The intercalations are divided into five types, such as muddy intercalation, silty intercalation, calcareous intercalation, marly intercalation, and gravel intercalation.

• 夹层类型主要有泥岩夹层、粉砂质泥岩夹层、灰质夹层、泥灰质夹层和砾石质夹层5种。