The Role of Cryogenic and Cryopedogenic Processes of the Past in the Formation of Al–Fe–Humus Soils in the Nadym–Pur Interfluve, Northern Western Siberia

The Al-Fe-humus soils in the Nadym–Pur interfluve (Novy Urengoy) are considered: Albic Podzols and Entic Podzols. The soils are formed on the sedimentation matrix of Karginsky alluvium, prepared in the Sartan time by low-temperature cryogenesis. The studied profiles are classified as podzoles of illuvial-ferruginous deep podzolic lingual cryoturbated sandy and illuvial-ferruginous podbours. Cryoturbation of Albic Podzols is associated with ongoing processes in the seasonally frozen layer, and a feature of their development is the formation on well-drained sandy terraces with polygonal-block surface relief created in the period preceding podzol formation – during the emergence and removal of Sartan polygonal-wedge ice. Currently, this relief is represented by gentle polygons with sides of 8–12 m, separated by depressions along the axes of pseudomorphoses along the former polygonal-vein ice. The height difference between such areas reaches 1 m, snow accumulates in the depressions, the substrate in them becomes more moistened and washed, and the Albic Podzols form elongated tongues, the most elongated within the illuvial horizon. The combined average thickness of the eluvial and illuvial horizons is about 50 cm, but languages are embedded in pseudomorphoses at a depth of 2–3 times more. It is assumed that this is not a factor of cryogenic transformation of podzols, but rather their inheritance of previously formed cryogenic structures. Lying on Sartan paleocryogenic relics and related cryohydromorphic paleosols, Albic Podzols began to form 7–8 thousand years ago. The Al-Fe-humus soils partially erase the evolutionary history of previous pedogenesis, the relics of which can be embedded in them. Such incorporation endows modern soils with features that can be taken as an indicator of a different type of soil formation.