GEOLOGICAL CHARACTERISTICS AND METALLOGENIC MODEL OF SUPER-LARGE PORPHYRY COPPER DEPOSITIN AKTOGAI ORE FIELD,KAZAKHSTAN

The Aktogai ore field consists of a group of porphyry Cu-Mo-Au deposits,such as Aktogai,Aidarly,and Kyzylkia deposits,in the Balkhash Metallogenic Belt of the Central Asian Metallogenic Domain.They are formed in the Balkhash volcanic arc of the north-central margin of Kazakhstan Orocline due to the large left-leteral strike-slip movement of the Ural-Tianshan Fault System and lateral crust-growth in the Late Paleozoic.Among them,the Aktogai deposit is a superlarge porphyry Cu-Mo-Au deposit.All of them are porphyry deposits with typical zoning of wallrock alterations and mineral assemblages.The metallogenesis is mainly related to the silicification of the early-stage alkaline alteration and the redeposition in the acid alteration stage.The occurrence of ore-bodies is controlled by the E-W,ENE,and WNW trending faults.The SHRIMP zircon dating of granodiorite has given the Aktogai deposit a metallogenic age of 327.5 ± 1.9 Ma in the late period of the Early Carboniferous.The deposit model of the porphy deposits in the Aktogai ore field is concluded asgranodioritetype in the hypabyssal porphyry copper system.