Because of Yizheng orogeny in Late Cretaceous,braided delta system of Anfeng was formed by rifting in Subei Basin and rising of sedimentary base level.

• 受晚白垩世仪征运动的影响,苏北盆地拉张断陷,沉积基准面上升,从而形成了比较完整的安丰退积型辫状三角洲沉积体系。