王晓青, 刘敏. 0: 华北克拉通中部造山带中条山地区古元古代盆地演化. 地质通报. DOI: 10.12097/gbc.2023.11.044
    引用本文: 王晓青, 刘敏. 0: 华北克拉通中部造山带中条山地区古元古代盆地演化. 地质通报. DOI: 10.12097/gbc.2023.11.044
    , Min LIU. 0: The Paleoproterozoic basin evolution of the Zhongtiao Mountain region in the Trans-North China Orogen, North China Craton. Geological Bulletin of China. DOI: 10.12097/gbc.2023.11.044
    Citation: , Min LIU. 0: The Paleoproterozoic basin evolution of the Zhongtiao Mountain region in the Trans-North China Orogen, North China Craton. Geological Bulletin of China. DOI: 10.12097/gbc.2023.11.044

    华北克拉通中部造山带中条山地区古元古代盆地演化

    The Paleoproterozoic basin evolution of the Zhongtiao Mountain region in the Trans-North China Orogen, North China Craton

    • 摘要: 通过对华北克拉通中部造山带南部中条山地区古元古代中条群和担山石群岩石组合及地层详细调查研究,认为中条群为一套由粗碎屑岩-泥质岩-碳酸盐岩组成的多旋回沉积岩,变质砂岩的地球化学特征显示中条群经历了早期的相对稳定到后期较为活跃的转变。结合前人碎屑锆石年龄、源区特征和斜长角闪岩夹层SIMS锆石U-Pb年龄显示中条群形成于~2.1Ga大陆边缘相关的弧后盆地内。担山石群为一套砾岩-砂岩组成的磨拉石建造,碎屑锆石年龄显示担山石群形成于~1.85Ga碰撞造山阶段的前陆盆地内。结合前人研究成果,我们总结出中条山地区早元古代盆地演化模式:从~2.1Ga开始,西部陆块的前导洋向东部陆块活动大陆边缘之下持续俯冲,东部陆块西缘活动大陆边缘弧后盆地沉积了中条群地层,从~1.85Ga开始,东部陆块与西部陆块之间的大洋闭合,陆陆碰撞作用开始,中条群发生挤压褶皱变形,随后发生弹性下弯,快速抬升和剥蚀形成的前陆盆地中沉积了担山石群磨拉石。中条山地区古元古代弧后盆地向弧背前陆盆地的转化支持华北克拉通最初西部陆块向东俯冲,经历了~1.85Ga东西陆块碰撞,并最终克拉通化的演化模式。

       

      Abstract: This paper conducted detailed investigations of the lithological assemblages and stratigraphy of the Zhongtiao Group and the Danshanshi Group in Zhongtiao Mountain region, Trans-North China Orogen (NTCO), North China Craton. The Zhongtiao Group comprises of a suit of metamorphic sedimentary rocks, consisting of multicyclic sedimentary rocks composed of clastic rocks, mudstones and carbonate rocks. The geochemical characteristics of the metamorphic sandstone show that the Zhongtiao group experienced a transition from early relative stability to late activity. Detrital zircons from the Zhongtiao Group and SIMS U-Pb analyses of zircon grains from an intercalated amphibolite indicate that they were deposited ~2.1Ga and formed in a back-arc basin of active continental margin. The Danshanshi Group is a series of conglomerates and sandstones forming a molasse basin during the collisional orogeny stage at approximately 1.85 Ga.  Taken together, we present a brief scenario for the evolution of the sedimentary basin in Zhongtiao mountain region. From approximately 2.1Ga, the estward-directed subduction of the ocean between Western block and Eastern block, back-arc basin (Zhongtiao Group) developed behind the arc that located in the west margin of Estern block, resulting in the deposition of the Zhongtiao Group in the back-arc basin on the western margin of the Estern block. Starting from approximately 1.85 Ga, the ocean between Western block and Eastern block closed, resulting in the collision of the two blocks along TNCO, the Zhongtiao Back-arc basin underwent fold deformation and is finally transformed into a retro-arc foreland fold-and-thrust belt. The Danshanshi foreland molasse basin is formed overlying this foreland fold-and-thrust belt. Such a shift from the back-arc basins to foreland basins in the Late Paleoproterozoic supports the model that the collision between Eastern and Western blocks occurred at ~1.85Ga.

       

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