Maliangou Fm
Type Locality and Naming
The First Regional Geological Survey Team of the Gansu Bureau of Geology and Mineral Resources erected the Maliangou Group in 1967. The type locality for the designation is in the Xincheng township of Yongchang County of Gansu. The reference section is at Maliangou of Xinchengzi of the Yongchang County (101°32′E; 38°01′N).
Lithology and Thickness
The Maliangou Formation is represented by gray, grayish green and gray purple clayey siltstone, sandy shale and siltstone and fine sandstone with mudstone and gypsum. It is 364 m thick.
Relationships and Distribution
Lower contact
Its base marked by gray green sandstone and sandy shale lies conformably on the Hekou Gr (Early Cretaceous). However, Hekou Gr is indicated as south Gansu, and the estimate of regional column for central Gansu would imply that the Qingtujing Gr of middle Jurassic is next older unit below the Maliangou Fm.
Upper contact
Its top marked by gray purple and gray green clayey siltstone with gray white arkose lies unconformably under the overlying Pliocene Linxia Fm marked by tangerine sandstone and mudstone.
Regional extent
The present formation occurs in the Yongchang County, the Jiutiaoling area of Sunan County of central Gansu. In the latter area it contains flora debris and is 997 m in thickness.
GeoJSON
Fossils
The formation yields Estherias Estherites linshinensis, Dimorphostracus nunjiangensis, and D. cf. tenellus.
Age
Depositional setting
It is of lacustrine deposition.
Additional Information