Waigucun Fm
Type Locality and Naming
Named in 1971 by the First Regional Geological Survey Team of Yunnan Geological Bureau. The named section is located near Waigu Village, Ma’anshan Township, Weishan County, Yunnan Province. Original Waigucun Fm is a set of detrital rocks in Weishan area, Yunnan Province, which represents the Late Triassic Carnian to Norian period.
Synonym:
Lithology and Thickness
Clastic rocks are dominant. Lower member (Purple-red rock member) is mainly purple red fine sandstone and slate with fine sandstone, the bottom part is yellow and purple red conglomerate slate and sandstone, the thick is 606 m; Upper member (Purple-red, gray-green rock member) is grey green, purple slate and siltstone with multiple layer limestone and marlstone. There are layers of shell in the limestone. There is a layer of coral reef limestone at the top with thickness of 297 m.
Relationships and Distribution
Lower contact
The Waigucun Fm is in disconformable contact with the underlying Upper Permian. Or it unconformably overlies the Cuiyibi Fm.
Upper contact
It is in conformable contact with the overlying Upper Triassic Sanhedong Fm
Regional extent
Mainly distributed in the Waigu Village of Weishan County, Ma’anshan, Luojiu Village and Qianjiang to Guanyindi of Jianchuan County, western Yunnan area, and is also exposed in Yiwanshui, Bixi District, Mojiang County. Lithology and thickness change greatly, in the Yiwanshui, Bixi District, Mojiang County, the bottom appears 400 m of coarse sandstone, gravelly coarse sandstone, unconformable to the Devonian.
GeoJSON
Fossils
Having bivalves: Halobia cf. gunziensis, H. yunnanensis, H. substyriaca, H. convexa, Daonella sp. etc.; Coral: Thecosmilia sp.
Age
Depositional setting
Waigucun Formation is shallow water face.
Additional Information