Abstract: There are three levels of alluvial terrace in the upper Yongding River drainage basin since late Pleistocene. We obtained the timescale of terraces by radiocarbon dating method and luminescence dating method. It shows that the degradational episodes of these terraces occurred at the same period and the climate is the primary control factor and plays a greater role on formation of the terrace. The T₃, T₂ and T₁ began to degrade about 30ka B.P., 10 ka B.P., 4ka B.P., respectively.

Key words: Yongding River, Terrance, Chronology

摘要： 应用¹⁴C测年法和热释光方法对采自永定河上游晚更新世晚期以来形成的堆积阶地样品进行了年代测定。研究结果表明,永定河上游三条一级支流的低阶地形成时代具有一定的同时性,第三级阶地的下切时间大约在30000a B.P.;第二级阶地的下切时间大约在10000a B.P.;第一级阶地的下切时间大约在4000a B.P.。气候变暖对第二级阶地形成起主导作用,构造作用对最新阶地形成有一定的影响。

关键词: 永定河, 阶地, 年代学