Meidang Fm
Type Locality and Naming
East-central Yunnan. The Meidang Fm was named by the No.7 Team, No.2 Party of Regional Geological Survey, Yunnan Bureau of Geology in 1969. The type section is in Zanlahei Ganlanruo, Meidang Village, Fulianpeng Township, Eshan County, Yunnan Province. The formation is the uppermost formation-level unit in current usage of Kunyang Gr.
Synonym: （美党组）; the equivalent stratigraphic unit is called Wangchang Fm, upper part of Sanjiachang Fm, upper part of Alayi Fm, upper part of Hekou Fm, as well as Guzhuang Slate.
Lithology and Thickness
The Meidang Fm is dominated by dark-grey, grey-green to black slate and calcareous slate containing marl lenticules intercalated with metamorphosed siltstone and marl; lower part is sandwiched with rudaceous limestone, limestone and stromatolite limestone, sometimes (Dongchuan) the base consists of quartzite bed. The thickness varies from 300 to 1400 m.
Relationships and Distribution
Lower contact
Schematic stratigraphic column shows as conformably transitional onto Dalongkou Fm
Upper contact
Schematic stratigraphic column shows as unconformably overlain by Liubantag Fm of Qingbaikouan (Tonian) in Central Yunnan.
Regional extent
East-central Yunnan. The formation is mainly distributed in Wuding, Yuanjiang, Jianshui, Shiping and Tangdan, Dongchuan etc. It is stable in lithological character. It is recorded as 1085 m thick in Jianshui, 616 m in Shiping, 606 m in Yimen, 467 m in Tangdan, Dongchuan.
GeoJSON
Fossils
Stromatolites recognized in it are mainly Gymnosolen altum, G. confragosum, Conophyton lituum, Colonnella cf. discreta, Jurusania f., Minjariauralica. The major microplant taxa found in slate in lower part of the formation are Trematosphaeridium, Taeniatum, Trachysphaeridium, Asperatopsophosphaera, Retinarites etc.
Age
Depositional setting
Additional Information