Geodynamic settings of the formation of non-ferrous and noble metal deposits of the Great Altai

Abstract

In this work, we investigated the geodynamic settings of the formation of non-ferrous and noble metal deposits in the territory of the Great Altai, including the folded systems of the South-Western Altai and the Irtysh-Zaisan. The structures of Southwestern Altai were formed in three stages: riftogenic, island-arc, and collisional. Rocks of two different age formations were formed during the rift stage: lead-zinc pyrite mineralization associated with basalt-bearing andesite-dacite-rhyolitic formations, and gold-silver-polymetallic mineralization associated with basalt-rhyolitic and basaltic andesite formations. In the collisional stage, deposits of gold-sulfide-quartz and gold-low-sulfide-quartz ore formations are associated with granitoid of gabbro-granodiorite-granite formations, and rare-metal deposits are associated with granite-leucogranite. In the Irtysh-Zaisan folded system, the riftogenic stage is occurred in the Chara Trough filled with volcanic-sedimentary and calcareous-terrigenous rocks of the flyschoid formation and in its eastern frontal part, where the Kalba-Narym Trough is composed of rocks of the slate formation, and the West Kalba is composed of flyschoid. Gold-sulfide-quartz deposits are confined to the Lower Carboniferous deposits of the terrigenous-carbonaceous formation. The island-arc stage is fixed in the structures to the west of the Chara Trough, where it is represented by the basaltic andesite formation (Zharma-Saur subzone) and carbonate-terrigenous flyschoid formation (Sarsazan subzone). In the collision stage, due to the development of granite-leucogranite formation, numerous rare-metal-rare-earth deposits have originated. The island-arc structures also contain deposits and occurrences of gold-quartz, copper-porphyry and other formations.