Abstract:
[Objective] To determine the Mesozoic granite type, age and tectonic setting and discuss the relationship between the granite and gold mineralization in Daliuhang, Jiaodong Peninsula. [Methods] In this study, the Mesozoic Yanshanian Linglong-type granites (Qijiagou monzonitic granite) and Gujialing-type granites (Gusidian monzonitic granite), which were located in the north of Qixia-Penglai gold metallogenic belt in eastern Jiaodong Peninsula. These samples are selected to analyze whole-rock geochemistry, U-Pb dating and Lu-Hf isotope study of zircon. [Results] The results show that the U-Pb age of the zircon from Qijiagou monzonite is 172.8±1.5 Ma, and the εHf(t) value of the zircon is -27.7 ~ -20.3. The zircon U-Pb age of Gusidian monzonitic granite is 127.3±0.8 Ma, the εHf(t) value of zircon is -15.7 ~ -13.4. The 87Sr/86Sr ratio of Gusidian monzonitic granite is 0.710937 ~ 0.712735, and the εNd (t) range is -16.8 ~ -11.3. [Conclusion] The source of Qijiagou monzonitic granite is ancient lower crust, which is mainly from the North China Craton lower crust. The magma source of Qijiagou monzonitic granite may be mixed with the Yangtze craton crust. Gusidian monzonitic granite is formed by partial melting of mafic rocks of lower crust, which added mantle components in the process. The diagenetic tectonic background of Gusidian magma formation is extensional, which may be caused by the subduction and retreatment of the Pacific plate. The Gusidian monzonitic granites have high coordination with the characteristics of early Cretaceous gold mineralization in Jiaodong Peninsula, suggesting that Gusidian monzonitic granite may be related to gold mineralization in this area.