Tarjados Formation
| Tarjados Formation | |
|---|---|
| Stratigraphic range: Early-Mid Triassic ~ | |
Sandstones in Talampaya National Park | |
| Type | Geological formation |
| Unit of | Paganzo Group |
| Underlies | Chañares Formation |
| Overlies | Talampaya Formation |
| Thickness | Up to 250 m (820 ft) |
| Lithology | |
| Primary | Sandstone |
| Other | Conglomerate |
| Location | |
| Coordinates | 29°48′S 67°48′W / 29.8°S 67.8°W |
| Approximate paleocoordinates | 48°00′S 38°54′W / 48.0°S 38.9°W |
| Region | La Rioja Province |
| Country | Argentina |
| Extent | Ischigualasto-Villa Unión Basin |
| Type section | |
| Named for | Sierra de Los Tarjados |
| Named by | Romer & Jensen |
| Year defined | 1966 |
The Tarjados Formation is an Early to Middle Triassic geologic formation in the Ischigualasto-Villa Unión Basin of La Rioja Province in northwestern Argentina. The red to whitish sandstones and conglomerates of the formation were deposited in an arid fluvial environment. The formation overlies the Talampaya Formation and is overlain by the Chañares Formation of the Agua de la Peña Group.
The formation has provided fossils of an archosaur and a kannemeyeriid dicynodont, both not yet placed in a dedicated genus. The formation crops out in the Talampaya National Park, which was designated a UNESCO World Heritage Site in 2000.