Banan Fm
Type Locality and Naming
The Banan Formation was named by Xu Deyou and Chen Kang in 1943. The named section is located near Xiaohegou about 1 km west of Wanlan (formerly called Bannan), Zhenfeng County, Guizhou Province. Merger of former Longchang claystone member of Franck Fm (see entry for Falang Fm) and the Jianan Fm sandstone.
Synonym: Panan Fm
Lithology and Thickness
Lower member (former Longchang Member of Franck Fm) is composed of gray, grey-green thin to medium thick claystone, calcareous claystone, sandy claystone, lithic siltstone, fine-medium grained lithic quartz sandstone with a thickness of 67 to 732 m. Upper member (the former Jianan Formation) is composed of yellowish-gray fine-grained quartz sandstone, siltstone, gray-green sandy claystone, and calcareous claystone and interbedded with different thickness. The upper sandstone is increased, often interbedded with marl and thin coal seams. Upper member thickness of 150 to 463 m.
Relationships and Distribution
Lower contact
The lower boundary is marked by the appearance of grey-green claystone, which is in concordant contact with the underlying Francs Fm (Falang Fm).
Upper contact
Concordant contact with the overlying Huobachong Fm.
Regional extent
It is mainly distributed in the southwest of Guizhou, with stable lithology and horizon, and well preserved in Guodi River, Zhenfeng Longchang, Guanling Guanqiao, Liuzhi Langdai and other places.
GeoJSON
Fossils
There are abundant bivalves in the upper section, and the Cassianella beyrichii assemblage and Costatoria kweichowensi-Heminajas forulata assemblage can be established from bottom to top. The next section can be the combination of Halobia rugosoides; In addition, there are also produced ammonoids and crinoids and other fossils.
Age
Depositional setting
Shallow sea deposits
Additional Information