Carboniferous U-Pb age of the Sebago batholith, southwestern Maine: Metamorphic and tectonic implications
J.H. Aleinikoff, R. H. Moench, J.B. Lyons
1985, Geological Society of America Bulletin (96) 990-996
Two phases (pink and white granite) of the Sebago batholith of southwestern Maine have been dated by the U-Pb zircon method. Identical upper concordia intercepts of both rocks indicate an intrusive age of 325 ± 3 m.y. for the batholith. The lower intercept...
Evolution and present state of the hydrothermal system in Long Valley caldera
M.L. Sorey
1985, Journal of Geophysical Research Solid Earth (90) 11219-11228
Evidence for previous periods of hydrothermal activity in Long Valley caldera exists in the form of extensive deposits of hydrothermal alteration products at several locations within the caldera and saline deposits in Searles Lake which contain mineral assemblages contributed by hot spring discharge from Long Valley. Hydrothermal activity was more...
Harmonic analysis of tides and tidal currents in South San Francisco Bay, California
R. T. Cheng, J. W. Gartner
1985, Estuarine, Coastal and Shelf Science (21) 57-74
Water level observations from tide stations and current observations from current-meter moorings in South San Francisco Bay (South Bay), California have been harmonically analysed. At each tide station, 13 harmonic constituents have been computed by a least-squares regression without inference. Tides in South Bay are typically mixed; there is a...
The role of erosion by fish in shaping topography around Hudson submarine canyon.
D.C. Twichell, Craig B. Grimes, R. S. Jones, K.W. Able
1985, Journal of Sedimentary Petrology (55) 712-719
An 800-km 2 area of rough topography around the head of Hudson Canyon off the eastern United States is attributed to erosion by tilefish ( Lopholatilus chamaeleonticeps ) and associated species of crustaceans. The rough topography has a relief of 1-10 m, occurs in water depths of 120-500 m, and has been...
The effects of grazers and light penetration on the survival of transplants of Vallisneria americana Michs in the tidal Potomac River, Maryland
Virginia Carter, Nancy B. Rybicki
1985, Aquatic Botany (23) 197-213
Poor light penetration and grazing are among the factors potentially responsible for the lack of submersed aquatic macrophytes in the tidal Potomac River. Between 1980 and 1983, plugs, springs and tubers of Vallisneria americana Michx were transplanted from the oligohaline Potomac Estuary to six sites in the freshwater tidal Potomac River. Transplants...
Geochemistry of groundwater in Cretaceous sediments of the southeastern coastal plain of eastern Mississippi and western Alabama
Roger W. Lee
1985, Water Resources Research (21) 1545-1556
Geochemical samples of waters along two hydrologic flow paths in four Upper Cretaceous aquifers of northeastern Mississippi and western Alabama indicate similar geochemical evolution of their respective waters. The waters of the Coker, Gordo, and Eutaw-McShan aquifers, noncalcareous sands, increase downgradient in dissolved solids and pH, and are dominated by sodium...
Review of radiometric data from the Yukon crystalline terrane, Alaska and Yukon Territory
Frederic H. Wilson, James G. Smith, Nora B. Shew
1985, Canadian Journal of Earth Sciences (22) 525-537
The results of more than 20 years of geochronological studies in the Yukon Crystalline Terrane in east-central Alaska and the western Yukon Territory suggest at least six igneous and thermal (metamorphic?) events. Plutonism during Mississippian, Early Jurassic, mid-Cretaceous, Late Cretaceous, and early Tertiary times is indicated. Evidence also indicates that...
Interannual streamflow variability in the United States based on principal components
Harry F. Lins
1985, Water Resources Research (21) 691-701
Interannual modes of streamflow variation at 106 locations across the United States during the period 1931–1978 are defined by using principal components. Five statistically significant components are found to account for more than 56% of the total streamflow variance. The first principal component represents a nationwide tendency for either above-...
