Study On Characteristics And Ore-Host Regularity Of Gold Mineral In The Western Qinling Region, Gansu Province

The tectonic position of the Western Qinling refers to BaoCheng railway bounded western part of Qinling orogenic belt, mainly in southern Gansu Province. Western Qinling Gansu has superior metallogenic geological condition and gold resources. Since the 1990 s, they have found lots of representative and typical large gold deposits have been found, for example Dashui, Laerma, Daqiao, Liba, Luerba, Liziyuan, Yangshan, Zhaishang, Zaozigou, Maquan and Jiagantan etc. Accorrding to gold prospecting in recent years, the exploitation of Western Qinling Gansu’s gold resources will taking a leading role in China. However, research on gold deposits in Western Qinling Gansu did not follow up the development of exploration, geological researching of single deposit is most, the summary researching reports for gold deposits in the region are less, which restricts the further development of regional resources prospecting and exploitation.The paper based on previous research on ore, structure, exploration, petrology, geochemistry of gold deposits in Western Qinling Gansu and other professional theories as a guide, systematically summaried geological characteristics of more than 190 gold deposits in the region, with a geological survey for Zaozigou and Liba gold deposits, comprehensive variety of metallogenic information of Western Qinling gold deposits, studied on characteristics and ore-host regularity, and the main results are as follows:1. The comprehensive geological characteristics of more than 190 gold deposits in Western Qinling Gansu, spatial distribution of gold deposits are divided as the six concentration area and zonation, MaQu- LuQu, XiaHe- HeZuo, Die Bu- ZhouQu, LiXian- MinXian, Tian Shui – LiangDang and WenXian – BiKou.2. According to previous studies about the deposit features, host rock and ore characteristics, classified gold deposits into structural altered rock type, quartz-vein type, siliceous rock type, skarn type, porphyry type and superimposed type.3. The host rock of gold deposits in the study area is clastic. The strata ages are mainly Devonian, Triassic and Lower Paleozoic etc. The gold abundance research of strata indicates that the main source of the gold is the strata rather than acidic dykes. Sulfur source belongs to crust sedimentary, δ32S has an uneven average value which changed a lot; C-O isotopic characteristics of Dashui gold deposits and others also indicates the same characteristics with S; Pb resources of all deposits in Western Qinling Gansu gold mineralization system come from orogenic belts and the lower crust.4. According to an actual observation of the ore bodies in Zaozigou and Liba gold deposits, proposed that secondary structures and fissures had played an important part in controlling mineralization.5. Through researching the relationship between gold mineralization and structure, stratigraphy, intrusive bodies in Western Qinling Gansu and summarizing the structure, stratigraphy, acid intrusive rocks group and other important ore-controlling factors, proposed Western Qinling Gansu gold mineralization model.