Chayeshao Fm
Type Locality and Naming
The type section is in Chayeshao, Bandang Town, Ziyun County, Guizhou Province. It was named by Zunzhou Wnag et al. in 1992. Originally, the Chayeshao Fm represented carbonate dominated strata of early Early Triassic in South Guizhou Province. But the strata have been assigned to Luolou Fm by Bureau of Geology and Mineral Resources of Guizhou Province in 1987.
Synonym: Chaishao Fm
Lithology and Thickness
The Chayeshao formation is dominated by greyish thin-medium micrite, marlstone and shale, which have been divided into two members. Difference between lower and upper members is the lower has dark grey or yellowish green shale interlayers. Thickness varies from 30 to 392 m.
Relationships and Distribution
Lower contact
The base of Chayeshao Fm was marked by the appearance of black gray, yellowish green calcareous shale and displayed conformable contact with the Upper Permian Changxing Fm or Dalong Fm below. In Cheheng, Wangmo and Ziyun, it is unconformably underlain by the Wujiaping Fm
Upper contact
It is conformably overlain by a thick, massive breccia-rich calcareous limestone at the base of the overlying Ziyun Fm.
Regional extent
This formation is mainly distributed in south Guizhou.
GeoJSON
Fossils
Lower member: Bivalves: Pseudoclaraia wangi, Claraia cf. clarai, C. concentrica; Ammonoids: Ophiceras sp., O. sinensis, Komnckites cf. ellipticus, Paranorites linguisellatus
Upper member: Bivalves: Claraia aurita, Eumorphotis cf. multiformis
Age
Depositional setting
Shallow marine facies
Additional Information