Hekou Formation
Geologic formation in China
From Wikipedia, the free encyclopedia
The Hekou Formation is a Cretaceous geologic formation in China. Pterosaur fossils have been recovered from the formation. It is a unit of the Guifeng Group and dates to the Late Cretaceous.[2] Dinosaur fossils from the formation include a nearly perfect oviraptorid embryo nicknamed Baby Yingliang, an unnamed large hadrosaurid, and hadrosauroid eggs with embryos.[3][4][5] Mammal fossils include Erythrobaatar and Yubaatar qianzhouensis.[6][7] The polyglyphanodontian lizards Xenodontolacerta and Yechilacerta has also been described from the formation.[8][9]
| Hekou Formation | |
|---|---|
| Stratigraphic range: Late Cretaceous, | |
| Type | Geological formation |
| Unit of | Guifeng Group |
| Underlies | Tangbian Formation |
| Overlies | Unconformity: Zhoutian Formation |
| Lithology | |
| Primary | Conglomerate, glutenite |
| Other | Sandstone, siltstone, tuff |
| Location | |
| Region | Jiangxi Province, Asia |
| Country | China |
Description
The Hekou Formation is a constituent of the Guifeng Group; a sequence of formations that were deposited in the Xinjiang Basin including the Hekou, Tangbian, and Lianhe formation which record aeolian-alluvial interactions in a palaeoplateau desert. Both a successional and coeval model of the deposition of these units have been proposed, with estimated ages of the Hekou formation ranging from Coniacian-Santonian to Maastrichtian.[10][11]The associated facies include alluvial fans and adjacent wadi river channels, with mudcracks indicating subaerial exposure of the deposits. Oxygen-18 isotope values recorded in Dinosaur eggshells indicated low annual precipitation and humidity, suggesting an arid to semi-arid environment. The occurrence of striated cobbles in the alluvial facies suggests glacial activity in the catchment areas of the Cretaceous plateau.[12][13]
