The high-resolution oxygen isotope diagram of late Pleistocene ice wedges of Seyaha yedoma, Eastern Yamal Peninsula

The main objective of this work is to study the oxygen isotope composition of late Pleistocene syngenetic ice wedges and to obtain a high-resolution isotope diagram from a carefully sampled outcrop of Seyaha yedoma within of the third lagoon-marine terrace near the Seyaha (Zelyonaya - Green) river mouth, on the bank of the Ob Bay. According to 3 new radiocarbon ages: from 25.2 to 23.3 kyr BP from +2 to +5 m a.s.l., as well as dates: 17.3 kyr from +18.8 m a.s.l. and 11.6 kyr BP from +21.2 m a.s.l., the age of the ice wedge is from 23 to 15 to 18 kyr BP approximately. Values of δ¹⁸O in the upper fragment of the ice wedge vary from -25.75 to -3.15‰. Horizontal variations of δ¹⁸O values at a height of +15.2 m amounted to 1.49‰, from -23.41 to -24.9‰. The ice of the lower fragment of the ice wedge, at +6 m a.s.l., is characterized by a wider range of δ¹⁸O values than in the upper fragment. The horizontal values of δ¹⁸O range from -23.41 to -26.63‰.  The obtained oxygen isotope diagram in the upper fragment of the ice wedge has resolution of 80-100 years. According to palaeoreconstruction the average January temperature 23-15 (18) kyr BP ranged from -35 to -39 °C.