Jiangjunding Formation

The Jiangjunding Formation is a geological formation in Shandong, China whose strata date back to the Campanian-Maastrichtian stages of the Late Cretaceous.^[1] Dinosaur remains are among the fossils that have been recovered from the group.^[2]

Jiangjunding Formation
Stratigraphic range: Campanian-Maastrichtian ~72.9–68.5 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Group
Unit of	Wangshi Group
Underlies	Jingangkou Formation
Overlies	Hongtuya Formation
Lithology
Primary	Conglomerate, sandstone, siltstone
Other	Marl
Location
Coordinates	36.9°N 120.7°E / 36.9; 120.7
Approximate paleocoordinates	37.3°N 111.0°E / 37.3; 111.0
Region	Shandong
Country	China
Jiangjunding Formation (China) Show map of China Jiangjunding Formation (Shandong) Show map of Shandong

The Jiangjunding formation consists purpley-grey or reddy-brown sandstones or various consistencies, siltstones and conglomerates. The Jiangjunding Formation was deposited in a fluvial to lacustrine environment. The climate was warm and humid during the majority of the timespan, although it was beginning to dry out after the Jiangjunding.^[3]

Paleofauna

Dinosaur eggs are known from this formation.^[4]

Paleofauna of the Jiangjunding Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Cheloniidae aff. Nanhsiungchelyidae[5]	Indeterminate[6]
Coelurosauria indet.[5]	Indeterminate[6]
Micropachycephalosaurus[7]	M. hongtuyanensis[7]			"Partial mandible, associated postcranial fragments."[5]
Pinacosaurus[8]	P. cf. grangeri[8]
Sauropoda indet.[5]	Indeterminate[5]
Shantungosaurus[6]	S. giganteus[6]		Xingezhuang Formation
Tanius[6]	T. sinensis[6]

Age of the formation

The Wangshi group of geologic formations is generally considered to be from the Late Cretaceous, although some regions are older. Based on the discovery of Pinacosaurus, only known elsewhere in the Djadokhta Formation or regions of the same age, the Wangshi Group was presumed to be a similar age of 75–71 million years old. The specific age for the Hongtuya Formation has been identified as 73.5–72.9 mya. As the Hongtuya is directly older than the Jiangjunding, it was identified that the Jiangjunding must be of latest Campanian to earliest Maastrichtian age, according to Borinder (2015).^[3]