ISSN 1000-3665 CN 11-2202/P

    川西南喜德县地质灾害发育特征及其沉积-构造孕灾规律研究

    Development and distribution characteristics of geohazards based on sedimentary-structural evolution in Xide County, southwest Sichuan

    • 摘要: 四川省喜德县地处扬子陆块西缘与青藏高原东缘造山带过渡区,区内地质演化复杂、差异显著,地质灾害分布广泛、类型多样,尽管前人对内动力致灾机理已开展大量研究,然而县域尺度下各关键基础地质孕灾因子相互叠加及其与地质灾害孕育的耦合关系仍有待深入研究。基于现场调查、基础地质资料与历史地质灾害数据收集,从区域地质历史演化角度,通过不同分区各异的基础地质孕灾条件与不同类型地质灾害发育趋势的对比分析,深刻剖析了两者的深层次耦合关系。结果表明:区域地层分布、构造改造差异以及地质演化历史是制约研究区不同类型地质灾害发育的关键主控因子,区内地质灾害类型以滑坡(240处)、泥石流(81处)为主,崩塌(7处)发育较少,全县可划分为变质基底区、被动陆缘沉积区、前陆盆地沉积区、陆内凹陷盆地区等4个孕灾模式区;软弱红层主控下宽缓褶皱构造是滑坡地质灾害的主要孕灾环境,断裂褶皱等强烈构造改造是泥石流发育的关键,坚硬碳酸盐岩、岩浆岩等地层叠加漫长的构造演化是崩塌发育的重要条件;松软的白果湾组炭质泥页岩分布与强烈断裂改造叠加是制约红莫镇一带滑坡-泥石流链式灾害的关键基础地质条件。该研究将进一步指导区域地质灾害早期识别,为防灾减灾提供重要参考。

       

      Abstract: Xide County, located in Sichuan Province, lies at transitional zone between the western margin of the Yangtze Block and the eastern margin of the Qinghai-Tibet Plateau. The geological evolution in the area is complex and diverse, with a wide distribution and various types of geohazards. While previous research has extensively studied the mechanisms of endogenic disaster causation by predecessors, further investigation is needed into how key foundational geological factors contribute to disaster formation and their interrelationship at the county level. Based on field investigations, foundational geological data, and historical records of geohazards, this study conducted a comparative analysis of the geological conditions for disaster formation in different zones and the developmental trends of various types of geohazards, from the perspective of regional geological evolution. The deep coupling relationship between the two is deeply analyzed. The results show that distribution of regional stratigraphy, differences in structural transformation, and geological evolution history are key factors controlling the development of different types of geohazards in the study area. The main types of geohazards in the area are landslides (240 occurrences) and debris flows (81 occurrences), with less development of collapses (7 occurrences). The county can be divided into four disaster gestation model zones: the metamorphic basement area, the passive continental margin sedimentary area, the foreland basin sedimentary area, and the intracontinental depression basin area. The wide and gentle fold structures in red beds are the disaster-prone environment for landslide. Strong structural transformations are the primary factor driving the development of debris flows. Collapses occur primarily in areas where hard carbonate rocks and magmatic rocks overlay, combined with a long history of structural evolution. The distribution of the Baiguowan Formation carbonaceous mudstone and intense fault transformations are the key geological conditions that constrain the chain disasters of landslides and debris flows around Hongmo Town. This study provides further insight into the early identification of regional geohazards and offers important guidance for disaster prevention and reduction.

       

    /

    返回文章
    返回