Ages and controlling factors of Cu-Au mineralization in Papua New Guinea

The Papua New Guinea region evolved within the obliquely and rapidly converging Australian and Pacific plate boundary zone. It is arguably one of the most tectonically complex regions in the world, and its geodynamic evolution involved subduction and formation of volcanic (magmatic) arcs, arc-continent collision and collisional orogenesis, exhumation of continental crust, magmatic intrusion and mineralization. The geochronology of New Guinea suggests the geodynamic sequence of ① collision causing uplift and exhumation, then ②intrusion during or shortly after exhumation, and finally ③mineralizing event during the late stages of the intrusive system. In the geodynamic sequence, ages of Cu-Au mineralization are mainly concentrated in the range of 25~0Ma. Most of the world class deposits in PNG are much younger (6~0Ma). On the basis of ages of mineralization, the authors divide Cu-Au mineralization into the three boom periods: the first boom of mineralization (23~12Ma); the second boom of mineralization (7~1Ma); the third boom of mineralization (0.5~0Ma) (still continuous at present). The controlling factors of Cu-Au mineralization in Papua New Guinea include tectonics, intrusive complex, special host strata, transfer structure, folds, various faults, caldera or diatreme and so on. In summary, Papua New Guinea has a relatively young (Meso-Cenozoic) and complex history of tectonic and metallogenic evolution with plate convergence, collisional orogenesis, and strong and frequent magmatic-hydrothermal activities，including Cu-Au mineralization.