Huincul Formation

The Huincul Formation is a geologic formation of Late Cretaceous (Early Cenomanian to Late 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. The Huincul Formation is a geologic formation of Late Cretaceous (Early Cenomanian to Late 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. 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 metres (820 ft) 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. Fossil bones are rarely found in the Huincul Formation. However, remains of Argentinosaurus huinculensis, one of the largest land animals known, were found in the Huincul Formation, and this species is named after it. One of the largest predators known, Mapusaurus, has also been recovered from a bonebed in this formation.