Edmonton Group

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Edmonton Group Stratigraphic range: Late Cretaceous PreЄ Є O S D C P T J K Pg N
Horseshoe Canyon Formation of the Edmonton Group
Type	Geological formation
Sub-units	Battle Formation, Whitemud Member, Horseshoe Canyon Formation
Underlies	Paskapoo Formation
Overlies	Bearpaw Formation, Belly River Group
Thickness	328 metres (1,080 ft) to 763 metres (2,500 ft)^[1]
Lithology
Primary	Sandstone, shale
Other	Bentonite, coal
Location
Region	WCSB
Country	Canada
Type section
Named for	Edmonton
Named by	Joseph Tyrrell, 1887

The Edmonton Group is a stratigraphical unit of Late Cretaceous age in the Western Canadian Sedimentary Basin.

It takes the name from the city of Edmonton, and was first described in outcrops on the banks of the North Saskatchewan River near the city by Joseph Burr Tyrrell in 1887.^[2]

Lithology

The Edmonton Group is composed fine grained calcareous sandstone and sandy shale with bentonite, ironstone concretions and coal. The sediments were deposited in fresh and brackish water environments. ^[1]

Paleontology

Vertebrate fossils are found in the formation, including Triceratops remains. Molluscs such as Ostrea and Unio can also be retrieved from the Edmonton Group.

Distribution

The Edmonton Group reaches a maximum thickness of 763 metres (2,500 ft) in the Canadian Rockies foothills, and is typically 350 metres (1,150 ft) thick in the plains.^[1] It forms the erosional surface in Central Alberta and often forms badlands topography.

Relationship to other units

The Edmonton Group is disconformably overlain by the Paskapoo Formation and conformably overlays the Bearpaw Formation or Belly River Formation.^[1]

It is equivalent to Fox Hills Formation in Saskatchewan and is not differentiated in the upper Montana Group. It can be correlated with the Horsethief Formation in Montana, the Lennup Formation and Muteetse Formation in Wyoming, the Blood Reserve Formation and St. Mary River Formation in southern Alberta, with the Eastend Formation, Whitemud Formation, Battle Formation and Frenchman Formation in the Cypress Hills, with the Fox Hills Formation and Lace Formation in Montana, as well as with the Wapiti Group and Brazeau Group in the Canadian Rockies foothills.

Subdivisions

Subdivisions of the Edmonton Group include:

Sub-unit	Age	Lithology	Max Thickness	Reference
Battle Formation	Maastrichtian	bentonitic silty shale, montmorillonitic clay	14 m (50 ft)	^[3]
Whitemud Member	Maastrichtian	bentonitic shale, argillaceous sandstone	6 m (20 ft)	^[4]
Horseshoe Canyon Formation	Maastrichtian	sandstone, siltstone, shale	227 m (740 ft)	^[5]

References

↑ 1.0 1.1 1.2 1.3 Lexicon of Canadian Geologic Units. "Edmonton Group". Retrieved 2009-03-01.
↑ Tyrrell, J.B., 1887. Report on a part of northern Alberta and portions of adjacent Districts of Assiniboia and Saskatchewan. Geological Survey of Canada, Ann. Rept.1886, new ser., v.11, Part E, p.1-176.
↑ Lexicon of Canadian Geologic Units. "Battle Formation". Retrieved 2010-01-03.
↑ Lexicon of Canadian Geologic Units. "Whitemud Member". Retrieved 2010-01-03.
↑ Lexicon of Canadian Geologic Units. "Horseshoe Canyon Formation". Retrieved 2010-01-03.

v t e Western Canadian Sedimentary Basin

Hydrocarbon history	Oil sands and heavy oil Frontier exploration and development Natural gas liquids Natural gas

Depositional Regions	Southern Alberta Central Alberta Northwestern Alberta Plains South-central Canadian Rockies foothills North-east Plains North-central foothills Liard River Fort Nelson Northern Rocky Mountains Fort St. John Saskatchewan Western Manitoba

Central Alberta	Paskapoo FM Scollard FM Edmonton GRP Battle FM Whitemud MBR Horseshoe Canyon FM Bearpaw FM Belly River GRP Ribstone Creek MBR Victoria MBR Brosseau MBR Lea Park FM Colorado GRP Cardium FM Mannville GRP Glauconitic Sandstone Ostracod Beds Sunburst Member Taber Member Detrital Beds Fernie GRP Rock Creek MBR Nordegg MBR Rundle GRP Mount Head FM Elkton MBR Shunda FM Pekisko FM Banff FM Exshaw FM Canadian Shield

Southern Alberta Plains	Cypress Hills FM Porcupine Hills FM Ravenscrag FM Edmonton GRP Belly River GRP Oldman FM Foremost FM Pakowki FM Milk River FM Colorado GRP Mannville GRP Ellis GRP Swift FM Rierdon FM Sawtooth FM Rundle GRP Banff FM Exshaw FM Bakken FM Wabamun FM Crowfoot FM Nisku FM Ireton FM Leduc FM Cooking Lake FM Beaverhill Lake GRP Elk Point GRP Canadian Shield

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