Wujiatun Fm
(15), mid-Guadalupian Epoch (mid-Middle Permian)
Type Locality and Naming
The type section is located at the West Hills of the Duqingtaohai-Xiculutu area, Wujiatun, the Front Banner of the Kirxin Right Wing, Inner Mongolia. It was named by Li Yinhou et al. in 1956, and was cited officially by the Compiling Group for the Regional Stratigraphic Chart of the Inner Mongolia Autonomous Region (1978).
Lithology and Thickness
Clastics and Volcaniclastics. Composed largely of clastic rocks, intercalated with lenticular limestone and intermediate volcanic rocks. Lower member is composed of grey-black slate, intercalated with sandstone, conglomerate and limestone lenses, and gradating upwards into yellow-brown siltstone and clayey slate, containing limonite concretions, with a thickness of 961 m. Upper member is composed of yellow-brown and grey-yellow-coarse-grained and fine-grained sandstones intercalated with limestone lenses, further upward it consists mainly of slate, containing phosphorus concretions, with a thickness of 267 m. Its Middle and Upper parts containing phosphorus and limonite concretions, forming some small-scale iron ore deposits locally. Total thickness of 1228 m.
Relationships and Distribution
Lower contact
Conformable contact with the underlying Dazhizhai Fm
Upper contact
Conformable continuous deposit with the overlying Suolun Fm
Regional extent
Distributed in a vast area extending from the Taonan District of Baicheng City to the Wujiatun Village to the northwest of the Wulanhot City. It has been fairly well developed in the Dashizhai area of Suolun Region. In the Xiaosanjiazi area to the Harlagentai area, the Upper member of the formation is composed essentially of shale, yielding abundant marine animal fossils. In the Mengjiu Mt. and the Jinjiadian area, the Lower member of the formation is intercalated with andesite. Southward from the Shanayingzi to the Wangjiatun area the volcanic components greatly increase in abundance with the conglomerate in it getting thicker.
GeoJSON
Fossils
Its Lower part yields the Waagenites deplanata-Horridonia-Liosotella assemblage zone of brachiopods, and Daubichites of ammonoids. Its Upper part yields the Licharewia grewingki-Neospirifer moosakhailensis assemblage zone of brachiopods.
Age
Depositional setting
It is interpreted as a shallow-sea-facies terrigenous clastic-rock formation.
Additional Information