Huangqikou Fm
Type Locality and Naming
North Ningxia. The Huangqikou Fm was named by the Party of Regional Geological Survey, Ningxia Hui Autonomous Region Bureau of Geology in 1978. The type section is at Binggou Gully, Huangqikou, Yinchuan City, Ningxia Hui Autonomous Region Hui Autonomous Region.
Synonym: （黄旗口组）
Lithology and Thickness
In the type section, the Huangqikou Fm is composed of neritic clastic rock association. The formation is subdivided into lower, middle, upper and top parts. Lower part is composed of purple-red, grey-white quartzite, quartzose sandstone with variegated silty slate. Middle part consists of intercalated with fine-grained glauconite quartz sandstone and silty slate, coarse quartz sandstone. Upper part is siliceous dolomite, with a grey massive clastic rock lay on the top. The maximum thickness seen is cited as 552 m.
Relationships and Distribution
Lower contact
The formation rests unconformably on underlying biotite-plagioclase granite of Proterozoic Erathem or older metamorphosed rocks.
Upper contact
It is conformable with Wangquankou Fm
Regional extent
North Ningxia. The Huangqikou Fm shows great lateral change both in lithofacies, character and thickness. For example, at Wangquankou area in north sector of Helan Mountains it is exposed only with carbonate rock in small amount (283 m thick), but in Taosigou, it is composed of quartzite and sandstone of 56 m thick, in Zhuozi Mt. and Gangdel Mt., it consists of quartz sandstone with argillaceous silty rock and shale, 300 m thick.
GeoJSON
Fossils
The stromatolites in the upper siliceous dolomite are Baicalia f. and the palaeomicropants seen in black slate are: Trachysphaeridium cultum, Taeniatum crassum, Trematosphaeridium sp., Leiopsophosphaera sp.
Age
Depositional setting
Additional Information