Clays of yedoma suite

The subject of the study is the permafrost strata composed of clayey soils, sandy loams, and loams. It has been shown that the layers of the permafrost complex are usually made up of ice-rich, dusty, sandy-loamy soils. However, they are often represented by ice-rich sandy, sandy-gravel, and even gravelly soils. The definition of permafrost layers is provided. Permafrost is characterized by high ice content (containing more than 50-90% ice), generally rich in organic material (containing more than 1-2% organic matter), silty and dusty sandy and fine sandy late Pleistocene deposits; in intermountain basins and on slopes, permafrost layers can be saturated with loam and gravel, while in river valleys and deltas, they may contain gravel and rock debris. The age of permafrost layers varies from 12 to 50 cal. ka BP. Permafrost deposits contain massive (up to 15-20 m high and more), often multilevel, cyclically arranged, syngenetic ice wedges. Exposed permafrost deposits typically emit a specific "old stable" odor due to decaying organic matter. The research methodology consists of a detailed review of the permafrost layers studied by the authors and colleagues. Permafrost with coarse clastic material has been found north of 80° N and in the south in the Western Sayan and Transbaikalia south of 55° N. The most interesting sections, studied by the authors in northern Russia, are the sections of the permafrost complex mainly composed of clayey, loamy, and sandy soils, exposed in the ice wedge complex at the Seyakha village (height over 20 m), permafrost outcrop at the Zelyony Mys village (exposure height over 40 m), the Duvanny Yar outcrop (height about 55 m), the Bison outcrop (up to 15 m high), Stanchikovsky Yar outcrop (height about 35 m), the Batagay megaslump (height over 75 m), and in the valley of the Mayn River. It is particularly emphasized that in Western Siberia, permafrost layers have been studied in the Yamal Peninsula in the Seyakha Late Pleistocene syngenetic yedoma suite, with heights ranging from 22 to 24 m.