LAN Jiang-Bo1*, LIU Yu-Ping1, YE Lin1, ZHANG Qian1, WANG Da-Peng1, SU Hang2
(1. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China;
2. Yunnan Hualian Mineral Resource Exploration Lt. Co. ,Qujing 655000, China)
Abstract: In this paper, Laojunshan granites were collected systematically. Zircon U-Pb dating, whole rock major and trace elements, and Sr-Nd-Pb isotope analysis were carried out to understand their petrogenesis and the relationship between respective mineralizations. Results show that Laojunshan granite belongs to high-K calc-alkaline series. The ACNK is higher than 1, and most of them higher than 1.1. CIPW results show that most of the samples contain standard corundum molecules (1%－5%), indicating that Laojunshan granite are peraluminous S-type granites. Whole rock major-trace elements and Sr-Nd-Pb isotopic characteristics indicate that Laojunshan granite is highly fractionated S-type granites. Geochemical and isotopic data suggest that these highly fractionated S-type granites originated from partial melting of the protolith, which has analogous components in mixture of metamorphosed pelitic and psammitic rocks from the Meso-Paleoproterozoic continental crust. LA-MC-ICPMS U-Pb dating results show that Laojunshan granite can be divided into three episodes, i.e. 80－88 Ma, 90－98 Ma, and 100－118 Ma. Laojunshan granite is consistent with the age of tin mineralization. The consistency implies that Dulong tin mineralization has close relation with granitic magmatic hydrothermal. Laojunshan granite may be likely an important source of minerals reservoir for Dulong tin zinc polymetallic deposits.The coupling between mineralization and emplacement in Gejiu, Bainiuchang, and Dulong, Southeast Yunnan Province imply that thoses deposits formed in similar dynamic background, and are closely related to the same magmatic events and lithospheric extension of South China.
Keywords: Granite; Geochemistry; Zircon U-Pb dating; Dulong tin-zinc polymetallic deposit; Laojunshan; Southeastern Yunnan Province
ACTA MINERALOGICA SINICA Vol. 36, No. 4, 2016, Page 441-454
