Caidiwan Fm
Period:
Silurian
Age Interval:
late Telychian (S1) (48)
Province:
Yunnan
Type Locality and Naming
It was named by the 7th division of Second Team of Yunnan Regional Geological Survey (1976). The type section is located at Huanggexi, Daguan Xian, Yunnan Province (103°52'E, 27°50'N).
Synonym: (菜地湾组)
Lithology and Thickness
The formation, 108.1m in thickness, is dominated by purple, grayish green mudstone, siltstone, interbedded occasionally with quartz sandstone and argillaceous dolomite.
The lithology of the upper part of the formation changed into purple argillaceous dolomite, the gypsum and hematite can be found occasionally eastward from the type section. The thickness of the formation is various from place to place, 211.2 m at Tianwan, 57.7 m at Xinfudong, 103.4 m at Jilipu, 109.8 m at Chahe in Daguan Xian, and 87.9 m at Lantianba of Zhaotong City, 63.5 m at Xinzhai of Jinyang Xian.
Lithology Pattern:
Sandy_claystone
Relationships and Distribution
Lower contact
It is conformable with the underlying Daluzhai Fm.
Upper contact
It is parallel unconformable with the overlying Posongchong Fm of Lower Devonian.
Regional extent
The formation is distributed in the northeastern Yunnan.
GeoJSON
null
Fossils
The fossils yielded include brachiopod Striispirifer shiqianensis and trilobite Coronocephalus changningensis, etc.
Age
Age Span:
Beginning stage:
Telychian
Fraction up in beginning stage:
0.8
Beginning date (Ma):
434.06
Ending stage:
Telychian
Fraction up in the ending stage:
1.0
Ending date (Ma):
432.93
Depositional setting
Depositional pattern:
Additional Information
Compiler:
Wang Chuanshang and Wang Xiaofeng