Chayihe Fm
Type Locality and Naming
It was named by the No. 12 Team of the Greater Khingan Survey Party under the former Ministry of Geology in 1957. The naming section is located at the crest on the right bank of the lower reaches of the Chayi River (now called the Chaihe River) 125 km south of Boketu, Hulunbaer Prefecture, Inner Mongolia.
Synonym: （查伊河组）
Lithology and Thickness
Composed of intermediate lava and acid extrusive rocks, intercalated with sedimentary clastic rocks. Lithologically, the formation can be divided into the lower and upper parts, with the Lower part consisting largely of porphyrite and thick-bedded conglomerate at its base with a thickness of 400-600 m; and with the Upper part representing intermediate acid extrusive rocks and sedimentary clastics, with a thickness of 300 m.
Relationships and Distribution
Upper contact
The relationship between it and the overlying Taipingchuan Fm is so far unknown.
Regional extent
The lithology of it has little changes, while its thickness varies in a range of 220 m to 1070 m. The formation is distributed on the lower reaches of the Chayi River, as well as in the West Bayin-Wulan area of Zhameite Banner.
GeoJSON
Fossils
The formation yields plant fossils such as Cladophlebis denticulata, Ctenis yabei, C. japonica, Neocalamites carrerei, Nilssonia sp., and Podozamites sp.
Age
Depositional setting
Additional Information