Qinjia Fm

The type section is located at near Qinjia Village of Yandong Town, 40 km southeast of Debao County. The name was proposed by Wu Y. and Yan C.X. in 1980, who includes two members: Pingcheng Mbr below and Duowen Mbr above. Lithologically, they are quite different: the former consists of medium to thick bedded limestone, dolomitic limestone and dolomite, while the latter is composed of thin to medium bedded argillaceous limestone with siliceous bands containing abundant dacryoconarids. The re-definition of Qinjia Fm here is only limited to the original Pingcheng Member. The Duowen Member refers to its overlying Debao Fm.

Limestone. The formation reaches a thickness of approximately 120 m in the stratotype. It can be divided into three units, from bottom to top: (1) gray, dark grayish medium to thick bedded argillaceous limestones, 17.41 m thick; (2) light to dark grayish medium to thick bedded limestone with dolomitic nodules yielding stromatoporoids and tabulate corals, 64.83 thick; (3) dark grayish medium to thick bedded limestone intercalated with bands and lenses of dolomitic limestone, 32.38 m thick.

[Figure: Outcrops of Qinjia Fm near Duowen Village]

The main fossils are Tabulate corals Pachyfavosites polymorphus, Cladopora sp.,

Yacutiopora sp., Caliopora sp.. Others are stromotoporoids Amphipora sp.,

Paramphipora sp.; brachiopods Rostrospirifer sp., Dicoelostrophia punctate; and Ostrocods Primitia sp. Conodonts Polygnathus dehiscens, P. perbonus.

It is interpreted as an open carbonate platform environment.