| Agrio Formation | |
|---|---|
| Stratigraphic range: Late Valanginian-earliest Aptian ~ | |
_en_su_localidad_tipo.jpg) Agrio Formation at its type section | |
| Type | Geological formation |
| Unit of | Mendoza Group |
| Sub-units | Pilmatué, Avilé & Agua de la Mula Members |
| Underlies | Huitrín & La Amarga Formations |
| Overlies | Mulichinco & Bajada Colorada Formations |
| Area | 220 km × 50 km (137 mi × 31 mi) |
| Thickness | Up to 1,500 m (4,900 ft) |
| Lithology | |
| Primary | Shale, sandstone |
| Other | Limestone, conglomerate |
| Location | |
| Coordinates | 38°00′S 70°00′W / 38.0°S 70.0°W |
| Approximate paleocoordinates | 38°12′S 33°42′W / 38.2°S 33.7°W |
| Region | Mendoza & Neuquén Provinces |
| Country | Argentina |
| Extent | Neuquén Basin |
| Type section | |
| Named for | Agrio River |
| Named by | Weaver |
| Year defined | 1931 |
  Agrio Formation (Argentina) | |
The Agrio Formation is an Early Cretaceous geologic formation that is up to 1,500 metres (4,900 ft) thick and is located in the southern Mendoza Province and northern-central Neuquén Province, in the Neuquén Basin of northwestern Patagonia, Argentina.[1] This formation is the youngest one of the Mendoza Group, overlying the Mulichinco and Bajada Colorada Formations and overlain by the Huitrín and La Amarga Formations. It is dated to the Late Valanginian to Early Hauterivian,[2] Late Valanginian to Early Barremian,[3] or Hauterivian to earliest Aptian.[4]
The Agrio Formation is considered the third most important source rock in the hydrocarbon-rich Neuquén Basin, after the Vaca Muerta Formation and Los Molles Formation. Similarly to these older units, it is potentially a source of shale gas.
This formation has provided fossils of ichthyosaurs, ammonites, gastropods, bivalves, decapods, echinoderm, corals and fish. The newly described species of fish, Tranawuen agrioensis, the ammonite Holcoptychites agrioensis, and the bivalve Pholadomya agrioensis have been named after the formation.