Charang Fm
Type Locality and Naming
Hualong basin (Xining). The naming section is located in the vicinity of Charanggou along the bank of the Yellow River in the Hualong basin, Qinghai. Established by No. 5 Team of the Comprehensive Geological Party, Qinghai Bureau of Geology, in 1989.
Lithology and Thickness
Grayish purple conglomerate, variegated fine conglomerate, yellowish brown sandstone and variegated conglomeratic mudstone. Generally coarse sediments predominate and medium- and small-scale cross bedding is well developed. Facies change is pronounced: at Lajun and Gequ, Hualong, it consists of variegated conglomerate with sandstone and mudstone, 178 m thick; at Garangkou, Guide, it is composed of typical diluvial deposits, marked by coarse conglomerate in the upper part, fine conglomerate in the middle and conglomeratic muddy siltstone at the base, 93 m thick.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Miocene Xianshuihe Fm (Guanjiashan Fm), but it has an unconformable contact with the Xianshuihe Fm at Garanggoukou in the Guide basin.
Upper contact
Conformable contact with the overlying Xiadongshan Fm.
Regional extent
This formation is distributed at Charanggou, Quanke, Lajun, and Gequ.
GeoJSON
Fossils
Lagomorpha: Alilepus annectens; Carnivora: Ictitherium gaudryi; Perissodactyla: Hipparion weihoense, Chilotherium sp., Aceratherium sp.; Artiodactyla: Gazella gaudryi, G. kueitensis, Palaeotragus sp.; Sporopollen is represented by the Artemisiaepollenites-Betulaceoipollenites-Chenopodiaceae assemblage; gymnosperms take a very small proportion and herbaceous plants account for more than 95%, reflecting that the basin had an arid steppe landscape at that time.
Age
Depositional setting
Fluvio-lacustrine deposits.
Additional Information