Fluorine in waters and soils of the Ulyunkhan depression (Baikal rift zone)

The article presentes primary data on fluorine activity in saline soils of the Ulyunkhan Depression’s tectonic fault zones (northwestern part of the Barguzin Basin). It has been revealed that the activity of fluorine ions varies in a very wide range from 0.02 to 112.20 mmol / L. The high activity of F ions is mainly represented at the evaporation barrier. Abnormally high rates are observed in the surface salt crusts. Fluorine activity inside the soil profile depends on the reaction of the media. The lowest values of aF are confined to the soils of wetland with acid reaction. aF increase in soils of alluvial elevation arises in horizons with more alkaline conditions. The fluorine ions are introduced due to the latent intra-profile gas-hydrothermal activity of the Kuchiger springs, which is carried out through tectonic cracks and faults and has a pulsating character.