regional ground-water flow concepts in the United States: Historical perspective
J.D. Bredehoeft, W. Back, B.B. Hanshaw
1982, Special Paper of the Geological Society of America (189) 295-316
A number of important ideas, developed during the past 100 years, form the framework of the present understanding of regional ground-water flow. The most important of these ideas are:Differences in topographic elevation provide the principal driving force for regional flow.Flow through confining layers...
On the distribution of species occurrence
Martin A. Buzas, Carl F. Koch, Stephen J. Culver, Norman F. Sohl
1982, Paleobiology (8) 143-150
The distribution of species abundance (number of individuals per species) is well documented. The distribution of species occurrence (number of localities per species), however, has received little attention. This study investigates the distribution of species occurrence for five large data sets. For modern benthic foraminifera, species occurrence is examined from...
Hazard analysis on the Mid-Atlantic Continental Slope, DCS lease sale 59 Area
Alex P. Cardinell, Frederick R. Keer
1982, Conference Paper, Offshore Technology Conference
A multi-parameter high-resolution seismic survey covering 253 offshore lease blocks was undertaken for analysis of critical structural and depositional features and a suite of piston cores was examined for geotechnical properties on the Mid-Atlantic continental slope in the OCS Lease Sale 59 area. The analysis of this data revealed complex...
Terranes and suture zones in east central Alaska
M. Churkin Jr., H.L. Foster, R. M. Chapman, F. R. Weber
1982, Journal of Geophysical Research B: Solid Earth (87) 3718-3730
East central Alaska, with its 17 terranes, forms a part of the mosaic of allochthonous terranes that join the North American and Siberian plates. These terranes range from continental and continental margin, such as the Tatonduk with its thick well-bedded succession of marine shelf rocks, to seamount, arc, and ocean...
The occurrence of the Complexiopollis-Atlantopollis zone (Palynomorphs) in the Eagle Ford Group (Upper Cretaceous) of Texas
Raymond A. Christopher
1982, Journal of Paleontology (56) 525-541
The Lower and lower Upper Cretaceous palynological zones defined in the Atlantic Coastal Plain Province and which occur in the eastern Gulf Coastal Plain Province are characterized by a paucity of marine invertebrate fossils. As a result, correlation of these zones with European and provincial stages, as well as with...
Uranium-lead isotopic ages from the Sierra Nevada Batholith, California
J. Chen
1982, Journal of Geophysical Research B: Solid Earth (87) 4761-4784
This study provides new information on the timing and distribution of Mesozoic magmatic events in the Sierra Nevada batholithic complex chiefly between 36° and 37°N. latitude. U-Pb ages have been determined for 133 zircon and 7 sphene separates from 82 samples of granitoid rocks. Granitoid rocks in this area range...
Volume of organic-rich Devonian shale in the Appalachian Basin: relating "black" to organic-matter content: Geologic notes
Ronald R. Charpentier, James W. Schmoker
1982, American Association of Petroleum Geologists Bulletin (66) 375-378
Some estimates of natural-gas resources in the Devonian shale of the Appalachian basin depend on the volume of organic-rich shale in the basin. A map by L. G. Wallace and W. de Witt showing the thickness and extent of Devonian "black" shale facies in the Appalachian basin is widely used...
The sea slope problem revisited
Robert O. Castle, M.R. Elliott
1982, Journal of Geophysical Research B: Solid Earth (87) 6989-7024
Discrepancies in sea surface topography based on comparisons between the results of steric leveling and repeated geodetic levelings have identified what is known as the ‘sea slope problem.’ This problem is actually twofold: (1) the sea surface relief based on steric leveling differs significantly from that based on geodetic leveling...
Source parameters of the 1980 Mammoth Lakes, California, earthquake sequence
Ralph J. Archuleta, Edward Cranswick, Charles Mueller, Paul Spudich
1982, Journal of Geophysical Research B: Solid Earth (87) 4595-4607
From the more than 1500 Mammoth Lakes earthquakes recorded on three-component digital seismographs (Spudich et al., 1981), 150 were used in an analysis of the locations, mechanism, and source parameters. A composite fault plane solution of nine earthquakes 3.9 ≤ M ≤ 5.1 defines a right-lateral strike slip mechanism on...
