Reconstruction of the mean January air temperature in the Early Holocene on the eastern coast of Chukotka

• Published in: The Canadian Field-Naturalist
• Main Authors: N. Budantseva A., A. Maslakov A., Yu. Vasil’chuk K., A. Vasil’chuk C., L. Kuzyakin P., Н. Буданцева А., А. Маслаков А., Ю. Васильчук К., А. Васильчук К., Л. Кузякин П.
• Other Authors: This work was supported by the Russian Foundation for Basic Research (grant no. 20- 05-00782, stable isotope analysis), the Development program of the Interdisciplinary Scientific and Educational School of M.V. Lomonosov Moscow State University “Future Planet and Global Environmental Change” and state budget theme 1.4. “Anthropogenic geochemical transformation of the components of landscapes” (Center for Information Technologies and Systems number 121051400083-1)., Работа выполнена при поддержке РФФИ (грант № 20-05-00782, изотопные определения), в рамках Программы развития Междисциплинарной научно-образовательной школы Московского государственного университета имени М.В. Ломоносова “Будущее планеты и глобальные изменения окружающей среды” и госбюджетной темы 1.4. “Антропогенная геохимическая трансформация компонентов ландшафтов”, № ЦИТИС 121051400083-1.
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: IGRAS 2023
• Subjects: ice wedges;eastern Chukotka;peatlands;oxygen isotopes;hydrogen isotopes;Holocene;paleotemperature reconstructions;radiocarbon age; повторно-жильный лёд;восточная Чукотка;торфяники;изотопы кислорода;изотопы водорода;голоцен;палеотемпературные реконструкции;радиоуглеродный возраст; Anadyr; Anadyr’; Lorino; Uelen; Anadyr'; Chukotka; Ice; permafrost; Permafrost and Periglacial Processes; wedge*; ЧУКОТКА
• Online Access: https://ice-snow.igras.ru/jour/article/view/1154; https://doi.org/10.31857/S2076673423010039

The investigation is concerned with the Early Holocene syngenetic massive wedge ice exposed in the outcrop of a polygonal peatland in the upper part of the third marine terrace near Lorino settlement on the eastern coast of Chukotka. Based on the obtained radiocarbon dates of peat, it was found that the formation of a peatland in the area began about 14–13 cal ka BP, at the end of the Younger Dryas, while the termination of the active stage of peat accumulation was dated to about 10–9 cal ka BP. The beginning of peat accumulation at the end of the Younger Dryas, earlier the officially accepted limit of the lower boundary of the Holocene (11.7 cal ka BP), and the termination of its formation by the middle of the Greenlandian Holocene period is not a rare phenomenon in Russian permafrost zone, although it is traditionally assumed that the most active formation of peatlands has been going on during the thermal maximum in the middle of the Holocene. The age inversions noted in the peat vertical profiles are the most likely indicative of the processes of re-deposition of ancient organic material due to erosion by water of the third marine terrace sediments and the separation of the allochthonous peat. During the period from 2015 to 2021, six fragments of peatland exposures with the ice wedges were studied. Analysis of the obtained data on the content of stable oxygen isotopes in the ice show that δ18О values vary within the range from –15.5 to –18‰. These values are in good agreement with the data for Early Holocene ice wedges earlier obtained in other areas of the eastern coast of Chukotka (Anadyr town, Uelen settlement), where authors report the δ18O values from –16 to –19.4‰. This suggests that the ice wedge growth as well as the peat accumulation were the most active in Early Holocene. The highest δ18О values (from –13.1 to –16.8‰) were obtained for the modern ice veinlets. The ratio δ2 H–δ18O in the ice wedges, in general, is indicative of a good preservation of isotope signature of winter precipitation. It has ...