长江三峡库区滑坡发育与河道演变的地质过程分析

Landslide Development and the Geological Process of Watercourse Evolution in the Three Gorges Reservoir Area

据区域地质灾害调查,三峡库区发育有数以千计的滑坡.年代学研究表明,三峡地区的滑坡均发生于第四纪中更新世中后期,并具有明显的阶段性特征,滑坡的高发期大致为:(41～37)×104aBP、(31～27)×104aBP和(17～5)×104aBP.滑坡发育与区域新构造抬升和河流地貌形成的地质过程相一致,且主要发生在第四纪的间冰期,表明滑坡与构造抬升、气候变暖、长江河道快速下切贯通发展具有一定的耦合关系.三峡地区尚未发现年龄超过54×104aBP的滑坡,据此推测长江贯通三峡的时间可能在早更新世.

According to the regional survey for geo-hazards, thousands of landslides occurred in the Three Gorges reservoir area. Chronology studies show that these landslides mostly occurred after the Mid-Pleistocene and could be divided in 3 stages, namely, （41-37） × 10^4 aBP, （31-27）× 10^4 aBP and （17-5）× 10^4 aBP. These landslides mostly occurred in the interglacial period and could be well related with the regional uplift and geological process of the formation of river landform in the Three Gorges area. Based on these, we conclude that the occurrence of the landslides can be well correlated with tectonic uplift, cli- mate change, rapidly down-cutting and breakthrough development in the Yangtze River. It is inferred that the cut-through timing of the Three Gorges probably be Early Pleistocene mainly owing to the loss of landslides which ages older than 54 ×10^4 aBP.