Dashanpu Formation

The Dashanpu Formation is a Mid to Late Jurassic rock formation in China, most notable for the wealth of dinosaurs that have been excavated from the area. The Dashanpu Formation sits 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 (simplified Chinese: 大安区; pinyin: Dà'ān qū).

Geology

The Dashanpu Formation includes four layers of rock: The upper and lower Shaximiao Formations (simplified Chinese: 上·下沙溪庙地层; traditional Chinese: 上·下沙溪廟地層; pinyin: shàng / xià Shāxīmiào dìcéng), although they are commonly referred to as one, simply being called “Shaximiao Formations”. The upper Shaximiao Formation is also known as the Shangshaximiao Formation, and the lower Shaximiao Formation is also known as the Xiashaximiao Formation. The Shaximiao Formations are the most productive, despite being only two of four. The last two formations, the Zhenchuchong Formation and the Ziliujing Formation, are noticeably less productive and remain relatively unexplored.

Dinosaur finds

The Dashanpu Formation has produced mainly sauropods, but has also held numerous other dinosaur types, such as theropods and stegosaurians amongst others. In total, over 8,000 pieces of bone have been unearthed from the area – amounting to nearly 40 tonnes. The site was unknown until the early 1970s, when a Chinese gas company unearthed Gasosaurus in 1972. It would be the first of the many dinosaurs to be uncovered from the area. Most specimens found are held at the Zigong Dinosaur Museum (自貢恐龍博物館) which has been placed on the area during the mid-1980s.

Despite being a frequented “dinosaur-quarry” at present, the Dashanpu Formation was once a lush forest, evidence of which has been found alongside dinosaur remains in the form of fossilised wood. Paleontologists speculate that the area also had a lake that was fed by a large river. Dinosaur remains would have been swept toward the lake over millions of years, thus accounting for the hundreds of specimens found. Paleontologists have dated parts of the formation at about 168 to 161 million years old, between the Bathonian to Callovian stages of the Mid Jurassic.

Zhiming's research

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 Zhiming first saw the area. Amongst the extensive clearings, Zhiming found numerous bone fragments which were exposed.

However, the specimens were being damaged due to bulldozers in the area and there would be little chance of closing the area as the state had invested millions of yuan in the site already. It was not until 1985 that the government finally agreed to close the construction on the site, and by then Zhiming and his team had already excavated over 100 dinosaurs from the area, including several rare sauropod skulls. A dinosaur was found in the Dashanpu Formation which was named in tribute of both Dashanpu and Dong Zhiming; Dashanpusaurus dongi.

Paleobiota of the Dashanpu Formation

In addition to dinosaur finds, many other prehistoric finds have been uncovered from the Dashanpu Formation. Amongst these finds are fishes, amphibians, turtles, marine reptiles such as crocodiles and also pterosaurs. A mammal-like reptile called Bienotheroides has been found there, and so has a member of the Subclass Labyrinthodontia.

Amphibians

Mammal-likes

Ornithichians

Indeterminate Stegosauridae remains have been found in the Upper Shaximiao Formation of Sichuan.^[1]

Genus	Species	Location	Member	Abundance	Description	Images
Agilisaurus[2]	A. louderbacki[2]	Sichuan[2]	Lower Shaximiao Formation[2]			Agilisaurus. Chialingosaurus. Chungkingosaurus. Huayangosaurus.
	A. multidens[2]
Chialingosaurus[1]	C. kuani[1]	Sichuan	Upper Shaximiao Formation.[1]
Chungkingosaurus[1]	C. jiangbeiensis[1]	Sichuan[1]	Upper Shaximiao Formation[1]
Gongbusaurus[1]	G. shiyii[1]	Sichuan[1]	Upper Shaximiao Formation[1]		Later determined to be indeterminate ornithischian remains.[1]
Hexinlusaurus
Huayangosaurus[2]	H. taibaii[2]	Sichuan[2]	Lower Shaximiao Formation[2]
Sanpasaurus[3]	S. yaoi[3]	Sichuan[3]	Ziliujing Formation[3]		Later determined to be indeterminate ornithopod remains.[3]
Tuojiangosaurus[1]	T. multispinus[1]	Sichuan[1]	Upper Shaximiao Formation[1]
Xiaosaurus[2]	X. dashanpensis[2]	Sichuan[2]	Lower Shaximiao Formation[2]		Later determined to be indeterminate ornithischian remains.[2]
Yandusaurus[2]	Y. hongheensis[2]	Sichuan[2]	Lower Shaximiao Formation[2]

