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延边天佛指山花岗岩年代学和地球化学研究表明,花岗岩中的锆石U-Pb年龄为(188.5±2.2)Ma,其侵位时间为早侏罗世。岩石总体上具有高硅、低铝、贫钙镁及富碱的特征,属高钾钙碱性系列I型花岗岩;富集轻稀土元素(LREE)和大离子亲石元素(LILE)Rb、Th、U、K等,相对亏损高场强元素(HFSE)Zr、Hf、Y、Yb等,显著亏损Ba、Nb、Ta、P、Ti等元素,δEu呈轻微程度负异常。该花岗岩岩浆源于地壳物质的部分熔融,可能形成于与古太平洋板块俯冲相关联的活动大陆边缘环境。
The geochronology and geochemistry of the granodiorites of the Yanzidazhi Mountain in Yanbian shows that the zircon U-Pb age of granite is (188.5 ± 2.2) Ma, and the emplacement time is Early Jurassic. The rock is generally characterized by high silicon, low aluminum, poor calcium and alkali-rich features and belongs to the high-K calc-alkaline series I type granite; it is rich in LREE and LILE Rb, Th , U, K and so on. Relatively depleted in HFSE Zr, Hf, Y, Yb, etc., significant depletion of Ba, Nb, Ta, P, Ti and other elements, δEu showed a slight negative anomaly. The granite magma originates from the partial melting of crustal material that may form at the active continental margin associated with subduction of the Paleo-Pacific plate.