The A³³ content of two potassium minerals

Abstract

Gerling, Levskii and Afanasyeva (1956) have presented evidence indicating the presence of A³⁸ in potassium micas and feldspars. Their data indicate that the A³⁸/K ratio is constant for potassium minerals of a given age and that this ratio increases regularly with the age of the sample. They state that the observed data may be explained by assuming that K³⁸ occurs in nature with an abundance of K³⁸/K = 1 x 10⁻¹⁰ and that the K³⁸ has along lived isomeric state (K³⁸ ->- A³⁸ + β+; t1/2 = 7·70 x 10⁸ yr). The only known isomers of K³⁸ have half lives of the order of minutes. Because of the implications of their conclusion, we have investigated the A³⁸ content of two minerals--MMI, a muscovite mica from Dickinson Co., Michigan, U.S.A., and N-45, a lepidolite from Bikita Quarry, So. Rhodesia.

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