Chengqianggou Fm
Type Locality and Naming
The type section is located at Chengqianggou, Oulongbuluk Mt., Huaitoutala, Delingha, Qinghai Province. It was named by Mu Enzhi et al., in 1958−1963.
Lithology and Thickness
Limestone. Composed of limestone, sandy limestone and marl, 192.70 m thick.
The formation is 612.1 m thick at Amunike Mt., where it can be divided into two parts: the lower part consists of organic limestone and siliceous banded limestone intercalated with thin-bedded calcareous shale and siltstone; the upper part is of silty limestone.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Chuanshangou strata
Upper contact
Conformable contact with the overlying strata (Wutumeiren Fm, Xihansitegou Fm or Huaitoutala Fm, depending on region).
Regional extent
GeoJSON
Fossils
Corals Stiphonophyllum oppressa-Rylstonia oulongbulukensis assemblage and Brachiopods Echinoconchus elegans-Grandispirifer myldensis assemblage.
Age
Depositional setting
It is interpreted as a
Additional Information
After the Tournaisian Chuanshangou biota was discovered (1975), serious disputes arose on the present formation: some thought it represented the Tournaisian deposits of the region (The Regional Stratigraphical Scale of Qinghai, 1980), others placed it at the transitional layer between Tournaisian and Visean (Hou Hongfei et al., 1980), while Yu Jianzhang et al. (1978) attributed it to the early Visean.