王志伟, 彭佳, 于静文, 朱泰昌, 张焱杰, 田英杰, 徐备, 史金田. 2022: 兴安地块西部晚石炭世花岗岩中—新元古代捕获锆石:超大陆演化的记录. 地质通报, 41(2-3): 486-497. DOI: 10.12097/j.issn.1671-2552.2022.2-3.025
    引用本文: 王志伟, 彭佳, 于静文, 朱泰昌, 张焱杰, 田英杰, 徐备, 史金田. 2022: 兴安地块西部晚石炭世花岗岩中—新元古代捕获锆石:超大陆演化的记录. 地质通报, 41(2-3): 486-497. DOI: 10.12097/j.issn.1671-2552.2022.2-3.025
    WANG Zhiwei, PENG Jia, YU Jingwen, ZHU Taichang, ZHANG Yanjie, TIAN Yingjie, XU Bei, SHI Jintian. 2022: Meso- to Neoproterozoic zircon xenocrysts in Late Carboniferous granite from the western Xing'an Block: Record of the supercontinent evolution. Geological Bulletin of China, 41(2-3): 486-497. DOI: 10.12097/j.issn.1671-2552.2022.2-3.025
    Citation: WANG Zhiwei, PENG Jia, YU Jingwen, ZHU Taichang, ZHANG Yanjie, TIAN Yingjie, XU Bei, SHI Jintian. 2022: Meso- to Neoproterozoic zircon xenocrysts in Late Carboniferous granite from the western Xing'an Block: Record of the supercontinent evolution. Geological Bulletin of China, 41(2-3): 486-497. DOI: 10.12097/j.issn.1671-2552.2022.2-3.025

    兴安地块西部晚石炭世花岗岩中—新元古代捕获锆石:超大陆演化的记录

    Meso- to Neoproterozoic zircon xenocrysts in Late Carboniferous granite from the western Xing'an Block: Record of the supercontinent evolution

    • 摘要: 中亚造山带东部的微陆块(如兴安地块)是否及如何参与Columbia和Rodinia超大陆演化过程,是地质学研究的热点问题之一。兴安地块西部艾力格庙地区出露含有大量元古宙(尤其是格林威尔期)年龄捕获锆石的晚石炭世花岗岩,为揭示兴安地块与超大陆演化之间的联系提供了重要的制约。LA-ICP-MS锆石U-Pb定年研究显示,侵入艾力格庙群中的黑云母二长花岗岩形成年龄为317±3 Ma,也产出大量古—新元古代(1827~1768 Ma、1556~1526 Ma、1195~1082 Ma、964 Ma、665 Ma)和早古生代(485~441 Ma)的捕获锆石。古—新元古代捕获锆石可能不是来源于艾力格庙群变质沉积岩,而是来自研究区可能存在的同期岩浆岩,其中约1.8 Ga、1.5 Ga和0.95 Ga岩浆作用在兴安地块及邻区已有报道。元古宙捕获锆石的Hf同位素、微量元素随时间的变化趋势与Columbia裂解到Rodinia汇聚过程基本对应,例如,1.5~1.4 Ga捕获锆石揭示的亏损Hf同位素特征和较厚的地壳厚度,可能与Columbia超大陆周缘的俯冲作用有关;1195~1082 Ma捕获锆石Eu/Eu*和(La/Yb)N值升高,可能与Rodinia超大陆聚合有关的地壳加厚有关,而964 Ma和665 Ma捕获锆石记录了更高的温度、更低的Eu/Eu*和(La/Yb)值,与格林威尔造山(1080~980 Ma)后的垮塌伸展及Rodinia的裂解过程吻合。上述研究表明,兴安地块在元古宙可能参与了超大陆的演化过程。

       

      Abstract: Whether and how the micro-continents in eastern Central Asian Orogenic Belt, such as Xing'an Block, were involved in the evolution of Columbia and Rodinia supercontinents, is a hot issue.A large number of Proterozoic (especially Greenville age) zircon xenocrysts present in the late Carboniferous granite from the Airgin Sum area in the western Xing'an Block, provide important constraints on the connection between the Xing'an Block and the supercontinent evolution.LA-ICP-MS zircon U-Pb dating shows that the biotite monzogranite intruded into the Airgin Sum Group at 317±3 Ma, and the biotite monzogranite captured numbers of Paleo- to Neoproterozoic (1827~1768 Ma, 1556~1526 Ma, 1195~1082 Ma, 964 Ma, 665 Ma) and Early Paleozoic (485~441 Ma) zircon xenocrysts.Those Paleo- to Neoproterozoic zircon xenocrysts might be derived from the coeval magmatic rocks in the study area instead of the meta-sedimentary rocks of the Airgin Sum Group, of which the ca.1.8 Ga, 1.5 Ga and 0.95 Ga magmatism has been reported in the Xing'an Block and its adjacent regions.The variation trends of Hf isotopes and trace elements of the Proterozoic zircon xenocrysts with time correspond to the process through Columbia breakup to Rodinia assembly.For instance, the depleted Hf isotope characteristics and thicker crustal thickness revealed by 1.5~1.4 Ga zircon xenocrysts might be related to the peripheral subduction around the Columbia supercontinent.The increased Eu/Eu* and (La/Yb)N ratios of zircons from 1195 Ma to 1082 Ma might be related to the crustal thickening associated with the Rodinia assembly, while the higher temperatures and lower Eu/Eu* and (La/Yb)N ratios of 964 Ma and 665 Ma zircons are consistent with the collapse extension after the Greenville Orogeny (1080~980 Ma) and the breakup of Rodinia.These studies indicate that the Xing'an Block might have been involved in the Proterozoic supercontinent evolution.

       

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