Hongshuigou Fm
Type Locality and Naming
The type locality is situated at the Hongshui Gully on the southern foothill of the Ahati Mts to the northwest of the Chaidamu Basin. It was named by Si Xingjian, Zhou Zhiyan as the “Hongshuigou Group” in 1962.
Synonym: （红水沟组）
Lithology and Thickness
It is composed mainly of brown-red sandy mudstone and mudstone, intercalated with light-grey fine-grained sandstone, blue-grey siltstone and calcareous mudstone, with no base being found. It is with an exposed thickness of 447 m.
Relationships and Distribution
Lower contact
Except for the Hongshuigou section, in other areas the formation is in a conformable contact with the underlying Caishiling Fm
Upper contact
The top is a discontinuity marked by tangerine and yellow-grey mudstone with abundant Cretaceous fauna at the base of the Quangyagou Gr (Quanyagou Gr) that distinquishes it from the dark brown sandstone of the upper Hongshuigou Fm.
Regional extent
The formation is distributed on the northwestern margin of the Chaidamu Basin, as well as in the areas of Mongya, Yuka, Ludong River and Wanggaxiu of Wulan County on the northern margin of the Chaidamu Basin.
GeoJSON
Fossils
It yields Ostracod fossils as represented by Cetacella hongshuigouensis, C. chaidamensis, Djungarica sp., Darwinuta oblonga and D. suboblonga; conchostracan fossils as represented by Sinoestheria tsaidamensis, and Qinghaiestheria hungshuikouensis.
Age
Depositional setting
Additional Information