Gabbro-peridotite massif of Beltau (Western Tien-Shan, Uzbekistan): geological and petrographic features, accessory-mineralogical and geochemical specialization

The results of a study on the geological position and internal structure, petrographic and petrochemical features of the Beltau gabbro-peridotite massif are presented. Original data on the species and material composition of rock-forming minerals are presented. It is concluded that the massif is stratified due to crystallization-gravitational differentiation of primary basaltic magma, the products of which are represented by separate horizons of lherzolites, troctolites, olivine gabbro, titanavgite gabbro, gabbronorite, gabbropyroxenite, and anorthosite. It is confirmed by the internal structure of the intrusive massif — anorthosites and beolin-free leuko- and mesocratic gabbroids are located closer to the central part of the massif, hypsometrically higher than melano-cratic gabbroids and peridotites, and the latter gravitate to its peripheral and deeper parts. The forms of occurrence and material compositions of the main concentrating minerals and carrier minerals of iron, titanium, copper, nickel, cobalt, chromium, platinum, gold, silver, and other metals are determined. The geochemical specialization of peridotites is characterized by pronounced elevated contents of nickel and cobalt, which sharply exceed the contents of these elements than in melano- and mesocratic gabbro, leukograbbro and anorthiosites. Melanocratic, mesocratic gabbroids and their vein derivatives are relatively melliferous than other rocks of the massive.