Naijiahe Fm
Type Locality and Naming
Liupanshan Basin. The No.125 Geological Team under the Yinchuan Bureau of Petroleum Exploration erected the Naijiahe bed in 1959. The section for the designation is at Naijiahe in the central part of Xiaoguanshan of Ningxia. The reference section is in Heshangpu of Guyuan county (106°14'E; 35°41′N).
Lithology and Thickness
The Naijiahe Formation is mainly represented by grayish green and blue gray mudstone, marl and sandy mudstone with a number of schistose gypsum. It is often intercalated with gypsum beds and small amounts of oil shale. The Naijiahe Formation is 43 m thick.
Relationships and Distribution
Lower contact
Its base marked by gray green thick-bedded mudstone with limy rocks and sandy mudstone lies conformably on the underlying Madongshan Fm.
Upper contact
Its top marked by purple red mudstone lies unconformably under light red conglomerate of the overlying Paleogene Sikouzi Fm.
Regional extent
The present formation occurs generally in SN direction in the Liupanshan area of south Ningxia, and is mainly exposed in Qingshan, Yaoshan and Kangjiawan of the Tongxin County and Sizikou, Choushuigou and Heshangpu of the Guyuan County. In the Kangjiawan area of north Ningxia, it increases in the amount of sandstone. It is up to 525 m at maximum in thickness.
GeoJSON
Fossils
In the Sizikou section, it yields estherias Eosestheria middendorfii, Yanjestheria cf. proamurensis, Bairdestheria guyuanensis; on the Kangjiawan section of the Tongxin County, bivalves Sphaerium sp., Pisces Tongxinchthys microdus; and in Maxigou, Huoshizhai, Madongshan, Qingshizui and Kangjiawan, it also yields estherias Yanjiestheria kansuensis, Y. sinensis, ostracods Cypridea concina, C. vitimensis, C. priva, Ziziphocypris sp. and floras Onychiopsis sp., Brachyphyllum sp., Pagiophyllum sp., etc.
Age
Depositional setting
It is marked by lacustrine deposition.
Additional Information