李利阳, 韩瑶, 伍光英, 侯红星, 刘博, 刘根源. 大兴安岭乌奴耳地区石炭纪花岗闪长岩锆石U-Pb年龄及形成地质背景[J]. 地质与资源, 2022, 31(6): 707-715, 728. DOI: 10.13686/j.cnki.dzyzy.2022.06.001
    引用本文: 李利阳, 韩瑶, 伍光英, 侯红星, 刘博, 刘根源. 大兴安岭乌奴耳地区石炭纪花岗闪长岩锆石U-Pb年龄及形成地质背景[J]. 地质与资源, 2022, 31(6): 707-715, 728. DOI: 10.13686/j.cnki.dzyzy.2022.06.001
    LI Li-yang, HAN Yao, WU Guang-ying, HOU Hong-xing, LIU Bo, LIU Gen-yuan. ZIRCON U-Pb AGE AND GEOLOGICAL BACKGROUND OF CARBONIFEROUS GRANODIORITES IN WUNUER AREA, DAXINGANLING MOUNTAINS[J]. Geology and Resources, 2022, 31(6): 707-715, 728. DOI: 10.13686/j.cnki.dzyzy.2022.06.001
    Citation: LI Li-yang, HAN Yao, WU Guang-ying, HOU Hong-xing, LIU Bo, LIU Gen-yuan. ZIRCON U-Pb AGE AND GEOLOGICAL BACKGROUND OF CARBONIFEROUS GRANODIORITES IN WUNUER AREA, DAXINGANLING MOUNTAINS[J]. Geology and Resources, 2022, 31(6): 707-715, 728. DOI: 10.13686/j.cnki.dzyzy.2022.06.001

    大兴安岭乌奴耳地区石炭纪花岗闪长岩锆石U-Pb年龄及形成地质背景

    ZIRCON U-Pb AGE AND GEOLOGICAL BACKGROUND OF CARBONIFEROUS GRANODIORITES IN WUNUER AREA, DAXINGANLING MOUNTAINS

    • 摘要: 对乌奴耳地区花岗闪长岩进行的LA-ICP-MS锆石U-Pb测年和岩石地球化学测试结果表明: 花岗闪长岩的锆石U-Pb加权平均年龄为332.6±6.9Ma(MSWD=3.1), 时代为早石炭世. 岩石地球化学数据显示, 花岗闪长岩属准铝质低钾(拉斑)系列.花岗闪长岩总体富集大离子亲石元素, 亏损高场强元素. Th、U表现, 为明显正异常, Nb、Ta、Zr、Ti表现明显负异常, La、Hf、Lu等富集, δEu值为0.61~0.69, 具有负铕异常, 与I型花岗岩相似, 具有火山弧花岗岩的特征, 表明该侵入岩的形成与俯冲作用有关. 综合区域地质特征及本研究认为, 花岗闪长岩为早石炭世古亚洲洋俯冲时的产物, 可为古亚洲洋及东北地块构造演化研究提供新的约束和佐证实例.

       

      Abstract: The LA-ICP-MS zircon U-Pb dating and petrogeochemical results show that the granodiorite in Wuluer area was formed in the Early Carboniferous, with weighted mean zircon U-Pb age of 332.6±6.9 Ma(MSWD=3.1), belonging to the quasi-aluminous low potassium(tholeiite) series. The granodiorite is generally characterized by enrichment of LILEs and depletion of HFSEs, as well as obviously positive Th and U anomalies, notably negative Nb, Ta, Zr and Ti anomalies, enriched La, Hf and Lu, and negative Eu anomaly, which is similar to I-type granite and has the characteristics of volcanic arc granite, indicating that the formation of the intrusive rock is related to subduction. Combined with the regional geological characteristics, it is concluded that the granodiorite is the product of subduction of Paleo-Asian Ocean in Early Carboniferous, which may provide new constraint and evidence for the study of tectonic evolution of Paleo-Asian Ocean and Northeast China block.

       

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