Edmonton Group
Within the earth science of geology, the Edmonton Group is a Late Cretaceous (Campanian stage) to early Paleocene stratigraphic unit of the Western Canada Sedimentary Basin in the central Alberta plains. It was first described as the Edmonton Formation by Joseph Burr Tyrrell in 1887 based on outcrops along the North Saskatchewan River in and near the city of Edmonton. E.J.W. Irish later elevated the formation to group status and it was subdivided into four separate formations. In ascending order, they are the Horseshoe Canyon, Whitemud, Battle and Scollard Formations. The Cretaceous-Paleogene boundary occurs within the Scollard Formation, based on dinosaurian and microfloral evidence, as well as the presence of the terminal Cretaceous iridium anomaly.
| Edmonton Group | |
|---|---|
| Stratigraphic range: | |
Horseshoe Canyon Formation of the Edmonton Group | |
| Type | Geological group |
| Sub-units | Scollard Formation, Battle Formation, Whitemud Formation, Horseshoe Canyon Formation |
| Underlies | Paskapoo Formation |
| Overlies | Bearpaw Formation, Belly River Group |
| Thickness | 328 metres (1,076 ft) to 763 metres (2,503 ft) |
| Lithology | |
| Primary | Sandstone, shale |
| Other | Bentonite, coal |
| Location | |
| Region | Alberta |
| Country | Canada |
| Type section | |
| Named for | Edmonton |
| Named by | Joseph Tyrrell, 1887 |