Morphology of Soils in the Impact Zone of Kuchiger Hot Springs, the Barguzin Depression

Abstract

First data on the specific morphology and physicochemical properties of soils forming in the zone of active discharge of ascending solutions of deep thermal water of Kuchiger hot springs of the fluoride hydrosulfuric bicarbonate–sulfate–sodium type are presented. The soil cover was studied along the transect crossing the mire with active gas hydrothermal griffons, an island within the mire, and the adjacent margin of alluvial plain in the northwestern part of the Barguzin Depression near the village of Kuchiger, Kurumkan district of the Buryat Republic. The features of peat–mucky gley soils (Eutric Rheic Sapric Histosols (Fluvic, Sodic)) predominating within the mire are described. The profiles of weakly developed and alluvial soils (Eutric Sodic Gleyic Fluvisols (Epiloamic, Endoarenic, Humic)) forming under the impact of ascending gas hydrothermal fluids bear the features of turbation and impregnation with condensed organic matter in their mineral and organic horizons. These features are not included in the international and Russian soil classification systems. It is suggested that they should be diagnosed and indicated by symbols imp (various degrees of impregnation), int (intruded material), and IMP (black sandy–silty horizon strongly impregnated with condensed organic matter). The inclusion of these features into the list of diagnostic properties allows us to specify impregnated and hydrothermally turbated soil subtypes in the new Russian soil classification system. Hypotheses of the genesis of soils along the entire transect and the appearance of islands within the mire massif are suggested.