Lisandro-Formation

The Lisandro - Formation, also known as Cerro Lisandro Formation is a sequence of continental sedimentary rocks of the Upper Cretaceous of Argentina, which is known for its fossil fauna. She is the youngest layer member of the Río Limay - subgroup, the lowest portion of the Neuquén Group. Earlier this subgroup was even considered as a formation, the formation was known as Lisandro ( Cerro ) Lisandro Members. These rocks were deposited in the late Cenomanian and early Turonian in front of about 94 to 91 million years. Outcrops of this geological formation to find the Argentine province of Neuquén; Type locality is a hill called Cerro Lisandro.

The Lisandro - Formation lies conformably on the Huincul formation and is covered by the Portezuelo lineup, which belongs to the Río Neuquén - subgroup. It is with a thickness of 35 to 75 meters, the smallest of the three formations of the Río Limay - subgroup. The rocks are reddish clay and siltstones, which were probably deposited under swampy conditions. Most of the red rocks of the Lisandro Formation are well distinguished from the greenish to yellowish deposits of Huincul lineup.

Fossils of the formation close shells, fish, turtles, crocodiles, and at least one bird species with a. Dinosaurs are not as common as in some other formations of the Neuquén Group. Among the finds are a theropod and ornithopod abelisauroider as Anabisetia.