Soil formation on derivatives of dense rocks of different composition in Transbaikalia

The soils on the eluvium of dense rocks of different ages, genesis and composition were studied in Transbaikalia. The ecological niches of the soils and their classification position were determined. Under humid conditions, in the permafrost zone under the larch taiga on the rubble-loamy derivatives of metamorphic effusive rocks, limestones, shales, and sandstones of the Cambrian, the profile of cryometamorphic coarse-humus podzolized soils are formed with a thickness of more than 1 m. The main pedogenic processes are claying, aggregation, coarse humus forming, podzolization and illimerization. Under the conditions of a semi-arid climate, deep and prolonged freezing, within the belt of dry pine forests, on the products of weathering of biotite granites, granodiorites, syenites of the early Paleozoic intrusions of the Vitimkan complex, the soil profile has a thickness of less than 0.2 m. The processes of sandification, siltization, inhibited humification with the formation of a brownish-gray horizon AY are developed in the soil. These factors and processes lead to the gray-humus lithozems forming. Under the arid climate conditions, deep and prolonged freezing within the cryoarid steppe belt, cryohumus lithozems are formed on the products of weathering of trachybasalts, subalkaline basalts and plagiobasalts of the Jurassic period, with the processes of siltization, sandification, denudation, humification, and the formation of a chestnut horizon AK of the reddish tone.