金沙江堵江堰塞事件及其地貌环境效应研究进展

Research Progress of Landslide Dam Events of Jinsha River and Its Geomorphologic and Environmental Effects

摘要: 强烈的新构造运动和区域地质地貌条件使得堵江堰塞事件在金沙江河谷广泛发育，通过总结前人研究与笔者野外考察和分析研究后认为，堵江堰塞事件发育对金沙江河谷演化的作用与影响大致为以下次序：构造活动及气候异常事件→发生滑坡堵江事件→形成堰塞坝(湖)→堰塞坝(湖)解体消亡→河谷地貌及环境变化→现代金沙江河谷地貌的形成。同时，堵江堰塞现象有在地质构造破碎带、河谷纵比降变化、构造运动活跃和异常气候事件高发期高频发育之规律和具有突发性、短暂性等显著特点；堵江堰塞造成区域沉积过程和河流下切动力过程的快速改变以及水文、局域气候、地质稳定性、河谷地貌和生态环境的快速变化。堵江堰塞事件在各河段的发生形式、发育年代和机制、期次及次生地貌环境效应表现各异，加上后期侵蚀及堵江过程对于前期遗迹的破坏作用使得其研究变得十分复杂而困难。因此，在其系统研究、年代的确定、堰塞坝(湖)的识别、堰塞湖钻探采样及其沉积物信息提取研究等方面还有更大的深入探讨和提升空间。

Abstract: Strong neotectonic movements and regional landscape conditions results in landslide damming events are widely exist in JinshaRivervalley. Through summarizing the study results by other researchers and the our field invest- tigations, the development processes of the landslide damming of Jinsha River and its effects on the evolution of land- scape can be described as following sequences: strong neotectonic activities and climatic anomaly events → the occur- rence of landslide blocking river → landslide dam (dammed lakes) formation → landslide dam (dammed lakes) bro- ken/collapse → river re-shaping the valley geomorphology and environments → Modern Jinsha River valley landscape formation. It is clear that most of the damming occurred in the places with developed fault structures, rich in broken matters, with step and narrow valleys, high frequency earthquakes and climate abnormal. Even most of the landslides damming events occur suddenly and without any sign and are unpredictable, but after the damming and broken of the dams, the local, even the regional landscapes, environments, climate, ecology and the geomorphological processes, geological stabilities changed completely. The mechanisms and frequencies of landslide damming are unpredictable till now, together with the damage of the existed damming relics, it is difficult to get a complete and clear picture of the landslide damming history of the river system and makes more complex and difficult to conduct a study. Therefore, a comprehensive study planning is necessary to improve our understanding of the system, as there are a lot of aspects on how, when and why the landslide damming events happen in the area need to be investigated.