Gold Telluride Dominated Epithermal Gold Mineralization, Sandaowanzi Deposit, China

We present the first report of a gold telluride dominated epithermal deposit, i.e., the Sandaowanzi deposit containing 0.5 Moz, in NE China. Extremely high grade ores of up to more than 20,000 g/t Au are in the form of gold telluride. Tellurides contribute to more than 95% of the gold budget. Gold tellurides, e.g. calaverite, sylvannite, krennerite, stutzite and hessite predominate over electrum and native gold in the deposit. Coarse telluride grains of up to 3 cm in diameter and micron scale bamboo shoot-like grains of electrum or native gold grains are distinct from other gold telluride-bearing deposits. The electrum or native gold grains never occur as inclusions in other minerals, but grow only along cracks in gold telluride grains or along grain boundaries of the grains. Six stages of mineralization, from early high to late low sulphidation with increasing gold in tellurides, are revealed to be due to both open space filling and replacement in an extensional setting. We anticipate that the Sandaowanzi gold telluride deposit may provide a key to the understanding of gold mineralization processes.