李利阳, 冯欣, 焦晓宇, 金鹏, 杨征. 大兴安岭乌奴耳地区白音高老组的厘定及其地质意义[J]. 地质与资源, 2024, 33(2): 135-142, 151. DOI: 10.13686/j.cnki.dzyzy.2024.02.001
    引用本文: 李利阳, 冯欣, 焦晓宇, 金鹏, 杨征. 大兴安岭乌奴耳地区白音高老组的厘定及其地质意义[J]. 地质与资源, 2024, 33(2): 135-142, 151. DOI: 10.13686/j.cnki.dzyzy.2024.02.001
    LI Li-yang, FENG Xin, JIAO Xiao-yu, JIN Peng, YANG Zheng. DETERMINATION OF THE BAIYINGAOLAO FORMATION IN WUNUER AREA, DAXINGANLING MOUNTAINS: Geological Implication[J]. Geology and Resources, 2024, 33(2): 135-142, 151. DOI: 10.13686/j.cnki.dzyzy.2024.02.001
    Citation: LI Li-yang, FENG Xin, JIAO Xiao-yu, JIN Peng, YANG Zheng. DETERMINATION OF THE BAIYINGAOLAO FORMATION IN WUNUER AREA, DAXINGANLING MOUNTAINS: Geological Implication[J]. Geology and Resources, 2024, 33(2): 135-142, 151. DOI: 10.13686/j.cnki.dzyzy.2024.02.001

    大兴安岭乌奴耳地区白音高老组的厘定及其地质意义

    DETERMINATION OF THE BAIYINGAOLAO FORMATION IN WUNUER AREA, DAXINGANLING MOUNTAINS: Geological Implication

    • 摘要: 中国东北大兴安岭地区发育大量中生代火山岩, 早白垩世火山岩是其重要的组成部分. 目前关于早白垩世早期火山岩的地层单位归属及构造背景存在较大争议, 笔者以大兴安岭乌奴耳地区的早白垩世流纹岩为研究对象, 进行锆石U-Pb定年和岩石地球化学测定工作. 结果表明: 流纹岩LA-ICP-MS锆石U-Pb年龄为134.3±1.8 Ma, 时代为早白垩世早期. 根据岩石组合、时空展布等, 将其归为白音高老组. 岩石地球化学分析结果显示: 乌奴耳地区的流纹岩为高硅高钾弱过铝质钙碱性系列, 岩石整体富集大离子亲石元素K、Rb、Ba等, 亏损大离子亲石元素Sr和高场强元素Nb、P、Ti等, 轻稀土元素相对富集, 重稀土元素相对亏损, 具有中等的负Eu异常(δEu=0.57~0.96). 结合区域地质背景及前人研究成果, 认为乌奴耳地区的白音高老组形成于古太平洋西向俯冲的火山弧环境.

       

      Abstract: A large number of Mesozoic volcanic rocks are developed in Daxinganling Mountains of Northeast China, among which the Early Cretaceous volcanic rocks serve as an important part. The stratigraphic attribution and tectonic setting of the Early Cretaceous volcanic rocks of the early stage are controversial currently. Taking the Early Cretaceous rhyolites in Wunuer area of Daxinganling Mountains as the study object, the authors carry out the zircon U-Pb dating and lithogeochemical determination. The results show that the LA-ICP-MS zircon U-Pb age is 134.3±1.8 Ma, indicating the early Early Cretaceous. According to rock association and spatiotemporal distribution, the rhyolites are assigned to Baiyingaolao Formation. The lithogeochemical analysis indicates that the rhyolites in the area belong to high-Si high-K weak peraluminous calc-alkaline series, characterized by enrichment of LILEs(K, Rb and Ba), and depletion of Sr and HFSEs(Nb, P and Ti), relative enrichment of LREEs and depletion of HREEs, with moderate negative Eu anomaly. Combined with the regional geological background and previous research results, it is concluded that the Baiyingaolao Formation in Wunuer area was formed in the volcanic arc setting related to the westward subduction of Paleo-Pacific Ocean.

       

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