赵江林, 曾忠诚, 陈宁, 李琦, 张若愚, 王星, 杜彪, 袁璋. 阿尔金南缘玉苏普阿勒克塔格北侧冰沟南组变质火山岩地球化学特征及其地质意义[J]. 地质通报, 2018, 37(4): 655-668.
    引用本文: 赵江林, 曾忠诚, 陈宁, 李琦, 张若愚, 王星, 杜彪, 袁璋. 阿尔金南缘玉苏普阿勒克塔格北侧冰沟南组变质火山岩地球化学特征及其地质意义[J]. 地质通报, 2018, 37(4): 655-668.
    ZHAO Jianglin, ZENG Zhongcheng, CHEN Ning, LI Qi, ZHANG Ruoyu, WANG Xing, DU Biao, YUAN Zhang. Geochemical characteristics and geological signifi-cance of Binggounan Formation meta-volcanic rocks on the northern side of Yusupualeketage at the southern edge of the Al-tun Mountains[J]. Geological Bulletin of China, 2018, 37(4): 655-668.
    Citation: ZHAO Jianglin, ZENG Zhongcheng, CHEN Ning, LI Qi, ZHANG Ruoyu, WANG Xing, DU Biao, YUAN Zhang. Geochemical characteristics and geological signifi-cance of Binggounan Formation meta-volcanic rocks on the northern side of Yusupualeketage at the southern edge of the Al-tun Mountains[J]. Geological Bulletin of China, 2018, 37(4): 655-668.

    阿尔金南缘玉苏普阿勒克塔格北侧冰沟南组变质火山岩地球化学特征及其地质意义

    Geochemical characteristics and geological signifi-cance of Binggounan Formation meta-volcanic rocks on the northern side of Yusupualeketage at the southern edge of the Al-tun Mountains

    • 摘要: 阿尔金南缘玉苏普阿勒克塔格北侧青白口系冰沟南组变质火山岩为一套与滨浅海相细粒陆源碎屑岩和碳酸盐岩共生的基性火山岩,主要岩性为蚀变玄武安山岩和安山质凝灰熔岩。岩石地球化学结果显示,SiO2含量在48.28%~51.98%之间,平均为50.31%,富碱、低钛,里特曼指数δ为0.33~2.30,铝饱和指数A/CNK为0.45~0.88,属于低钾(拉斑)系列。Mg#值介于40.46~56.28之间,平均值为50.12,表明基性火山岩岩浆经历了较弱程度的结晶分异作用。稀土元素弱富集、弱负Eu异常,呈右倾型。大离子亲石元素Rb、Ba、K、Sr亏损,高场强元素P、Ti、Nb、Hf亏损,强不相容元素Th、U富集,为强不相容富集型。岩石微量与稀土元素具有板内玄武岩的特征。根据构造环境判别系列图解综合分析认为,基性火山岩形成于板内裂谷环境。结合区域地质背景,研究区古元古代古大陆的裂解从长城纪一直持续到青白口纪早期,形成基性火山岩,从青白口纪中晚期开始转为罗迪尼亚超大陆的挤压汇聚阶段。

       

      Abstract: The Binggounan Formation volcanic rocks on the northern side of Yusupualeketage at the southern edge of the Altun Mountains are a suite of basic volcanic rocks associated with littoral neritic facies terrigenous clastic rocks and carbonate rock. The gneiss rocks are composed mainly of basalt-andesite and andesitic tuff lava. Geochemical analysis shows that the SiO2 content of the rocks is between 48.28% and 51.98% with an average of 50.31%. The rocks have rich alkal and low titanium. The Rittman index(δ) is 0.33~2.30 and the aluminum saturation index(A/CNK) is 0.45~0.88, suggesting calc-alkaline series.The value of Mg# is between 40.46 and 56.28, with an average of 50.12. It is shown that the basic volcanic rocks experienced higher crystallization differentiation, suggesting a weaker right-inclined LREE enrichment type. Eu anomaly is not obvious, and δEu is between 0.81 and 1.17. Lithophile elements Rb, Ba, K, Sr and high field strength elements P, Ti, Nb, Hf are depleted, and incompatible elements Th, U are enriched, implying incompatible enrichment type. The trace elements and rare earth elements have the characteristics of intraplate basalt. Ac-cording to the tectonic environment discrimination series diagram and the comprehensive analysis, the basic volcanic rocks were formed in an inner-plate rift environment. The regional plate breakup of the Paleoproterozoic continent occurred from Changcheng period to the early Qingbaikou period, forming basic volcanic rocks. In the late Qingbaikou period, the evolution began to turn to the Rodinia supercontinent squeeze convergence stage.

       

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