Shiti Fm
Type Locality and Naming
It was named by Xie Jiarong, Wang Zhi as the “Shiti System” in 1938. The naming section is located in the vicinity of the Shiti area, Xiwan region, Hexian County, Guangxi, with its reference section being situated in the vicinity of the Huilong Village, Zhongshan County.
Synonym: （石梯组）
Lithology and Thickness
Lower part is composed of grey-green medium-, and coarse-grained arkosic quartz-sandstone or gritstone, turning upwards into purple shale. Middle part is fine-grained sandstone. Upper part found to occur only in the Qinzhou Basin, is purple argillaceous siltstone. Thickness varying in a range from 112 m to 522 m.
Relationships and Distribution
Lower contact
The formation is to some people’s points of view in a conformable contact, or in a disconformable contact (to the points of view of others) with the underlying Daling Fm.
Upper contact
In the Dongxing region it overlies unconformably the Silurian System. Regionally, the schematic strat column indicates the next younger unit as Tanglong Fm
Regional extent
It is distributed essentially in the Xiwan area of Hexian County and the Gongcheng, Qinzhou and Dongxing areas. The thickness of the strata in various regions varies greatly, being of about 480 m in the Xiwan Basin, of 330 m in the Huiling Basin, of 371 m in the Gongcheng Basin, and of 112-522 m in the Qinzhou Basin. In the Huilong and Qinzhou Basins the lower part of the formation is gradating facially into pebble-bearing gritstone or conglomerate.
GeoJSON
Fossils
It yields bivalve fossils whose key genera and species are represented by Psilunio ovalis, P. chaoi, Cuneopsis johannisboehmi, C. sichuanensis, Lamprotula (Eolamprotula) cf. huizhouensis, Ferganoconcha sp. and Sphaerium cf. subplanum.
Age
Depositional setting
The formation belongs to continental fluvial-lacustrine clastic deposits.
Additional Information