Earth’s Cryosphere, 2010, Vol. XIV, No. 4, p. 3-16

VALIDITY OF THE YOUNGEST RADIOCARBON DATES IN SYNCRYOGENIC PERMAFROST

Yu.K. Vasil’chuk, A.C.  Vasil’chuk

Lomonosov Moscow State University, Department of Geography and Geology, 119991, Moscow, Leninskie Gory, Russia, vasilch@geol.msu.ru, alla-vasilch@yandex.ru

Developed strategy of the most authentic radiocarbon date selection in dating syncryogenic sediments takes into account the fluvial origin of the predominant part of syncryogenic strata (such as marine, alluvial, lacustrine), good proservation of organic material in permafrost conditions and the numerous reburials of the fossils from ancient deposits into younger ones. Contemporary redeposition of organic material is examined under the conditions of subaqueous syncryogenic sedimentation together with the possible redeposition of organic material in subaeral or subaeral-subaqueous conditions. The advantages and the complications of dating of organic microinclusions from ice wedges by the method of accelerating mass spectrometry are discussed. It is shown that the results of accelerating mass spectrometry ¹⁴C dating depend on the difference in the weight of dated samples.
Comparison of radiocarbon dates of different organic materials from the same samples is fulfilled. The large set of ¹⁴C dates from cross-sections of Duvanny Yar in the Kolyma River and Mamontova Khayata in the Lena River mouth is critically analyzed. The younger age of these ice wedge complexes is substantiated.

Key words: Syncryogenic strata, permafrost, ice wedge, radiocarbon dating, Siberia.

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