The bottom boundary of sequence 3, sequence 4 and sequence 5 results from integrated effect of change of climate, sediment source and tectonic activity under falling global eustacy.

• 层序3、层序4和层序5的底界面是在构造作用稳定、全球海平面下降背景之上由相对海平面次一级旋回变化形成的，是古气候变化、沉积物供给及构造沉降共同作用的结果。