Dieshan Fm
Type Locality and Naming
The type section is located in the Yiwagou area about 22 km to the north of Diebu County, Gansu Province. It was named by Shi Meiliang in 1976, and was first cited by the Compiling Group (1980) on the Regional Stratigraphic Chart of Gansu Province.
Lithology and Thickness
Marl. It can be divided into two parts, with lower part consisting of black carbonaceous calcareous shale, intercalated with thin-bedded limestone; and with the upper part consisting of dark-grey thin-bedded limestone, intercalated with calcareous siltstone. Its basal part consists of black shale. Its thickness is as great as 113 m.
Relationships and Distribution
Lower contact
Disconformable contact with the underlying Maokou Fm.
Upper contact
Conformable contact with the overlying Changxing Fm. Or in Zhangxian county, regionally the Shiguan Fm (also of Changhsingian age)
Regional extent
GeoJSON
Fossils
Lower part yields Brachiopods as represented by Spinomarginifera kueichowensis, Haydenella kiangsiensis and Avonia janus. Upper part yields Brachiopods such as Chonetes tenuilirata, Chonetella chonetoides, Derbyia sp., Neoplicatifera sp., Urushtenia crenulata, Spiriferellina sp., Composita sp.; and Corals such as Lophophyllidium sp., Liangshanophyllum sp.
Age
Depositional setting
It is interpreted as marine deposits.
Additional Information