The development of the Ingul megablock of the Ukrainian Shield during the formation of the Novoukrainsky and Korsun-Novomirgorod Plutons

Abstract

Analysis of geological structure and the studies of composition of magmatic complexes of the Ingul block of the Ukrainian Shield makes possible to come to some conclusions on its deep structure during the period of 2,1-1,7 Ga. It has been found that the melts of the initial phases of the Novoukrainka and the Korsun-Novomirgorod plutons were differentiated at the border the crust - the mantle, and the melts of the final phases were differentiated within the crust. The appearance of the melting source at the border the crust - the mantle was produced by the melt supply along the permeable "transforming" zone. Appearance of crustal asthenosphere was caused by heat and material supply from the mantle asthenosphere. Combination of metasomatic and magmatic processes, as well as conductive heating lead to production of vast crustal melting source. Vertical component of the deep process during formation of the Novoukrainka and Korsun-Novomirgorod plutons is the same or similar but during the period 2,0-1,6 Ga lateral decrease of melting sources is noticed. Possibly, it was that period, which could be considered as the time of undepleated mantle formation, when its composition approaches lherzo-lite one and the temperatures become lower than its solidus temperature under the major part of the Ukrainian Shield.