周玉, 龚大兴, 周雄, 周家云, 岳相元. 东昆仑西段卧龙岗花岗斑岩岩石地球化学特征和锆石U-Pb年龄——对可可西里-松潘-甘孜地块构造环境及区域锑成矿时代的限定[J]. 地质通报, 2018, 37(10): 1853-1865.
    引用本文: 周玉, 龚大兴, 周雄, 周家云, 岳相元. 东昆仑西段卧龙岗花岗斑岩岩石地球化学特征和锆石U-Pb年龄——对可可西里-松潘-甘孜地块构造环境及区域锑成矿时代的限定[J]. 地质通报, 2018, 37(10): 1853-1865.
    ZHOU Yu, GONG Daxing, ZHOU Xiong, ZHOU Jiayun, YUE Xiangyuan. Petrogeochemistry and zircon geochronology of the Wolonggang granite porphyry in the western segment of the East Kunlun: Implications for tectonic setting of the Hoh Xil-Songpan-Ganzi Block and regional antimony mineralization timing[J]. Geological Bulletin of China, 2018, 37(10): 1853-1865.
    Citation: ZHOU Yu, GONG Daxing, ZHOU Xiong, ZHOU Jiayun, YUE Xiangyuan. Petrogeochemistry and zircon geochronology of the Wolonggang granite porphyry in the western segment of the East Kunlun: Implications for tectonic setting of the Hoh Xil-Songpan-Ganzi Block and regional antimony mineralization timing[J]. Geological Bulletin of China, 2018, 37(10): 1853-1865.

    东昆仑西段卧龙岗花岗斑岩岩石地球化学特征和锆石U-Pb年龄——对可可西里-松潘-甘孜地块构造环境及区域锑成矿时代的限定

    Petrogeochemistry and zircon geochronology of the Wolonggang granite porphyry in the western segment of the East Kunlun: Implications for tectonic setting of the Hoh Xil-Songpan-Ganzi Block and regional antimony mineralization timing

    • 摘要: 为了解可可西里-松潘-甘孜地块西北缘的构造演化及侵入岩与区域浅成低温热液矿床成矿的关系,在野外地质调查的基础上,采集了东昆仑西段的卧龙岗岩体花岗斑岩样品,对其中的12件和2件样品分别进行了岩石地球化学及LA-ICP-MS锆石U-Pb年龄测定。结果表明,花岗斑岩SiO2含量为64.96%~71.24%,高钾、富钠、贫钙。AR值为1.97~2.95,A/CNK值为0.98~1.16,为高钾钙碱性系列。岩石相对富集Cs、Rb、Ba、U和Nd,亏损Zr、Hf、Sr、Ti和Y。稀土元素总量为151×10-6~239×10-6,LREE/HREE值为8.10~14.53,δEu为0.54~0.70,具有明显的负Eu异常。锆石206Pb/238U年龄分别为205.6±1.6Ma和204.7±2.6Ma,表明卧龙岗岩体形成于晚三叠世末期。综合分析认为,可可西里-松潘-甘孜地块西北缘在晚三叠世末期应处于后碰撞伸展构造背景,区域浅成低温热液矿床形成时代晚于晚三叠世末期。

       

      Abstract: The 12 petrogeochemistry and 2 zircons LA-ICP-MS U-Pb age tests were carried out on the basis of field investigation for the granite porphyry samples of the Wolongang pluton in the western part of the East Kunlun in order to understand the tectonic evolution of the northwestern margin of the Hoh Xil-Songpan-Ganzi block and the relationship between the intrusive rocks and the regional shallow metamorphic hydrothermal deposits. The results show that the content of SiO2 in granite porphyry is 64.96%~71.24%, they were high potassium, sodium rich and poor calcium. Their AR values were 1.97~2.95 and A/CNK were 0.98~1.16, which were high potassium calcareous alkaline series. The rocks are relatively enriched with Cs, Rb, Ba, U and Nd and are depleted of Zr, Hf, Sr, Ti and Y. The total amount of REE is 151×10-6~239×10-6, LREE/HREE is 8.10~14.53 and δEu is 0.54~0.70, which has obvious negative europium anomaly. The results of zircon 206Pb/238U dating were 205.6±1.6Ma (MSWD=0.34, n=17) and 204.7 ±2.6Ma (MSWD=2.0, n=16), indicating that the Wolonggang pluton formation was at the end of the Late Triassic. According to the comprehensive analysis, it is concluded that the northwestern margin of the Hoh Xil-Songpan-Ganzi block should be in the extensional post-collision tectonic setting at the end of the Late Triassic, and the formation time of the regional shallow metamorphic hydrothermal deposits is later than the end of late Triassic.

       

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