The Migmatization and Granite Formation Processes within the Western Exocontact of the Aduyskiy Massif. Middle Urals

摘要

The mechanisms and sources of magma generation for the large Permian Aduyskiy granite massif, well known for rare metal, semi-precious stone and molybdenum deposits, are considered. Valuable information was obtained from study of the Kamenskiy and Krutikhinskiy massifs located at the base of Aduyskiy granite body. The migmatites of these two massifs as well as the accompanying partial melting have approximately the same zircon and Rb-Sr age. These processes range about 309-298 Ma in the Kamenskiy and 308-283 Ma in Krutikhinskiy massifs with the main and most intense stage within 296-298 Ma. That time, the main volume of the granite melt for Kamenskiy, Krutikhinskiy, and Aduyskiy massifs was formed. The migmatites of magma generation zone have banded texture in Kamenskiy massif, but, in Krutikhinskiy massif, anatectic melt formed the numerous veins and small intrusive bodies. These magmatic differences were formed mainly due to protolith composition. Камenskiy migmtites are characterized by Devonian – Carboniferous quartz diorites and granodiorites. Predominantly granitic rocks are characteristic for Krutikhinskiy massif. Basic dykes accompanied the migmatization in both massifs.