Geological features and tectonic setting of porphyry copper deposits rounding the Balkhash region, Central Kazakhstan, Central Asia

Central Kazakhslan located in the center of the Central Asia Orogenic Belt (CAOB), is one of the largest porphyry copper deposit metallogenic domains, wherein hosts tens of large and superlarge ore deposits. In the area, three major subtypes of porphyry copper deposits have been recognized: porphyry Cu-Au deposits, porphyry Cu deposits and porphyry Cu-Mo deposits, mostly associated with contemporaneous volcanic rocks. Established alteration zonation consists of alkaline and acidic alterations. delta(34) S (err) values of sulfides from porphyry copper deposits range from -7.1 parts per thousand to 4.2 parts per thousand, showing it deep source. Pb isotope analyses reveal that ore-forming materials were generated from lower crust and upper mantle. In the central Kazakhstan multistage tectonic evolutions were followed by formation of multistage porphyry copper deposits. Early Paleozoic porphyry copper deposits have been formed during early stages of island ares evolution, but late Paleozoic porphyry copper deposits are confined in the Devonian volcano-platonic belts, and their Carboniferous-Permian volcano-plutonic belts. From northwest to southeast towards the central Kazakhstan, ore-forming ages of porphyry copper deposits are successively younger. Whereas study on porphyry copper deposits in the region throughout tens yeah, some key problems yet remain uncertain,e. g. high-precise age-dating on intrusive stocks and mineralizations for the major porphyry copper deposits, temparol-spatial distribution framwork and geodynamic settings. The linkage and comprehensive correlation between Balkhash porphyry copper belt and adjacent Chinese western Jungar and western Tienshan is of great significance for further exploration.