The authors have attempted to identify the genesis and paleo‐geographical conditions prevailing during formation of the icy sediments of northeastern Yakutia on the basis of a study of two sections in the Omolon valley. Both sections represent alluvial sediments displaying considerable variety in terms of facies; details of cryogenic structure, granulometric composition, mineralogical composition, and chemistry are presented in each case. Palynological studies revealed the presence of a moss‐grass tundra on the floodplains and a more xeric flora on the interfluves. An innovative feature of this study is the use of fossil beetle remains, in combination with palynology. Taken in combination they reveal extensive areas of cryoxeric steppe‐tundra on the interfluves, involving well‐drained areas with a sparse vegetative cover; cushions ofDryason a gravelly or sandy substrate were dominant. Overall the vegetation strongly resembled the present mountain tundra of the Chaun area and Ayon Island. July temperatures were around 12–15°C, i.e., higher than at present; soil surface temperatures in July were in the range 16–20°C, and the relative humidity was 50% or lower.