Bantou Fm
Type Locality and Naming
Western Fujian. In 1943 Chen Kai erected the Bantou series arround the Bantou Village to the north of the Yongan City, Fujian. The reference section is at Bantou of Jishan of Yongan County, Fujian Province.
The Bantou series erected stands for the fluvial-lacustrine sandy shales over the volcanic rock series and below the hematitic bed in the Yongan-Chongan area of Fujian, which has been attributed to Cretaceous. In 1942 Si Xingjian assigned the Bantou series to Early Cretaceous according to floras. In 1962 Gu Zhiwei called the Bantou series as the Wuyi Gr. The middle and lower parts of the group were called the Yanfang sub-group while the upper part was called the Bantou Formation and was attributed to Late Jurassic.
Lithology and Thickness
The Bantou Foramtion is dominated by fluvial-lacustrine clastic sediments intercalated with pyroclastic rocks, which is lithologically divided into two parts: Lower part is represented by gray purple, gray green and gray white tuffaceous sandy conglomerate, fine sandstone, siltstone and shale. Upper part is gray green thick-bedded conglomerate, tuffaceous conglomerate interbedded with gray green tuffaceous siltstone, with feldspar-quartz sandstone. It is 1070.8 m thick.
Relationships and Distribution
Lower contact
The basal part is differentiated from gray tuff lava and tuff of the underlying Xiadu Fm by the appearance of gray green tuffaceous siltstone with siltstone bands. It is in disconformable or unconformable contact with the underlying Xiadu Fm (upper formation of the Douling Gr).
Upper contact
The top part is bounded conformably by the appearance of gray and gray green greatly thick-bedded conglomerate of the JishanFujian Fm.
Regional extent
The Bantou Formation is mainly distributed in western Fujian and varies greatly both in lithology and thickness. In the Chongan, Yongan-Kengbian, Baibuqiao and Biancheng-Bizhou basins, it is mainly represented by purple red and gray green varicolored shale with a thickness generally ranging from 400 to 600 m. In the Yongan-Jian and Ninghua-Yanqian basins, its upper part is represented mostly by a set of gray black microclastic rocks with a thickness up to 800-1071 m.
GeoJSON
Fossils
The formation yields floras Cupressinocladus gracilis, C. clegans, Brachyphyllum obesum, Blatocladus manchurica, Onychiopsis sp.; estherias Orthestheria internedia , Yanjestheria sinensis; ostracods Cypridea shouchangensis, C.(Morinina) sp., C. (Bisulcocypridea) sp.; Pisces Mesoclupea showchangensis; bivalves Nakamuranaia chingshanensiis, N.elongata; gastropods Probaicalia itimensis; insects Ephemeropsis sp.
Age
Depositional setting
The formation is of fluvial-lacustrine facies.
Additional Information