Hydrothermal alteration and gold mineralization of the Awak Mas metasedimentary rock-hosted gold deposit, Sulawesi, Indonesia

摘要

The Awak Mas gold deposit is hosted by phyllites and schists. Indicated and infered resource are around 38.4 Mt at 1.41 g/t Au, equaling to total resource of 1.74 Moz gold. Hydrothermal alteration zones proximal to the gold-bearing veins, are characterized by the mineral assemblage albite-ankerite-pyrite and marked by elevated Na/Al ratios and depleted 3*K/Al ratios. These changes are manifested by the replacement of muscovite by albite. Carbonate alteration with ankerite and siderite occured simultaneous to albitization proximal to the veins. Distal alteration zones are characterized by chlorite-albite in phyllites, and albite-quartz in schists.