Funing Fm

The naming section is located in well Fuji No. 1, Funing County, northern Jiangsu basin. Named by the Petroleum Reconnaissance Party of Jiangsu Geoglogy Bureau and East China Bureau of Petroleum Exploration, in 1958.

From below to above four members may be distinguished: First member, ~700 m thick, is alternating beds of brownish red sandstone and dark brown mudstone, with black mudstone at the top, containing rich gypsum concretions; Second member, ~200–300 m thick, is dominated by grayish black mudstone with thin-bedded of muddy limestone, bioclastic limestone, muddy dolostone and oil shale, the base of which is marked by marlstone, oolitic limestone and bioclastic limestone; Third member, ~0–380 m thick, is alternating beds of grayish black and dark gray mudstone and muddy siltstone and sandstone; Fourth member, ~0–560 m thick, consists dominantly of dark gray and grayish black mudstone and silty mudstone, the upper part of which is intercalated with thin beds of organic limestone, oolitic limestone and worm tube limestone. The total thickness may reach more than 1500 m.

This formation contains abundant fossils, mainly including ostracods, charophytes, sporopollen and vertebrates.

The formation is lakeshore, deltaic-brackish lake sedimentary sequence.