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K-Ar age of the East Peripheral kimberlite at De Beers Mine, Kimberley, R.S.A.

Published online by Cambridge University Press:  01 May 2009

F. J. Fitch  and
J. A. Miller
F. J. Fitch
Affiliation:
Department of Geology, Birkbeck College, University of London, Malet Street, London WCIE 7HX, U.K.
J. A. Miller
Affiliation:
Bullard Laboratories, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB3 0EZ, U.K.
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Abstract

Summary. The kimberlite pipe at De Beers Mine, Kimberley is a complex, multiple structure. Three concordant argon-40/argon-39 age spectra have been obtained from samples from the 720 m level in the East Peripheral kimberlite. Each spectrum is dominated by a major plateau-feature between 84 and 89 Ma and none shows significant evidence of either excess argon or argon loss discrepancy. The available evidence suggests that the K-Ar age of normal magmatic emplacement-cooling of the East Peripheral kimberlite at De Beers Mine was close to 86 ± 2 Ma.

Type
Research Article
Information
Geological Magazine , Volume 120 , Issue 5 , September 1983 , pp. 505 - 512
Copyright
Copyright © Cambridge University Press 1983

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