User:A Cynical Idealist/sandbox3
Yixian Formation
[edit]Research history
[edit]Geologic history
[edit]Stratigraphy
[edit]- Age of the Jehol biota[6]
The Yixian Formation is broadly subdivided into several geological subunits. In ascending order (lowest to highest):
- Lujiatun Unit: 20–40 metres (66–131 ft) thick; composed of sandstone, conglomerate, and breccia
- Lower Lava Unit: unknown thickness; composed of basalt and andesite
- Jianshangou Unit: 230–420 metres (750–1,380 ft) thick; composed of shale and tuff ("Chaomidianzi Formation")[7]
- Upper Lava Unit: more than 600 metres (2,000 ft) thick; composed of basalt and andesite
- Upper Yixian: 360–650 metres (1,180–2,130 ft) thick; composed primarily of conglomerate with breccia, but also contains strata of shale and tuff, tuffaceous sandstone, and sandstone conglomerate (Dawangzhangzi unit?)
- Huanghuanshan Unit: 200–300 metres (660–980 ft) thick; composed primarily of conglomerate with breccia with some sandstone conglomerate in the lower strata
| Publication | Lujiatun | Lower Lava | Jianshanggou | Upper Lava | Dawanzhangzi | Jinggangshan |
|---|---|---|---|---|---|---|
| Chang et al. 2009 | 129.7 Ma at the oldest | Up to 122.1 Ma | ||||
| Chang et al. 2017 | ~124—123 Ma | 125.6—125.4 Ma | ||||
| Qin et al. 2019 | ||||||
| Zhong et al. 2021 | 125.755—125.684 Ma | Up to 124.122 Ma | ||||
| Li et al. 2022 | 125.541—125.793 Ma | 125.374—125.572 Ma | ||||
Fossil content
[edit]Geography and human use
[edit]References
[edit]- ^ Wang, Tiehui; Gong, Enpu; Liang, Yue; Cui, Ying; Huang, Wentao (2022). "Varves in the Yixian Formation, western Liaoning: Constraining the palaeoclimate in the Early Cretaceous". Geological Journal. 57 (1): 166–185. Bibcode:2022GeolJ..57..166W. doi:10.1002/gj.4289.
- ^ Tian, Xing; Gao, Yuan; Ma, Jian; Huang, He; Pan, Jinjiang; Wang, Chengshan (2024). "Lacustrine varves in the Lower Cretaceous Yixian Formation of western Liaoning, Northeast China: Implications for seasonal to sub-decadal palaeoclimate variability associated with the Jehol Biota and "Dinosaur Pompeii"". Palaeogeography, Palaeoclimatology, Palaeoecology. 646. Bibcode:2024PPP...64612241T. doi:10.1016/j.palaeo.2024.112241.
- ^ Cui, Ying; Gong, Enpu; Wang, Tiehui; Guan, Changqing; Zhang, Yongli; Liang, Junhong (2015). "Palynomorph assemblages and paleoclimate records from the Zhuanchengzi Bed of the Yixian Formation, western Liaoning Province, China". Science China Earth Sciences. 58 (9): 1538–1552. Bibcode:2015ScChD..58.1538C. doi:10.1007/s11430-015-5147-x.
- ^ Wang, Yaqiong; Olsen, Paul E.; Sha, Jingeng; Yao, Xiaogang; Liao, Huanyu; Pan, Yanhong; Kinney, Sean; Zhang, Xiaolin; Rao, Xin (2016). "Stratigraphy, correlation, depositional environments, and cyclicity of the Early Cretaceous Yixian and ?Jurassic-Cretaceous Tuchengzi formations in the Sihetun area (NE China) based on three continuous cores". Palaeogeography, Palaeoclimatology, Palaeoecology. 464: 110–133. Bibcode:2016PPP...464..110W. doi:10.1016/j.palaeo.2016.06.043.
- ^ Chen, P.; Wang, Q.; Zhang, H.; Cao, M.; Li, W.; Wu, S.; Shen, Y. (2005). "Jianshangou Bed of the Yixian Formation in west Liaoning, China". Science in China Series D: Earth Sciences. 48 (3): 298–312. Bibcode:2005ScChD..48..298C. doi:10.1360/04yd0038. S2CID 130825449.
- ^ Chang, Su-Chin; Gao, Ke-Qin; Zhou, Chang-Fu; Jourdan, Fred (2017). "New chronostratigraphic constraints on the Yixian Formation with implications for the Jehol Biota". Palaeogeography, Palaeoclimatology, Palaeoecology. 487: 399–406. Bibcode:2017PPP...487..399C. doi:10.1016/j.palaeo.2017.09.026.
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