United States Geological Survey Report TEI-696

Abstract: "The relative isotopic abundance of copper has been measured in a number of minerals. Suites of samples from Michigan and the Colorado Plateau have been examined to determine if local variations due to isotopic exchange or diffusion could be found. The relative isotopic abundance of copper in specimens from a number of other places was also determined. The variations noted were small but in most cases were felt to be significant because they were larger than the experimental error (0.1 percent in the ratio). A total spread of +3 to -8 parts per mil compared to the standard was found in the specimens tested.

United States Geological Survey Reports

From abstract: "The isotopic abundances of uranium and the radium activity ratios of 11 samples of uranium ore from the Colorado Plateau have been measured." Experimental data and discussion is included with information regarding the samples used

Some natural variations in the relative abundance of copper isotopes /

"August 1957."Work done on behalf of the Division of Research, U.S. Atomic Energy Commission.Includes bibliographical references (leaves 28-29).Mode of access: Internet