Wandianba Fm
Type Locality and Naming
Third Regional Geological Survey Team of Yunnan Geological Bureau named in 1980. The named section is located in Wandianba Town, Ning County, Yunnan Province.
Synonym:
Lithology and Thickness
Mainly gray, purple-red siltstone, sandstone with mudstone and glutenite (=gravel-rich sediment). Lower member is sandstone, conglomerate and sandy mudstone with the thickness of 460 m. Upper member is silty mudstone and siltstone with fine sandstone with a thickness of more than 246 m. The bottom boundary is marked by the first occurrence of purple glutenite.
Relationships and Distribution
Lower contact
The contact relationship is unknown. At present, there is no continuous section between the Wandianba Fm and the underlying Nanshuba Fm, and their Upper Triassic fossil features are very similar. Therefore, the Chengdu Institute of Geology and Mineral Resources of the Chinese Academy of Geological Sciences and the Sichuan Regional Geological Survey (1992) believe that the two formations are upper/lower or phase transition relationships, which need to be studied further.
Upper contact
The overlying Sanchahe Fm shows disconformity. Overlain by Mengga Fm ?
Regional extent
Mainly distributed in Baoshan, Fengqing County and Changning County, Yunnan Province. The lithology varies slightly, and there are up to six layers of conglomerate in the lower part of the Fengqing County area, and some dolomite interbeds in the upper part of the Tengchong area, besides the increase of purple beds.
GeoJSON
Fossils
They are composed of bivalve Burmesia lirata-Costatoria mansuyi Indopecten; Conodont Epigondolella abneptis, etc., Ammonoidea: Placites cf. myophirus, and gastropods and plant fragments.
Age
Depositional setting
Wandianba Formation is a shallow water facies
Additional Information