Discovery of roquesite in the Zijinshan Cu-Au deposit, Fujian Province, and its implications for deep exploration

As a rarely observed mineral, roquesite (CuInS2) has not been reported in China yet. During the investigation of the mineral assemblages of the Zijinshan epithermal Cu-Au deposit at the depth, the authors discovered roquesite through electron microprobe analysis. Its chemical composition is Cu1.01In0.91S2.00, resembling the ideal formula Cu1.00In1.00S2.00 of roquesite. As roquesite is usually existent in the mesothermal to hypothermal ore-forming system, the discovery of such hypothermal minerals as kiddcreekite, hemusite, mawsonite, colusite, stannoidite and molybdenite in the deep orebody of southeast Zijinshan Cu-Au deposit suggests that the ore-forming temperature might have been much higher at the depth than estimated before. The authors have also come to the conclusion that the content of In, Sn, Pb, Zn, Mo, W in the ore-forming fluid was high. It can also be inferred that there probably existed a porphyry-like ore-forming system beneath the present high sulfidation-style epithermal Zijinshan Cu-Au deposit.