Xigou Fm
Type Locality and Naming
The type section is located at the Minbaogou, 25 km northwest Wenxian County of Gansu Province. It was named by Lin Zhile in 1966, and published by Regional Stratigraphical Scale of Northwest China, Volume Gansu in 1981.
Lithology and Thickness
Shale, limestone. Xigou Formation is characterized by a lower part of blackish-gray to dark-gray shale and sandy shale, dark-greenish-gray siltstone with thin- to medium-bedded clayey limestone and quartz sandstone; and an upper part of dark-gray medium- to thick- bedded limestone with thin-bedded clayey limestone. The thickness of the Formation varies from 108 m in Malianhe of Linjiang, 192 m in Minbaogou to 459 m in south flank of Huanglong Anticline, Songpan.
Relationships and Distribution
Lower contact
The formation rests disconformably on the Shifang Group with a basal siliceous breccia.
Upper contact
Regional extent
The thickness of the Formation varies from 108 m in Malianhe of Linjiang, 192 m in Minbaogou to 459 m in south flank of Huanglong Anticline, Songpan.
GeoJSON
Fossils
The limestone yields coral Favosites regularissimus, Squameofavosites mironova, S. dubatolovi, Parastriatopora sp., Corolites sp., Mesofavosites sp. and Aulacophyllum sp.
Age
Depositional setting
Additional Information