Possible Conditions and the Formation Time
of the Chukchi Plateau Pockmarks

A. S. Astakhov^a, V. S. Markevich^b, A. N. Kolesnik^a, Wang Rujian^c, V. V. Kononov^d,
M. S. Obrezkova^a, and A. A. Bosin^a

^a Il’ichev Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences, Russia

e-mail: astakhov@poi.dvo.ru

^b Institute of Biology and Soil Science, Far Eastern Branch, Russian Academy of Sciences, Russia

e-mail: markevich@ibss.dvo.ru

^c Tongji University, Shanghai, China

^d Far Eastern Geological Institute, Far Eastern Branch, Russian Academy of Sciences, Russia

e-mail: kononov46@mail.ru

Received February 7, 2013; in final form, July 27, 2013

Abstract—The study of the bottom sediments accumulated during the last 60–65 ka in the pockmark craters
of the Chukchi Plateau in the Arctic Ocean showed that their composition and lithostratigraphy in general are
similar to those of the background areas. A specific feature is the presence of sedimentary interlayers and hori-
zons with signs of gravitational stirring, carbonate mineralization, and accumulation under H₂S contamination
conditions. The micropaleontological remains found in the pockmark sediments accumulated during the glacial
periods are represented by redeposited species from Paleozoic, Mesozoic, and Cenozoic deposits, which are
locally exposed in the pockmark walls. It was concluded that the pockmarks were formed under the influence
of pulsed fluid flows. The present-day topography of the pockmarks was formed at the last stage of active deflu-
idization (35–20 ka ago).

DOI: 10.1134/S000143701404002X

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