Enping Fm

Pearl River Mouth Basin (offshore). The naming section is located in well EP18-1-1A in the Enping depression, Pearl River Estuary basin. The reference section is located in well EP17-3-1. Named by the Eastern South Sea Branch, China National Offshore Oil Corp. in 1985. The stratotype section is in the 2976–3426 m interval of well EP18-1-1A and now refers to a sequence of coal-bearing clastic rocks between the Eocene Wenchang Formation and Oligocene Zhuhai Formation.

Lower part consists of light gray, thick-bedded sandstone and pebbly sandstone with dark gray mudstone. Upper part is marked by alternating beds of black gray mudstone and thin-bedded sandstone with coal seams and carbonaceous shale. The thickness is 450 m. The thickness varies relatively greatly, from 0 to 1115 m, with the thickest in the Wenchang, Baiyun and Enping depressions. This formation is equivalent to the reflector group between seismic profiles T₇–T₈.

This formation contains abundant sporopollen, represented by the Dicolpopollis kockelii-Gothanipollis bassensis assemblage. Calcareous nannofossils are scarce, and only Micula decussata was found in well EP13-3-1.

It belongs to fluvial plain, swampy and deltaic deposits and is widespread.