金沙江上游特米古滑坡堰塞湖形成与溃决时间讨论

Conducting research on the formation and evolution process of ancient landslide-dammed lakes can reveal the geological environmental effects of ancient disasters and reconstruct the regional tectonic historical activity sequence and the characteristics of paleoclimate evolution. The Temi ancient landslide developed in the Batang section of the upper Jinsha River, and the landslide accumulation landform and lacustrine sediments of the dammed lake are well preserved, making it an excellent carrier of the ancient geological environment in the study area. Based on remote sensing interpretation, unmanned aerial vehicle (UAV) mapping, on-site investigation and geological dating, and combined with previous research results, the development characteristics of the Temi ancient landslide, the formation time of the dammed lake and the process of its breach and evolution were analyzed and discussed. The results show that the Temi ancient landslide is an extremely large rock historical river-blocking landslide, and the actual formation time of the landslide-dammed lake should be much earlier than 2.15 ka BP. There have been multiple breaches in history, and the complete breach time was approximately 1.08 ka BP, and the stable preservation time of the dammed lake is greater than 1.07 ka. The large river-blocking landslide group in the Batang section of the Jinsha River was not formed by a single geological event, but was induced by multiple strong earthquakes in the Jinsha River fault zone.

开展古滑坡堰塞湖形成演化过程研究,可以揭示古灾害地质环境效应,重建区域构造历史活动序列和古气候演变特征。特米古滑坡发育于金沙江上游巴塘段,滑坡堆积地貌和堰塞湖相沉积物保存较好,是研究区内古地质环境的良好载体。在遥感解译、无人机测绘、现场调查和地质测年的基础上,结合前人研究成果,分析探讨了特米古滑坡发育特征、堰塞湖形成时间与溃决演化过程。结果表明,特米古滑坡是特大型岩质历史堵江滑坡,滑坡堰塞湖实际形成时间应该远早于2.15 ka BP,历史上曾发生过多次溃决,完全溃决时间大约为1.08 ka BP,堰塞湖稳定保存时间大于1.07 ka。金沙江巴塘段大型堵江滑坡群并非由单次地质事件形成,而是由金沙江断裂带多次强烈地震诱发。