Influence of Thermodenudation on the Formation of Synlithogenous Soils and Ecosystem Development in the Permafrost Zone

The major part of soil cover in the permafrost zone develops under the influence of cryogenic slope processes. Most significantly soil structure on relatively steep slopes and in permafrost-affected ecosystems, where thermocirques and thermoterraces form, is influenced by processes of thermodenudation and thermoerosion that lead to irreversible background soil profiles and underlying soil-cryogenic complexes frozen layers destruction, and to development of the specific synlithogenous soils – thermodenudationally-accumulated stratozems. Structures, properties, formation processes, and areas occupied by such soils are poorly studied. The mixed organo-mineral substrate, recently processed by soil formation, and now transporting into the thermocirque or thermoterrace floor via slumping and further lateral matter redistribution, here acts as the soil-forming material. The principal scheme of thermodenudationally-accumulated stratozems formation and development was suggested during fieldworks in North-Eastern Yakutia and Central Yamal peninsula. It includes 4 main stages, each of that is characterized by a combination of soil-forming material and vegetation cover properties. Stages could change each other consequently or recur cyclically in case of thermodemulation processes reactivation. The specificity of development, accumulation, and soil-forming material procession, made it possible to suggest the new "thermodemudationally-accumulated" sub-type to be distinguished in stratozems order in the further version of Russian soil classification system. Studied ecosystems in thermocirque's and thermoterrace's present the significant interest for further research as biodiversity hearths, areas of potential permafrost new-formation, paleo-archives, and possible carbon sequesters.