| Baratal limestone | |
|---|---|
| Stratigraphic range: Ediacaran-Cambrian | |
| Type | Geologic formation |
| Thickness | 8km |
| Lithology | |
| Primary | Limestone |
| Location | |
| Coordinates | 50°15′N 87°53′E / 50.250°N 87.883°E[1] |
| Region | Siberia |
| Country |  Russia |
  Baratal limestone (Russia) | |
Baratal limestone, also known as the Baratal Formation, is a limestone formation in the Altai Republic of Russia that formed during the Cambrian and Ediacaran, presumably on top of an ancient seamount that was later accreted to a continent. It may constitute the oldest known atoll in the world.
- ^ Buslov et al. 2001, p. 217.