Dubyna O. Petrology of alkaline rocks of the Dnister-Bug area (Ukrainian Shield)

The dissertation is devoted to the geological structure, peculiarities of chemical composition of main rock types and minerals, geochemical characteristic and petrogenesis of alkaline ultrabasic and potassic rocks of the Dnister-Bug area in the Ukrainian Shield. The peculiarities of mineral composition can be evidences on abyssal conditions of formation and significant erosion cut of alkaline ultrabasic massifs. Some geochemical peculiarities of these rocks, especially low contents of Ti and some rare incompatible elements (Nb, Ta, Zr) can testify to collision condition of formation of these massifs. The distribution of trace elements in main rock types and chemical composition of rock-forming minerals denote on principal role of liquation and termodiffusion mechanism during crystallization of alkaline ultrabasic massif. The prospects of the alkaline rocks of the Dnister-Bug area for a search of apatite, nepheline and other deposits are also considered.