Gold, Silver Metallogeny In Eastern Kunlun Orogenic Belt, Qinghai Province

Eastern Kunlun orogenic belt, western part of China's central orogen, is located in the northern margin of Qinghai-Tibet plateau. And it starts from Altun fault zone in Xinjiang in the west and ends at Wahongshan-Wenquan fault zone in Qinghai in the east. The Qaidam massif is in its north and Bayan Har Indochinese fold belt in the south. The belt has undergone complex orogenic processes named typical Peripheral Orogeny Model, which controlled the formation of different kinds of ore deposits. Based on the date made by former researchers and the author's investigation, the geological history of the orogen has been divided into four stages, i.e. Pre-Caledonian metaplatform formation and oceanic plateau accumulation, Caledonian subduction, back arc rifting and plateau accretion, Hercynian-Early Indochinese Andes-type orogeny, Late Indochinese-Himalayan intra-continental evolution. From north to south, Eastern Kunlun orogenic belt can be divided in to Kunbei back-arc basin, Kunzhong basement uplift and granitic belt and Kunnan composite belt. South of Kunnan composite belt is the Bayan Har Indochinese fold belt.Different geodynamic evolutions control different type mineralization. From geological setting, general geology, mineral deposits, geochemistry of deposit, genesis of deposit and ore prospecting, author studies the characteristics gold, silver deposits detailedly in different metallogenic belt, compares their similarities and differences and summaries regional metallogenic regularities and potential assessment.Four characteristic gold, silver deposits are selected and studied detailedly, i.e. Dachang gold antimony deposit which is controlled by Tertiary turbidites in Indochinese Bayan Har fold belt, Wulonggou gold deposit in Kunzhong basement uplift and granitic belt,Suolagou silver deposit in Elashan metallogenic belt and Kendekeke cobalt, bismuth and gold deposit in Kunbei back-arc basin. Investigations have indicated that Dachang gold antimony deposit and Wulonggou gold deposit are orogenic gold deposits. The mineralization can be divided into two stages of gold mineralization belonged to mesozonal mineralization and antimony mineralization belonged to epizonal mineralization. Wulonggou gold deposit is the typical orogenic gold deposit, which is thecharacteristic Mesothermal gold deposit similar to the Jiaojia type gold deposits in Jiaodong Peninsular. Comparisons with the Muruntau gold deposit in Uzbekistan, except the lower mineralized depth and later mineralized age, Dachang gold antimony deposit is similar to the Muruntau type gold deposit. Furthermore, its potentiality of ore prospection for gold is gigantic. Suolagou silver deposit is the stratabound epizonal silver deposit and develops exhalative sedimentation Cu, Pb and Zn mineralization and epizonal silver mineralization. The early stage Sedex mineralization formed the sillcalite formation bearing argillite enriched metallogenic elements, i.e. Cu, Pb and Zn in Suolagou silver deposit. Accompanying the transition of the Wahongshan-Wenquan fault zone, hydrothermal activities happened frequently in the later stage and invaded along the Wahongshan-Wenquan fault and its secondary faults taking partial mineralization Ag element. Therefore, the vein, thin vein silver ore bodies were formed controlled by faults. Kendekek cobalt, bismuth and gold deposit enriched several usable elements Cu, Mo and Ni reached industry standard. Through analysis of our research team, Kendekeke deposit is controlled by fractured zone, skarnaliation and formation of hydrothermal sedimentation obviously is superposed several geological activities. Based on study of metallogenic tectonic setting, analysis of ore-controlling factors and geological characteristics, Kendekeke deposit have undergone multistage and polyperiod mineralized stage. The formation of hydrothermal sedimentation formed back-art extensional phase. During the closure of rift basin and late several stages tectono-magmatism, several hydrothermal activities can be superimposed.Indochinese is the major...