Saline soils of the Barguzin basin as an object of the red book of soils of the Baikal rift zone

On the North-Eastern flank of the Baikal rift zone in the Barguzin basin saline soils unusual for this natural area are formed. Some of them have no analogues among known soils on a global scale and differ in a number of new diagnostic features: the presence of ascending intra-soil injection intrusions (open and closed diapirs) from the material of underlying soils, as well as previously not encountered and not described in soil classifications impregnated with oil bitumen horizons. The area of localization is confined to the Kuchiger thermal field (Ulunkhan depression) and to the sandy upland “Nizhniy Kuitun”, within which the central elevated part with saline solonetzic soils and the drainless basin of the saline Nukhe-Nur lakes with quasi-gley solonetzic soils are separately distinguished. These unique soils were formed during hydrothermal and gas-fluid discharge of water, gas and mineral substrate from seismically active faults of the earth’s crust. As a result of the processes of endogenous input of matter and energy instead of the typical horizontal and sub-horizontal layers strongly inclined or vertical morphons are formed that are not typical for soils. Also there is a manifestation of turbulence, impregnation with oil bitumen, gleyzation and salinization. The most active effect of endogenous factors on soils is manifested within the Ulunkhan depression in the area of Kuchiger hydrotherms, the less expressed - in deep drainage basins of Nukhe-Nur lakes. Presumably, the fluid unloading and salt input took place at the elevated point of “Nizhniy Kuitun” sand massif, where solonetzic soils were found in the absence of salts in the soil-forming substrate and the routes of entry from other known sources. These soils show geochemical affinity as in salt content and salinization chemistry, so in material composition with characteristic elevated or abnormal gross concentrations of a number of elements. In the studied soils the “classical” manifestations of alluvial, floodplain, metamorphic, and organic-accumulative processes are poorly expressed or completely erased, and the system of genetic horizons typical of zonal soils is not expressed at all. These unique highly saline soils with a contrasting combination of pH values, texture, salinity, impregnation with petroleum bitumen, and profile turbations are unique markers of endogenesis activity. It is proposed to attach these soils to the number of soils included in the category of rare and unique and to give them the status of specially protected soils formed under a special combination of endo- and exogenous soil formation factors. We recommend including the saline soils of the Barguzin depression considered in the article in the Red Book of Soils of Russia.