Lisandro Formation
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]
| Lisandro Formation Stratigraphic range: Late Cenomanian-Early Turonian ~94–91 Ma | |
|---|---|
| Type | Geological formation |
| Unit of | Neuquén Group Río Limay Subgroup |
| Underlies | Río Neuquén Subgroup Portezuelo Formation |
| Overlies | Huincul Formation |
| Thickness | 35–75 m (115–246 ft) |
| Lithology | |
| Primary | Siltstone, claystone |
| Other | Mudstone, sandstone |
| Location | |
| Coordinates | 34.1°S 68.9°W |
| Approximate paleocoordinates | 40.1°S 64.8°W |
| Region | Mendoza, Río Negro & Neuquén Provinces |
| Country |  Argentina |
| Extent | Neuquén Basin |
| Type section | |
| Named for | Cerro Lisandro |
| Named by | Herrero Ducloux |
| Year defined | 1938 |
  Lisandro Formation (Argentina) | |
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 35 and 75 metres (115 and 246 ft) 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.[1][3]
Fossil content
Not many dinosaurs are represented in the Lisandro Formation; other types of animals are frequently found. Fossils documented from this formation are:
- freshwater bivalve molluscs
- fish (Ceratodus)
- turtles
- a carcharodontosaurid theropod
- crocodilians
- an abelisauroid theropod
- "Bayosaurus pubica"
- at least one bird
- ornithopods (including Anabisetia)
- a peirosaurid Bayomesasuchus hernandezi
- a titanosaur sauropod Quetecsaurus rusconii[4]
See also
- List of fossil sites
- Bajo Barreal Formation, contemporaneous formation of the Golfo San Jorge Basin
- Mata Amarilla Formation, contemporaneous formation of the Austral Basin
- List of dinosaur bearing rock formations
References
- Sánchez et al., 2006
- Fossa Mancini et al., 1938
- Leanza et al., 2004, p.69
- Bernardo González Riga, Leonardo Ortiz David (2014). "A new titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous (Cerro Lisandro Formation) of Mendoza Province, Argentina". Ameghiniana. in press. doi:10.5710/AMGH.24.12.2013.1889.
Bibliography
- Fossa Mancini, E.; E. Feruglio, and J.C. Yussen de Campana. 1938. Una reunión de geólogos de YPF y el problema de la terminología estratigráfica ("A YPF geologists' reunion and the problem of stratigraphy terminology"). Boletín de Informaciones Petroleras 15. 1–67.
- Leanza, H.A.; S. Apesteguia; F.E. Novas, and M.S. De la Fuente. 2004. Cretaceous terrestrial beds from the Neuquén Basin (Argentina) and their tetrapod assemblages. Cretaceous Research 25. 61–87. Accessed 2019-02-16.
- Sánchez, María Lidia; Susana Heredia, and Jorge O. Calvo. 2006. Paleoambientes sedimentarios del Cretácico Superior de la Formación Plottier (Grupo Neuquén), Departamento Confluencia, Neuquén (Sedimentary paleoenvironments in the Upper Cretaceous Plottier Formation (Neuquen Group), Confluencia, Neuquén). Revista de la Asociación Geológica Argentina 61. 3–18. Accessed 2019-02-16.