黄河中上游流域烧变岩地质构造成因机理

Tectonic genetic mechanisms of burnt rocks in the upper and middle reaches of the Yellow River basin

  • 摘要:
    目的 黄河中上游流域是我国重要的煤炭基地,煤火高温形成的烧变岩是影响该区煤炭安全绿色开采的重要因素。研究黄河中上游流域烧变岩分布规律和地质成因机理具有重要的科学意义和实践价值。
    方法 系统调研黄河中上游流域内烧变岩分布范围与规律,通过地质过程剖析,探讨不同区域烧变岩的地质成因机理及主控因素。
    结果和结论 黄河中上游流域内烧变岩主要集中出露于陕西韩城段、陕晋蒙段、贺兰山段与甘肃窑街段4个区域,呈现为沿盆缘、黄河及其支流带状分布特征。地质构造控制了黄河中上游流域烧变岩的形成与发育,韩城段烧变岩受燕山期禹门口大断裂的挤压抬升控制;陕晋蒙段烧变岩受多期次区域性的隆升和剥蚀影响;贺兰山段强烈挤压性地质构造活动是该地区烧变岩形成的重要因素,尤其是晚侏罗世以来的燕山运动和始新世以来的喜马拉雅运动;窑街段烧变岩显著受到燕山期及喜马拉雅期挤压运动形成的东部压剪性断裂影响。黄河流域中上游烧变岩分布与鄂尔多斯盆地和民和盆地的燕山期强烈构造活动密切相关,新生代鄂尔多斯盆地周缘断裂发育,盆山耦合作用加剧,现代黄河水系形成并强烈剥蚀和下蚀作用是煤层自燃高温形成带状烧变岩的重要原因。研究结果可为区域煤炭开采的水害防治和生态环境保护提供理论指导。

     

    Abstract:
    Objective The upper and middle reaches of the Yellow River basin represent significant coal bases of China, while burnt rocks formed by the high temperature of coal fires greatly affect the safe and green coal mining in this region. Therefore, investigating the distribution patterns and geological genetic mechanisms of burnt rocks in this region is of great scientific significance and practical value.
    Methods This study systematically investigated the distribution range and patterns of burnt rocks in the upper and middle reaches of the Yellow River basin. Using analysis of geological processes, this study explored the geological genetic mechanisms and primary controlling factors of burnt rocks in different areas across the upper and middle reaches.
    Results and Conclusion The burnt rocks in the upper and middle reaches of the Yellow River basin are predominantly exposed in the Hancheng section in Shaanxi Province, the Shaanxi-Shanxi-Inner Mongolia (SSIM) section, the Helanshan section, and the Yaojie section in Gansu Province, exhibiting a zonal distribution pattern along basin margins, as well as the Yellow River and its tributaries. The formation and development of the burnt rocks were governed by geological-tectonic processes. Specifically, the burnt rocks in the Hancheng section were subjected to the compressional uplift of large-scale Yumenkou majior fault (i.e., the Hancheng fault) during the Yanshanian, while those in the SSIM section were influenced by multi-stage regional uplift and denudation. In the Helan Mountain section, burnt rocks were formed primarily due to intense compressional tectonic activities, especially the Yanshanian movement since the Late Jurassic and the Himalayan movement since the Eocene. In contrast, the burnt rocks in the Yaojie section were significantly influenced by the east compressive shear fault, which was formed by the compressional movements during the Yanshanian and Himalayan. The distribution of burnt rocks in the upper and middle reaches of the Yellow River basin is closely associated with the intense Yanshanian tectonic activities in the Ordos and Minhe basins. During the Cenozoic, faults were formed at the periphery of the Ordos Basin, and basin-mountain coupling intensified. Concurrently, the modern Yellow River was formed, inducing intense denudation and downward erosion. These activities represent the key reasons for the zonal distribution of burnt rocks formed by the high temperature attributed to the spontaneous combustion of coal seams. The results of this study can provide a theoretical guide for the prevention and control of water hazards, as well as ecological protection, for regional coal mining in the upper and middle reaches of the Yellow River basin.

     

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