The Shaximiao Formation (simplified Chinese: 沙溪庙组; traditional Chinese: 沙溪廟組 / 沙溪廟層; pinyin: Shāxīmiào zǔ) is a Middle to Late Jurassic aged geological formation in Sichuan, China, most notable for the wealth of dinosaurs fossils that have been excavated from its strata.

The Shaximiao Formation is exposed in and around the small township of Dashanpu (simplified Chinese: 大山铺镇; traditional Chinese: 大山鋪鎮; pinyin: Dàshānpū zhèn), situated seven kilometres north-east from Sichuan's third largest city, Zigong, in the Da'an District.

Both subunits primarily consist of purple-red mudstones, with variable sand inclusion.

The Shaximiao Formation has produced mainly sauropods, but has also held numerous other dinosaur types, such as theropods and stegosaurians amongst others.

The site was unknown until the early 1970s, when a Chinese gas company unearthed Gasosaurus in 1972.

[1] Despite being a frequented "dinosaur-quarry" at present, the Shaximiao Formation was once a lush forest, evidence of which has been found alongside dinosaur remains in the form of fossilised wood.

Dinosaur remains would have been swept toward the lake over millions of years, thus accounting for the hundreds of specimens found.

A paper by Wang et al. (2018), (recalibrated dates reported in Moore et al. (2020)), reported a zircon U-Pb age of 160.4 ± 0.4 mya for the lower part of the Shaximiao Formation, suggesting that the Shaximiao Formation is younger than previously thought.

[3] The paleontologist who has made the largest contribution to the formation and its excavation is Dong Zhiming.

He first examined the formation in 1975, after bone fragments were found embedded in rock from the area.

The site was being demolished to make way for both a natural gas field facility and a vehicle park when Dong first saw the area.

It was not until 1985 that the government finally agreed to close the construction on the site, and by then Dong and his team had already excavated over 100 dinosaurs from the area, including several rare sauropod skulls.

A dinosaur found in the Shaximiao Formation, Dashanpusaurus dongi, was named in tribute of both Dashanpu and Dong Zhiming.

Amongst these finds are fishes, amphibians, turtles, marine reptiles such as crocodiles and also pterosaurs.

Huayangosaurus H. taibaii Shunosaurus-Omeisaurus assemblage, Lower Shaximiao Formation A huayangosaurid with more spike-like plates than Stegosaurus.

Yingshanosaurus[10] Y. jichuanensis[10] Upper Shaximiao Formation[10] Nearly complete skeleton[10] A stegosaurian.

Zigongosaurus Z. fuxiensis Chienkosaurus C. ceratosauroides Mamenchisaurus assemblage, Upper Shaximiao Formation