Mingyuefeng Fm

Depressions north of Taiwan. The naming section is located in Mingyuefeng No. 1 well of the Oujiang depression in the East China Sea continental shelf basin at 122º15′51"E and 27º07′54"N. Named by the Shanghai Marine Geological Party, former Ministry of Geology and Mineral Resources in 1988.

Lying below the Oujiang Fm and above the Lingfeng Fm, the Mingyuefeng Formation is a sequence of coal-bearing sandy mudstone with scarce marine fossils. The seismic wave group is the T₄⁰ unconformity at the top of the coal measures and the T₄¹ seismic boundary at the bottom. The formation takes the 1973–2318 m interval of Mingyuefeng No. 1 well as the stratotype section. The formation is divided into two members: the Lower member consists dominantly of gray fine sandstone in the lower part and non-isopachous alternating beds of light gray fine sandstone and siltstone and gray mudstone in the upper part; the Upper member is light gray sandstone with variegated mudstone and bituminous coal. The thickness is 400–500 m.

Marine fossils contained in the strata have been greatly reduced. The benthic foraminifera are Haplophragmoides lingfengensis and the planktic foraminifera are Globorotalia wilcoxensis and G. chapmani (P₅–P₇); ostracods are monotonous, and only Neomonoceratina donghaiensis appears in large numbers; calcareous nannofossils are those of zones NP9–NP11: Chiasmolithus bidens, Neochiastozygus distentus and tribrachiatus contortus etc.; dinoflagellates are Ascodinium etc. The sporopollen assemblage is dominated by Triporopollenites, being Myricaceoipollenites-Casuarinaepollenties-Nyssapollenites.

This formation is coal measures in a regressive environment, belonging to littoral-swampy deposits.