Huincul Formation

The Huincul Formation is a geologic formation of Late Cretaceous (Cenomanian to Early Turonian) age of the Neuquén Basin that outcrops in the Mendoza, Río Negro and Neuquén Provinces of northern Patagonia, Argentina. It is the second formation in the Río Limay Subgroup, the oldest subgroup within the Neuquén Group. Formerly that subgroup was treated as a formation, and the Huincul Formation was known as the Huincul Member.

Description
The type locality of the Huincul Formation is near the town of Plaza Huincul in Neuquén Province after which the formation was named by Wichmann in 1929. This formation conformably overlies the Candeleros Formation, and it is in turn overlain by the Lisandro Formation.

The Huincul Formation is thought to represent an arid environment with ephemeral or seasonal streams. In some areas, it is up to 250 m thick. It is mainly composed of green and yellow sandstones and can easily be differentiated from the overlying Lisandro Formation, which is red in color. The Candeleros Formation, underlying the Huincul, is composed of darker sediments, making all three formations easily distinguishable.

Paleobiota
Dinosaur fossils are frequently found in the Huincul Formation. The titanosaurian sauropod Argentinosaurus huinculensis, one of the largest known land animals, is named after the formation. Another noteworthy Huincul dinosaur is the carcharodontosaurid theropod Mapusaurus roseae, which is regarded as one of the largest known terrestrial predators.

Dinosaurs
Apart from sauropods and theropods, rare fossils of iguanodonts and other ornithopods have been recorded in the formation. Ichnofossils (footprints) of abelisaurid theropods and hadrosaurs are also known.

Other reptiles
Apart from the taxa named here, fossils of unnamed squamates and neosuchian crocodyliforms have been discovered in the formation.