Late Paleozoic and Early Mesozoic rare-metal magmatism of Central Asia: Stages, provinces, and formation settings

Late Paleozoic and Early Mesozoic epochs in the formation history of the Central Asian Foldbelt are distinguished by high rare-metal productivity. A number of large REE, Ta, Nb, Zr, Be, Sn, Li, Mo, Re, and other deposits were formed at that time. As a rule, they are of the magmatic origin and related to the intrusions of highly evolved igneous rocks varying in composition from alkaline ultramafic with carbonatites to alkali and Li-F granites. In general, the occurrences of rare-metal magmatism are related to the rift zones of the Central Asian Rift System formed 310-190 Ma ago and conjugated with a consecutive series of the Barguzin, Hangay, and Hentiy zonal igneous provinces characterized by the large batholiths in their centers and rift zones in the framework. Such a structure indicates that these provinces were formed above isometric mantle sources or plumes with participation of large-scale crustal anatexis. The evident links of rare-metal deposits to occurrences of mantle magmatism within the zonal igneous provinces show that plume sources played an important role in their formation.