Geologicheskii Vestnik

A mineralogical description of apatite crystals in thin sections and polished samples from gabbroids of Late Devonian–Early Carboniferous complexes (Nauruz, Faysullino, Utlyktash and Basaevo) of the Western Magnitogorsk zone was made. On the basis of study of the morphology of grains and paragenetic associations of apatite with rock-forming minerals, a conclusion was made about the primarily magmatic origin of apatite, represented by euhedral crystals with acicular, columnar and prismatic habit. The chemical composition of the mineral was studied and three apatite groups were distinguished based on the content of F, Cl and S: 1) high fluorine apatites with a medium increased amount of chlorine and insignificant amount of sulfur (Nauruz and Fayzullino complexes); 2) high-fluorine apatites with a moderately reduced amount of chlorine and insignificant amount of sulfur (Utlyktash and partly Basaevo complexes); 3) lowfluorine and low-chlorine apatites with increased amount of sulfur (Basaevo complex). It is suggested that the ore-bearing capacity of the studied gabbroid complexes is poor in Ti-Fe mineralization, however some intrusions of the Basaevo complex may carry a small Au mineralization.

Western Magnitogorsk Zone, Late Devonian, Early Carboniferous, gabbroids, apatite, halogens, sulfur, Ti-Fe mineralization

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