From Cretaceous Period to Paleocene-Eocene, subsidence and sedimentation area migrated gradually towards inside basin because the major thrust belts were piggyback and developed towards inside basin.

• 白垩纪至早第三纪古、始新世，由于主干逆冲断裂带背驮式地向盆内发展，沉降-沉积中心逐渐向盆内迁移；