Mineralization Of The Xincheng Gold Deposit,Northwest Jiaodong Peninsula:Multiple Isotope Tracer

The Northwestern Jiaodong peninsula is the most gold resources enrichment area in the Jiaodong gold province which is one of the most famous gold concentration area in our country. And, the Xincheng gold deposit which is one of the deposit has proven initial reserves more than 200 tons in this area.This suggests that the good metallogenic conditions in the Xincheng gold deposit is extremely rare. For this reason, mineral research in this deposit is very typically. The source of Ore-forming material and ore-forming fluid has long been one of the key problems in the study of mineral deposit geology. In the study of gold deposit which includes sources of ore-forming fluid and gold element. This research is based on the previous geological data and detailed field observations, and H-O, C-O, S, Pb isotope geochemical research. Finally, we have a certain degree of understanding to the source and the migration of ore fluid, the source and concentration of gold element. The main achievement as follws:1. In the Xincheng gold deposit, in stage Ⅰ, the main part of ore fluid is metamorphic water, and it maybe mixed with a small amount of the Guojialing magmatic water. Then, the proportion of Atmospheric water increased gradually from stage Ⅱ to stage Ⅳ. Carbon-oxygen isotopic characteristics indicated that the ore-forming fluid may also contain a mantle source composition.2. Through the study of oxygen isotopes of ore-forming fluid show that the ore-forming fluid of metamorphic water dominates the mineralization. It maybe the main end member which carry gold element. And, flowed along the Jiaojia fracture from deep to shallow, eventually, enriched in the fractures which in the footwall of main faults. Among them, the ore-forming fluid of altered rock type ore and quartz vein type ore have obvious difference. The former was given priority to with pervasive type fluid flow, the latter was given priority to with channelized type fluid flow.3. The Jiaojia gold mine field where’s the Xincheng gold deposit located in isn’t a high gold element abundance area. Consider that S and Pb isotopic analyses show that they have a characteristics of crust-mantle mixed source. Indicate that the main source of gold element in ore-forming fluid is deep crust or mantle.4. In the Xincheng gold deposit, altered rock type ores has more 34 S relative to the quartz vein type ore. And this differentiation seems caused of the difference of their ore-bearing structure lead to different degree of fractionation. It always means that tectonic stress between fracture and ore-forming fluid in the process of mineralization was repeatedly pulsing. This process and the enrichment of gold mineralization are closely associated...