Portezuelo Formation
The Portezuelo Formation is a geologic formation of Late Cretaceous (Late Turonian to Early Coniacian) age, outcropping in the Mendoza, Río Negro and Neuquén provinces of Argentina.[1] It is the fourth-oldest formation in the Neuquén Group and the older of the two formations in the Río Neuquén Subgroup. Formerly, that subgroup was treated as a formation, and the Portezuelo Formation was known as the Portezuelo Member.[2]
| Portezuelo Formation Stratigraphic range: late Turonian-early Coniacian ~91–88 Ma | |
|---|---|
| Type | Geological formation |
| Unit of | Neuquén Group Río Neuquén Subgroup |
| Underlies | Plottier Formation |
| Overlies | Río Limay Subgroup Lisandro Formation |
| Thickness | 95–130 m (312–427 ft) |
| Lithology | |
| Primary | Sandstone |
| Other | Conglomerate, limestone |
| Location | |
| Coordinates | 38.5°S 68.7°W |
| Approximate paleocoordinates | 44.4°S 47.2°W |
| Region | Mendoza, Río Negro & Neuquén Provinces |
| Country |  |
| Extent | Neuquén Basin |
| Type section | |
| Named for | Sierra del Portezuelo |
  Portezuelo Formation (Argentina) | |
Description
The type locality of the Portezuelo Formation is the mountain range known as Sierra del Portezuelo in Neuquén Province.[3] This formation conformably overlies the Lisandro Formation of the Río Limay Subgroup. In the top layers it grades into the Plottier Formation, the younger formation within the Río Neuquén Subgroup.
Sandstones and siltstones, probably deposited under fluvial conditions, make up the Portezuelo Formation. There are also occasional cemented claystone deposits, as well as numerous paleosols (fossil soils). The formation varies between 95 and 130 metres (312 and 427 ft) thick throughout its range.[2][4]
Fossil content
Many dinosaur fossils have recently been described from this formation, as well as remains of several other types of animals:
- teleosteid fish including Leufuichthys
- abundant and diverse turtles including Portezueloemys and a species of Prochelidella
- titanosaurian sauropods including Malarguesaurus, Futalognkosaurus, Baalsaurus
- dromaeosaurid theropods (Neuquenraptor, Unenlagia, Pamparaptor)[5][6]
- a Megaraptorid theropod (Megaraptor)[5]
- an alvarezsaurid theropod (Patagonykus)[5]
- several other theropods, including a modern, possibly galliform bird[5]
- ornithopods including possible iguanodonts
- a possible azdarchoid pterosaur Argentinadraco
See also
- List of fossil sites
- List of dinosaur bearing rock formations
References
 |
Wikimedia Commons has media related to Portezuelo Formation. |
- Portezuelo Formation at Fossilworks.org
- Sánchez et al., 2006
- Wichmann, 1929
- Leanza et al., 2004
- Agnolin et al., 2006
- Porfiri et al., 2007
Bibliography
- Agnolin, Federico L.; Fernando E. Novas, and Gabriel Lio. 2006. Neornithine bird coracoid from the Upper Cretaceous of Patagonia. Ameghiniana 43. 245–248. Accessed 2019-02-16.
- 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.
- Porfiri, Juan D.; Jorge Orlando Calvo; Domenica Diniz Dos Santos, and Ruben D. Juárez Valieri. 2007. New record of Neuquenraptor (Theropoda, Dromaeosauridae) from the Late Cretaceous of Patagonia, 34R. Jornadas Argentinas de Paleontología de Vertebrados. 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.
- Wichmann, R. 1929. Los Estratos con Dinosaurios y su techo en el este del Territorio del Neuquén ("The dinosaur-bearing strata and their upper limit in eastern Neuquén Territory"). Dirección General de Geología, Minería e Hidrogeología Publicación 32. 1–9.