Ziliujing Formation | |
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Stratigraphic range: Sinemurian-Toarcian, | |
Type | Geological formation |
Sub-units | Dongyuemiao Member, Maanshan Member, Daanzhai Member |
Underlies | Xintiangou Formation |
Overlies | Zhenzhuchong Formation |
Thickness | Dongyuemiao M. 5 to 11.2 metres (20 to 40 ft), Maanshan M. 131 to 180 metres (430 to 590 ft) Daanzhai M. 18 to 45.2 metres (60 to 150 ft) |
Lithology | |
Primary | Mudstone |
Other | Sandstone |
Location | |
Country | China |
Extent | Sichuan Basin |
Type section | |
Named for | Ziliujing District |
The Ziliujing Formation is a geological formation in China, It is Early Jurassic in age. It is part of the stratigraphy of the Sichuan Basin. The dinosaur Gongxianosaurus and indeterminate theropod material are known from the Dongyuemiao Member of the formation, as well as dinosaur footprints, Zizhongosaurus and indeterminate prosauropods from the Da'anzhai Member.[1] The basal sauropod Sanpasaurus is known from the Maanshan Member.[2] An possible unnamed stegosaur and the pliosauroid plesiosaur Sinopliosaurus are also known from this formation but they were found an indeterminate member.[2] An unnamed teleosaurid known from a complete skull has also been found in the formation, pending a formal description.[3] The deposition environment during the Da'anzhai Member in the lower Toarcian is thought to have been that of a giant freshwater lake encompassing the whole of the Sichuan basin, around 3 times larger than Lake Superior, coeval with the Toarcian Oceanic Anoxic Event around 183 Ma.[4] The Sinemurian-Pliensbachian boundary event (192.9 Ma) has been recorded on the top of the Dongyuemiao Member, while lower parts of this member are of Earliest Sinemurian age (around 199 Ma).[5][6]
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