The significance of late-stage gold mineralization at Big Gossan and Wanagon Gold in the Ertsberg District evolution, Irian Jaya, Indonesia

The Ertsberg district hosts multiple skam and porphyry-related deposits comprising one of the largest Cu-Au resources in the world. At Big Gossan, an overprinting late-stage pyrite-sphalerite¬arsenopyrite-gold occurrence with localised Bi-sulphides and tellurides is potentially the youngest significant mineralisation in the district. Two kilometres along strike to the NW, Wanagon Gold contains a similar late¬stage sulphide occurrence. Both deposits also contain earlier skam chalcopyrite-gold mineralisation devel¬oped in carbonate sediments at the contact of Tertiary and Cretaceous sequences. The many similarities be¬tween the deposits suggest they were in part formed by the same hydrothermal events. Independent geochro¬nology could be used to constrain the genetic relationship between the deposits and illustrate the longevity of magmatic-hydrothermal processes in the Ertsberg District. If the occurrences are linked, the implication of 2 km scale hydrothermal fluid flow enhances prospectivity between the deposits