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Radioactive age determinations have been made on 16 minerals from the Brown Derby pegmatite and the Quartz Creek granite. A high degree of consistency has been found among the Rb-Sr ages measured on micas and feldspars. A similar degree of consistency exists in the K-A ages of micas. These consistencies are indicative of the usefulness of measurements of the decay of K40 and Rb87 in determining relative ages of igneous rocks. U-Pb and Th-Pb ages determined from minerals obtained from the pegmatite and granite were not concordant. Different minerals showed different types of partial separation of parent and daughter elements. Comparisons of Rb-Sr and K-A ages with concordant U-Pb ages have been made on other pegmatites. The measurements are most consistent with an age of 1350±100 m.y. for the pegmatite and the granite.
Knowledge graph centered on Radioactive ages of minerals from the Brown Derby with 5 nodes and 4 connections. Top connected: L. T. Aldrich, G. L. Davis, G. R. Tilton, G. W. Wetherill.
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