Development of the south fold-thrust belt took place slightly earlier than that of the north fold-thrust belt.Presence of multiple unconformities further indicates pulses of thrust faulting.

• 根据这两个前陆褶皱冲断带中地层不整合的层位不一一对应和分布范围、展布特点有不同 ,认为南缘冲断活动稍早于北缘 ,二者的冲断规模也不完全相当。