Edmonton Group | |
---|---|
Stratigraphic range: | |
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)[1] |
Lithology | |
Primary | Sandstone, shale |
Other | Bentonite, coal |
Location | |
Region | Alberta |
Country | Canada |
Type section | |
Named for | Edmonton |
Named by | Joseph Tyrrell, 1887 |
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.[2] 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.[3] E.J.W. Irish later elevated the formation to group status and it was subdivided into four separate formations.[4] In ascending order, they are the Horseshoe Canyon, Whitemud, Battle and Scollard Formations.[2][1] The Cretaceous-Paleogene boundary occurs within the Scollard Formation, based on dinosaurian and microfloral evidence,[5] as well as the presence of the terminal Cretaceous iridium anomaly.[6]
CSPG_Lexicon
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