The object of research is organic-mineral deposits of the Late Pleistocene polygonal ice-wedge complex. They are studied in the outcrop of the second terrace, located on the left bank of the Mongatalyangyakha River, 3 km west of the estuary (71 ° 58'60 "N, 75 ° 16'0" E), on the Yavai Peninsula in the north of the Gydan Peninsula. The botanical composition of allochthonous peat in the upper part of the section is dominated by the remnants of Ledum palustre, and in the organic-mineral sediment the remains of Drepanoladus fluitans, Calliergonella cuspidata (or Calliergon cordifolium) are prevailed. A field outcrop study was performed, three wells were drilled. Palynological and hydrochemical diagrams were constructed and the radiocarbon age of the Late Pleistocene polygonal massif was determined. The main conclusions of the study are:1. The age of the organo-mineral deposits varies from 30,200 to 21,900 years BP.2. The rate of accumulation of organo-mineral deposits in the Karginsky time at the mouth of the river. Mongatalyangah is about 0.25 mm / year.3. According to the palynological analysis, three local pollen zones are distinguished.

Data was submitted and proofread by Yurij K Vasil'chuk and Lyubov Bludushkina at the faculty of Geography, department of Geochemistry of Landscapes and Geography of Soils, Lomonosov Moscow State University.