Rb/Sr ISOTOPE STUDIES OF CRETACEOUS GRANITOIDS IN THE CENTRAL CHUKCHI REGION: CORRECTNESS OF GEOCHRONOLOGICAL INTERPRETATION OF RESULTS
S.V. Efremov, S.I. Dril', G.P. Sandimirova, and I.V. Sandimirov
A.P. Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, ul. Favorskogo 1a, Irkutsk, 664033, Russia
Keywords: Granitoids, isotopic age, ultrapotassic basites
Pages: 1257-1261
Abstract
The validity of the Rb/Sr isotopic ages of Cretaceous granitoid complex in the central Chukchi region has been verified. The performed studies showed that the Rb/Sr isotopic ages of late-orogenic granitoids are not reliable. Their variation can be explained in terms of the mixing of primary mantle magmas with continental-crust matter. Most probably, the variation is due to the constant compositions of mixing components and their proportions.
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