Magnetic Susceptibility of Soils in the Southern Circuit-Baikal Region under the Conditions of Paleocryogenic Hummocky-Depression Microrelief

Magnetic susceptibility methods are widely used as effective and sensitive express methods for establishing soil genesis and evolution and their diagnostics. At the same time, there is absolutely no information on the magnetic properties of soils in the Southern Cis-Baikal region. The paper considers the magnetic susceptibility (MS) of gray metamorphic soil and clay-illuvial chernozem (on hummocks) located in the conditions of paleocryogenic hummocky-depression complex with gray- and dark-humus stratozems (in depressions). It is established that the values of specific magnetic susceptibility confirm the weak textural differentiation of the gray metamorphic soil profile associated with the attenuation of the podzolic process. Low values of magnetic susceptibility in clay-illuvial chernozem and their sharp drop with depth are caused primarily by a decrease in humus content, a decrease in the acidity level, and an increase in the amount of carbonates in the parent rock. Under conditions of paleocryogenic microrelief, magnetic susceptibility is noticeably higher in the buried humus horizon of the forest landscape depression soil compared to the modern horizon, which indicates a clear change in soil formation conditions and processes. On the contrary, no such changes have been found in dark-humus stratozem: magnetic susceptibility values show the same values in the modern and buried humus horizons. The dependences of this indicator on such soil properties as specific electrical resistance, soil acidity, content of humus, exchangeable cations, carbonates, silt, physical clay, total iron, and soil age have been revealed.