Abundance and distribution of uranium and thorium in zircon, sphene, apatite, epidote, and monazite in granitic rocks

Abstract

Analyses were made of uranium and thorium in ziircon, sphene, apatite, epidote, and monazite separated as accessory minerals from samples of granitic rock from widely scattered localities to indicate the abundance and distribution of these two elements among the five mineral phases. For any pair of mineral phases the distribution ratio remains within the same order of magnitude over the different rocks tested, although the variability of the data is such that only wide departures from constancy could be ascertained. Such gross differences have not been found.