Genesis Of PGEs In Polymetallic Copper Deposit Of Jiujiang-Ruichang Area，Jiangxi

In China,PGEs is one of the scarcest resources of precious metals,and it plays animportant role in the national economy and technological development.This paperhas collected datas about the production and consumption of platinum reserves athome and out, which provides a reference for the use of resources,trade andprospecting strategy of China.Lower Yangtze metallogenic belt is a metallogenic prospect areaof hydrothermalPGE deposits.Then the tailing samples in Wushan and Chengmenshan copper depositswere collected by myself and tested.there is platinum and palladium elementsanomaly in the samples. On the another hand, there is a positive correlation amongPGEs and copper at el ore-forming elements. It has showed that PGEs is closelyrelated to copper at el ore-forming elements.so the Pd,Pt and Cu evidently existsimilarity,homology and anatectic character.Based on the characteristic of trace element geochemistry and isotope of ore inWuShan and Chengmenshan copper deposits,I have summarized the evolution rulesof magmas, structures and hydrothermal solution and analysised the resource ofmagma and metallogenic material.It suggests that abnormal enrichment of platinum group in Jiurui area has thecharacteristics of the hydrothermal deposits. The platinum group elements anomaly ismainly rich in Pd and Pt,in which the Pd content far exceeds the Pt but others israre.Platinum group elements mainly exist in the copper-bearing pyrite and copperbearing skarn, which indicates that the anomaly has a close relationship with thecopper sulfide. By studying the correlation between the platinum group elements andCu，Au. It has found that Pt had a strong correlation with copper and gold,butPd showed a strong correlation with silver.To sum up, the exception of the platinum group in this area has the samemetallogenic source as copper and gold,that is Deep I-type granite. Intermediate-acidmagmatite in this region was evolved by the crust-mantle mixed I-type granite.Because of crustal extension thinning the deep crust-mantle mixed magma invade along the fissure which provides source for platinum group elements anomaly. Due totemperature, pressure and fluid, Magma formed I-type ore-bearing granite when itintruded into the medium and deep. The magmatic hydrothermal intruded into shallowcrust along the shallow tectonic fractures due to tectonic activity, and formed acidrock strains which mainly consists of quartz diorite porphyry and granodioriteporphyry.The magmatic intrusion in evolutionary process owned high oxygen fugacity,and make a large number of platinum group elements increased their solubility.As aresult, the complex moved tot2-3Km of the crust accompanied with rockmass.At this point, the temperature of the entire magmatic fluid system downto250～400℃, oxygen fugacity decreased and pH value increased.At last， themagmatic fluid began to precipitate platinum group elements mineral.