| Elk Point Group Stratigraphic range: Middle Devonian |
|
|---|---|
| Type | Geological formation |
| Sub-units | Dawson Bay Formation Prairie Evaporite Formation Muskeg Formation Presqu'ile Formation Winnipegosis Formation Contact Rapids Formation Chinchaga Formation Cold Lake Formation Ernestina Lake Formation Lotsberg Formation Prairie Evaporite Formation Winnipegosis Formation Ashern Formation |
| Underlies | Souris River Formation, Beaverhill Lake Formation |
| Overlies | Pre-cambrian to Ordovician basement |
| Thickness | up to 610 metres (2,000 ft)[1] |
| Lithology | |
| Primary | Dolomite, shale |
| Other | Anhydrite, potash, limestone |
| Location | |
| Named for | Elk Point |
| Named by | McGehee, 1949 |
| Region | Alberta |
| Country | Canada |
The Elk Point Group is a stratigraphical unit of Middle Devonian age in the Western Canadian Sedimentary Basin.
It takes the name from the town of Elk Point, and was first described in the Anglo-Canadian Elk Point No. 11 well by McGehee in 1949.[2]
Contents |
The Elk Point Group is composed of dolomite, shale, anhydrite, potash and limestone. [1]
The Elk Point Group extends from the North Dakota in the south-east, through Manitoba, Saskatchewan and Alberta to north-eastern British Columbia.[1] It reaches a maximum thickness of 610 metres (2,000 ft) in eastern Alberta.
The Elk Point Group is conformably overlain by the Souris River Formation in Manitoba and Saskatchewan, and by the Beaverhill Lake Formation in Alberta. It rests unconformably on pre-Cambrian basement in the Peace River Arch and the Tathlina uplift, on Cambrian strata in north-eastern Alberta and Saskatchewan, on Ordovician formations in western Alberta, Saskatchewan and southwestern Manitoba.[1]
It is equivalent to Stone Formation, Arnica Formation, Funeral Formation and Landry-Manetoe Formation. Its equivalents in north-eastern British Columbia are the Headless Formation and Nahanni Formation. It includes the Pine Point Formation or the sum of Lonely Bay Formation and Horn River Formation in parts of northeastern British Columbia, and grades westward to the Horn River Formation and the lower part of the Besa River Formation.
In northern Alberta and central Alberta, the Elk Point Group contains the following sub-divisions, from top to base:
The Elk Point Group is dolomitic and is not differentiated.
| Sub-unit | Age | Lithology | Max. Thickness |
Reference |
|---|---|---|---|---|
| Dawson Bay Formation | Givetian | dolomitic mudstone, crystalline limestone, argillaceous carbonate, bituminous limestone, dolomite, anhydrite, halite | 50 m (160 ft) | [16] |
| Prairie Evaporite Formation | Givetian | halite, carnallite, sylvite | 218 m (720 ft) | [17] |
| Winnipegosis Formation | Givetian | dolomite, bituminous carbonates, anhydrite | 100 m (330 ft) | [18] |
| Ashern Formation | early Middle Triassic to early Middle Devonian | argillaceous dolomite and dolomitic shale; anhydrite | 55 m (180 ft) | [19] |
| Meadow Lake Formation | Eifelian | dolomite with mudstone interbeds limestone and sandstone in the base | 56 m (180 ft) | [20] |