The Ore Genesis And Prospecting Direction Of Jinqingding Gold Deposit Of The Muping-Rushan Gold Ore Belt In Eastern Shandong

Jinqingding gold deposit is located in the middle part of Muping-Rushan metallogenic belt in Shandong, There is Penglai-Qixia and Zhaoyuan-Yexian ore belt in the west side of Jinqingding gold deposit, and there is famous Sulu UHP metamorphic belt in the east of it. In recent years, this deposit is currently the largest quartz vein-type gold deposit in china in terms of gold resources in single lode (>40t), which produced in Kunyu granite ore body. With the increasing exploration and development, resources reserves has been substantial increased, the deposits has now became the only super huge gold deposit in eastern of Shandong. Typical Jinqingding gold deposit was selected detailed study, focusing on the key ore genesis issues of quartz vein-type gold deposit:①the relationship among formation, wall rock and the ore-controlling structures;②ore genesis and metallogenic model;③Prospecting direction. The regional structure, the ore-bearing country rocks, ore, ore genesis and metallogenic model, etc., aspects of the research system were carried out based on petrology, mineralogy, element geochemistry, S and Pb isotope geochemistry. The following are the main results:Optical Microscope and Electron microscope analyses with EDX indicate that calaverite is first discovered in this research in the deep No. II ore vein, which not only further proves previous assumptions, but also breaks up the traditional understanding that there is no petzite in the deep. The experiments show that mainly precipitation order of Au-Ag tellurides is:hessite-petzite-calaverite-Electrum, which means that there may be gradually gold-rich in Au-Ag tellurides with the evolution of ore-forming fluid. The conclusions will provid a foreseeable knowledge about Au-Ag tellurides paragenesis for similar gold deposits. There are tellurides-rich in No.Ⅱ ore vein, which displayed a good prospecting foreground in the deep orebody.Research of Pb isotope and geochemistry of rare earth elements showed that the metallogenic material drived from precambrian metamorphic basement, Kunyushan granite and deep orebody. Sulfur isotope of sulphide analysis shows that its value is higher degree of uniformity in different middle section and ore body, the value range between+7.43～+8.69‰, less than2‰, an average of7.83‰, Kunyushan granite and pyrite with sulfur isotopic composition is similar, reflecting metallogenic material S mainly from the granite. In quartz δD-δ18O diagram, projection points of quartz are mostly in the area of meteoric water and magmatic water.And the projection points of the main mineralization stage are closer to the area of magmatic water. The author holds that the main ore-forming fluids are magmatic water, with the meteoric water later. The ore-forming characteristics of physical and chemical show that Jinqingding gold deposits formed in the environment of medium temperature, hypabyssal, weak acidity and reduction.The Kunyu granite orogenic granite is formed mainly in the post-orogenic granite (POG) and continental arc granitoids (CAG) after studying of major and trace element. Combined with other information that wall rock of Jinqingding gold deposit-Kunyu granite formed in the stage of the dive of Pacific plate to Eurasian plate the early Yanshan. Based on the previous studies and combined with its judgement of the tectonic environment, diagenetic age is Yanshanian which concentrated in diagenetic age of between160～110Ma. The data of mineralization age form in between the ages of125Ma～110Ma, indicating that the mineralization lag behind diagenetic, and late Yanshan period asmain is mineralization period.With the "polygenetic compound" genesis theory, we conclude firstly that Jinqingding gold deposit with the features of multi-material source, multi-ore-controlling factors and multi-mineralization. The paper proposed that Jinqingding gold deposit belongs to a Precambrian metamorphic rock and magmatic hydrothermal gold deposit, which is controlled by the Yanshan fault. We also established a corresponding metallogenic model. The new view of the genesis reflects the whole evolution of the long geological history of Jinqingding gold deposit:It formed from prosses source bed preliminary enrichment in Archean to hydrothermal alteration and mineralization of useful material in late Yanshan.Based on study of regional metallogenic regularity, the author dealt with prospecting criteria and direction of study area, pointing out that the main prospecting direction are the deep of known deposits, such as inside or outside near the contact zone of Jingshan Group and Kunyu granite, NNE, NE trending structural faults intersections, development area of pyrite-quartz veins, intensive development of NNE trending lamprophyre, accompanied by NNE, NE tectonic fracture zones, altered granite, gold containing pyrite-quartz veins gold ore veins, and so on.Through the analysis of regional geological background, regarding the geological structure is the mechanical theory method as guidance, treating the field investigation of Muping-Rushan gold belt as the basis, accepting ore-controlling structures as the main line, and combined data of withremote sensing geology, geophysical and geochemical, we find out mineralization of ore-controlling structures, favorable metallogenic location of six faults. The author suggest that prospecting should be first selected Qinghushan-Tangjiagou fault belt, Shigou-Wushan fault belt, Chahe-Sanjia fault belt, Jiangjunshi-Quhezhuang fault belt, and then is the rest sub-band a few times. At last, the paper predicted seven favorable metallogenic area.