A new data on the isotope composition of oxygen (δ18О) and hydrogen (δD) of the ice-wedge ice in central Yamal Peninsula near Bovanenkovo gas field are presented. In the summer of 2019, ice wedges in the thermal circus of the third sea terrace was studied. On the terrace surface a polygon size of about 10-20 m is widespread. The ice wedge № 1 had a width in the upper part of 1.5, the apparent depth in exposure was 2.3 m. The ice wedge № 2 was stretched perpendicular to of the ice wedge № 1 and had a width of about 60 cm. A fragment of ice wedge № 3 in longitudinal section was opened 20 m from the ice wedges. Age of ice is established by AMS dating to be 13.6 cal. BP. The isotopic signature of ice (average δ18О and δD values were -24.8 and -187.6 ‰ respectively), corresponds to ice-wedges of the Yamal Peninsula formed during the MIS-2 isotope stage (end of Late Pleistocene). The oxygen isotope composition of ice indicates temperatures of the cold period of wedges formation around -22.8 ÷ -26.8 ⁰С (on average 7 ⁰С colder than modern), and January temperatures from -34.2 ÷ -40.2 ⁰С (on average 10 ⁰С colder than modern). For some ice samples, high values of deuterium excess were noted (from 12 to 17 ‰), which is unusual for this type of ice.

The analysis of the isotopic composition of oxygen and hydrogen was carried out in the Isotope laboratory of the Russian University of Chemical Technology by DI. Mendeleev on the Los Gatos Research Triple-Liquid Water Isotope Analyzer (LGR T ‑ LWIA, Model 912-0050). International standard V-SMOW was used for calibration. The error of determination is ±0.1 ‰ for δ18О and ±1 ‰ for δD.