Zhongshigong Fm
Type Locality and Naming
The type section is located in the Zhongshigong area 55 km to the northwest of the Yangkang Country, Tianjun County, Qinghai Province. It was named by Liu Guangcai in 1980, and was issued publicly in 1984. Upper formation in the Nuoyinhe Gr.
Lithology and Thickness
Clastics. Composed of dark grey-green and purple very thick shale, siltstone, medium-grained feldspar-rich sandstone, calcareous siltstone and variegated clastic rocks; with a thickness of 447 m.
Relationships and Distribution
Lower contact
Conformable contact with the dark-grey thick-bedded shale of the underlying Hajier Fm
Upper contact
Overlain by the Xiahuancang Gr of early Triassic
Regional extent
Distributed in the South Qilian Mts. and the western segment of the Central Qilian Mts., starting from the Daban Mt. in the Turgen area in the west, to the Retong Mt. in the east, and bordering on the northern boundary of the Zongwulong Mt. in the south.
GeoJSON
Fossils
Yields Plant fossils (phytolites) such as Gigantopteris sp. and Sphenopteris, and Brachiopods such as Araxathyris aff. kueichouensis, Spinomarginifera sp.
Age
Depositional setting
It is interpreted as paralic deposits (marginal marine). The Nuoyinhe Gr in the southern marine-facies region is composed mainly of limestone, less of feldspar and quartz, with a thickness of 11.7-269.6 m, yielding abundant brachiopods. In the northern part of the area, it represents a paralic deposit region.
Additional Information