DISCOVERY AND GEOLOGICAL SIGNIFICANCE OF THE LATE NEOPROTEROZOIC GRANITE IN HUANERKU, DAXINGANLING REGION

The latest research shows that the assemblage of ophiolite is developed in Jifeng, Gaxian and Huanerku areas along the eastern part of Xinlin-Xiguituqi fault in Daxinganling Mountains. Based on the study, the LA-ICP-MS zircon U-Pb age of 557.2±2.2 Ma is obtained from the granite in the ophiolitic melange in Huanerku area, indicating it was formed in Neoproterozoic period. The rock is generally characterized by slightly poor alkali, weakly peraluminous calc-alkaline with indistinct negative Eu anomaly, enrichment of LREEs and Hf, Ba, Nd and U, and relative depletion of Th, Nb, Ta and Zr, belonging to weak peraluminous calc-alkaline I-type granite. Considering the existence of Neoproterozoic ocean basin in Xinlin-Jifeng area, it is concluded that the granite is possibly the product of ocean subduction.