Isotopic Ages of the Basic Charnockite and Khondalite from Kondapalli, Andhra Pradesh, India

R. L. Grasty and C. Leelanandam
Department of Geodesy and Geophysics, University of Cambridge
Department of Mineralogy and Petrology, University of Cambridge

Summary: The isotopic ages of three biotites from the Kondapalli area, Andhra Pradesh, India, have been determined by the 40Ar/40K method. The results (440–524 Myr) indicate that the basic charnockite and khondalite of pre-Cambrian age have been subjected to at least one subsequent metamorphism the age of which must be 440 Myr or younger. The significance of the results is discussed in the light of the available geochronological evidence from Peninsular India.

Mineralogical Magazine; September 1965 v. 35; no. 271; p. 529-535; DOI: 10.1180/minmag.1965.035.271.08
© 1965, The Mineralogical Society
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