Guixi Fm
Type Locality and Naming
The Guixi Fm is the lowest formation in the Pingyipu Gr. The type section is located at the road side near the Grain Supply Center of Guixi Village in Beichuan County, Sichuan Province. It was named by Hou Hongfei and Wan Zhengquan in 1988.
Lithology and Thickness
Sandstone. It is dominated by brown to dark-gray, medium- to thick-bedded quartz sandstone intercalated with fine-grained greywacke and black clayey siltstone.
This formation in its Guixi section can be divided into lower and upper members: the Lower member, the Zhaobiyan Member, is composed of light-gray to dark-gray medium- to thick-bedded, medium- to fine-grained quartz sandstone containing brachiopods Lingula and trace fossils.
The Upper member, the Raoheba Member, is dominated by brown to dark-gray medium- to thick-bedded sandy mudstone intercalated with fine-grained quartz greywacke and black clayey siltstone containing brachiopod Lingula longmenshanensis.
It is 688 m in total thickness.
Relationships and Distribution
Lower contact
It overlies disconformably on the Silurian Maoxian Gr
Upper contact
It has an upper conformable contact with the overlying Muerchang Fm
Regional extent
This formation is best developed in the Guixi area; and at the southeast limb of Tangwangzhai syncline, the thickness decreases or even dies out.
GeoJSON
Age
Depositional setting
Delta to coastal facies.
Additional Information