Geochemical,Geochronology And Oxygen Fugacity Characteristics Of Xishan Granite And Constraint To The Tin Mineralization In Yangchun Basin,Guangdong,South China

The Nanling Range in South China is characterized by well-developed non-ferrous and rare metal deposits as well as related various cycles of polygenetic granitic rocks.The Yangchun Basin is located in the south of the Nanling Range.This paper studied the petrology,mineralogy,oxygen fugacity,geochronology,trace and REE elements geochemistry of the Xishan granite in Yangchun Basin,Guangdong,South China.In addition,the paper discussed the genetic association between the tin mineralization and the granite body and the relationship between oxygen fugacity and tin mineralization.Zircon U-Pb dating results of Xishan and Mashui pluton defines granite emplacement age at 80 Ma and 77 Ma.According to the trace and REE elements geochemistry,show the granitic rocks in Xishan and Mashui have the same source region and same processes of the evolution.It has been fully shown from the evidences that the rock mass in Xishan is the product of the magma of continental crust partial melting evolved to the late stage.Tin mineralization and biotite granite has a direct genetic link.Tin mineralization occured in the post-magmatic gasification-hydrothermal stage.The analysis of the composition of biotite showed that the oxygen fugacity represented by Xishan rock biotite is lower than Ni-NiO line.The results of Ce4+/Ce3+ ratios in Zircon is 7.48~77.37 and the average date is 26.63,actually as the same from other Sn-bearing granites in the Nanling Range.Therefore,it could be judged preliminarily that Xishan rock may belong to a reductived-type granite and the low oxygen fugacity and greisenization characteristics are good at tin mineralization.