Yongde Fm
(45), Kungurian Stage (late Cisuralian Epoch) through Guadalupian Epoch [latest-Early through Middle Permian]
Type Locality and Naming
The type section is located in the Anpaitian area 2 km to the east of the Yongde County Town, Yunnan Province; and the reference section is situated in the Xiaoxinzhai Village of the Gengma County. It was named by Lan Chaohua et al. in 1983.
Synonym: (1) Bingma Fm (The typical profile is the measured profile of the Lower Permian in Hewan Street, Baoshan County, Yunnan (99°18'00"E; 25°09'00"N) Yunnan Regional Geological Survey Brigade, surveyed in 1980). (2) Manli Fm (曼里组; The Manli Formation was named in 1966 by the first sub-unit of the Yunnan First Regional Geological Survey Brigade. It has the same name as the Bingma Fm and has been discontinued), (3) Yongde Fm (永德组)
Lithology and Thickness
Clastics. Composed of light-yellow siltstone, siltstone, sandy conglomerate and shale, with a thickness of 52 m. Bingma Fm (equivalent) is purple silty claystone, gray silty shale and tuff, tuffaceous sand and shale interbedded, and the bottom is clastic rock of iron-bearing tuffaceous sandstone. Contains corals, brachiopods, bryozoans, bivalves, etc. Thickness: 52-135 meters.
Relationships and Distribution
Lower contact
Disconformable or an unconformable contact with the underlying Woniusi Fm
Upper contact
Conformable contact with the overlying Shazipo Fm
Regional extent
Distributed in the areas of Baoshan City, Zhenkang, Yongde and Luxi Counties.
GeoJSON
Fossils
Yields abundant biologic fossils, including brachiopods such as Leptodus, Costiferina, Waagenites, Orthotichia, Spiriferella, etc.; corals such as Iranophyllum; Fusulinids represented by Schwagerina; Plant fossils (phytolites) such as Pecopteris, Taeniopteris and problematic fossil such as Glossopteris.
Age
Depositional setting
It is interpreted as littoral shallow-sea deposits.
Additional Information