title: Fossil alpha-recoil analysis of certain variant radioactive halos.
abstract: The distribution of alpha-radioactivity in the vicinity of uranium and of certain variant radioactive halos in biotite was investigated by the fossil alpharecoil method. Within the limits of the method I could not confirm a previously proposed hydrothermal mechanism for the origin of certain variant halo types due to polonium isotopes.
authors.forename: R V
authors.initials: RV
authors.lastname: Gentry