Hongshantou Fm
Period:
Ordovician
Age Interval:
Katian-Hirnantian, (63)
Province:
Xizang (Tibet)
Type Locality and Naming
Himalayas. The type section is in roadcuts along the highway from Jiacun to Yali by the road from Lhasa to Zham, Nyalam County, southern Tibet. The Hongshantou Fm was named by Wang Yigang (1974).
Synonym: (红山头组）
Lithology and Thickness
The formation is composed of brownish gray calcareous and silty shale intercalated with fine-grained sandstone. In the type area, the Hongshantou Fm is about 70 m thick.
Lithology Pattern:
Sandy claystone
Relationships and Distribution
Lower contact
This stratigraphic unit rests conformably on the argillaceous limestone and bioclastic limestone of the upper formation of the Jiacun Gr, the present Jiaqu Fm, which yields Sinoceras chinense.
Upper contact
Regionally, the next younger unit is the Shiqipo Fm of Early Silurian.
Regional extent
It is exposed only in the type area.
GeoJSON
null
Age
Katian-Hirnantian.
Age Span:
Beginning stage:
Katian
Fraction up in beginning stage:
0.4
Beginning date (Ma):
449.73
Ending stage:
Hirnantian
Fraction up in the ending stage:
1.0
Ending date (Ma):
443.07
Depositional setting
Depositional pattern:
Additional Information
Compiler:
Jianpo Wang and Xiaofeng Wang