Cobalt mineralization of the South Siberia: types of ores, geochemical characteristics and age

South Siberia is part of the large cobalt-bearing Altay-Sayan province. Three main types of hydrothermal cobalt ores are recognized in this province: Ni-Co-arsenic (Ni-Co-As), Co-suifoarsenic (Co-As), and Cu-Co-sulfoarsenic-sulfosolts (Cu-Co-As). Analysis of the relationships among the different types of hydrothermal cobalt mineralization at deposits of the Attay-Sayan fold area shows that Co-As, Ni-Co-As, and Cu-Co As ores were formed during separate stages. Ore associations are usually separated by intrusions of dikes of dolerite or syenite. Cobalt ore formation in most ore cluster also is a multiple-stage process associated with mafic and granitoid magmatism of different ages. New geochronological data and analysis of the relationships between cobalt mineralization and magmatism in ore clusters of the Altay-Sayan fold area has shown a close spatial and time connection of cobalt mineralization with mafic and granitoid intrusions, as well as with mafic dikes.