In situ stress, natural fracture distribution, and borehole elongation in the Auburn Geothermal Well, Auburn, New York
Stephen H. Hickman, John H. Healy, Mark D. Zoback
1985, Journal of Geophysical Research (90) 5497-5512
Hydraulic fracturing stress measurements and a borehole televiewer survey were conducted in a 1.6‐km‐deep well at Auburn, New York. This well, which was drilled at the outer margin of the Appalachian Fold and Thrust Belt in the Appalachian Plateau, penetrates approximately 1540 m of lower Paleozoic sedimentary rocks and terminates...
Stratigraphic and interregional changes in Pennsylvanian coal-swamp vegetation: Environmental inferences
T.L. Phillips, R.A. Peppers, William A. DiMichele
1985, International Journal of Coal Geology (5) 43-109
Quantitative analysis of Pennsylvanian coal-swamp vegetation provides a means of inferring organization and structure of communities. Distribution of these communities further provides inferences about environmental factors, including paleoclimate. Our observations are based on in situ, structurally preserved peat deposits in coal-ball...
A seismic-refraction profile across the San Andreas, Sargent, and Calaveras faults, west-central California
Walter D. Mooney, Robert H. Colburn
1985, Bulletin of the Seismological Society of America (75) 175-191
In 1981, the United States Geological Survey recorded a seismic-refraction profile across the southern Santa Cruz Mountains in west-central California to examine the shallow velocity structure of this seismogenic region. This 40-km-long profile, which consisted of three shotpoints, extended northeastward from near Watsonville, California, to Coyote Lake, crossing the San...
Character and regional significance of Great Falls tectonic zone, east-central Idaho and west-central Montana
J. Michael O’Neill, David A. Lopez
1985, American Association of Petroleum Geologists Bulletin (69) 437-447
The Great Falls tectonic zone, here named, is a belt of diverse northeast-trending geologic features that can be traced from the Idaho batholith in the Cordilleran miogeocline, across thrust-belt structures and basement rocks of west-central and southwestern Montana, through cratonic rocks of central Montana, and into southwesternmost Saskatchewan, Canada. Geologic...
A note on the effect of bottom currents on an ocean bottom seismometer
Anne M. Trehu
1985, Bulletin of the Seismological Society of America (75) 1195-1204
Two three-component ocean bottom seismometers and a current meter were deployed a few hundred meters apart on the southern Blake Plateau off the United States eastern coast to study the effect of near-bottom currents on the background noise level of seismometers. Although analysis of the data is limited somewhat by...
Paleomagnetism and geology of Eocene volcanic rocks of southwest Washington, implications for mechanisms of tectonic rotation
Ray E. Wells, Robert S. Coe
1985, Journal of Geophysical Research (90) 1925-1947
Paleomagnetic and geologic investigations in Eocene volcanic rocks of the southwest Washington Coast Range demonstrate a close relationship between tectonic rotations and the local structural geology. The allochthonous middle Eocene submarine basalt basement of the Crescent Formation consists of...
Kinds of damage that could result from a great earthquake in the central United States
M. G. Hooper, S. T. Algermissen
1985, Earthquake Information Bulletin (USGS) (17) 84-97
In the winter of 1811-12 a series of three great earthquakes occurred in the New Madrid, Missouri seismic zone in the central United States. In addition to the three principal shocks, at least 15 other earthquakes of intensity VIII or more occurred within a year of the first large earthquake...
New York Bight fault
Deborah R. Hutchinson, John A. Grow
1985, Geological Society of America Bulletin (96) 975-989
High-resolution, single-channel and multichannel seismic-reflection profiles in the New York Bight provide 7 crossings of a 50-km-long fault that trends north-northeast for 30 km from its southern end, then bends northeast, and may continue northward beneath Long Island. Displacement, which is consistently down to the west, decreases upsection and suggests...
Block Island fault: A Paleozoic crustal boundary on the Long Island platform
Deborah R. Hutchinson, Kim D. Klitgord, R. S. Detrick
1985, Geology (13) 875-879
A major fault cutting through most of the crust can be identified and mapped on the Long Island platform using multichannel seismic reflection profiles and magnetic data. The fault, here called the Block Island fault (BIF), strikes north-northeast, dips westward at low angle, and does not resemble the thin-skinned thrust...
