Xintiangou Formation Explained

Xintiangou Formation
Period:	Middle Jurassic
Type:	Geological formation
Prilithology:	Mudstone, Sandstone
Otherlithology:	Limestone
Underlies:	Shaximiao Formation
Overlies:	Ziliujing Formation
Thickness:	Over 400m (1,300feet)
Region:	Sichuan
Extent:	Sichuan Basin

The Xintiangou Formation is a geological formation in China. Part of the stratigraphy of the Sichuan Basin, it is of an uncertain Middle Jurassic age, with preliminary U-Pb estimates giving an age range of 170 ma. It predominantly consists of interbedded mudstone and sandstone, with subordinate shelly limestone. At the Laojun site remains of lungfish, bony fish, freshwater sharks, temnospondyls, plesiosaurs,^{[1] [2]} crocodyliformes, the Xinjiangchelyid turtle Protoxinjiangchelys and tritylodontids are known.^[3] The dinosaurs Sanxiasaurus, Yunyangosaurus, and indeterminate sauropods are also known from the formation.^{[4] [5]} Theropod and ornithopod tracks have also been reported from the formation.^{[6] [7]}

Notes and References

1. Zhang. Feng. Yu. Hai-Dong. Xiong. Can. Wei. Zhao-Ying. Peng. Guang-Zhao. Wei. Xue-Fang. December 2020. New freshwater plesiosaurian materials from the Middle Jurassic Xintiangou Formation of the Sichuan Basin, southwestern China. Journal of Palaeogeography. en. 9. 1. 23. 10.1186/s42501-020-00072-y. 2524-4507. free.
2. Ma . Qingyu . Li . Ning . Lin . Yu . Xiong . Can . Wei . Xuefang . 2023-10-11 . Isolated freshwater pliosaurid teeth from the Middle Jurassic Xintiangou Formation of Chongqing, China . Historical Biology . en . 1–10 . 10.1080/08912963.2023.2268617 . 264056915 . 0891-2963. subscription .
3. Hu. Xufeng. Li. Lu. Dai. Hui. Wang. Ping. Buffetaut. Eric. Wei. Guangbiao. Xiong. Can. Tong. Haiyan. August 2020. Turtle remains from the Middle Jurassic Xintiangou Formation of Yunyang, Sichuan Basin, China. Annales de Paléontologie. 106 . 4 . en. 102440. 10.1016/j.annpal.2020.102440. 225451666 . subscription.
4. Li. Ning. Dai. Hui. Tan. Chao. Hu. Xufeng. Wei. Zhaoying. Lin. Yu. Wei. Guangbiao. Li. Deliang. Meng. Li. Hao. Baoqiao. You. Hailu. 2019-10-31. A neornithischian dinosaur from the Middle Jurassic Xintiangou Formation of Yunyang, Chongqing, China: the earliest record in Asia. Historical Biology. 33 . 7 . en. 1089–1102. 10.1080/08912963.2019.1679129. 209583081 . 0891-2963.
5. Hui Dai . Roger Benson . Xufeng Hu . Qingyu Ma . Chao Tan . Ning Li . Ming Xiao . Haiqian Hu . Yuxuan Zhou . Zhaoying Wei . Feng Zhang . Shan Jiang . Deliang Li . Guangzhao Peng . Yilun Yu . Xing Xu . 2020 . A new possible megalosauroid theropod from the Middle Jurassic Xintiangou Formation of Chongqing, People's Republic of China and its implication for early tetanuran evolution . Scientific Reports . 10 . 1 . Article number 139 . 10.1038/s41598-019-56959-x. 31924836 . 6954265 . free .
6. Xing. Lida. Peng. Guangzhao. Ye. Yong. Lockley. Martin G.. Klein. Hendrik. Persons. W. Scott. Zhang. Jianping. Shu. Chunkang. Hao. Baoqiao. 2014-04-03. Sauropod and Small Theropod Tracks from the Lower Jurassic Ziliujing Formation of Zigong City, Sichuan, China, with an Overview of Triassic–Jurassic Dinosaur Fossils and Footprints of the Sichuan Basin. Ichnos. en. 21. 2. 119–130. 10.1080/10420940.2014.909352. 129220218 . 1042-0940. 10.1.1.663.3037.
7. Xing. Lida. Lockley. Martin G.. Wang. Yongdong. Pole. Mike S.. Klein. Hendrik. Peng. Guangzhao. Xie. Xiaoping. Zhang. Guoquan. Deng. Chuntao. Burns. Michael E.. August 2017. New Middle Jurassic dinosaur track record from northeastern Sichuan Province, China. Swiss Journal of Palaeontology. en. 136. 2. 359–364. 10.1007/s13358-016-0123-4. 132256539 . 1664-2376. subscription.