Zayu Fm
Type Locality and Naming
The type section is at Guqin in Zayü County, eastern Xizang. In the type area, the Chayu (Zayü) Fm is 25 m thick. The Zayu Fm was named by Chen Ting'en (1986a).
Synonym: (察隅组); Chayu Fm, Zayü Fm
Lithology and Thickness
The formation is composed of dark gray banded argillaceous limestone and medium-bedded argillaceous limestone. In Zayü, this formation is 25 m thick, and in Haitong, it is 30 m thick, with a very persistent lithology and thickness.
Relationships and Distribution
Lower contact
It rests conformably on the dolomitic limestone in the upper part of the Guqin Fm
Upper contact
It is conformably overlain by the purple argillaceous limestone of the Goyu Fm.
Regional extent
With a very persistent lithology, this formation is Haitong.
GeoJSON
Fossils
This stratigraphic unit yields brachiopods Glyptomena sp., Orthambonites sp., Glyptambonites sp., Leptelina sp. and cephalopod Protocycloceras sp. Additionally, brachiopods Orthis cf. calligramma and O. ellipsoides have been found from the equivalent strata at Haitong in Markam County by Sichuan Party of Regional Geological Survey.
Age
Depositional setting
Additional Information