Sunjiawan Formation
Geological formation in Liaoning, China
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The Sunjiawan Formation (simplified Chinese: 孙家湾组; traditional Chinese: 孫家灣組; pinyin: Sūnjiāwān Zǔ) is a geological formation in Liaoning, China, with strata possibly dating back to the early Late Cretaceous, specifically the Cenomanian[1]. Dinosaur remains are among the fossils that have been recovered from the formation.[2] It forms part of the same geological sequence as the older and underlying Yixian Formation and Jiufotang Formation. It primarily consists of variegated conglomerates with rare intercalations of thin bedded sandstones, siltstones and mudstones.[3]
OverliesUnconformity with Fuxin Formation
PrimaryConglomerate
| Sunjiawan Formation | |
|---|---|
| Stratigraphic range: Early Cenomanian ~ | |
| Type | Geological formation |
| Overlies | Unconformity with Fuxin Formation |
| Lithology | |
| Primary | Conglomerate |
| Other | Sandstone, siltstone, mudstone |
| Location | |
| Coordinates | 41.7°N 120.8°E |
| Approximate paleocoordinates | 46.2°N 112.1°E |
| Region | Liaoning |
| Country | China |
| Extent | Beipiao Basin |
  Sunjiawan Formation (China)  Sunjiawan Formation (Liaoning) | |
Fossil content
Remains of the following dinosaurs have been found in the formation:
Color key
|
Notes Uncertain or tentative taxa are in small text; |
Dinosaurs
Ankylosaurs
| Ankylosaurs of the Sunjiawan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Crichtonpelta[4] | C. benxiensis[5] | A partial skeleton. | A ankylosaurine ankylosaurid | |||
| Crichtonsaurus[6] | C. bohlini | A partial skeleton. | A ankylosaurine ankylosaurid | |||
Ornithopods
| Ornithopods of the Sunjiawan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Hadrosauroidea Indet. | Indeterminate | Dental remains[7] | Different with Shuangmiaosaurus from the same stratigraphic unit | |||
| Shuangmiaosaurus[8] | S. gilmorei | A partial left upper jaw and lower jaw. | A styracosternan ornithopod | |||
Sauropods
| Sauropods of the Sunjiawan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Borealosaurus[9] | B. wimani | Two caudal vertebra, humerus and isolated tooth crown | A titanosaurian sauropod | |||
| Titanosauriformes Indet. | Indeterminate | Single tooth[7] | Provisionally attributed to Borealosaurus | |||
Theropods
| Theropods of the Sunjiawan Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Tyrannosauroidea Indet. | Indeterminate | Single tooth[7] | ||||