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C. A. Bush

Publications and source records attributed to C. A. Bush.

32 records · Page 2Linked to original sources
USGS1977

Geochemical and petrological studies of a uraniferous granite from the Granite Mountains, Wyoming

Granite rocks from the Granite Mountains, Wyo. have been proposed as the source of uranium deposits in the Crooks Gap, Gas Hills and Shirley Basin uranium districts, Wyoming. We have divided these granitic rocks into four units: (1) a biotitic phase which forms the dominant unit at the western end of the Granite Mountains, (2) a leucocratic phase which was found from 215 to 405 metres in drill hole GM-1, (3) silicified zones which crosscut the granitic rocks and form topographic highs, and (4) fractured zones, in drill hole GM-1, which seem to have been hydrothermally altered. The biotitic phase is hypidiomorphic-granular to xenomorphic-granular alkali granite with anomalously high contents of U (10 parts per million), Th (50 ppm), and Pb (50 ppm). Fission-track studies show that uranium is located in zircon, sphene, apatite, monzite, xenotime, biotite, chlorite, epidote, and magnetite; no intergranular uranium was found. The leucocratic phase is mineralogically similar to the biotitic phase, but contains less than half as much iron. It is xenomorphic granular and commonly contains rounded and retrograded garnets, which suggests that this phase is either metamorphic or contaminated with metamorphic materials. The leucocratic phase has anomalously high contents of U (8 ppm) and Pb (55 ppm), but has a low Th content (10 ppm). The silicified phase and fracture zones exhibit cataclastic and crystalloblastic textures and are highly variable in mineralogy. Potassium-bearing minerals are generally absent. Microcline is replaced by albite and (or) quartz, and biotite is replaced by clinozoisite. Uranium values may be anomalously high in the fracture zones. One sample contains 1100 ppm radium-equivalent uranium. In this and other uranium-rich samples from the fracture zones, the uranium is associated with iron oxides which commonly fill microfractures. According to our model and currently available data, an alkali granite is the best crystalline source rock for uranium, especially if it is unmetamorphosed and rapidly exposed to near-surface conditions for the first time when a favorable basin existed nearby.

Wyoming↗
USGS1976

Ground radioactivity measurements in South Carolina and Georgia with radioelement analyses of surficial sediments

Recently published aeroradioactivity maps of parts of the South Carolina and Georgia Coastal Plain, have defined numerous areas of anowlously high total gamma ray intensity (Coastal Plain Regional Commission and U.S. Geological Survey, 1975, Aeroradioactivity maps of parts of Georgia, South Carolina, and North Carolina: U.S. Geol. Survey Open-file Report 75-400, 1:250,000, 15 pls.). During the present study, areas in South Carolina and Georgia having high total gamma aeroradioactivity were sampled in one of two ways. Individual samples labeled "Georgia grab samples", "Columbia grab samples", and "Frogmore samples" were each collected as close as possible to the center of aeroradioactivity highs. Groups of samples labeled St. Matthews, Tillman, Gray's Hill, Route 99, Route 196, and Route 276 were collected by sampling along existing roads that transect aeroradioactivity highs. At each sample location five to ten pound samples were taken from the top two-to-three inches of sediment. The samples were dried, split, and analysed for uranium, thorium, and potassium by gamma-ray spectrometry. In the accompanying table uranium contents are presented as RAEU (radium equivalent uranium) in parts per million (ppm). Thorium is presented in parts per million (ppm) and potassium in percentage (pct). Ground counts of total gamma intensity were taken in the field with a McPhar IV four-channel scintillometer. Gamma ray intensity is presented as counts per minute (cpm) averaged over ten second intervals. More samples and ground radioactivity measurements were taken than are presented in the following table. Only those samples that were analysed for radioelements are listed. Collection of the "Georgia grab samples" was a joint effort of the Georgia Geologic and Water Division and the U.S. Geological Survey. Brenda B. Higgins, John Hack, Isidore Zeitz and Robert Schmidt provided useful discussions concerning the selection of areas to be sampled.

Georgia, South Carolina↗
USGS1975

Abundances of uranium, thorium, and potassium for some Australian crystalline rocks

This report contains a tabulation of the basic radioelement and radiogenic heat data obtained during an Australian National University (ANU) - United States Geological Survey (USGS) heat-flow project, directed jointly by J. C. Jaeger (ANU) and J. H. Sass (USGS). Most samples were collected during the periods June through September, 1971 and 1972. The measurements were made subsequently by two of us (C. M. Bunker and C. A. Bush) using the gamma-ray spec trometric techniques described by Bunker and Bush (1966, 1967). Interpreting the spectra for quantitative analyses of the radioelements was accomplished with an iterative leastsquares computer program modified from one by Schonfeld (1966). Uranium content determined by gamma-ray spectrometry is based on a measurement of the daughter products of 226 Ra. Equilibrium in the uranium-decay series was assumed for these analyses . Throughout the report, when U content is stated, radium-equivalent uranium is implied. The coefficient of variation for the accuracy of the radioelement data, when compared to ana lyses by isotope dilution and flame photometry is about 3 percent for radium-equivalent uranium and thorium and about 1 percent for potassium. These percentages are in addition to minimum standard deviations of about 0.05 ppm for U and Th, and about 0.03 percent for K.

Open-File Report↗
USGS1973

Radioelement and radiogenic heat distribution in Drill Hole UCe-1, Belmont Stock, Central Nevada

Uranium, thorium, and potassium concentrations were measured in 60 samples collected from an exploratory hole drilled in the Belmont stock about 40 miles north-northeast of Tonopah, Nev. The results indicate that, at least within 2,000 feet of the surface, the granitic pluton contains radioelement concentrations similar to those in average granodiorites and that local variations in concentrations may reflect the effects of argillic alteration.

Nevada↗
USGS1973

Radioelement distribution in the basement complex of the Yukon-Tanana upland, Eielson deep test hole, Alaska

Uranium, thorium, and potassium contents were determined in 94 samples of drill cuttings from a 9,774-foot-deep exploratory hole drilled entirely in crystalline schists of the basement complex of the Yukon-Tanana Upland. The data indicate two distinctively different rock types and reflect differences in the calcite content of the rock. Zones of anomalously high concentrations of the radioelements probably reflect the effects of the emplacement of the nearby Eielson pluton.

Alaska↗