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...
Isotopic studies of the late Archean plutonic rocks of the Wind River Range, Wyoming
J. S. Stuckless, C. E. Hedge, R. G. Worl, K. R. Simmons, Ignatius T. Nkomo, D. B. Wenner
1985, Geological Society of America Bulletin (96) 850-860
Isotopic studies of the Rb-Sr and U-Th-Pb systems in whole-rock samples and the U-Pb systematics for zircons document the existence of two late Arehean intrusive events in the Wind River Range. All of the systems examined indicate an age of ∼2,630 ± 20...
Petrology and tectonic significance of augen gneiss from a belt of Mississippian granitoids in the Yukon-Tanana terrane, east- central Alaska
Cynthia Dusel-Bacon, John N. Aleinikoff
1985, Geological Society of America Bulletin (96) 411-425
An approximately E-W-trending belt of porphyritic peraluminous granitic rocks, metamorphosed and deformed to augen gneiss, is exposed for 400 km across the Yukon-Tanana terrain. Chemical, textural, and isotopic data from large augen-gneiss bodies indicate that these bodies originated as early Mississippian granitic rocks that assimilated, or were anatectically derived from,...
Global geologic mapping of Mars: The western equatorial region
D. H. Scott
1985, Advances in Space Research (5) 71-82
Global geologic mapping of Mars was originally accomplished following acquisition of orbital spacecraft images from the Mariner 9 mission. The mapping program represented a joint enterprise by the U.S. Geological Survey and other planetary scientists from universities in the United States and Europe. Many of the Mariner photographs had low...
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...
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...
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...
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...
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...
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...
Ground-water flow in the Prairie du Chien-Jordan aquifer related to contamination by coal-tar derivatives, St. Louis Park, Minnesota
J. R. Stark, M. F. Hult
1985, Water-Resources Investigations Report 85-4087
A three-dimensional, ground-water-flow model of the Prairie du Chien-Jordan aquifer and associated hydrogeologic units was developed to evaluate the movement of coal-tar derivatives from a coal-tar distillation and wood-preserving plant in St. Louis Park, Minnesota. A finite-difference grid was superimposed on the modeled area, which includes most of eastern Hennepin...
Streamflow statistics and drainage-basin characteristics for the southwestern and eastern regions, Washington: Volume I. Southwestern Washington
John R. Williams, Harold E. Pearson
1985, Open-File Report 84-145-A
No abstract available....
Characteristics of the aftershock sequence of the Borah Peak, Idaho, earthquake determined from digital recordings of the events
John Boatwright
1985, Bulletin of the Seismological Society of America (75) 1265-1284
The U.S. Geological Survey, Menlo Park, deployed and maintained a network of twelve digital instruments over the 2 weeks following the 28 October 1983 Borah Peak, Idaho, earthquake. The network recorded 45 events with M ≧ 3.0, and 6 events with M ≦ 4.0. The epicenters are located in a...
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...
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...
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...
Map of Antelope Valley-East Kern Water Agency area, California, showing ground-water subunits and areas, location of wells, and lines of equal depth to water for spring 1983
W. R. Moyle Jr., Florence M. Glenn
1985, Open-File Report 84-726
No abstract available....
Composition and morphology of ferromanganese coatings on glacial erratics in Lydonia Canyon, United States East Coast
L.J. Poppe, Dennis W. O’Leary, R.F. Commeau
1985, Geo-Marine Letters (5) 127-133
Ferromanganese coatings have been found on glacial erratics in Lydonia Canyon, off the United States northeastern coast. The coatings, which are about 17 ??m thick, consist of an outer manganese-rich layer which covers the top of the erratic, a middle transitional layer, and an internal iron-rich layer that encircles the...
Hydrologic and geochemical monitoring in Long Valley caldera, Mono County, California, 1982-1984
C. D. Farrar, M.L. Sorey, S. Rojstaczer, C. J. Janik, Robert H. Mariner, T. L. Winnett, M. D. Clark
1985, Water-Resources Investigations Report 85-4183
The Long Valley caldera is a potentially active volcanic area on the eastern side of the Sierra Nevada in east-central California. Hydrologic and geochemical monitoring of surface and subsurface features began in July 1982 to determine if changes were occurring in response to processes causing earthquakes and crustal deformation. Differences...
Trondhjemite and metamorphosed quartz keratophyre tuff of the Ammonoosuc volcanics (Ordovician), western New Hampshire and adjacent Vermont and Massachusetts
G. W. Leo
1985, Geological Society of America Bulletin (96) 1493-1507
The Ammonoosuc Volcanics and equivalent rocks of Ordovician age are exposed in the Oliverian domes along the Bronson Hill anti-clinorium (BHA) between northern New Hampshire and southern Connecticut. In western New Hampshire and adjacent Vermont and Massachusetts, the Ammonoosuc lithology consists of a...
DISTRIBUTION OF TRACE ELEMENTS IN COAL MINERALS OF SELECTED EASTERN UNITED STATES COALS.
C.A. Palmer, M.-V. Wandless
1985, Conference Paper
The association of 34 elements with minerals found in coal was determined by a combination of analytical techniques on size and density fractions of low-temperature ash (LTA). Instrumental neutron activation analysis was used to determine the concentrations of the elements, and X-ray diffraction analysis, scanning electron microscopy, and scanning transmission...
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...
40Ar/39Ar and K-Ar data bearing on the metamorphic and tectonic history of western New England
J. F. Sutter, N. M. Ratcliffe, S.B. Mukasa
1985, Geological Society of America Bulletin (96) 123-136
40Ar/39Ar ages of coexisting biotite and hornblende from Proterozoic Y gneisses of the Berkshire and Green Mountain massifs, as well as 40Ar/39Ar and K-Ar mineral and whole-rock ages from Paleozoic metamorphic rocks, suggest that the thermal peak for the dominant metamorphic recrystallization in western New England occurred 465 ± 5 m.y....
