Geological Features of Nanjinshan Gold Deposit and Prediction to Mineralization at Depth in the Beishan Area,Gansu Province

The Nanjinshan gold deposit is a typical epithermal deposit in the Beishan area,Gansu Province. As shown on the map of original geochemical reconnaissace of scale 1:200000,there as an abnormal combination of W,Mo and other high-temperature elements in this deposit,significantly different from general epithermal deposits where exists only an abnormal combination of low temperature elements. Under the guidance of the prospecting thought based on series mineralization theory,we have collected geochemical samples of the Nanjinshan gold deposit at different depths,analyzed the characteristics of the ore deposit,alteration and mineralization,and the enrichment of ore-forming elements. We noted that this deposit is a typical high-sulphidation epithermal deposit with high-temperature elements of W,Mo and medium temperature element Cu that increases with depth. By comparing it with the typical geochemical characteristics of copper-gold deposits,high-sulphidation epithermal deposits in other countries and spatial configuration of related copper-gold deposits,this work suggests that the a porphyry copper deposit probably exists at depth in the Nanjinshan gold deposit area.