Stratotype of the Chaya Formation of the Akitkan Group in the North Baikal volcanoplutonic belt: age and time of sedimentation
T.V. Donskaya a , A.M. Mazukabzova, E.V. Bibikova b , D.P. Gladkochub a , A.N. Didenko c , T.I. Kirnozovab, V.Yu. Vodovozov d , A.M. Stanevich a
a Institute of the Earth's Crust, Siberian Branch of the RAS, 128 ul. Lermontova, Irkutsk, 664033, Russia
b Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, 19 ul. Kosygina, Moscow, 119991, Russia
c Geological Institute of the RAS, 7 Pyzhevsky per., Moscow, 119017, Russia
d Shmidt Institute of the Earth's Physics, Russian Academy of Sciences, 10 ul. Bol. Gruzinskaya, Moscow, 123995, Russia
Keywords: Rhyodacites; geochronology; Early Proterozoic; North Baikal volcanoplutonic belt; Siberian craton
Pages: 707-710
Abstract
With U-Pb zircon dating, we determined the age of rhyodacites composing sedimentary covers among coarse-terrigenous rocks of the lowermost Chaya Formation of the Akitkan Group (North Baikal volcanoplutonic belt). These rocks are considered to have formed during the sedimentation. The dates (1863 ± 9 Ma) permitted estimation of the age of basal beds of the Chaya Formation and substantiate the age boundary between the Khibelen and Chaya Formations of the Akitkan Group. The determined age and earlier dates of igneous rocks intruding the Chaya Formation deposits suggest that the latter accumulated for ~10 Myr.
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