Yixian Formation
| Yixian Formation Stratigraphic range: Barremian–Aptian, 125–121 Ma |
|
|---|---|
| Type | Geological formation |
| Unit of | Jehol Group |
| Sub-units | Jingangshan Bed Dawangzhangzi Bed Jianshangou Bed Lujiatun Bed |
| Underlies | Jiufotang Formation |
| Overlies | Dabeigou Formation?, Tuchengzi Formation |
| Lithology | |
| Primary | Basalt |
| Other | Siliciclastic |
| Location | |
| Region | Liaoning |
| Country |
 China
|
The Yixian Formation (simplified Chinese: 义县组; traditional Chinese: 義縣組; pinyin: Yìxiàn zǔ) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans 11 million years during the early Cretaceous period. It is known for its exquisitely preserved fossils, and is mainly composed of basalts interspersed with siliciclastic sediments.
The potential importance of the Yixian Formation was initially recognized during the time the Empire of Japan occupied China's Rehe ("Jehol") Province after the First battle of Hopei in 1933. Many Japanese scientists had noticed fossil remains of extinct fish and reptiles, possibly the champsosaurs. These initial fossil discoveries made by Japanese scientists vanished once World War II ended in 1945.
By 1949, when administration of the area passed to the Chinese Communist Party and its leader Mao Zedong, the fossils of Yixian were studied only by Chinese scientists. It was not until the 1990s when remarkable fossils of birds and dinosaurs were excavated. Since 1996, a number of dinosaur fossils that have revolutionized knowledge of these animals have been found at Yixian; among them are the first known non-avian theropods with feathers. See Jehol Biota.
...
Wikipedia