The Geodynamic and Physicochemical Conditions of the Formation of the Stepninsky Monzogabbro-Granosyenite-Granite Complex (Southern Urals)

Abstract

The geological structure of the Stepninsky, Vandyshevsky, Biryukovsky, and Uisky massifs, which belong to the Stepninsky monzogabbro-granosyenite-granite complex, is described. It was concluded that the crystallization depth of granitoid massifs decreases successively in this series of rocks from hypabyssal to hypabyssal-subsurficial facies. It was shown that intrusions in the Stepninsky complex belong to intraplate formations. At the initial stage, mafic-intermediate rocks of the deep mantle origin considered as derivatives from a separate plume were formed; at the later stage, granites and leucogranites of the calc-alkaline series formed. In terms of geochemistry the later group of rocks is characterized by rare-metal specialization.