Muskeg Formation

Muskeg Formation Stratigraphic range: Givetian PreЄ Є O S D C P T J K Pg N ↓
Type	Geological formation
Underlies	Watt Mountain Formation
Overlies	Keg River Formation
Thickness	up to 270 metres (890 ft)^[1]
Lithology
Primary	Anhydrite, dolostone
Other	Halite, limestone
Location
Coordinates	59°10′21″N 118°44′54″W / 59.1725°N 118.7482°W / 59.1725; -118.7482 (Steen River 2-22-117-5W6M)Coordinates: 59°10′21″N 118°44′54″W / 59.1725°N 118.7482°W / 59.1725; -118.7482 (Steen River 2-22-117-5W6M)
Region	Alberta British Columbia
Country	Canada
Type section
Named by	J. Law^[2]

The Muskeg Formation is a geologic formation of Middle Devonian (Givetian) age in the Western Canada Sedimentary Basin. It extends from the plains of northwestern Alberta to northeastern British Columbia,^[3] and includes important petroleum and natural gas reservoirs in the Zama lake and Rainbow Lake areas of northwestern Alberta.^[4]

Lithology

The Muskeg Formation consists primarily of anhydrite, with dolostone, halite (rock salt) and limestone.^[1]

Environment of Deposition

The Muskeg Formation was deposited at the northern end of an embayment called the Elk Point Basin, adjacent to an extensive reef complex called the Presqu'ile Barrier. The reef had developed across the mouth of the embayment, blocking the area from the open ocean and restricting the inflow of sea water. The low water levels and excessive evaporation resulted in the deposition of anhydrite, halite and carbonate rocks.^[3]^[4]

Distribution and Thickness

The Muskeg Formation is present in the northern half of the Elk Point Basin, in northeastern British Columbia and northwestern Alberta.^[3] It reaches a maximum reported thickness of 270 metres (890 ft).^[1]^[5]

Stratigraphy

The Muskeg Formation is part of the Elk Point Group and was established by J. Law in 1955, based on core from a well (California Standard Steen River 2-22-117-5W6M) that was drilled north of Zama Lake.^[1]^[2]

The formation is usually divided into five members. The Black Creek Member at the base consists of halite. The overlying Lower Anhydrite Member consists of microcrystalline anhydrite with minor beds of fine- to medium-crystalline dolostone. The Zama Member at the center consists of fragmental carbonate, and is overlain by the Upper Anhydrite which consists of interbedded microcrystalline anhydrite and fine- to medium-crystalline dolostone. The Bistcho Member at the top is a fragmental carbonate unit.^[4]

Relationship to other units

The Muskeg Formation is disconformably overlain by the Watt Mountain Formation and conformably underlain by the Keg River Formation. It is correlated with the Pine Point Formation, Presqu'ile Formation and Sulphur Point Formation.^[1]^[5] It grades into the halite-rich Prairie Evaporite Formation to the southeast through a decrease in its anhydrite content and an increase in its halite content.^[3]

Petroleum and Natural Gas

The porous carbonate units of the Muskeg Formation contain important oil and natural gas reservoirs in the Zama and Rainbow Lake areas of northwestern Alberta. The impermeable anhydrite and halite beds of the formation act to seal the reservoirs.^[4]

References

1 2 3 4 5 Lexicon of Canadian Geological Units. "Muskeg Formation". Retrieved 2009-02-10.
1 2 Law, J. 1955. Rock units of northwestern Alberta. Journal of the Alberta Society of Petroleum Geologists, v. 3, no. 6, p. 81-83.
1 2 3 4 Mossop, G.D. and Shetsen, I., (compilers), Canadian Society of Petroleum Geologists and Alberta Geological Survey (1994). "The Geological Atlas of the Western Canada Sedimentary Basin, Chapter 10: Devonian Elk Point Group of the Western Canada Sedimentary Basin". Retrieved 2014-10-17.
1 2 3 4 McCamis, J.G. and Griffith L.S. 1967. Middle Devonian facies relationships, Zama area, Alberta. Bulletin of Canadian Petroleum Geology, v. 15, no. 4, p. 434-467.
1 2 Glass, D.J. (editor) 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba. Canadian Society of Petroleum Geologists, Calgary, 1423 p. on CD-ROM. ISBN 0-920230-23-7.

Western Canadian Sedimentary Basin

Hydrocarbon history	Oil sands and heavy oil Frontier exploration and development Natural gas liquids Natural gas

Depositional Regions	Southern Alberta Central Alberta Northwestern Alberta Plains South-central Canadian Rockies foothills North-east Plains North-central foothills Liard River Fort Nelson Northern Rocky Mountains Fort St. John Saskatchewan Western Manitoba

Northwest Plains	Paskapoo FM Scollard FM Wapiti GRP Smoky GRP Puskwaskau FM Badheart FM Muskiki FM Cardium FM Kaskapau FM Pouce Coupe MBR Doe Creek MBR Dunvegan FM Fort St. John GRP Shaftesbury FM Peace River FM Spirit River FM Bullhead GRP Bluesky FM Gething FM Cadomin FM Nikanassin FM Fernie GRP Rock Creek MBR Poker Chip Shale Nordegg MBR Schooler Creek GRP Baldonnel FM Charlie Lake FM Halfway FM Doig FM Montney FM Belloy FM Stoddart GRP Taylor Flat FM Kiskatinaw FM Golata FM Rundle GRP Debolt FM Shunda FM Pekisko FM Banff FM Exshaw FM Wabamun FM Trout River FM Kakisa FM Redknife FM Jean Marie MBR Woodbend GRP Irteton FM Fort Simpson FM Leduc FM Duvernay FM Cooking Lake FM Beaverhill Lake GRP Waterways FM Swan Hills FM Fort Vermilion FM Elk Point GRP Watt Mountain FM Gillwood MBR Presqu’ile FM Sulphur Point FM Pine Point FM Muskeg FM Zama MBR Black Shale Keg River FM Rainbow MBR Chinchaga FM Cold Lake FM Ernestina FM Basal Red Beds Granite Wash Canadian Shield

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