INTEGRAL-DIFFERENTIATED PALOGEODYNAMICS OF THE NEW UKRAINIAN GRANITE-GNEIS DOME OF THE UKRAINIAN SHIELD

Abstract

The article discusses the results of comprehensive studies of the integral and differential geodynamics of the Early Proterozoic Novoukrain-skyi granite gneiss dome, which does not have its own petrological, parametric and specialized analogue on the Ukrainian shield. A feature of this geostructure is a large-scale formation of rheomorphic (on ancient granitoids) coarse-porphyroblastic granites (Novoukrainskyi) within its limits, as well as granitization of the gneiss formation, represented here by the Checheliiv suite of the Ingul-Inguletsk series and the stone-Kostuvatska suite of the Buh series. The formation of a powerful gravitational minimum as a result of granitization processes led to an intense uplift of granitized rocks and the pulling into the uplift of adjacent non-granitized rock complexes. Based on a comparison of reference dates - the completion of the crystallization processes of Novoukrainskyi granites and the formation of uranium ore industrial concentrations, in the apogranite and apogneiss albitites, equal to the pre-ore and post-ore denudation sections of the Novoukrainskyi dome were determined. The migration of the apical part of the dome, associated with tectono-magmatic activation of the Hercynian era, was traced. The tectonic activation of the Novoukrainskyi granite-gneiss dome in the Cenozoic was investigated, the depths of the denuda-tion section of its constituent structures were determined, and the safety of the deposits of the sodium-uranium formation from ore-denudation was estimated. The stages of dome geodynamics were established, which are coordinated with the processes of formation and evolution of the Ukrainian shield, connected with the split of the Sarmatian shield of the East European platform, the formation of adjacent geostructures and the transportation of low concentrations of uranium in sedimentary volcanic deposits of the pre-Baikal era, which formed the basement of the Scythian platform during the Baikal and Hercynian periods. The absence of industrial deposits (with over 200-meter wide uranium mineralization) in the southern part of the Novoukrainskyi granite-gneiss dome is the result of the differentiated geodynamics of this structure at the post-ore stage of its evolution.

Keywords

• granitoids
• gneisses
• dome
• massif
• pluton
• geodynamics
• uranium mineralization
• process
• stage
• paleo-valley
• ascending
• movements
• ab-solute age