Metallogenic characteristics and controlling factors of the Ok Tedi Cu-Au deposit, Papua New Guinea

Lying in Mt Fubilan of West Papua New Guinea, the Ok Tedi deposit is a world class copper-gold deposit. Tectonically, it belongs to the Papua fold belt of the New Guinea Orogenic belt. Copper-gold mineralization of the deposit occurs in the Fubilan monzonite porphyry, and its surrounding magnetite skarn and sulfide skarn. The primary sulfide ores which are composed of such minerals as magnetite, pyrite, pyrrhotite, marcasite, chalcopyrite and chalcocite constitute the predominant ore type. There exists a secondary oxidation-secondary enrichment zone in the deposit. The alteration types include skarnization, potassic alteration, argillic alteration and propylitic alteration. The supergene ore minerals include digenite, chalcocite, native copper, covellite and electrum. Mineralization is mainly controlled by regional structures, intrusive complex, limestones of the Darai Formation and faults. According to the features of host rock, ore and alteration as well as the controlling factors of mineralization, the authors classify the Ok Tedi deposit as a typical skarn-porphyry Cu-Au deposit.