InGen Database Description
The Iren Dabasu Formation is situated in the Iren Nor region of Inner Mongolia and dates to the Cenomanian age of the Late Cretaceous, 100 million years ago. It overlies the Arshanto Formation. The first dinosaurs were discovered here in 1922, but as yet the collections haven't been completely studied.
Combined studies from Canadian and Chinese teams in 1988 and 1990 renewed interest in the location for the variety of finds there.
The formation comprises of sandstone with claystone and siltstones mixed in. The deposits come from a network of broad rivers and streams. It likely had a humid climate and this may have contributed to the gigantism seen in dinosaurs compared to similar dig sites.
Dinosaur eggs and turtle fossils have been excavated here. It's also a rich source of dinosaur and microfossil finds.