Time-predictable bimodal volcanism in the Coso Range, California
Charles R. Bacon
1982, Geology (10) 65-69
The bimodal Pleistocene part of the Coso volcanic field has erupted rhyolite and basalt at constant long-term rates during the past ∼0.5 m.y. Both basalt and high-silica rhyolite were erupted in several independent, geologically brief episodes. The interval between eruptions of rhyolite was proportional to the volume of the preceding...
The use of vertical seismic profiles in seismic investigations of the earth
Alfred H. Balch, Myung W. Lee, J. J. Miller, Robert T. Ryder
1982, Geophysics (47) 906-918
During the past 8 years, the U.S. Geological Survey has conducted an extensive investigation on the use of vertical seismic profiles (VSP) in a variety of seismic exploration applications. Seismic sources used were surface air guns, vibrators, explosives, marine air guns, and downhole air guns. Source offsets have ranged from...
Diatom biostratigraphy and paleoecology of the type section of the Luisian Stage, central California
Jack G. Baldauf, John A. Barron
1982, Micropaleontology (28) 84
Diatoms from the type section of the Luisian Stage in central California correlate with the lowermost part of the Denticulopsis lauta Zone through the lower part of subzone "a" of the Denticulopsis hustedtii-D. lauta Zone and are early Middle Miocene in age (about 6.0 to 14.0 Ma), Rocks assigned to...
Marine ice-pushed boulder ridge, Beaufort Sea, Alaska
Peter W. Barnes
1982, Arctic (35) 312-316
A steep-faced boulder ridge up to 4m high by 300m long was encountered along the arctic coast east of Prudhoe Bay, Alaska, in the summer of 1979. Marine occurrences of similar ridges are rare. Since ice-push sorts cobble- and boulder-sized material in the construction of a ridge, recent onshore excursions of ice due to wind stress on the fast ice...
Recent trends in the west Greenland salmon fishery, and implications for Thick-billed Murres
John F. Piatt, David G. Reddin
1982, Conference Paper, Marine birds: Their feeding ecology and commercial fisheries relationships
In the late 1960s and early 1970s, a high net-mortality of seabirds, particularly Thick-billed Murres (Uria lomvia), was associated with the west Greenland salmon fishery. Since 1972, the domestic fishery has been controlled by quotas and fishery opening dates and non-Greenlandic offshore drift-net fishery was phased out in 1975. These...
A 40-foot static cone penetrometer
R.M. Beard, H.J. Lee
1982, Conference Paper
The Navy needs a lightweight device for testing seafloor soils to sub bottom depths of 12 meters in water depths to 60 meters. To meet this need a quasistatic cone penetration device that uses water jetting to reduce friction on the cone rod has been developed. This device is called...
Strata-bound sulfide deposits, wall-rock alteration, and associated tin-bearing minerals in the Carolina slate belt, South Carolina and Georgia
Henry Bell
1982, Economic Geology (77) 294-311
Massive sulfide deposits, gold deposits, and tin-bearing minerals occur in rocks of the Carolina slate belt in South Carolina and adjacent Georgia. The belt of greenschist metamorphic rocks in which the ore deposits occur is mostly Cambrian in age. It is divided into an upper metasedimentary unit and a lower...
The emplacement of ophiolites by collision
Zvi Ben-Avraham
1982, Journal of Geophysical Research (87) 3861-3867
Ophiolites, recognized in most of the world's orogenic belts, are generally interpreted to be oceanic crust and upper mantle (lithosphere) fragments that have been incorporated into continental margins at consuming plate boundaries. We suggest that the mechanism for ophiolite emplacement is the same in both the Alpine and Andean-type orogenes....
Representation of multiaquifer well effects in three-dimensional ground-water flow simulation
Gordon D. Bennett, Angelo L. Kontis, Steven P. Larson
1982, Groundwater (20) 334-341
The presence of multiaquifer or multilayer wells changes the nature of the equations which must be solved in a three-dimensional ground-water flow simulation and, in effect, alters the stencil of computation. A method has been devised which takes this change into consideration by allowing simulation of the hydraulic effects of...
