| Lisandro Formation | |
| Type: | Geological formation |
| Period: | Turonian |
| Age: | Middle-Late Turonian ~ |
| Prilithology: | Siltstone, claystone |
| Otherlithology: | Mudstone, sandstone |
| Namedfor: | Cerro Lisandro |
| Namedby: | Herrero Ducloux |
| Year Ts: | 1938 |
| Region: | Mendoza, Río Negro & Neuquén Provinces |
| Country: | Argentina |
| Coordinates: | -34.1°N -68.9°W |
| Paleocoordinates: | -40.1°N -64.8°W |
| Unitof: | Neuquén Group Río Limay Subgroup |
| Underlies: | Río Neuquén Subgroup Portezuelo Formation |
| Overlies: | Huincul Formation |
| Thickness: | 35- |
| Extent: | Neuquén Basin |
The Lisandro Formation, alternatively known as the Cerro Lisandro Formation, is a Late Cretaceous (Late Cenomanian to Early Turonian) geologic formation with outcrops in the Neuquén, Río Negro and Mendoza Provinces of Argentina. It is the youngest formation within the Río Limay Subgroup, the lowest section of the Neuquén Group. Formerly that subgroup was treated as a formation, and the Lisandro Formation was known as the (Cerro) Lisandro Member.[1]
The type locality of the Lisandro Formation is the hill known as Cerro Lisandro in Neuquén Province.[2] This formation conformably overlies the Huincul Formation, and it is in turn overlain by the Portezuelo Formation, which is a part of the Río Neuquén Subgroup.
The Lisandro Formation varies between 35mand75mm (115feetand246feetm) thick, the thinnest of the three formations in its subgroup. It is composed of siltstones and claystones, red in color, which have been interpreted as a swampy to fluvial environment. Usually, the red Lisando Formation rocks are easy to distinguish from the greenish or yellowish deposits of the Huincul Formation.[3]
Not many dinosaurs are represented in the Lisandro Formation; other types of animals are frequently found. Fossils documented from this formation are: