Yaogou Fm
Type Locality and Naming
The type section is located in the Yaogou area 32 km to the north by east of the Sunan County, Gansu Province; and the reference section is situated at Dashankou of Yumen City. It was named by Yuan Fuli in 1925.
Lithology and Thickness
Clastics. Composed chiefly of purplish red pebbled coarse-grained sandstone, sandstone, sandy siltstone and variegated clastic rocks. Lower member consisting of dark-purple thin-bedded siltstone and grey medium-bedded pebbled medium- and coarse-grained sandstone. Middle member consisting of grey-green, yellow-green and purplish-red medium- and thin-bedded siltstones. Upper member consisting of interbeds of variegated (grey-brown, purplish-red, grey-green) clayey siltstone, siltstone and medium-bedded sandstone. The formation is characterized by the development of purplish-red strata. Thickness is 448 m.
Relationships and Distribution
Lower contact
Disconformable contact with the underlying Dahuanggou Fm
Upper contact
Disconformable contact with the overlying Sunan Fm
Regional extent
In the Daqinggou area of Sunan County it is 262 m thick, in the area of the Yanglu River of Sunan County it is over 770 m thick; and in the area of the Wufo Temple the thickness of the formation is over 805 m. Coeval with the Hongquan Fm of south-central Gansu (column 34)
GeoJSON
Fossils
Age
Depositional setting
It is interpreted as alluvial-facies deposits.
Additional Information