Barrier biogeochemical

zone of the sharply raised concentrations of these or those chemical elements as contrasted to their average contents in a given landscape (landscape clarke). B.b. arises, as a rule, in a zone of contact between elementary landscapes, biomocenosises (facies), distinguished by physical (e.g., filtration), chemical (distinction of oxidation-reduction, acid-alcalinous conditions) or biological (fissile activity of particular groups of micro-organisms) properties.