Ulansuhai Formation

The Ulansuhai Formation (simplified Chinese: 乌兰苏海组; traditional Chinese: 烏蘭蘇海組; pinyin: Wūlánsūhǎi Zǔ) is a geological formation in Inner Mongolia, north China. Dinosaur remains are among the fossils that have been recovered from the formation.^[1]

Ulansuhai Formation
Stratigraphic range: Turonian ~92 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Unit of	Dashuigou Group
Lithology
Primary	Claystone, siltstone
Location
Coordinates	40.3°N 105.9°E / 40.3; 105.9
Approximate paleocoordinates	41.5°N 97.2°E / 41.5; 97.2
Region	Inner Mongolia
Country	China
Ulansuhai Formation (China) Show map of China Ulansuhai Formation (Inner Mongolia) Show map of Inner Mongolia

The Ulansuhai Formation has traditionally been considered to date to the Aptian-Albian stages of the Lower Cretaceous, due to similarities between the Ulansuhai fauna and known Aptian formations.^[1] However, radiometric dating done on underlying formations has shown this to be incorrect. Due to the age of underlying rocks, the Ulansuhai Formation cannot be older than the Turonian stage of the Late Cretaceous, about 92 Ma.^[2][3]

Fossil content

Dinosaurs

The carcharodontosaurid Shaochilong and ankylosaurid Gobisaurus were initially reported from this formation, but actually derive from the Miaogou Formation, which has outcrops nearby.^[4]

Dinosaurs
Taxa	Presence	Description	Images
Chilantaisaurus tashuikouensis[1]		A theropod of uncertain affinities,[3] known from a fragmentary postcranial skeleton.[5]	Chilantaisaurus
Sinocephale bexelli[6]		A pachycephalosaurid, known from now lost skull fragments. Formerly Troodon bexelli.
Sinornithomimus dongi[7][1]		An ornithomimid. "[Fourteen] skeletons, juvenile to adult."[8]	Sinornithomimus
Iguanodontia indet.[1]

Testudines

Turtles

Taxa	Presence	Description	Images
Kuhnemys maortuensis[9]		A pantrionychid turtle

Ostracods

Caption text

Taxa	Presence	Description	Image
cf. Cypridea[7]		A cyprideid

See also

• List of dinosaur-bearing rock formations