The subject of the study are Late Pleistocene and Holocene ice wedges exposed near Chersky settlement, lower Kolyma River, and in the yedoma of the Stanchikovsky Yar on the Maly Anyuy River. In the yedoma of the Stanchikovsky Yar, multi-tiered syngenetic ice wedges were exposed at different levels - from 10 to 35 m above river level. Ice wedge in the lower tier was sampled in detail. In the yedoma near Chersky relatively small fragments of ice wedges up to 1.5 m wide and up to 2 m high were exposed. 1.5-2 km from Chersky settlement within the lacusrtine-paludal depression Holocene ice wedges were exposed. Ice wedges in these three sections was sampled to clarify the geochemical conditions of their formation. It is shown that concentration of Na+, K+, Mg2+, Cl- and SO42- in Holocene and Late Pleistocene ice wedges is very low and mean values do not exceed 5 mg/L. The highest values were obtained for Ca2+, which corresponds to the predominance of this ion in the modern snow of Yakutia and indicates that ice wedges were formed mainly from melted snow. Rather high values of NO3-, reaching 14-27 mg/L, are quite likely due to the swampy environment within polygonal landscapes, where organic matter of both plant and animal origin is decomposed. For comparison, in the water of the Kolyma and Maly Anyu rivers, concentration of nitrates is quite low and does not exceed 0.3 mg/L.

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.The ionic composition of ice was determined on a Stayer ion chromatograph by ion chromatography in the laboratory of the Ecological and Geochemical Scientific and Educational Center of the Department of Landscape Geochemistry and Soil Geography, Faculty of Geography, Lomonosov Moscow State University. The detection limit for the chloride ion was 0.02 mg/l.# = mean values