Changes of base-level faces make the change of the ratio of accommodation space and sedimentary alimentation (A/S).Low ratio means the light heterogeneity, high ratio causes the heavy heterogeneity.

• 因此，层间非均质性受控于基准面旋回变化造成的A/S值的变化，A/S值小非均质性弱，A/S值大非均质性强。