Beaverhill Lake Group

Beaverhill Lake Group
Stratigraphic range: Middle to Late Devonian ~390–365Ma
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
Coordinates 53°18′05″N 112°23′27″W / 53.30142°N 112.3908°WCoordinates: 53°18′05″N 112°23′27″W / 53.30142°N 112.3908°W
Region  Alberta
 British Columbia
 Northwest Territories
Country  Canada
Type section
Named for Beaverhill Lake
Named by Imperial Oil, 1950

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 since 1957, which is a similar Devonian reef structure as the Leduc Formation and the Rainbow Member in Alberta.[3][4]

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) [5]
Moberly Member Middle Devonian to Late Devonian grey, fine grained, thin bedded limestone, coral limestone 95.7 m (310 ft) [6]
Christina Member Middle Devonian to Late Devonian argillaceous limestone and shale with brachiopods 27.4 m (90 ft) [7]
Calmut Member Middle Devonian to Late Devonian fine-grained argillaceous limestone with olive green shales and brachiopods 31.1 m (100 ft) [8]
Firebag Member Middle Devonian to Late Devonian green calcareous shale with green argillaceous limestone containing brachiopods 61 m (200 ft) [9]
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) [10]
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) [11]
Waterways Formation Givetian to Frasnian nodular limestone and shale with brachiopods, corals and ostracods 230 m (750 ft) [12]

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.[13] 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. ↑ 1.0 1.1 1.2 1.3 Lexicon of Canadian Geologic Units. "Beaverhill Lake Group". 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. ↑ Barss, D.L., Copland, A.B., and Ritchie, W.D., 1970, Middle Devonian Reefs, Rainbow Area, Alberta, in Geology of Giant Petroleum Fields, AAPG Memoir 14, Halbouty, M.T., editor, Tulsa: American Association of Petroleum Geologists, pp. 18-49
  4. ↑ Hemphill, C.R., SMith, R.I., and Szabo, F., 1970, Geology of Beaverhill Lake Reefs, Swan Hills Area, Alberta, in Geology of Giant Petroleum Fields, AAPG Memoir 14, Halbouty, M.T., editor, Tulsa: American Association of Petroleum Geologists, pp. 50-90
  5. ↑ Lexicon of Canadian Geologic Units. "Mildred". Retrieved 2009-12-24.
  6. ↑ Lexicon of Canadian Geologic Units. "Moberly". Retrieved 2009-12-24.
  7. ↑ Lexicon of Canadian Geologic Units. "Christina". Retrieved 2009-12-24.
  8. ↑ Lexicon of Canadian Geologic Units. "Calmut". Retrieved 2009-12-24.
  9. ↑ Lexicon of Canadian Geologic Units. "Firebag". Retrieved 2009-12-24.
  10. ↑ Lexicon of Canadian Geologic Units. "Fort Vermilion Formation". Retrieved 2009-12-24.
  11. ↑ Lexicon of Canadian Geologic Units. "Swan Hills Formation". Retrieved 2009-12-24.
  12. ↑ Lexicon of Canadian Geologic Units. "Waterways Formation". Retrieved 2009-12-24.
  13. ↑ 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.