Ionium Dating of Igneous Rocks

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Science  19 May 1967:
Vol. 156, Issue 3777, pp. 932-934
DOI: 10.1126/science.156.3777.932


Local fractionation of uranium and thorium, between minerals within a sample of igneous rock at the time of crystallization, makes it possible to date its solidification by use of ionium and uranium. Results on samples of granite, pumice, and lava suggest that this method of dating is reliable.