The Alapaevsk-Sukhoi Log porphyry copper zone, Middle Urals: The U-Pb age of productive magmatism

The Alapaevsk-Sukhoi Log zone about 100 km long and 3–10 km wide with numerous porphyry copper occurrences and small deposits is located in the eastern part of the East Ural volcanic megazone, Middle Urals. The long evolution of productive magmatism (according to the U-Pb (SHRIMP-II and LA-ICP-MS age of zircon) and its rejuvenation are established from the north and the south (Ma): from 411 ± 3 (Yalunina Gora pluton, town of Alapaevsk) to 404–406 ± 3 (Altynai-Artemovsk pluton, town of Artemovsk) and to 397 ± 4 (porphyric rhyodacites of the Shata area, town of Sukhoi Log). The K 2 O content in productive quartz diorites is 0.4–0.7, 0.8–1.2, and 0.4–0.7 wt %, respectively. The Mo-Cu porphyry occurrences are abundant in the Altynai-Artemovsk area. The granitic rocks of the quartz dioritic East Artemovsk pluton, which was recently found, are sericitized and contain significant sulfide mineralization. The structural position, age (365 ± 39 Ma, Rb-Sr errochron), composition of granitic rocks, and its mineralization are similar to those of the large (1.7 Mt Cu) Mikheevka deposit (U-Pb SHRIMP-II age of zircon is 356 ± 6 Ma) in the South Urals.