LANDSCAPE-GEOCHEMICAL REGIONALIZATION OF THE SELENGA RIVER BASIN

Abstract

A map of landscape-geochemical regionalization of theSelengaRiver basin(1:2,5 M) was compiled to study factors and processes of geochemical flows formation and modification. Traditionally the zonal approach is used for landscape-geochemical regionalization of vast territories, which takes into account the general parameters of biological cycle of matter and the classes of water migration. Within theSelengaRiver basinthe predominant relief of mountain depressions is combined with the complicated geological structure, varied lithogeochemical background, contrasting climatic conditions and several spectra of altitudinal zones. Therefore it is lithological-morphological factors governing the nature and trends of migration processes that became a principal criterion for identifying the main territorial units of landscape-geochemical regionalization of the basin. The system of landscape-geochemical regionalization of the basin includes three hierarchical levels with different criteria of identification. The both upper levels are of typological character and represent general physical-geographical conditions of geochemical migration processes. The units of the lower classification level were identified with the account of complex combinations of local conditions within the framework of general lithological-morphological and climatic prerequisites of migration, accumulation and input of matter into river systems. Combination of typological and regional approaches stems from a wide variety of natural conditions and geochemical migration features within the area under study. Methodological bases of regionalization may be of utility for the landscape-geochemical studies of mountain territories.