Madaoyu Fm
Period:
Ordovician
Age Interval:
Floian-Dapingian, (49)
Province:
Hunan
Type Locality and Naming
The type section is at Jiuxi 35 km northwest of Taoyuan City, Hunan. The Madaoyu Fm was named by Liu Yiren in 1973, and was published by Central-South Compiling Group for Regional Stratigraphic Scale (1974).
Synonym: (马刀堉组）
Lithology and Thickness
The Madaoyu Fm is composed of dark gray dolomitic limestone. In the type area, it recorded thickness of 97 m thick.
Lithology Pattern:
Dolomitic limestone
Relationships and Distribution
Lower contact
It rests conformably on the Panjiazui Fm.
Upper contact
Regional extent
This stratigraphic unit is exposed in Wulingshan, northwestern Hunan.
GeoJSON
null
Fossils
It yields very poorly preserved broken nautiloids and Dendrograptids.
Age
Floian-Dapingian; and entry for underlying Panjiazui Fm implies extends down into upper Tremadocian.
Age Span:
Beginning stage:
Tremadocian
Fraction up in beginning stage:
0.7
Beginning date (Ma):
480.01
Ending stage:
Dapingian
Fraction up in the ending stage:
0.5
Ending date (Ma):
470.34
Depositional setting
Depositional pattern:
Additional Information
Compiler:
Jianpo Wang and Xiaofeng Wang