Comparison of fission-track, K-Ar, and Rb-Sr radiometric age determinations from some granite plutons in Maine
C. W. Naeser, D. G. Brookins
1975, Journal of Research of the U.S. Geological Survey (3) 229-231
Fission-track ages have been determined on eight apatite and four sphene concentrates separated from plutonic rocks in Maine. K-Ar and Rb-Sr ages for some of these rocks were previously published. In northeastern Maine the whole-rock Rb-Sr, biotite K-Ar, and apatite fission-track ages are concordant at 400-420 million years, whereas in...
Estimates of temperature and precipitation for northeastern Utah
F.K. Fields, D. B. Adams
1975, Journal of Research of the U.S. Geological Survey (3) 131-136
Estimates of temperature and precipitation were made for northeastern Utah from information that was collected at 67 locations. The variable-length records were converted to the common-time base of 1941-70; then general relations were developed to extend the converted point values to unsampled sites. Regression techniques were used to fill voids...
Information through color imagery
Alden P. Colvocoresses
1975, Journal of Research of the U.S. Geological Survey (3) 127-129
The color-sensing capability of the human eye is a powerful tool. In remote sensing we should use color to display data more meaningfully, not to re-create the scene. Color disappears with distance, and features change color with viewing angle. Color infrared film lets us apply color with additional meaning even...
Spectrophotometric-isotope dilution determination of arsenic in soils and rock
F. W. Brown, F.O. Simon, L. P. Greenland
1975, Journal of Research of the U.S. Geological Survey (3) 187-190
Arsenic in soil and rock samples may be determined in part-per-million concentrations using a radiochemical-isotope dilution method. Arsenic in the sample plus added As76 tracer is separated as arsine and determined spectrophotometrically as a molybdenum blue complex. The As76 activity in the absorbing solution allows corrections for chemical losses. A lower limit...
Relative efficiencies of square and triangular grids in the search for elliptically shaped resource target
Donald A. Singer
1975, Journal of Research of the U.S. Geological Survey (3) 163-167
The relative efficiencies of equivalent-density, square and equilateral triangular (hexagonal) grids used in the search for elliptical targets are determined for ellipses having relative semi-major axes ranging from 0.50 to 1.00 of the square grid spacing and having shapes (minor axes/major axes) ranging from 0.2 to 1.0. Using the probability...
Preliminary results of a gravity survey of the Henrys Lake quadrangle, Idaho and Montana
Donald L. Peterson, Irving J. Witkind
1975, Journal of Research of the U.S. Geological Survey (3) 228
A gravity survey of the Henrys Lake quadrangle shows that a gravity low with about 10 milligals of closure coincides with the Henrys Lake basin. The low is interpreted to reflect a basin fill of 1,100 m or more of Cenozoic sediments and volcanic rock. The data indicate that on...
Analysis for tellurium in rocks to 5 parts per billion
John R. Watterson, George J. Neuerburg
1975, Journal of Research of the U.S. Geological Survey (3) 191-195
In the proposed method, a 12.5-g sample is digested with nitric acid and evaporated to dryness; the excess nitric acid is removed by reaction with formic acid. Tellurium is extracted from the dried residue into hydrobromic acid and is then coprecipitated with arsenic, using hypophosphorous acid as the reducing agent....
Perched silica minerals on mordenite fiber
Robert B. Finkelman
1975, Journal of Research of the U.S. Geological Survey (3) 197-202
Ellipsoidal quartz grains and spherulitic chalcedony are perched on mordenite fibers in geodes from Chihuahua, Mexico. Examination of samples of fibrous mordenite from six additional localities indicated that most mordenites have perched quartz crystals. A linear relationship exists between the Si:Al ratios and the refractive indices of the mordenites. The...
Experimental abrasion of detrital gold
Warren E. Yeend
1975, Journal of Research of the U.S. Geological Survey (3) 203-212
The physical breakdown and abrasion rates of gold were studied using a tumbler to simulate natural high-energy environments. The gold fragments were tumbled for periods ranging from 30 to 240 h with different combinations of sand, cobbles, and water at velocities of 0.5 and 2.0 mi/h (0.85 and 3.22 km/h)....
Cylindrical jointing in mafic dikes, central Beartooth Mountains, Montana
Theodore J. Armbrustmacher, Frank S. Simons
1975, Journal of Research of the U.S. Geological Survey (3) 213-221
Cylindrical joints are well displayed in two Precambrian mafic dikes that cut granitic gneiss in the central Beartooth Mountains, Mont. The dikes are vertical and about 23 m (75 ft) and 23 to 46 m (75-150 ft) thick, respectively. The cylindrical joints are perpendicular to the dike walls, and the...
Ice ages and the thermal equilibrium of the earth, II
D.P. Adam
1975, Quaternary Research (5) 161-171
The energy required to sustain midlatitude continental glaciations comes from solar radiation absorbed by the oceans. It is made available through changes in relative amounts of energy lost from the sea surface as net outgoing infrared radiation, sensible heat loss, and latent heat...
