Typification of zircon of alkaline granite Khaldzan-Buregteg massif (Western Mongolia)

The article describes the typomorphic features of zircon massif Khaldzan-Buregteg. The typochemistry and morphological features are typomorphic for mineral and evolve with the changing conditions of its formation. Therefore, the study of the chemical composition and morphological features of zircon has important scientific and practical value. Zircons were classified on the basis of its morphological signs and typochemism. The research was conducted on chemical composition, especially the mineral structure and ontogenic analysis was made. Two genetic types of zircon were determined - magmatic and metasomatic. For the first type - igneous, typical of rare-metal granites and pegmatites Thahirin and Khaldzan-Buregteg, the predominance of morphotypes P3 and S14 was revealed. The second type of metasomatic - morphotypes characterized by Q2, G1 and P1.It is established that the crystallization of zircon occurred in the temperature range from 750° (late-magmatic and pegmatitic) to 650-600 °C (pneumatolytic-hydrothermal). The change of the types and subtypes of zircon reveals the evolution of the formation of alkali-granite massif Khaldzan-Buregteg.