AMS radiocarbon ages of organic matter from ice wedges and enclosing peat were determined for the polygonal
peatland at the Lorino site on the eastern coast of the Chukchi Peninsula. The study’s goal was to fill a knowledge
gap about the dynamics of polygonal peatlands with ice wedges and winter climate conditions during the Holocene
in this easternmost region of the Russian Arctic. It has been found that peatland accumulated during the Younger
Dryas and early Holocene, mostly between 14 and 9.9 cal ka BP, while ice wedges were dated from 7.7 to 6.6 cal ka
BP. Since ice wedges have features of syngenetic growth, the discrepancy in the age of ice wedges and enclosing
peatland may result from the significant presence of early and pre-Holocene peat. It is assumed that the older
polygonal peatland deeply thawed during the Holocene optimum, and subsequently, when the permafrost aggraded,
a new generation of ice wedges was formed. The AMS 14C age (18.1 cal ka BP) of the ice wedge exposed below the
peat indicates the presence of a Late Pleistocene generation of ice wedges at the study site. Paleotemperature
reconstructions based on the stable isotope composition of ice wedges show that the mean January air temperature
during the Northgrippian stage of the Holocene varied from –27 to –23°C, and at the end of the Late Pleistocene,
from –32 to –26°C.

Kuzyakin L.P. .