Hydrogeology of a zone of secondary permeability in the surficial aquifer of eastern Palm Beach County, Florida
L. J. Swayze, W. L. Miller
1984, Water-Resources Investigations Report 83-4249
The surficial aquifer is the primary source of freshwater for the heavily developed coastal area in eastern Palm Beach County, Florida. Well fields are generally located in a discontinuous zone of higher secondary permeability, the northernmost extension of the Biscayne aquifer in the surficial aquifer, that extends from the Juno...
Earthquakes in the eastern United States
Henry Spall, editor(s)
1984, Earthquake Information Bulletin (USGS) (16) 212-214
[none]...
Ground-water reconnaissance of the central Weber River area, Morgan and Summit Counties, Utah
Joseph S. Gates, Judy I. Steiger, Ronald T. Green
1984, Technical Publication 77
During July 1978 to June 1980, the U.S. Geological Survey conducted a reconnaissance of ground-water conditions and ground- and surface-water relationships in the central Weber River area. This reconnaissance was done in cooperation with the Utah Department of Natural Resources, Division of Water Rights.The study area is a series of...
Age and correlation of emerged pliocene and pleistocene deposits, U.S. Atlantic Coastal Plain
T. M. Cronin, L.M. Bybell, R.Z. Poore, B. W. Blackwelder, J. C. Liddicoat, J. E. Hazel
1984, Palaeogeography, Palaeoclimatology, Palaeoecology (47) 21-51
Paleontologic and paleomagnetic investigations were conducted on several hundred Pliocene and Pleistocene marine samples from five regions of the emerged Atlantic Coastal Plain: (1) the Delmarva Peninsula, (2) eastern Virginia, (3) central and northern North Carolina, (4) southern North Carolina and northeastern South Carolina, and (5) the Charleston area, South...
An overview of paleogene molluscan biostratigraphy and paleoecology of the Gulf of Alaska region
L. Marincovich Jr., S. McCoy Jr.
1984, Palaeogeography, Palaeoclimatology, Palaeoecology (47) 91-102
Paleogene marine strata in the Gulf of Alaska region occur in three geographic areas and may be characterized by their molluscan faunal composition and paleoecology: a western area consisting of the Alaska Peninsula, Kodiak Island, and adjacent islands; a central area encompassing Prince William Sound; and an eastern area extending...
Depositional environments and paleogeography of the Upper Miocene Wassuk Group, west-central Nevada
R.T. Golia, John H. Stewart
1984, Sedimentary Geology (38) 159-180
Fluvial and lacustrine deposits of the Miocene Wassuk Group, exposed in Coal Valley, west-central Nevada, are divided into five lithofacies: (1) diatomite, claystone, siltstone, and carbonaceous siltstone deposited in a lake with paludal conditions at the margin; (2) upward-coarsening sequences of sandstone deposited on a delta and fan-delta; (3) channel-form...
A review of crust and upper mantle structure studies of the Snake River Plain-Yellowstone volcanic system: A major lithospheric anomaly in the western U.S.A.
H. M. Iyer
1984, Tectonophysics (105) 291-308
The Snake River Plain-Yellowstone volcanic system is one of the largest, basaltic, volcanic field in the world. Here, there is clear evidence for northeasterly progression of rhyolitic volcanism with its present position in Yellowstone. Many theories have been advanced for the origin of the Snake River Plain-Yellowstone system. Yellowstone and...
A seismic hazard map of India and adjacent areas
K.N. Khattri, A. M. Rogers, D. M. Perkins, S. T. Algermissen
1984, Tectonophysics (108) 93-134
We have produced a probabilistic seismic hazard map showing peak ground accelerations in rock for India and neighboring areas having a 10% probability of being exceeded in 50 years. Seismogenic zones were identified on the basis of historical seismicity, seismotectonics and geology of the region. Procedures for reducing the incompleteness...
