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Carl Maurice Bunker

Publications and source records attributed to Carl Maurice Bunker.

11 recordsLinked to original sources
USGS1977

Radioelement concentrations and preliminary radiometric ages of rocks of the Kigluaik Mountains, Seward Peninsula, Alaska

A sequence of old metamorphic rocks including the Kigluaik and Nome Groups is exposed in the Kigluaik Mountains of the Seward Peninsula. The high-grade metasedimentary rocks give a whole-rock Rb-Sr age of 735 m.y. This late Precambrian age is believed to be the time of metamorphism. Orthogneisses, intrusive into the metasedimentary rocks, are probably also Precambrian in age; but many samples have had their ages disturbed by Cretaceous intrusions and thrusting. Samples of Precambrian metagabbro are low in radioelements (U, Th, and K) typical of basalitc rocks. The Precambrian metasedimentary rocks have normal radioelement concentrations, but both the Precambrian orthogneisses and the Cretaceous granitic rocks are unusually rich in thorium.

Alaska↗
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↗
USGS1957

Effects of radon in drill holes on gamma-ray logs

Drill holes in uranium deposits in the Todilto limestone of Late Jurassic age near Grants, New Mexico, do not yield duplicate gamma-ray logs when probed at different times; some logs show equivalent uranium greatly in excess, in thickness and grade, of the chemical and laboratory radiometric analyses. Radon and its daughter products principally cause the discrepancies. Experimental work was undertaken by the writers to learn the relations of the radon to the uranium deposits and its behavior under different physical conditions. The work is based on the interpretation of about 600 gamma-ray logs, taken from 480 drill holes.Abnormally high amounts of radon, referred to here as contamination, ranged from barely detectable amounts to amounts that emitted as much radiation as ore-grade material. Most contaminated holes were in the higher-grade ore, and the contamination increased with elapsed time after drilling. Geologic conditions favorable for contamination by radon and its daughter products in drill holes are: proximity to uranium deposits and fractured or highly permeable rocks above the water table. Most drill holes can be decontaminated by blowing them out with compressed air or filling them with water. Water, however, tends to reduce the thickness-times-grade figures below the amounts determined in air.

New Mexico↗