乐昌峡水库岸坡的活动性研究

THE ACTIVITY OF THE BANKSIDE OF LECHANG GORGE

本文运用热释光测年方法对乐昌峡水库岸坡松山子、半岭地质体滑动面上的石英砂进行年代测定。结果认为,松山子地质体的最后一次活动时间为距今20000年左右,半岭地质体沿与河床走向垂直的方向运动的最后一次活动时间为距今19500年左右,沿与河床走向平行的方向运动的时间为距今13400年左右,以后均处于比较稳定的阶段。

The Lechang Gorge hydropower station will be built at middleupper course of Wushui river, north of Lechang county. The stability of the bankside of Lechang Gorge is very important, because it decide whether the hydropower station will be built and where the dam will be built. In order to determine the activity of some bankside of Lechang Gorge, Four samples were got from two structure units which someone call landslide and use the thermoluminescence chronology to date their activity. Two samples of Songshanzi are debris which are in the same structural plane. Two samples of Banling are sandy clay which are in the same structural plane but this two samples have striation in two different direction. The result indicate that the last activity of the structural plane in Songshanzi is about 20000 a. BP, the last activity of the structural plane along the bed direction in Banling is about 13440 a.BP, and about 19500 a.BP alone the bed direction vertically. They are stable from that time. Also the possibility using the thermoluminescence chronology to determine the activity of structural plane was discussed.