New Data on Crystallization Conditions of Monzodiorite—Granite Massifs on the Eastern Slope of the Urals

Abstract

The geological structure of monzodiorite—granite massifs (Stepninskii, Biryukovskii, Vandyshevskii, and Uiskii) of the Stepninskii complex extending as a chain of intrusive bodies crossing the submeridional structures of the Ural Fold Belt is described. These granite massifs are ascribed to the Permian and, as suggested, are related to a mantle plume. Based on the results of studying melt and gas—liquid inclusions in quartz from granitoids, it was established that the rock crystallization depth in the given series of massifs decreases gradually in the northwesterly direction from hypabyssal to hypabyssal—subsurface facies. It is shown that leucocratic and aplitic varieties of granites with a higher level of fluid content have rare-metal metallogenic specificity and are promising in the search for W—Mo ore mineralization.