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    靳松, 张瀚文, 韩亚彬, 李晓峰, 王星琰, 吴立昂, 王子洋. 新疆西准噶尔苏根萨拉岩体锆石U-Pb年龄与Hf同位素及对构造演化的制约[J]. 中国地质, 2022, 49(5): 1624-1635. DOI: 10.12029/gc20220517
    引用本文: 靳松, 张瀚文, 韩亚彬, 李晓峰, 王星琰, 吴立昂, 王子洋. 新疆西准噶尔苏根萨拉岩体锆石U-Pb年龄与Hf同位素及对构造演化的制约[J]. 中国地质, 2022, 49(5): 1624-1635. DOI: 10.12029/gc20220517
    JIN Song, ZHANG Hanwen, HAN Yabin, LI Xiaofeng, WANG Xingyan, WU Li'ang, WANG Ziyang. Zircon U-Pb ages and Hf isotopic compostions of Sugensala pluton in the western Junggar: Constraints on the tectonic evolution[J]. GEOLOGY IN CHINA, 2022, 49(5): 1624-1635. DOI: 10.12029/gc20220517
    Citation: JIN Song, ZHANG Hanwen, HAN Yabin, LI Xiaofeng, WANG Xingyan, WU Li'ang, WANG Ziyang. Zircon U-Pb ages and Hf isotopic compostions of Sugensala pluton in the western Junggar: Constraints on the tectonic evolution[J]. GEOLOGY IN CHINA, 2022, 49(5): 1624-1635. DOI: 10.12029/gc20220517

    新疆西准噶尔苏根萨拉岩体锆石U-Pb年龄与Hf同位素及对构造演化的制约

    Zircon U-Pb ages and Hf isotopic compostions of Sugensala pluton in the western Junggar: Constraints on the tectonic evolution

    • 摘要:
      研究目的 为了进一步了解西准噶尔地区构造演化。
      研究方法 对西准谢米斯台西段苏根萨拉岩体的花岗岩进行了LA-ICP-MS锆石U-Pb年龄和Hf同位素测试。
      研究结果 定年结果呈现出2期年龄:一期集中在440~450 Ma,第二期集中在410~420 Ma,根据锆石CL图像特征,认为(444.2±2.2) Ma(MSWD=0.99)代表了捕获锆石的年龄,(415.6±1.1)Ma代表了岩体的结晶年龄,为晚志留世,指示博什库尔—成吉斯岩浆弧至少在晚志留世就开始了广泛的岩浆活动。锆石的εHf(t)值变化范围为+8.6~+13.2,加权平均值为10.8±1.4,显示其原岩来源于地幔物质,其一阶段Hf模式年龄TDM1为521~742 Ma,两阶段模式年龄TDM2变化于565~858 Ma,本区花岗岩是亏损地幔物质上升到地壳,并在此停留一段时间后的熔融产物,其来源于年轻的地壳物质,表明花岗岩类的源岩为新生地壳物质的部分熔融,加入到大陆地壳中的新生组分可能主要为来自亏损地幔的玄武质岩浆。
      结论 推测准噶尔盆地可能是以新元古代晚期至早古生代早期,由亏损地幔演化而来的洋壳和岛弧建造组成的年轻地壳为主。这为进一步认识西准噶尔博什库尔—成吉斯岩浆弧的性质及构造演化提供了证据。

       

      Abstract:
      This paper is the result of geological survey engineering.
      Objective In order to further understand the tectonic evolution of the West Junggar region.
      Methods In this paper, the zircon UPb geochronology and Hf isotopes of Sugensala granites were carried out.
      Results The dating results show two stages of age. The first phase focused on 440-440 Ma and the second phase is concentrated in the 410-420 Ma. According to the characteristics of the zircon CL images, we consider a capture zircon age of (444.2±2.2) Ma and a crystallization zircon age of (415.6±1.1) Ma. It is implied there was a wide range of magmatic activity at least on late- Silurian in Boshchekul—Chingiz magmatic arc. The εHf(t) values of the zircon range of 8.6-13.2, with a weighted average of 10.8±1.4, indicating that its original rock is derived from mantle materials. The one-stage Hf model ages (TDM1) are 521-742 Ma and two-stage Hf model ages (TDM2) are 565-858 Ma. The granite was derived from the younger crustal materials from partial melting of the depleted mantle which raised to crust and stayed for a period of time. It shows that the source rocks of granites were generated from partial melting of new crustal material. The new components of continental crust may mainly come from depleted mantle-derived basaltic magma.
      Conclusions We speculate that Junggar basin is composed of young crust which evolved from depleted mantle in the period of late Neoproterozoic to Early Paleozoic. It is helpful to the further understanding the nature and tectonic evolution for Boshchekul-Chingiz magmatic arc.

       

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