The study presents new data on the cryolithological structure of a ridge-shaped peat plateau typical for the north of Western Siberia, located in the lower reaches of the Nadym River. Two wells were drilled at the top of the ridge and in the inter-ridge depression, with subsequent core analysis. Grain size distribution, shape and surface structure of sand quartz grains, botanical composition and radiocarbon age of organogenic deposits were determined. The study revealed the presence of a three-layer peat-sand-loam ridge structure. The lower loam layer with a ~60 % volumetric ice content was affected by frost heaving. Layers of pure ice are identified below this loam layer. The ridge was formed as a result of water migration with the complementary influence of ice injection; it is of the peat-mineral type. In the ridge formation history, we identified the stages of loam and sand deposits accumulation at the end of the Late Pleistocene; bogging occurred at the beginning of the Holocene (10.6-9.8 ka BP), while active frost heaving was during the Subboreal stage (5.5-5.0 ka BP). Currently, there is a decrease in the upper organic horizon thickness and some erosion. It is proposed to consider peat-mineral and mineral frost heave landforms (mounds and ridges) as separate type of cryogenic landforms.