title: Isotopic Fractionation of Uranium in Sandstone.
abstract: Relatively unoxidized black uranium ores from sandstone deposits in the western United States show deviations in the uranium-235 to uranium-234 ratio throughout a range from 40 percent excess uranium-234 to 40 percent deficient uranium-234 with respect to a reference uranium-235 to uranium-234 ratio. The deficient uranium-234 is leached preferentially to uranium-238 and the excess uranium-234 is believed to result from deposition of uranium-234 enriched in solutions from leached deposits.
authors.forename: J N
authors.initials: JN
authors.lastname: Rosholt
authors.forename: W R
authors.initials: WR
authors.lastname: Shields
authors.forename: E L
authors.initials: EL
authors.lastname: Garner