河流水位变幅是影响阶地划分与新构造分析的重要因素——以长江三峡段为例

WATER LEVEL CHANGE AMPLITUDE──A KEY FACTORINFLUENCING TERRACE DIFFERENTIATION AND NEOTECTONIC ANALYSIS

本文分析了长江三峡地区河流水位变幅对阶地的影响,认为水位变幅是影响阶地划分与新构造分析的重要因素。为了剔除水位变幅的影响,作者提出了阶地相对位相图的概念;并从三峡阶地远距离对比以及新构造上升的中心、幅度、速度等方面作了尝试。

The author has analysed the influence of water level change amplitude in determining the relative heights of Changjiang (Yangtze) River terraces in the Sanxia Gorge (Three Gerges) area, and has canceled this effect in neotectonics analysis. The extraordinary relative height of first terrace (T1 for short) is mainly the result of greater water level change amplitude in gorge area. To eliminate the effect of water level change amplitude, the new concept------ter-race relative phase diagram is put forward. Taking the line joining T1 as the base line (straight line), and measuring the relative heights of other terraces above it, the terrace relative phase diagram (Fig. 3-b) was obtained- and from it, true amplitudes of neotectonic uplift along def-ferente secions of the river were measured.