张钶, 焦建刚, 刘琦, 马一嘉, 段俊, 赵联党, 贾力, 刘健. 甘肃龙首山地区古生代岩浆核杂岩隆起:来自金川矿区脉岩年龄与地球化学的证据[J]. 地质通报, 2023, 42(2-3): 343-362. DOI: 10.12097/j.issn.1671-2552.2023.2-3.013
    引用本文: 张钶, 焦建刚, 刘琦, 马一嘉, 段俊, 赵联党, 贾力, 刘健. 甘肃龙首山地区古生代岩浆核杂岩隆起:来自金川矿区脉岩年龄与地球化学的证据[J]. 地质通报, 2023, 42(2-3): 343-362. DOI: 10.12097/j.issn.1671-2552.2023.2-3.013
    ZHANG Ke, JIAO Jiangang, LIU Qi, MA Yijia, DUAN Jun, ZHAO Liandang, JIA Li, LIU Jian. Uplift of Paleozoic magmatic core complex in the Longshoushan area, Gansu: evidence from geochronology and geochemistry of rock veins in the Jinchuan deposit area[J]. Geological Bulletin of China, 2023, 42(2-3): 343-362. DOI: 10.12097/j.issn.1671-2552.2023.2-3.013
    Citation: ZHANG Ke, JIAO Jiangang, LIU Qi, MA Yijia, DUAN Jun, ZHAO Liandang, JIA Li, LIU Jian. Uplift of Paleozoic magmatic core complex in the Longshoushan area, Gansu: evidence from geochronology and geochemistry of rock veins in the Jinchuan deposit area[J]. Geological Bulletin of China, 2023, 42(2-3): 343-362. DOI: 10.12097/j.issn.1671-2552.2023.2-3.013

    甘肃龙首山地区古生代岩浆核杂岩隆起:来自金川矿区脉岩年龄与地球化学的证据

    Uplift of Paleozoic magmatic core complex in the Longshoushan area, Gansu: evidence from geochronology and geochemistry of rock veins in the Jinchuan deposit area

    • 摘要: 新元古代形成的金川铜镍硫化物矿床位于华北板块西南缘龙首山中部,由于古生代造山过程中的构造挤压作用及变质热液叠加,矿床中铜铂得到再次富集。矿区及周边出露大量古生代基性—中酸性脉岩与岩基,暗示龙首山地区古生代发生了岩浆核杂岩隆起作用。综合研究了矿区切穿赋矿岩体的辉绿岩脉、煌斑岩脉和花岗斑岩脉,通过锆石U-Pb定年,获得侵入金川铜镍矿床的花岗斑岩锆石U-Pb年龄为367.1±2.0 Ma;煌斑岩锆石U-Pb年龄为400.6~425.3 Ma;前期工作获得辉绿岩中锆石的U-Pb年龄为423.5±1.4 Ma。初步认定矿区各类脉岩的形成时代为古生代。岩石地球化学及同位素地球化学分析结果显示,辉绿岩样品的εNd(t)值为-4.59~-1.58,(87Sr/86Sr)i值为0.7056~0.7077;煌斑岩样品的εNd(t)值为-2.97~-2.03,(87Sr/86Sr)i变化范围为0.7083~0.7085;证明基性脉岩的源区为富集型岩石圈地幔;获得花岗斑岩锆石的εHf(t)值介于5.11~12.84之间,指示其为新生地壳部分熔融的产物。结合区域古生代岩浆活动背景,提出了龙首山地区构造-岩浆演化模型。

       

      Abstract: The Neoproterozoic Jinchuan Cu-Ni sulfide deposit is located in the central Longshoushan, southwestern margin of the North China Craton.Due to the tectonic compression and metamorphic hydrothermal superposition in the process of the Paleozoic orogeny, Cu-Pt-rich ores were enriched again.A large number of mafic-felsic rock veins and batholiths crop out in the Jinchuan deposit and its vicinity, which indicates existence of uplift of Paleozoic magmatic core complex in the Longshoushan area.This comprehensive study focuses on dolerite, lamprophyre, and granite porphyry veins crosscutting ore-bearing intrusions of the Jinchuan deposit area.Zircon U-Pb dating indicates that granite porphyry and lamprophyre formed at 367.1±2.0 Ma and 400.6~425.3 Ma, whereas the dolerite formed at 423.5±1.4 Ma based on previous work, preliminarily suggesting the Paleozoic formation ages for various types of rock veins in the deposit area.Petrochemical and isotope geochemical results show the dolerite and lamprophyre have εNd(t)values ranging from -4.59 to -1.58 and -2.97 to -2.03, with corresponding (87Sr/86Sr)i values of 0.7056 to 0.7077 and 0.7083 to 0.7085, respectively, indicating that the magma sources of these mafic rock veins were derived from an enriched lithospheric mantle.The granite porphyry has zircon εHf(t)values of 5.11 to 12.84, suggesting it was sourced from partial melting of the juvenile crust.Combined with previous studies on regional Paleozoic magmatic activities, the authors put forward an integrated tectonic-magmatic evolution model.

       

    /

    返回文章
    返回