Chechetko E.S., Churilin N.A. The properties and the mineralogical composition of dark-humus quazi-glei solonchak solonetzic cryoturbed cryosols of BarguzinHollow (Buryatia)

Morphological, physical-chemical properties, texture, salt composition mineralogical composition of the particle-size fractions 5 mkm of dark-humus quasigleyic solonchakous solonetzic cryoturbated deeply permafrost loamy-sandy soil developed from alluvial sediments (Salic Mollic Reductaquic Turbic Cryosol (Eutric, Loamic, Calcaric, Fluvic, Sodic)) are presented. The soil is situated at the northern-eastern part of Barguzin Depression in the impact zone of dumping of nitrogen siliceous thermal underground waters of Kuldur type (Kuchiger springs). The soil forms from materials of disintegration of high-content-potassium calcareous-alkali granites of Barguzin complex of Angara-Vitim Batholith. It was found soil salinity of weak to very strong degree, presumably sulfate-sodium with gypsum. There is a net of gypsum filaments in the solum that is observed by morphological analysis. Low amount of rectorite was found in clay fraction of undisturbed layers of alluvium at the depth of 54-145 cm in the studied soil profile. Regular structure of rectorite comprised mica (A) and smectite (B) packets with alternation motive ABAB… is transformed into irregular structure of mica-smectite interstratifications by impact of soluble sodium salts and cryoturbation of soil material in soil horizons at the depth of 0-54 cm formed from the alluvium. Regional peculiarity of studied soil is small shear of quartz in silt and sand fractions that is a result of mineral composition of biotite and amphibole-biotite granites and granitoids. Irregular mica-smectite interstratifications with high shear (>50%) of smectite packets are destroyed by impact of sodium sulfate and hydrocarbonates hydrogenic accumulation in the solum and are partially illuviated into middle part of soil profile with formation of humus-clay cutans on the lateral sides of aggregates by infiltration of rain waters. Existence of humus-clay cutans is an evidence of weak degree of solonetzic process.