THE TRIASSIC STAGE OF MAFIC MAGMATISM IN THE DZHUGDZHUR-STANOVOI SUPERTERRANE (southern framing of the North Asian craton)
I.V. Buchkoa, A.A. Sorokina, E.B. Sal'nikovab, A.B. Kotovb, S.D. Velikoslavinskiib, A.M. Larinb, A.E. Izokhc, and S.Z. Yakovlevab
aInstitute of Geology and Nature Use, Far Eastern Branch of the Russian Academy of Sciences, per. Relochnyi 1, Blagoveshchensk, 675000, Russia
b Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, nab. Makarova 2, Saint Petersburg, 199034, Russia
cV.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, prosp. Koptyuga 3, Novosibirsk, 630090, Russia
Keywords: Ultramafic-mafic massifs, framing of the North Asian craton, petrology, geochemistry, isotope dating
Pages: 1157-1166
Abstract
With U-Pb zircon dating, the ages of the Ul'degit (228 ± 1 Ma) and Chek-Chikan (203 ± 1 Ma) mafic massifs were determined. These massifs were earlier considered to form at the Early Precambrian stage of the geologic evolution of the Dzhugdzhur-Stanovoi superterrane. In geochemical features the igneous rocks of the massifs show relation with a within-plate source, on the one hand, and are similar to igneous rocks of subduction zones, on the other. They might have formed after subduction, which caused the intrusion of gabbroids of the Lucha massif (248 ± 1 Ma) and diorites of the Tok-Algoma complex (238 ± 2 Ma), followed by the fracturing of the subducted plate.
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