Donlin Creek
Other Names:
District: Kuskokwim Gold Belt
Commodities : Gold
The intrusive-related Donlin Creek refractory gold deposit is located in the Kuskokwim Gold Belt of south-western Alaska, USA. It contains an estimated gold resource in excess of 25 million ounces at a cut-off grade of 1.5 g/t, making it one of the world’s largest undeveloped gold deposits. It is situated in the Late Cretaceous Kuskokwim flysch basin, considered by the USGS (Goldfarb et al. 2004) to have developed in the back section of an arc region of an active continental margin, on previously accreted oceanic terranes and continental fragments. Primary host to mineralisation is a mainly rhyolitic to rhyodacitic dyke complex, 8 km by 3 km in extent, commonly porphyritic. Age of mineralisation is ca 70 Ma.
More than ten separate prospects are recognised within Donlin Creek, most of which contain dense quartz ± carbonate veinlet networks filling NNE–striking extensional fractures in the NE-trending igneous rocks. The sulphide mineral assemblage is dominated by arsenopyrite, pyrite and, typically younger, stibnite; gold is refractory within the arsenopyrite. Sericitisation, carbonatisation, and sulphidation were the main alteration processes. The Dome prospect on the northern margin of the cluster of mineralised locations comprises copper and gold bearing stockwork veins overprinted/cut by younger, lower temperature, auriferous veins which represent the main Donlin Creek gold mineralising event.
References:
Goldfarb R J, Ayuso R, Miller M L, Ebert S W, Marsh E E, Petsel S A, Miller L D, Bradley D, Johnson C, and McClelland Ê W 2004 - The Late Cretaceous Donlin Creek Gold Deposit, Southwestern Alaska: Controls on Epizonal Ore Formation: in Econ. Geol. v99 pp 643-671
