Metallogeny of endogenous gold in Tuva

Analysis shows that the occurrences of ore gold of different mineragenic types and ages widespread in the Republic of Tyva are related to the intricate and long geologic history of this region. The Tyva region is of polycyclic development; in the period from the Precambrian to the Cenozoic, there were stages of subduction, accretion-collision, and rifting processes accompanied by volcanism of different types and a wide manifestation of granitoid magmatism. Gold metallogeny was discretely developed throughout the geologic history of the region and was most widely manifested at the island arc stage (570-510 Ma), in connection with the formation of gold-bearing pyrite-polymetallic deposits. The late Cambrian-Ordovician period of granitoid magmatism was also productive for gold mineralization: It was marked by the formation of porphyry Au-Cu-Mo and gold deposits and gold-skarn, gold-quartz, and gold-beresite ore occurrences. Several gold-bearing clusters confined to different structure-formational zones are distinguished in the Tuva area. By now, commercial gold contents have been established in the Tardan gold deposit with Au reserves of 7371.8 kg, in the gold-bearing Kyzyl-Tashtyg pyrite-polymetallic deposit with estimated gold reserves of 15.08 tons and silver reserves of approximately 700 tons, and in the gold-bearing Ak-Sug porphyry Cu-Mo deposit with C (sub 2) gold reserves of 83 tons and silver reserves of 368 tons. In the course of prospecting and revision performed at many gold ore clusters in recent years, additional information about the high endogenous-gold potential of the Republic of Tyva has been obtained. There are a number of objects promising for commercial reserves of endogenous gold, such as the Kara-Bel'dir gold ore cluster with C (sub 1) and C (sub 2) gold reserves of 22.8 tons, the Aldan-Maadyr gold ore cluster with predicted P (sub 2) gold resources of 38 tons and P (sub 3) gold resources of 80 tons, the Eilig-Khem ore cluster with predicted P (sub 3) gold resources of 36 tons, the Kyzyk-Chadr ore cluster with predicted P (sub 1) +P (sub 2) gold resources of 39.7 tons and silver resources of 198 tons in the Kyzyk-Chadr deposit, and the East Tannu-Ola ore district with gold resources of 68.3 tons. Thus, the intricate geologic development of the Tyva area and various geologic events, including large-scale magmatic processes, led to the formation of both gold and gold-bearing deposits and ore occurrences, which give reason to anticipate revealing of large commercial reserves of endogenous gold and the development of gold mining industry in the republic.