Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.

The formation was first described and defined by Henry Fairfield Osborn in 1922 and it is located in the Iren Nor region of China.

[2][3] As indicated by the fluvial and lacustrine sedimentation, the Iren Dabasu Formation was a large floodplain terrain with braided rivers and meanders that supported extensive vegetation, evidenced on the prominent palaeosol development and the numerous remains from herbivorous dinosaurs.

[3][2] Egg nests, caliche and paleosols seem to indicate periodic subaerial intervals, in addition, the presence of plesiosaur and hybodont shark remains (which are also known in the Bayan Shireh Formation) are indicatives of a river system with connections to the ocean.

[4] Based on the ostracod and charophyte assemblages of the Iren Dabasu Formation, Itterbeeck et al. 2005 suggested a potential correlation with those of the Nemegt Formation, making its age Late Campanian to Early Maastrichtian.

[5] The turtle Khunnuchelys is known from both Iren Dabasu and Bayan Shireh equivalent units such as the Bostobe and Bissekty.

[2] In addition, a giant caenagnathid similar to Gigantoraptor is now known from the Bayan Shireh Formation at the locality of Tsagan Teg.

[6] However, strong evidence coming from biostratigraphic occurrences seems to support a correlation with the Bayan Shireh Formation, at least, with the upper boundary.

For instance, both formations bear similar dinosaur taxa, such as therizinosaurs (Erlikosaurus, Segnosaurus, Erliansaurus or Neimongosaurus) and ornithomimosaurs (Garudimimus or Archaeornithomimus), these similarities are even more intensified by the discovery of Gigantoraptor and the giant unnamed caenagnathid from Bayan Shireh.

[9] A 2022 study describing new ornithomimosaurian material, however, suggested that while the vertebrate faunal assemblage indicates that the age of the formation is likely Turonian based on its similarity to the Bissekty Formation of Uzbekistan, the invertebrate faunal assemblage indicates a much later age (Campanian-Maastrichtian).

[10] The Iren Dabasu Formation is rich on dinosaur fauna, with multiple species described, in the other hand, mammals seem to be extremely absent.

Compared, the fossil taxa between Iren Dabasu and Bayan Shireh are very similar, most notably therizinosaurs, tyrannosauroids, oviraptorosaurs and turtles.

Nevertheless, the fossils lacked enough diagnosis to be confined to a separate genus and species.

[4] Deinonychosaurs are not very common across the formation, however an indeterminate troodontid about the size of Saurornithoides is known from three isolated specimens.

Neimongosaurus "Two specimens with most of the axial column, many limb and girdle elements, and a partial dentary.

Gilmoreosaurus G. mongoliensis "Partial cranial and postcranial elements represented by more than ten specimens".

"[26] Sonidosaurus "Numerous cervical, dorsal and caudal vertebrae and some postcranial elements.