Elk Point Group

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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
Coordinates 53°54′19″N 110°37′49″W / 53.9053°N 110.6304°W / 53.9053; -110.6304 (Elk Point Group)Coordinates: 53°54′19″N 110°37′49″W / 53.9053°N 110.6304°W / 53.9053; -110.6304 (Elk Point Group)
Region  Alberta
Country  Canada
Type section
Named for Elk Point
Named by McGehee, 1949

The Elk Point Group is a stratigraphic unit of Middle Devonian age in the Western Canada 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]

Lithology[edit]

The Elk Point Group is composed of dolostone, shale, anhydrite, potash and limestone. [1]

Distribution[edit]

The Elk Point Group extends from the North Dakota in the south-east, through Manitoba, Saskatchewan and Alberta to northeastern British Columbia.[1] It reaches a maximum thickness of 610 metres (2,000 ft) in eastern Alberta.

Relationship to other units[edit]

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 Precambrian 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 northeastern 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.

Subdivisions[edit]

In northern Alberta and central Alberta, the Elk Point Group contains the following subdivisions, from top to base:

Sub-unit Age Lithology Max.
Thickness
Reference
Watt Mountain Formation Middle Devonian red and green shale, sandstone, anhydrite, dolostone, limestone 74.4 m (240 ft) [3]
Gilwood Member Middle Devonian coarse quartz and feldspathic sandstone 15.2 m (50 ft) [4]
Presqu'ile Formation Givetian crystalline dolostone 300 m (980 ft) [5]
Sulphur Point Formation Middle Devonian fossiliferous limestone, green shale 106 m (350 ft) [6]
Muskeg Formation Givetian salt, anhydrite, dolostone, limestone 270 m (890 ft) [7]
Zama Member Givetian sucrosic dolostone 24 m (80 ft) [8]
Keg River Formation Givetian porous dolostone, wackestone limestone, includes the Rainbow Member (dolomitized reef) 300 m (980 ft) [9]
Contact Rapids Formation Middle Devonian argillaceous dolostone, dolomitic shale 48.8 m (160 ft) [10]
Chinchaga Formation Eifelian to Givetian anhydrite, crystalline dolostone, quartz sandstone, dolomitic shale, salt 76 m (250 ft) [11]
Cold Lake Formation Eifelian halite, dolomitic shale 117 m (380 ft) [12]
Ernestina Lake Formation Eifelian red shale (base), carbonates, anhydrite (top) 23 m (80 ft) [13]
Lotsberg Formation Middle Devonian halite, calcareous shale 229 m (750 ft) [14]
Basal red beds Early Devonian red dolomitic or calcareous shales, silty or sandy, quartzose sandstone   [15]
In southern Alberta

The Elk Point Group is dolomitic and is not differentiated.

In Saskatchewan, Manitoba and Montana
Sub-unit Age Lithology Max.
Thickness
Reference
Dawson Bay Formation Givetian dolomitic mudstone, crystalline limestone, argillaceous carbonate, bituminous limestone, dolostone, anhydrite, halite 50 m (160 ft) [16]
Prairie Evaporite Formation Givetian halite, carnallite, sylvite 218 m (720 ft) [17]
Winnipegosis Formation Givetian dolostone, bituminous carbonates, anhydrite 100 m (330 ft) [18]
Ashern Formation early Middle Triassic to early Middle Devonian argillaceous dolostone and dolomitic shale; anhydrite 55 m (180 ft) [19]
Meadow Lake Formation Eifelian dolostone with mudstone interbeds limestone and sandstone in the base 56 m (180 ft) [20]

References[edit]

  1. ^ a b c d Lexicon of Canadian Geologic Units. "Elk Point Group". Retrieved 2009-03-01. 
  2. ^ McGehee, J.R., 1949. Pre-Waterways Paleozoic stratigraphy of Alberta Plains. Bull. American Association of Petroleum Geologists, 33:4, p. 603-613.
  3. ^ Lexicon of Canadian Geologic Units. "Watt Mountain Formation". Retrieved 2010-01-09. 
  4. ^ Lexicon of Canadian Geologic Units. "Gilwood Member". Retrieved 2010-01-09. 
  5. ^ Lexicon of Canadian Geologic Units. "Presqu'ile Formation". Retrieved 2009-12-26. 
  6. ^ Lexicon of Canadian Geologic Units. "Sulphur Point Formation". Retrieved 2010-01-09. 
  7. ^ Lexicon of Canadian Geologic Units. "Muskeg Formation". Retrieved 2009-12-26. 
  8. ^ Lexicon of Canadian Geologic Units. "Zama Member". Retrieved 2010-01-09. 
  9. ^ Lexicon of Canadian Geologic Units. "Keg Rive Formation". Retrieved 2010-01-09. 
  10. ^ Lexicon of Canadian Geologic Units. "Contact Rapids Formation". Retrieved 2009-12-26. 
  11. ^ Lexicon of Canadian Geologic Units. "Chinchaga Formation". Retrieved 2009-12-26. 
  12. ^ Lexicon of Canadian Geologic Units. "Cold Lake Formation". Retrieved 2009-12-26. 
  13. ^ Lexicon of Canadian Geologic Units. "Ernestina Lake Formation". Retrieved 2009-12-26. 
  14. ^ Lexicon of Canadian Geologic Units. "Lotsberg Formation". Retrieved 2009-12-26. 
  15. ^ Lexicon of Canadian Geologic Units. "Basal red beds". Retrieved 2009-12-26. 
  16. ^ Lexicon of Canadian Geologic Units. "Dawson Bay Formation". Retrieved 2009-12-26. 
  17. ^ Lexicon of Canadian Geologic Units. "Prairie Evaporite Formation". Retrieved 2009-12-26. 
  18. ^ Lexicon of Canadian Geologic Units. "Winnipegosis Formation". Retrieved 2009-12-26. 
  19. ^ Lexicon of Canadian Geologic Units. "Ashern Formation". Retrieved 2010-01-09. 
  20. ^ Lexicon of Canadian Geologic Units. "Meadow Lake Formation". Retrieved 2010-01-09.