Elevation changes in the central Transverse Ranges near Ventura, California
Jane M. Buchanan-Banks, Robert O. Castle, Joseph I. Ziony
1975, Tectonophysics (29) 113-125
Profiles of elevation changes developed from repeated levelings in the east-trending Transverse Ranges near Ventura, California, reveal three general types of vertical movements: 1. (1) broadly defined regional tilting; 2. (2) sharply defined differential movements across recently active faults; and 3. (3) differential subsidence centering on producing oil fields. Down-to-the-southeast...
The Pikes Peak batholith, Colorado front range, and a model for the origin of the gabbro-anorthosite-syenite-potassic granite suite
F. Barker, D. R. Wones, W. N. Sharp, G. A. Desborough
1975, Precambrian Research (2) 99-160
This study of the Pikes Peak batholith includes the mineralogy and petrology of quartz syenite at West Creek and of fayalite-bearing and fayalite-free biotite granite near Mount Rosa; major element chemistry of the batholith; comparisons with similar postorogenic, intracratonic, sodic to potassic intrusives; and genesis of the batholith.The batholith is...
Thermal-infrared spectra and chemical analyses of twenty-six igneous rock samples
R.K. Vincent, L. C. Rowan, R.E. Gillespie, C. Knapp
1975, Remote Sensing of Environment (4) 199-209
Emittance spectra in the 7.5 μm to 14 μm wavelength region and chemical compositions of 26 igneous rocks are reported. Experimental measurements on the rocks were made under simulated daytime field conditions. Some surface silicate contaminants, such as clayey silt, significantly...
Al-augite and Cr-diopside ultramafic xenoliths in basaltic rocks from western United States
H. G. Wilshire, J.W. Shervais
1975, Physics and Chemistry of the Earth (9) 257-272
Ultramafic xenoliths in basalts from the western United States are divided into Al-augite and Cr-diopside groups. The Al-augite group is characterized by Al, Ti-rich augites, comparatively Fe-rich olivine and orthopyroxene, and Al-rich spinel, the Cr-diopside group by Cr-rich clinopyroxene and spinel and...
Garnet peridotite xenoliths in a Montana, U.S.A., kimberlite
Hearn B. Carter Jr., F.R. Boyd
1975, Physics and Chemistry of the Earth (9) 247-255
Within a swarm of late middle Eocene subsilicic-alkalic diatremes, one diatreme 270 by 370 m and an associated dike contain common xenoliths of granulite and rare xenoliths of spinel peridotite and garnet peridotite. Six garnet lherzolite xenoliths have been found and these...
Magnitude and frequency of floods in small drainage basins in North Dakota
Orlo A. Crosby
1975, Water-Resources Investigations Report 19-75
This report describes methods for estimating flood-peak discharges having 2- to 50-year recurrence intervals on North Dakota streams draining less than 100 square miles ( 259 square kilometres). For gaged sites, frequency estimates are provided directly. For ungaged sites, flood peaks are estimated from multiple-regression equations using drainage-area size and,...
A summary of selected chemical-quality conditions in 66 California streams 1950-72
George A. Irwin, Michael Lemons
1975, Report
Water from California streams has been analyzed for concentrations of selected chemical constituents since the early 1950's. This summary includes about 1,200 water years of data from 88 sampling sites on 66 streams. Results of this summary show that about 80 percent of the sites had a mean dissolved-solids concentration...
Descriptions and chemical analyses for selected wells in the Tehama-Colusa Canal Service Area, Sacramento Valley, California
Ronald P. Fogelman
1975, Report
The Tehama-Colusa Canal Service Area is in the northwestern part of the Sacramento Valley, in parts of Yolo, Colusa, Glenn, and Tehama Counties. The area includes 450 square miles (1,160 square kilometres). The boundaries are: West, the eastern slopes of the Coast Ranges; north, Elder Creek; northeast, the Sacramento River...
In-situ measurements of seismic velocities at twelve locations in the San Francisco Bay region
J. F. Gibbs, T. E. Fumal, R. D. Borcherdt
1975, Open-File Report 75-564
No abstract available....
Thermal-infrared images as a basis for structure mapping, front range and adjacent plains in Colorado
Terry W. Offield
1975, Geological Society of America Bulletin (86) 495-502
High-altitude thermal-infrared images, taken at various times of the day over the Front Range and adjacent plains in Colorado, display many linear and circular topographic features. These features are enhanced by thermal shading effects and commonly are better displayed than in photographs. Comparison with geologic maps of a control area...
Geologic setting of the Glacier Peak and Mazama ash-bed markers in west-central Montana
Richard Walter Lemke, M. R. Mudge, R.E. Wilcox, H. A. Powers
1975, Bulletin 1395-H
Water resources data for Utah, water year 1974; Part 2: Water quality records
Water Resources Division, U.S. Geological Survey
1975, Water Data Report UT-74-2
No abstract available....
Water resources data for Utah, water year 1974; Part 1: Surface water records
Water Resources Division, U.S. Geological Survey
1975, Water Data Report UT-74-1
No abstract available....
Geologic map of the Kearny quadrangle, Pinal County, Arizona
Henry Rowland Cornwall, Medora Louise Hooper Krieger
1975, Geologic Quadrangle 1188
