Kaili Formation
The Kaili Formation(凯里組) is a stratigraphic formation which was deposited during the Lower and Middle Cambrian (~513 to 506 million years ago). The formation is approximately 200 metres (660 ft) thick and was named after the city Kaili in the Guizhou province of southwest China.
| Kaili Formation | |
|---|---|
| Stratigraphic range: Cambrian | |
| Type | Geological formation |
| Thickness | ~200 m (660 ft) |
| Lithology | |
| Primary | Claystone, mudstone, shale |
| Other | Siltstone, marl, limestone |
| Location | |
| Coordinates | 24.9°N 102.5°E |
| Approximate paleocoordinates | 35.1°N 161.3°E |
| Region | Guizhou |
| Country | China |
| Type section | |
| Named for | Kaili |
Kaili Formation (China) Kaili Formation (Guizhou) | |
| Part of a series on |
| The Cambrian explosion |
|---|
The depositional environment of the Kaili Formation is not entirely known, and there are two hypotheses for its formation. It may have been a nearshore marine environment with 'normal' levels of oxygenation; or it may have been a deeper water environment further from the shore, on the open continental shelf; in this setting oxygen would not be available below the surface layers of the deposited sediment. The trace fossil assemblages in the formation suggest that it was below the wave base and was reasonably well-oxygenated.