Elk Point Group

Elk Point Group Stratigraphic range: Middle Devonian PreЄ Є O S D C P T J K Pg N
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
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

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]

Lithology

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

Distribution

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.

Relationship to other units

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.

Subdivisions

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

Sub-unit	Age	Lithology	Max. Thickness	Reference
Watt Mountain Formation	Middle Devonian	red and green shale, sandstone, anhydrite, dolomite, 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 dolomite	300 m (980 ft)	[5]
Sulphur Point Formation	Middle Devonian	fossiliferous limestone, green shale	106 m (350 ft)	[6]
Muskeg Formation	Givetian	salt, anhydrite, dolomite, limestone	270 m (890 ft)	[7]
Zama Member	Givetian	sucrosic dolomite	24 m (80 ft)	[8]
Keg River Formation	Givetian	porous dolomite, wackestone limestone, includes the Rainbow Member (dolomitized reef)	300 m (980 ft)	[9]
Contact Rapids Formation	Middle Devonian	argillaceous dolomite, dolomitic shale	48.8 m (160 ft)	[10]
Chinchaga Formation	Eifelian to Givetian	anhydrite, crystalline dolomite, 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), carbonate, 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, 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]

References

1. ^ ^{a b c d} Lexicon of Canadian Geologic Units. "Elk Point Group". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:004569. 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". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:016136. Retrieved 2010-01-09. 
4. ^ Lexicon of Canadian Geologic Units. "Gilwood Member". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:005585. Retrieved 2010-01-09. 
5. ^ Lexicon of Canadian Geologic Units. "Presqu'ile Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:012204. Retrieved 2009-12-26. 
6. ^ Lexicon of Canadian Geologic Units. "Sulphur Point Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:014716. Retrieved 2010-01-09. 
7. ^ Lexicon of Canadian Geologic Units. "Muskeg Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:010435. Retrieved 2009-12-26. 
8. ^ Lexicon of Canadian Geologic Units. "Zama Member". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:016803. Retrieved 2010-01-09. 
9. ^ Lexicon of Canadian Geologic Units. "Keg Rive Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?. Retrieved 2010-01-09. 
10. ^ Lexicon of Canadian Geologic Units. "Contact Rapids Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:003295. Retrieved 2009-12-26. 
11. ^ Lexicon of Canadian Geologic Units. "Chinchaga Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:002901. Retrieved 2009-12-26. 
12. ^ Lexicon of Canadian Geologic Units. "Cold Lake Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:003194. Retrieved 2009-12-26. 
13. ^ Lexicon of Canadian Geologic Units. "Ernestina Lake Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:004688. Retrieved 2009-12-26. 
14. ^ Lexicon of Canadian Geologic Units. "Lotsberg Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:008746. Retrieved 2009-12-26. 
15. ^ Lexicon of Canadian Geologic Units. "Basal red beds". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:000833. Retrieved 2009-12-26. 
16. ^ Lexicon of Canadian Geologic Units. "Dawson Bay Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:003793. Retrieved 2009-12-26. 
17. ^ Lexicon of Canadian Geologic Units. "Prairie Evaporite Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:012175. Retrieved 2009-12-26. 
18. ^ Lexicon of Canadian Geologic Units. "Winnipegosis Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:016600. Retrieved 2009-12-26. 
19. ^ Lexicon of Canadian Geologic Units. "Ashern Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:000496. Retrieved 2010-01-09. 
20. ^ Lexicon of Canadian Geologic Units. "Meadow Lake Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:009544. Retrieved 2010-01-09.