V.G. KOLOKOLTSEV, S.A. SERGEEV (VSEGEI)

Origin and the U­-Pb isotopic age of detrital zircons from the Yaregsk oil­titanium and Pizhemsk titanium deposits (Timan)

Data on the U­Pb isotopic age of zircon detritus from leucoxene­quartz ores of the Yaregsk oil­titanium deposit, which indicate a sharp predominance (92%) of Riphean dating in the range of 900 to 1600 Ma, have been obtained for the first time. Their comparison with the published data on zircons from the Pizhemsk titanium deposit proves that the denudation products of the Riphean rock complexes were the dominant source of clastic material for both placers. In-significant amount of Late Archean detrital zircons in the ore of the Pizhemsk deposit confirms that the Pizhemsk de-posit provenance area differed from that of the Yaregsk deposit in a deeper erosional truncation of Riphean strata. It is shown that the isotope­geochronological data do not contradict the hypothesis that the Yaregsk oil-­titanium deposit be-longs to the two­stage sedimentary­naphthide­epigenetic leucoxene type.
Keywords: zircon detritus, U­Pb isotope age, Timan, Yaregsk oil­titanium deposit, Pizhemsk titanium deposit, naph-thide­hydrogen titanium, Riphean, Vendian.