Chejiang Fm
Type Locality and Naming
Hengyang Basin. The Chejiang Formation was erected by the Hengyang Sylvite Team of Hunan in 1962. The locality for the designation is in Chejiangzhen of the Hengnan County, Hunan. The section for the designation is at Niutoushan of Chejiang of the Hengnan County, Hunan Province. The Chejiang Formation stands for the medium and fine-grained clastic sedimentary rocks above the Daijiaping Fm and below the Paleogene Xialiushi Fm, which is attributed to Cretaceous.
Synonym: In 1972 the Central South Institute of Geology renamed it as the Dongtang Fm and referred it to Paleocene. In 1982 Zhang Jinjian redesignated it the Chejiang Formation, which is divided into two members.
Lithology and Thickness
The Chejiang Formation is dominated by gray white and brown red feldspar quartz sandstone and siltstone. It is 277.3 m thick.
Relationships and Distribution
Lower contact
Its conformable base is built up by gray white thick-bedded feldspar quartz sandstone with conglomerate lenses, which is differentiated from purple red mudstone intercalated with clayey siltstone of the underlying Daijiaping Fm.
Upper contact
Its top is bounded conformably by purple red mudstone with gray green mudstone at the base of the Zaoshi Fm (latest Maastrichtian-Danian)
Regional extent
The formation is mostly distributed in the Nanyang basin of southeastern Hunan and is persistent in lithology. It is 277 m thick in Hengnan, 50 m in Qiupotang of the Hengdong County, 250 m in the the Liuxiashi area, more than 700 m on the southern extremity of the Liyou basin, and 130-240 m near Zaoshi and Mabujiang of the Chashui basin.
GeoJSON
Fossils
The formation yields ostracods Cypridea (Morinina) xindianensis, C.longa, Cypridea oversa, Talicypridea sp., Cyprois sp., Candona declivio; Charophytes Gyragena zhahiangensis, Grovesichara chandeensis, Sphaerochara parvula. It yields bivalves Plicatounio hunanensis, P.hengdongensis in Qiupotang of the Hengdong County, and Dinosaurian eggs near Zaoshi and Mabujiang of the Chashui basin.
Age
Depositional setting
It is indicative of fluvial-lacustrine facies
Additional Information