Ziultsle O. Geochronologe suture zone Rosʼ-Tikich and Dniester-Bug megablock Ukrainian shield

The thesis is deals with determination of the age and conditions for the formation of structurally complex material of the Dniester-Bug and Rosʼ-Tikich megablocks within the northern part junction zone articulation based on isotope-geochemical studies of zircons and monazites. Tectonic boundary between the Dniester-Bug and Rosʼ-Tikich megabloks, in the northern zone of the junction, is Brusiliv seam zone. Petrographic study of metamorphic rocks both megabloks detect a number of mineral reactions that reflect the sequence of transformations of rocks formed under conditions granulitic facies in their diaphthoresis varieties. The existence diaphthoresis granulitic infrastructure within the western part Rosʼ-Tikich megablock, are confirmed by the presence in the area zircons isotopic age reaches 2,97 billion years. U-Pb isotopic method was used to date zircons and monazites sampled from the metamorphic and ultra-metamorphic rocks of Rosʼ-Tikich megablock within the northern part of Dniester-Bug and Rosʼ-Tikich megabloks suture zone. It was found that the isotopic age of zircons and monazites is 2.04—2.1 billion years. On the basis of assumption that the monazites occurrence in the mineral paragenesis of these rocks is connected with their kalifeldspatization at the final stage of formation, the monazites determined age reflects the kalifeldspatization processes development. These processes are synchronous with formation of Dniester-Bug megablock structural and substantial complexes and connected with the wide occurrence, within the Rosʼ-Tikich megablock, of palingenic and metasomatic processes which stipulate diaphthoresis of the megablock Archaean infrastructure and occurrence of feldspathic hydride "polmigmatite" and plagioclasetartan-pattern granitoids.