Chuanshangou Fm
Type Locality and Naming
The type section lies 5 km from the west side of Chuanshangou in the middle of Amunike Mt., Qinghai. It was named by the No. 1 Qinghai Party of Regional Geological Survey in 1975.
Lithology and Thickness
A suite of neritic carbonate rocks and clastic rocks, which can be divided into three members. Lower member, 174.9 m thick, is dominated by dark-gray limestone intercalated with gray to gray-green and purple thin-bedded calcareous and sandy shales. Middle member, 82.2 m thick, consists of gray bioclastic limestone intercalated with purple thick-bedded limestone and pseudo-oolitic limestone. Upper member, 194.9 m thick, is composed of gray and gray-black limestones intercalated with bioclastic limestone and calcareous limestone, containing the coral Siphonophyllum spinosa-Lophophyllum tertousaum assemblage, aged late Tournaisian.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Devonian of Amunike Fm (S. Qilian) or Shaliushui Gr (N. Qaidam)
Upper contact
Conformable contact with the overlying Chengqianggou Fm.
Regional extent
GeoJSON
Fossils
Lower member contains the Coral Kassinella amunikeensis-Lophophyllum densum assemblage and brachiopod Rhytiophora arcuata-Syringothyris halli assemblage, belonging to the early Tournaisian.
Middle member yields the Coral Enygmophyllum dubium-Kakwiphyllum qinghaiense assemblage and brachiopod Syringothyris cf. texta-Phipidomella altaico assemblage, being of the middle-late Tournaisian in age.
Upper member contains the Coral Siphonophyllum spinosa-Lophophyllum tertousaum assemblage, aged late Tournaisian.
Age
Depositional setting
It is interpreted as a neritic facies.
Additional Information