Irati Formation

Irati Formation is the name of a geological formation of Brazil. It has previously been dated as Upper Permian using palynomorphs but is now dated as Lower Permian using zircon ages obtained from bentonite layers. Exposures of the Irati Formation are to be found in the South (Geopark of Paleorrota), southeastern Brazil and in the states of Goiás and Mato Grosso do Sul.

The formation is particularly famous for its mesosaur occurrences. It is considered time equivalent to the Whitehill Formation of the Ecca Group of the Karoo Supergroup of southern Africa and the Mangrullo Formation of Uruguay.