Collón Curá Formation
The Collón Curá Formation (Spanish: Formación Collón Curá) is a Middle Miocene fossiliferous geological formation of the southern Neuquén Basin in northwestern Patagonia and the western Cañadón Asfalto Basin of central Patagonia, Argentina. The formation crops out from the southern Neuquén Province, the western Río Negro Province to the northern Chubut Province.
| Collón Curá Formation | |
|---|---|
| Stratigraphic range: Langhian-earliest Tortonian (typically Colloncuran) ~ | |
Area around the Comallo railway, with outcrops of this formation | |
| Type | Geological formation |
| Sub-units | Tobaceo Las Bayas & Pilcaniyeú Ignimbrite Members |
| Underlies | Caleufú Formation & Chenqueniyeu Basalt (Neuquén Basin) El Mirador, Río Negro Formation & alluvium (Cañadón Asfalto Basin) |
| Overlies | Cerro Bandera, Huitrera & Cerro Petiso Formations, crystalline basement (Neuquén Basin) Ñirihuau, Lefipán & La Pava Formations (Cañadón Asfalto Basin) |
| Thickness | Up to 300 m (980 ft) |
| Lithology | |
| Primary | Tuff, sandstone |
| Other | Siltstone, marl, limestone, calcareous concretions, pumice |
| Location | |
| Coordinates | 40.0°S 70.8°W |
| Approximate paleocoordinates | 40.6°N 66.4°W |
| Region | Neuquén, Río Negro & Chubut Provinces |
| Country | Argentina |
| Extent | Cañadón Asfalto & Neuquén Basins |
| Type section | |
| Named for | Collón Curá River & Estancia Collón Curá |
| Named by | Yrigoyen |
| Location | Lácar Department |
| Year defined | 1969 |
| Coordinates | 40°04′56.6″S 70°51′55.3″W |
| Region | Neuquén Province |
| Country | Argentina |
| Thickness at type section | 50 m (160 ft) |
Outcrop locations of the Collón Curá Formation | |
The formation, with a maximum thickness of 300 metres (980 ft), comprises tuffs and sandstones with minor siltstones, marls and limestones, deposited in a fluvial, deltaic and shallow to deep lacustrine environment in small basins separated by faults. The formation dates from the Langhian to earliest Tortonian epochs of the Middle to Late Miocene, typically Colloncuran.
The Collón Curá Formation is named after Estancia Collón Curá (1 on the map in the infobox) along the Collón Curá River (2), a tributary of the Limay River in the Río Negro watershed, and lends its name to the Colloncuran, one of the South American land mammal ages. The formation has provided many fossils of mammals, reptiles, among others the snake Waincophis australis, and the largest terror bird Kelenken guillermoi. The rodent Galileomys colloncurensis and the typothere Protypotherium colloncurensis were named after the formation.