Willow Creek Formation
| Willow Creek Formation | |
|---|---|
| Stratigraphic range: | |
| Type | Geological formation |
| Underlies | Porcupine Hills Formation |
| Overlies | St. Mary River Formation |
| Lithology | |
| Primary | Shale, sandstone |
| Location | |
| Coordinates | 49°46′19″N 113°22′09″W / 49.77208°N 113.36920°W |
| Approximate paleocoordinates | 57°36′N 87°06′W / 57.6°N 87.1°W |
| Region | Alberta, Montana |
| Country | Canada, United States |
| Extent | Western Canada Sedimentary Basin |
| Type section | |
| Named for | Willow Creek |
| Named by | G.M. Dawson |
| Year defined | 1883 |
The Willow Creek Formation is a stratigraphic unit of Late Cretaceous to Early Paleocene age in the Western Canada Sedimentary Basin of southwestern Alberta. It was first described by George Mercer Dawson in 1883 along the Willow Creek, a tributary of the Oldman River. Williams and Dyer defined the type section in 1930 at the mouth of Willow Creek, east of Fort Macleod.
The formation straddles the Cretaceous-Paleogene (K-Pg) boundary, which divides it into an upper, Early Paleocene member and a lower, Late Cretaceous member. Dinosaur remains are among the fossils that have been recovered from the Late Cretaceous portion.