Strike-slip faulting and veining in the Grasberg giant porphyry Cu-Au deposit, Ertsberg (Gunung Bijih) mining district, Papua, Indonesia

摘要

The Ertsberg mining district is in the core of the Central Range of west New Guinea, a mountain belt created by arc/continent collision in the late Miocene/Pliocene. The district is best known for the Grasberg igneous complex (GIC), the host of a giant Cu-Au deposit that was emplaced at 3 Ma. Structural analysis revealed abundant evidence for three domains of strike-slip faulting in the deposit. The southwestern domain is dominated by E-NE-trending faults. The middle domain, the centre of highest grade ore mineralization, is dominated by NW-trending faults. The northeastern domain is dominated by N-trending faults. Dip-slip normal faults are subordinate. Faults inside and outside the GIC formed in a left-lateral Riedel shear system trending ~N60W.