Dawangchong Fm
Type Locality and Naming
It was named as the Dawangchong Member by Chen Gongxin in 1983, and was first cited publicly and was renamed at the same time as the Dawangchong Formation by the Geological Bureau of Hubei Province in 1990. The naming section is located in the Dawangchong area of Echeng County, Hubei Province.
Synonym:（大王冲组）
Lithology and Thickness
The formation represents a set of coal-bearing deposits occurring in between the Chengchao Fm and the Jinshandian Fm. It is composed essentially of yellow-green siltstone and mudstone, intercalated with carbonaceous shale, thin coal layers and fine-grained sandstone, with its basal part serving as its base boundary consisting of a layer of medium-, and fine-grained feldspar-quartz sandstone. The present formation represents the major coal-bearing horizon in the region, containing 1-14 coal layers, with 1-3 mineable coal beds in some segments. There occur siderite concretions all over the whole formation. Its total thickness is of about 136 m.
Relationships and Distribution
Lower contact
The formation is in a conformable contact with the underlying Chengchou Fm
Upper contact
Regionally, the schematic strat column indicates the next younger unit as Jinshandian Fm
Regional extent
The formation is distributed essentially in the Chengchao, Dawangchong and Bishidu areas of Echeng County, Jinshandian and Damashan areas of Daye County, as well as in the Tuditang area of Wuchang County, Hubei Province, with a consistent lithology and a thickness varying from 60 m to 136 m.
GeoJSON
Fossils
It yields bivalves as represented by Apseudocardinia dazuensis, A. imparilis, Pseudocardinia carinata, P. hupehensis, Qiyangia inonata, Q. qipanlingensis, Unio yunanensis, Cunlopsis sichuanensis; and insect fossils: Wuchangicavabus latus, etc. The plant fossils belong to the Todites princeps-Ptilophullum assemblage, important members of which are more than 50 kinds, including Neocalamites carrerei, Coniopteris hymenophylloides, Todites princeps, Dictyophyllum nilssoni, Ptilophyllum conliguum and so on.
Age
Depositional setting
The formation belongs to lacustrine-swamp deposits.
Additional Information