| Pebas Formation | |
|---|---|
| Stratigraphic range: Early Aquitanian-Tortonian (Colhuehuapian-Huayquerian) ~ | |
 The Pebas Mega-Wetland (or Lake Pebas), on the western side of this map, corresponds to the Pebas Formation | |
| Underlies | Marañón Formation |
| Overlies | Chambira Formation |
| Area | 1,000,000 km2 (390,000 sq mi) |
| Thickness | ~350–1,074 m (1,148–3,524 ft) |
| Lithology | |
| Primary | Siltstone, mudstone |
| Other | Coal/lignite |
| Location | |
| Coordinates | 7°24′S 75°00′W / 7.4°S 75.0°W |
| Approximate paleocoordinates | 8°24′S 70°36′W / 8.4°S 70.6°W |
| Region | Amazon Basin |
| Country |  Brazil Colombia Ecuador Peru |
| Type section | |
| Named for | Pebas District |
The Pebas Formation is a lithostratigraphic unit of Miocene age, found in western Amazonia. The formation extends over 1,000,000 square kilometres (390,000 sq mi), including parts of Brazil, Peru, Ecuador and Colombia.[1] It is interpreted as representing the deposits of a lake ("Lake Pebas") or series of lakes, formed within the foreland basin of the Andes mountain belt. It is known for its abundant fossil ostracods and molluscs and an unusually diverse group of crocodylians.[2]