U-Pb, Ar-Ar, and Sm-Nd ISOTOPE-GEOCHRONOLOGICAL STUDY OF PORPHYRITIC SUBALKALIC GRANITES OF THE TARAKA PLUTON (Yenisei Range)
A.D. Nozhkin, E.V. Bibikova*, O.M. Turkina, and V.A. Ponomarchuk
United Institute of Geology, Geophysics and Mineralogy, Siberian Branch of the RAS,
3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
* Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences,
19 ul. Kosygina, Moscow, 117975, Russia
Keywords: Granites; U-Pb, Ar-Ar, and Sm-Nd dating; Precambrian, Yenisei Range
Pages: 842-852
Abstract
We present first results of complex U-Pb, Ar-Ar, and Sm-Nd isotope study of porphyritic subalkalic granites of the Taraka pluton (Yenisei Range), one of the largest Proterozoic Na-K plutons on the southwestern and southern periphery of the Siberian Platform. The obtained U-Pb dates for zircon indicate that the subalkalic granites formed 1837  3 myr BP. The trace-element composition and Nd isotope characteristics of the granites evidence that they were produced from a highly differentiated mature sialic source no older than 2566 Ma. With Ar-Ar dating of the granite minerals, we made an attempt to elucidate the time of subsequent tectonothermal events, each of which opened a new epoch in the development of the Ar-Ar systems. |