Pterosaurs

Sauropodomorphs

Indeterminate prosauropod remains formerly attributed to the anchisauridae have been recovered from Zhenzhunchong outcrops in Sichuan.^[3]

Genus	Species	Location	Member	Abundance	Description	Images
Abrosaurus[3]	A. dongpoi[3]	Sichuan[2]	Lower Shaximiao Formation[2]			Abrosaurus. Mamenchisaurus. Omeisaurus. Shunosaurus.
Dashanpusaurus
Datousaurus[2]	D. bashanensis[2]	Sichuan[2]			Lower Shaximiao Formation[2]
Gongxianosaurus[3]	G. shibeiensis.[3]	Sichuan[3]	Ziliujing Formation[3]
cf. Lufengosaurus[3]	cf. L. huenei[3]	Sichuan[3]	Zhenzhunchong Formation[3]
	cf. L magnus[3]	Sichuan[3]	Zhenzhunchong Formation[3]		Actually referrable to cf. L. huenei.[3]
Mamenchisaurus[1]	M. constructus[1]	Sichuan[1]	Upper Shaximiao Formation[1]
	M. fuxiensis
	M. hochuanensis.[1]	Sichuan[1]	Upper Shaximiao Formation[1]
	M. jingyanensis.[1]	Sichuan[1]	Upper Shaximiao Formation[1]
	M. youngi.[1]	Sichuan[1]	Upper Shaximiao Formation[1]
Omeisaurus[1]	O. changshouensis[1]	Sichuan[1]	Upper Shaximiao Formation[1]		Later determined to be indeterminate sauropod remains.[1]
	O. fuxiensis[1]	Sichuan[1]	Upper Shaximiao Formation[1]		Later determined to be indeterminate sauropod remains.[1]
	O. junghsiensis[2]	Sichuan[2]	Lower Shaximiao Formation[2]
	O. luoquanensis[2]	Sichuan[2]	Lower Shaximiao Formation[2]		Later determined to be indeterminate sauropod remains.[2]
	O. tianfuensis[2]	Sichuan[2]	Lower Shaximiao Formation[2]		Mamenchisaurus fuxiensis[2] may be O. tianfuensis?
Protognathosaurus[2]	P. oxyodon[2]	Sichuan[2]	Lower Shaximiao Formation[2]		Later determined to be indeterminate sauropod remains.[2]
Sanpasaurus[3]	S. yaoi[3]	Sichuan[3]	Ziliujing Formation[3]		Later determined to be indeterminate sauropod remains.[3]
Shunosaurus[2]	S. lii[2]	Sichuan[2]	Lower Shaximiao Formation[2]
Zizhongosaurus[3]	Z. chuanchengensis[3]	Sichuan[3]	Ziliujing Formation[3]		Later determined to be indeterminate sauropod remains.[3]

Theropods

Indeterminate Theropoda remains have been recovered from the Ziliujing Formation in Sichuan.^[3]

^[2]

^[1]

^[3]

Genus	Species	Location	Member	Abundance	Description	Images
Chuandongocoelurus[2]	C. primitivus[2]	Sichuan[2]	Lower Shaximiao Formation[2]		Later determined to be an indeterminate tetanuran.[2]	Gasosaurus pursuing prey. Sinraptor. Yangchuanosaurus.
Gasosaurus[2]	G. constructus[2]	Sichuan[2]	Lower Shaximiao Formation[2]
Kaijiangosaurus[2]	K. lini[2]	Sichuan[2]	Lower Shaximiao Formation[2]
Sinraptor[1]	S. hepingensis[1]	Sichuan[1]	Upper Shaximiao Formation[1]
Szechuanosaurus[2]	S. campi[1]	Sichuan[1]	Upper Shaximiao Formation[1]		Later determined to be an indeterminate theropod.[1]
	S. yandonensis	Sichuan[1]	Upper Shaximiao Formation[1]		Later determined to be an indeterminate theropod.[1]
	"S." zigongensis[2]	Sichuan[2]	Lower Shaximiao Formation[2]
Xuanhanosaurus[2]	X. qilixaensis[2]	Sichuan[2]	Lower Shaximiao Formation[2]
Yangchuanosaurus[1]	Y. magnus[1]	Sichuan[1]	Upper Shaximiao Formation[1]
	Y. shangyouensis[1]	Sichuan[1]	Upper Shaximiao Formation[1]

See also

• List of dinosaur-bearing rock formations

References

	Earth sciences portal
	Paleontology portal
	Dinosaurs portal

External links

• Dong Zhiming account of Dashanpu Formation
• "Xiashaximiao Formation" at DinoData