Abundance of lanthanoids in rock salts determined by neutron activation analysis

Contents of lanthanoids (Ln's) of rock salts have been measured by neutron activation analysis. Original salt samples were treated in advance of neutron irradiation so that Ln's were enriched and amounts of interfering nuclides were reduced. The contents of Ln's were at ppt-sub ppb levels and were comparable with or slightly lower than those of solar salts. The Ln abundance patterns of the salts were those with relative depletion in the heavy Ln's, thus having negative slopes. It was indicated that, when salt deposit was formed, Ln's were taken up by anhydrite more preferentially than by halite.