| Yixian Formation | |
|---|---|
| Stratigraphic range: Barremian–Aptian ~ | |
| Type | Geological formation |
| Unit of | Jehol Group |
| Sub-units | Jianshangou Bed Lujiatun Bed |
| Underlies | Jiufotang Formation |
| Overlies | Dabeigou Formation?, Tuchengzi Formation |
| Lithology | |
| Primary | Basalt |
| Other | Siliciclastic |
| Location | |
| Coordinates | 41°31′59″N 121°14′18″E / 41.5330°N 121.2383°E |
| Approximate paleocoordinates | 44°18′N 122°48′E / 44.3°N 122.8°E |
| Region | Liaoning |
| Country |  China |
| Type section | |
| Named for | Yixian, Liaoning |
| Named by | Amadeus William Grabau |
| Year defined | 1923[1] |
  Yixian Formation (China)  Yixian Formation (Liaoning) | |
The Yixian Formation (simplified Chinese: 义县组; traditional Chinese: 義縣組; pinyin: Yìxiàn zǔ; formerly transcribed as Yihsien Formation[1]) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the late Barremian and early Aptian stages of the Early Cretaceous. It is known for its exquisitely preserved fossils, and is mainly composed of basalts interspersed with siliciclastic sediments.[2]
- ^ a b Grabau, A. W. (1923). "Cretaceous Mollusca from North China". Bulletin of the Geological Survey of China. 5 (2): 183–197.
- ^ Zhou, Z (2006). "Evolutionary radiation of the Jehol Biota: chronological and ecological perspectives". Geological Journal. 41 (3–4): 377–393. Bibcode:2006GeolJ..41..377Z. doi:10.1002/gj.1045.