Yangliujing Formation
The Yangliujing Formation is a Middle Triassic geologic unit found in the Guizhou and Yunnan Provinces of southern China.
| Yangliujing Formation | |
|---|---|
| Stratigraphic range: late Anisian-Ladinian | |
| Type | Geological formation |
| Underlies | Zhuganpo Formation |
| Overlies | Guanling Formation |
| Lithology | |
| Primary | Dolomite |
| Other | Limestone |
| Location | |
| Coordinates | 25.9°N 105.5°E |
| Approximate paleocoordinates | 12.3°N 94.5°E |
| Region | Guizhou & Yunnan Provinces |
| Country |  China |
| Extent | Yunnan–Guizhou Plateau |
  Yangliujing Formation (China)  Yangliujing Formation (Guizhou) | |
Description
Most of the formation is represented by massive dolomites, indicative of a shallow-water depositional environment. Fossils are generally rare, but conodonts from the Anisian-Ladinian boundary (namely several species of Neogondolella) are known from the lower part of the formation. Some marine reptiles have been found in dolomitic limestone near Dingxiao, an area of Guizhou sometimes considered to preserve the upper part of the Yangliujing Formation. However, under a more restrictive definition of the Yangliujing Formation, the fossils of Dingxiao would instead belong to the overlying Zhuganpo Formation.[1][2]
Fossil content
The following fossils have been reported from the formation:
- Fish
- Omanoselache contrarius
- ?Parvodus sp.
- ?Semionotiformes indet.
- Brachiopods
- Mentzelia sp.
- Nudispiriferina sp.
- Bivalves
- Asoella illyrica
- Unionites sp.
- Crinoids
- Traumatocrinus hsui
- Conodonts
References
- Benton et al., 2013
- Sun et al., 2016
Bibliography
- Sun, Zuoyu; Dayong Jiang; Cheng Ji, and Weicheng Hao. 2016. Integrated biochronology for Triassic marine vertebrate faunas of Guizhou Province, South China. Journal of Asian Earth Sciences 118. 101–110. . doi:10.1016/j.jseaes.2016.01.004 ISSN 1367-9120
- Tong, Brian; Qiyue Zhang; Shixue Hu; Zhong-Qiang Chen; Wen Wen; Jun Liu; Jinyuan Huang; Changyong Zhou, and Tao Xie. 2013. Exceptional vertebrate biotas from the Triassic of China, and the expansion of marine ecosystems after the Permo-Triassic mass extinction. Earth-Science Reviews 125. 199–243. . doi:10.1016/j.earscirev.2013.05.014 ISSN 0012-8252
- Chen, L. D.; G. Cuny, and X. F. Wang. 2007. The chondrichthyan fauna from the Middle-Late Triassic of Guanling (Guizhou province, SW China). Historical Biology 19. 291–300. .
- Tong, J.-N., and Z.-L. Lui. 2000. The Middle Triassic stratigraphy and sedimentary paleogeography of South China. Albertiana 24. 37–47. .