First Data on Age of Metarhyolites from the Turan Group of the Bureya Terrane, Eastern Part of the Central Asian Foldbelt

摘要

Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, ul. B. Khmel'nitskogo 2, Blagoveshchensk, 675000 Russia;Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, ul. B. Khmel'nitskogo 2, Blagoveshchensk, 675000 Russia;Institute of Geology and Nature Management, Far East Branch, Russian Academy of Sciences, ul. B. Khmel'nitskogo 2, Blagoveshchensk, 675000 Russia;Geological Institute, Kola Scientific Center, Russian Academy of Sciences, ul. Fersmana 14, Apatity, 184209 Russia;%The U—Pb geochronological studies showed that metarhyolites from the Turan Group of the Bureya (Turan) Terrane to the east of the Central Asian Foldbelt are Middle Cambrian (504 ± 8 Ma), not Neoproterozoic in age, as was suggested before. Metarhyolites are younger than the Early Cambrian terrigenous—carbonate sediments from this terrane characterized by the Atdabanian archaeochyatid. Considering that volcanic rocks have features of intraplate origin, it may be assumed that their formation corresponds to the breakup of the Early Paleozoic passive continental margin.