Beaverhill Lake Group

Beaverhill Lake Group Stratigraphic range: Middle to Late Devonian ~390–365 Ma PreЄ Є O S D C P T J K Pg N
Type	Geological formation
Sub-units	Mildred Member Moberly Member Christina Member Calmut Member Firebag Member Fort Vermilion Formation Swan Hills Formation Waterways Formation
Underlies	Cooking Lake Formation, Woodbend Formation, Muskwa Formation
Overlies	Elk Point Group, Slave Point Formation
Thickness	up to 220 metres (720 ft)[1]
Lithology
Primary	Limestone, shale
Other	Anhydrite, dolomite
Location
Named for	Beaverhill Lake
Named by	Imperial Oil, 1950
Coordinates	53°18′05″N 112°23′27″W / 53.30142°N 112.3908°W / 53.30142; -112.3908 (Beaverhill Lake Group)Coordinates: 53°18′05″N 112°23′27″W / 53.30142°N 112.3908°W / 53.30142; -112.3908 (Beaverhill Lake Group)
Region	Alberta  British Columbia  Northwest Territories
Country	Canada

The Beaverhill Lake Group is a stratigraphical unit of Middle Devonian to Late Devonian age in the Western Canadian Sedimentary Basin.

It takes the name from Beaverhill Lake, and was first described in the well Anglo-Canadian Beaverhill Lake No. 2 (drilled south-east of the lake, near Ryley) by geological staff from Imperial Oil in 1950.^[2]

Lithology

The Beaverhill Lake Group is composed of carbonates and shale, with repeated calcareous shale and argillaceous micrites sequences. It becomes more argillaceous to the west. ^[1]

Hydrocarbon production

Oil is produced from the Swan Hills Formation in the Swan Hills area of northern Alberta.

Distribution

The Beaverhill Lake Group has a thickness of up to 220 metres (720 ft) in central Alberta.^[1]

Subdivisions

Central Alberta

Sub-unit	Age	Lithology	Max Thickness	Reference
Mildred Member	Late Devonian	argillaceous limestone and shale	42.7 m (140 ft)	[3]
Moberly Member	Middle Devonian to Late Devonian	grey, fine grained, thin bedded limestone, coral limestone	95.7 m (310 ft)	[4]
Christina Member	Middle Devonian to Late Devonian	argillaceous limestone and shale with brachiopods	27.4 m (90 ft)	[5]
Calmut Member	Middle Devonian to Late Devonian	fine-grained argillaceous limestone with olive green shales and brachiopods	31.1 m (100 ft)	[6]
Firebag Member	Middle Devonian to Late Devonian	green calcareous shale with green argillaceous limestone containing brachiopods	61 m (200 ft)	[7]
basal limestone		limestone

Swan Hills area

Sub-unit	Age	Lithology	Max Thickness	Reference
Fort Vermilion Formation	Middle Devonian	brown to white anhydrite with dolomite or limestone	37 m (120 ft)	[8]
Swan Hills Formation	Middle Devonian to Late Devonian	stromatoporoid reef (micritic and pelletoidal limestone facies or coarse, porous, bioclastic limestone facies)	152 m (500 ft)	[9]
Waterways Formation	Givetian to Frasnian	nodular limestone and shale with brachiopods, corals and ostracods	230 m (750 ft)	[10]

In northern Alberta and northeastern British Columbia it has formation status, and is not differentiated.

Relationship to other units

The Beaverhill Lake Group is conformably overlain by the Cooking Lake Formation in eastern Alberta, and unconformably overlain by the Woodbend Formation west of the Leduc reef trend. In north-western Alberta and north-eastern British Columbia, it is disconformably overlain by the Muskwa Formation. It is conformably underlain by the Elk Point Group in central Alberta, and by the Slave Point Formation in north-western Alberta and north-eastern British Columbia.^[1]

It is equivalent to the Slave Point Formation and Waterways Formation in north-eastern Alberta, with the Slave Point Formation and the lower Hay River Formation in the District of Mackenzie, as well as the Horn River Formation and Fort Simpson Formation north-west of the Slave Point-Keg River facies in north-eastern British Columbia and the Northwest Territories.^[11] It is equivalent to the Souris River Formation in southeastern Alberta, Saskatchewan and Manitoba, and to the Flume Formation of the Fairholme Group in the Canadian Rockies.

References

1. ^ ^{a b c d} Lexicon of Canadian Geologic Units. "Beaverhill Lake Group". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:001026. Retrieved 2009-03-01. 
2. ^ Geological Staff, Imperial Oil Limited, Western Division, 1950. Devonian Nomenclature in Edmonton Area, Alberta, Canada. Bulletin of the American Association of Petroleum Geologists, Vol. 34, No. 9, pp. 1807-1825.
3. ^ Lexicon of Canadian Geologic Units. "Mildred". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:009775. Retrieved 2009-12-24. 
4. ^ Lexicon of Canadian Geologic Units. "Moberly". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:009971. Retrieved 2009-12-24. 
5. ^ Lexicon of Canadian Geologic Units. "Christina". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:002938. Retrieved 2009-12-24. 
6. ^ Lexicon of Canadian Geologic Units. "Calmut". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:002194. Retrieved 2009-12-24. 
7. ^ Lexicon of Canadian Geologic Units. "Firebag". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:004951. Retrieved 2009-12-24. 
8. ^ Lexicon of Canadian Geologic Units. "Fort Vermilion Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:005173. Retrieved 2009-12-24. 
9. ^ Lexicon of Canadian Geologic Units. "Swan Hills Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:014805. Retrieved 2009-12-24. 
10. ^ Lexicon of Canadian Geologic Units. "Waterways Formation". http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:016127. Retrieved 2009-12-24. 
11. ^ Griffin, D.L., 1965. "The facies front of the Devonian Slave Point - Elk Point sequence in northeastern British Columbia and the Northwest Territories"; Journal of Canadian Petroleum Technology, vol. 4, no. 1, pp. 13-22.