Abstract

Isotope dilution analyses for He, U, and Th have been performed on magnetite and pyrite samples from the Cornwall, Pennsylvania magnetite deposits. If the extra-lattice U and Th are removed by leaching, the method gives an age for the ore of 194+ or -4 m.y. in agreement with a K-Ar age of 195+ or -5 m.y. on associated muscovite and 197+ or -5 for biotite from the Palisades diabase. It appears that the He age method can be quantitative and can be useful in dating ore deposits under suitable conditions.

First Page Preview

First page PDF preview
You do not currently have access to this article.