广东河谷地貌

Valley Landform in Guangdong Province

广东河流从上游或源头区到中下游，上更新统为主的第一级阶地变形为半埋藏阶地，到三角洲再变形为埋藏阶地．阶地变形的动力：①冰后期海面回升使洋盆增荷下沉，从而牵引大陆沉降；②溯源堆积．燕山运动使先前的河流消失，所形成的向斜谷、断陷谷是最早的河谷，而横谷才是次成河并成为向斜谷、断陷谷的支流．顺着横谷方向没有红层盆地是横谷发育较晚的证据．由此判断东江形成最早，其次北江。

From the upper reaches or source area to the middle lower reaches of rivers in Guangdong Province, the first stage terrace of late Pleistocene Series is deformed into semi buried terrace, and to the delta deformed into buried terrace in the delta. The deform power of the terrace are:(1) The re rise of sea level in postglacial age caused the water load increase and the ocean basin fall, thus pulled the continent fall;(2) Accumulation upwards. Yianshan Movement resulted in disappearance of rivers before the movement. Synclinal valleys and rift valleys formed by the movement are the earliest valleys, while the cross valleys are tributary of the synclinal valley and rift valley. An evidence of the cross valley developing later is that there is not red beds basin along the cross valley. It is concluded that the Dongjiang River formed earliest, followed by the Beijiang River. The Xijiang River formed latest.