关键词: 新林镇, 花岗闪长岩, U-Pb年龄, Sr-Nd-Hf同位素, 地壳增生

Abstract: The Xinlin Town pluton locates in the northern Great Hinggan Mountains. Lithologically, it comprises granodiorite, adamellite, quartz-monzodiorite and alkaline-feldspar granite, with locally fine-grained gabbroic and dioritic enclaves. Petrological and geochemical characteristics indicate that the pluton is high-K calc-alkaline I-type granite. Zircon LA-ICP-MS U-Pb dating of two granodiorites yielded emplacement ages of (132±3)Ma and (131±3)Ma. The ages indicate that the pluton was the product of the Early Cretaceous magmatic event. Though Sr-Nd isotopic compositions of the samples are relatively uniform, their ε_{Hf(t) values are relatively varied, ranging between 1.32 and 8.32; the yielded Nd and Hf model ages are Neoproterozoic. The isotopic data indicate that the granitic magma mainly originated from the juvenile Neoproterozoic accreted crustal materials with the involvements mantle components. The isotopic characteristics indicate that the Erguna terrain accreted in Neoproterozoic at least,}

Key words: Xinlin Town, granodiorite, U-Pb dating, Sr-Nd-Hf isotopes, crustal growth