δ18O values for samples of recent syngenetic ice wedges and temperature parameters for Yamal Peninsula and adjacent regions and Russian Arctic Islands (from Vasil'chuk & Kotlyakov 2000 with additions).The oxygen stable isotope analysis was carried out in the Stable Isotope Laboratory of the Geography Department at Lomonosov Moscow State University, using a Delta-V mass spectrometer equipped with a standard gas bench. Oxygen isotope ratio was determined using equilibration techniques: samples for δ18О analysis were equilibrated with СО2 for 24 hours. For the measurements, international standards V-SMOW and international laboratory standards of the IAEA, as well as of the isotope laboratory of the Austrian Institute of Technology, were used. The precision of the measurements is 0.1‰.