Gas-Hydrothermal Turbation of Soils as a Factor of Microhighs Forming

Ridges and tussock-like microhighs of unknown genesis were discovered in the northern part of the Barguzin Depression within the area of Kuchiger hydrotherms along the periphery of mires and within slightly concave surfaces of the alluvial plain. The classical mechanism of the formation of tussocks in herbal mires is replaced by a diapiric heave under the pressure of ascending gas-hydrothermal fluids from seismically active deep faults. The morphology and some properties of the soils in the transitional area from the mire with active hydrothermal griffons (vents) of the Kuchiger Hot Springs to the alluvial plain. In this area, the microtopography of the surface is represented by the chains of microhighs against the background of a network of microvalleys. Empirical statistical cumulative distributions of the morphometric characteristics of this microtopography have been obtained. The studied microhighs form a genetic series of gas-hydrothermally turbated soils: from organic soils with minimum intrusions of sandy material along the periphery of the mire to predominantly mineral variants represented by the extruded upwards gley horizon of different oxidation degrees on the alluvial plain.