Sundance Formation
| Sundance Formation | |
|---|---|
| Stratigraphic range: Bathonian - Oxfordian | |
| Type | Geological formation |
| Sub-units | Canyon Springs Sandstone Member, Hulett Sandstone Member, Lak Member, Pine Butte Member, Redwater Shale Member, Stockade Beaver (Shale) Member, Windy Hill Sandstone Member |
| Underlies | Morrison Formation |
| Overlies | Gypsum Springs Formation |
| Thickness | Up to 100 m |
| Lithology | |
| Primary | shale |
| Other | limestone, sandstone |
| Location | |
| Region | Western North America |
| Country | United States |
| Type section | |
| Named for | Sundance, Wyoming |
| Named by | Darton |
| Year defined | 1904 |
The Sundance Formation is a western North American sequence of Middle Jurassic to Upper Jurassic age Dating from the Bathonian to the Oxfordian, around 168-157 Ma, It is up to 100 metres thick and consists of marine shale, sandy shale, sandstone, and limestone deposited in the Sundance Sea, an inland sea that covered large parts of western North America during the Middle and early Late Jurassic.