DOI: 10.7256/2453-8922.2018.3.25807

Abstract: The object of this research is the epicryogenic sands developed in the territory Russia. They are located in all parts of the permafrost zone, but mostly concentrated within the ancient and young platforms. At the same time, within the zone of compact spreading of permafrost rocks, epicryogenic sands are often covered with syncryogenic sediments; and in the zone of joint spreading of thawed and frozen rocks are embedded in the surface. Sands of this type occur as part of glacial, aqueoglacial, glaciolacustrine, marine, alluvial-marine, glacial-marine, lacustrine-alluvial, alluvial and eolian genetic units of quaternary deposits. In certain districts, the epigenetic permafrost sands are identified as a part of the ancient pre-quaternary formations. In the Timan-Pechora platform it is the terrigene gray-colored formation of the Middle Jurassic-Lower Cretaceous; in the Western Siberia – the terrigene lignite-bearing Oligocene; in the Khatanga trough – the terrigene of Upper Cretaceous and Jurassic-Lower Cretaceous, as well as the coal-measure of the Upper Cretaceous. Within the limits of Vilyuy syneclise and Predverkhoyansk foredeep, the epicryogenic sands are confined to the molasse of Lower and Middle Jurassic, coal-bearing formations of Upper Jurassic–Lower Cretaceous, terrigene formations of Upper Cretaceous and Neogene. In the territories of folded mountain constructs, epicryogenic sandy soils are meagerly developed in hollows and river valleys as part of alluvial, lacustrine-alluvial, aqueoglacial and eolian quaternary complexes.

DOI: 10.7256/2453-8922.2018.3.27019

Abstract: The object of this research is the permafrost sandy soils of Eastern Siberia. Their age range spans from the Mesozoic through the Holocene. The pre-quaternary permafrost sands are developed within the limits Vilyuy syneclise and Khatanga trough, and fall into the epicryogenic category. The quaternary sands are composed of aqueoglacial, glaciolacustrine, marine alluvial-marine, eolian, lacustrine-alluvial and alluvial genetic units. In the northern districts, the syncryogenic soils usually compose the upper part of the cutoffs of these units, while underlying the epicryogenic soils. In central and southern districts, the epicryogenic sands are often embedded on the surface. The study of archive and published materials allowed revealing and generalizing the peculiarities of composition, structure and characteristics of permafrost sands of the platform and mountain territories of Eastern Siberia. It is noted that their granulometric composition extensively varies – from gravelly to silty types. The higher is the sand dispersion, the higher is their natural moisture and porosity factor, and the lower is the density of soil and soil skeleton. The fine and silty sandy soils often have a schlieren cryogenic structure, significantly settle during thawing and frequently develop into the running sands. The larger sands have a predominantly massive cryogenic structure, and settle insignificantly during thawing.