Geochemistry And Genesis Of Deposit In Baishun Ore Field

Baishun ore field, which located in southern Zhuguangshan granite, is a typical granite type uranium deposit. In this dissertation, Baishun ore field is the main research subject. Based on detailed geological survey, sampling, and testing, it systematically analyzed the composition of major elements, trace elements, REE and some stable isotopes, like hydrogen isotope, carbon isotope and sulfur isotope combining with other researchers' findings. At last, the source of ore-forming fluid and metallogenic materials are discussed and the cause of deposit formation was preliminary illustrated. After all work above, I got some conclusion: ?Compared the major elements contention of granite, altered rock, ore and diabase, it shows that their major elements contention changes regularly. The metallogenic materials of ore stem from wall-rocks and its major elements contention is similar to granites and different from diabase's, which shows that both them have the same source; analysis on trace elements and REE indicates that granites in this area are rich in uranium and can provide enough U for deposit. Multiple comparison among granite, altered rock, ore and diabase demonstrated that spider diagram of all geologic bodies show coherence except the diabase's, there is a obvious difference in their compositions of trace elements and REE, which implied that the sources of material in these geologic bodies are different, which implies that the metallogenic materials in deposits come from granite. different; ? By sampling about 24 samples of fresh diabase, mineralized diabase, Ore-bearing siliceous vein and uranium ore collected in several deposits and analyzing sulfur isotopic composition of pyrite existing in these samples. The results show that the ?34SCDT value of pyrites from ore vary from-18.9‰ to-17.3‰, different from this of mineralized diabase which vary from-6.5‰ to-10.9‰, which demonstrate that sulfur in ore improbably comes from the mantle and is same with granites' and biogenic sulfur; ?The research on hydrogen and oxygen isotopes shows that metallogenic fluid comes from atmospheric precipitation; ?Testing and analysis on carbon isotope of 30 calcite samples show that the carbon isotopic composition of metallogenic fluid vary from-10.25‰ to-4.56‰, which is close to the granites' and the mantle's. Further analysis on the composition of carbon and oxygen isotopes demonstrate it can also come from granite;?The study of Pb isotope in ore and granite turns out that they both come from upper crust.According to these analysis above, the sources of metallogenic fluid and metallogenetic materials in deposits of this area derive from the atmospheric precipitation which cycles along the deep fractures and heated and became hydrothermal fluid and then rolled up in fractures and faults with extracting the U form wall-rocks, and eventually formed uranium-rich deposits.