Enlarged pore, oversized pore and intragranular pore have been developed on the base of residual original intergranular pore by the dissolution of framework constituents.

• 本地区，在剩余原生粒间孔发育的基础上、发生溶蚀作用，形成一些原生扩大孔，超大孔、粒内溶孔等。