Geochemical Features of Cryogenic and Al–Fe-Humus Soils of Mountainous Taiga in Northern Mongolia

Abstract

Geochemical features of permafrost-affected (Folic Protic Leptic Cryosols, Histic Protic Leptic Cryosols) and Al-Fe-humus soils (Folic Leptic Entic Podzols, Histic Leptic Entic Podzols) have been studied. These soils are widespread in taiga forests of Khentei, Eastern Sayan, and Khangai mountains. Data on the microelemental composition of parent rocks are given. The dispersion coefficients of most of the studied microelements in parent rocks relative to the lithosphere exceed 1.0, which indicates the predominance of processes of material removal. Differences in the concentrations of microelements in soils largely depend on the texture of parent rocks. Data on the morphology, physicochemical and chemical properties of soils and on the distribution of microelements in the soil profiles are discussed. The studied soils differ both in the absolute contents of microelements involved in the biological cycle and the intensity of their biogenic migration. The intensive biogenic migration of elements results in their accumulation in organic and raw-humus soil horizons and in the accumulative patterns of element distribution in the soils of the altitudinal zones of forest vegetation. In contrast to Cryosols, the organic and raw-humus horizons of Entic Podzols are characterized by a less intensive accumulation of microelements. In the Al–Fe-humus (spodic) horizon of Podzols, the concentrations of Pb, Cr, Mo, and B are above the clarke level. Spodic horizons of the studied soils act as chemosorption geochemical barrier for some biophilous elements and elements of the iron group.