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Rb-Sr age determinations on shales associated with the Varanger Ice Age

Published online by Cambridge University Press:  01 May 2009

I. R. Pringle*
Affiliation:
Department of Geodesy and Geophysics, Madingley Rise, Cambridge

Summary

Rb–Sr whole-rock isochron ages from shale horizons in the Late Pre-Cambrian tillite succession in Varangerfjord, Northern Norway, are presented. Although data from the Stappogiedde Formation, which overlies the tillite horizons, give a Caledonian, metamorphic age of 530±50 m.y., ages obtained from shales occurring between and below the tillites are believed to represent the approximate times of deposition of the sediments. An age of 810±90 m.y. for the Tanafjord Group enables this group to be correlated with the Upper Torridonian and the age of 668±23 m.y. for the Nyborg Formation, which is taken as the age of the Varanger Ice Age, allows a tentative correlation to be made with the Egan and Marinoan Glaciation in Australia.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1972

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