Discussion of the Genesis of Super-Large Gold Deposit in Yangshan,Gansu

Yangshan gold deposit,a worldwide super-large gold deposit discovered recently in China,locates in Mianlue suture of the west Qinling.Based on the previous geochemical studies of stable isotopes and fluid inclusions,and combined with information of the tectonic background and the mineral combination types,this article discussed the cause of formation of Yangshan gold deposit.The formation time of Yangshan gold deposit is close to the tectonic-magma event,which happened during collision of Mianlue suture(late Trias to early Jurassic).A large-scale granitic magma event was generated by the collision and orogeny processes,abundant of magma hydrotherm driven by magma heat streamed up along the aureole of granitic porphyry and fractural phyllite,and extracted the relatively gold-enriched stratum,and then gold was carried around as complex to form gold deposit.Yangshan gold deposit has some characteristics similar to both the Carlin-type and the orogeny-type gold deposits,and is still significantly different from their geological and geochemical features.Yangshan gold deposit is an important typical gold deposit in the west Qinling China.