Sifengya Fm
Type Locality and Naming
The formation was established by the Second Regional Geological Survey of Yunnan Province in 1976. The type section is located in the Huanggexi section, Daguan County, Yunnan Province. Coordinate: 103°52′21″E, 27°50′N.
Synonym: （嘶风崖组）. The Niugundang Fm was proposed by the Yunnan Regional Geological Survey in 1986 and shares the same type section with both the Huanggexi and the Sifengya formations. The authors agree with the idea to reject the Niugundang Fm as Rong (1998) suggested.
Lithology and Thickness
The formation, 165.3 m in thickness at the type section, is distinguished by the appearance at the base and disappearance at the top boundary of the purple, dark purple shale, siltstone. The middle part of the formation is dominated by gray green and yellowish green shale interbedded with sandstone or/and limestone.
Relationships and Distribution
Lower contact
The formation is conformably contacted onto the underlying Huanggexi Fm
Upper contact
The formation is conformably contacted with the overlying Daluzhai Fm
Regional extent
The formation is distributed northeastward to Shuanghe area of Daguan County with finer grained, more shaly and limy rocks; and southwestward to Ludian County with more coarse-grained siltstone and sandstone.
GeoJSON
Fossils
The formation yields corals Palaeofavosites, Mesofavosites, Halysites, Alveolites, Ketophyllum, Brachyelasma, Ceriaster, Codonophyllum, etc.; brachiopods Nucleospira, Striispirifer, Nalivkinia, Mesoleptostrophia; and some bivalves, trilobites, etc.
Age
Depositional setting
Additional Information