GEOCHEMICAL TYPES AND ORE CONTENT OF CRUSTS OF WEATHERING

The carbonatite crusts of weathering are considered as an unique ore-concentrating geochemical system and one of the most ore-bearing rare-metal ore formations. This formation is heterogeneous and subdivided into some geochemical types differing in the manner and intensity of ore-concentrating processes. Type weathering profiles are given for the basic geochemical types of crusts of weathering forming in different facial conditions. Stability of minerals, mobility of components, compositions of weathering products have been considered for every crust type, the basic ore-concentrating factors have also been studied. The geochemical crust types and weathering profiles considered describe all the range of conditions of deposit formation in the carbonatite crusts of weathering and control spatial and genetic location of the main ore types peculiar to this ore formation.