imported>Volcanoguy: removed Category:Dolomite formations; added Category:Dolomite formations of Canada using HotCat

2025-06-21T20:56:48Z

removed Category:Dolomite formations; added Category:Dolomite formations of Canada using HotCat

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{{Short description|Canadian oil and gas reserve}}
{{Infobox Rockunit
| name = Muskeg Formation
| image =
| caption =
| type = [[Geological formation]]
| age = {{Fossil range|Givetian|Givetian|[[Givetian]]}}
| period = Givetian
| prilithology = [[Anhydrite]], [[Dolomite (rock)|dolomite]]
| otherlithology = [[Halite]], [[limestone]]
| namedfor =
| namedby = J. Law<ref name=Law />
| region = [[Alberta]]<br>[[British Columbia]]
| country = [[Canada]]
| coordinates = {{coord|59.1725|N|118.7482|W|name=Steen River 2-22-117-5W6M|display=inline,title}}
| unitof =
| subunits =
| underlies = [[Watt Mountain Formation]]
| overlies = [[Keg River Formation]]
| thickness = up to {{convert|270|m|ft|-1}}<ref name=lexicon>{{Cite web|url=http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:010435| title= Muskeg Formation|author=Lexicon of Canadian Geological Units|accessdate=2009-02-10}}</ref>
| extent =
| area =
| map =
| map_caption =
}}
The '''Muskeg Formation''' is a [[Formation (geology)|geologic formation]] of [[Middle Devonian]] ([[Givetian]]) age in the [[Western Canadian Sedimentary Basin|Western Canada Sedimentary Basin]]. It extends from the plains of northwestern [[Alberta]] to northeastern [[British Columbia]],<ref name=Mossop10>{{Cite web|url=http://www.ags.gov.ab.ca/publications/wcsb_atlas/a_ch10/ch_10.html|title=The Geological Atlas of the Western Canada Sedimentary Basin, Chapter 10: Devonian Elk Point Group of the Western Canada Sedimentary Basin|author=Mossop, G.D. and Shetsen, I., (compilers), Canadian Society of Petroleum Geologists and Alberta Geological Survey|year=1994|accessdate=2014-10-17}}</ref> and includes important [[petroleum]] and [[natural gas]] [[petroleum reservoir|reservoirs]] in the [[Zama lake]] and [[Rainbow Lake, Alberta|Rainbow Lake]] areas of northwestern Alberta.<ref name=McCamis>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.</ref>

==Lithology==
The Muskeg Formation consists primarily of [[anhydrite]], with [[Dolomite (rock)|dolomite]], [[halite|halite (rock salt)]] and [[limestone]].<ref name=lexicon/>

==Environment of Deposition==
The Muskeg Formation was deposited at the northern end of an [[bay|embayment]] called the [[Elk Point Group|Elk Point Basin]], adjacent to an extensive [[reef#geologic reef structures|reef complex]] called the [[Presqu'ile Formation|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 rock]]s.<ref name=Mossop10 /><ref name=McCamis />

==Distribution and Thickness==
The Muskeg Formation is present in the northern half of the Elk Point Basin, in northeastern [[British Columbia]] and northwestern [[Alberta]].<ref name=Mossop10 /> It reaches a maximum reported thickness of {{convert|270|m|ft|-1}}.<ref name=lexicon /><ref name=Glass>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}}.</ref>

==Stratigraphy==
The Muskeg Formation is part of the [[Elk Point Group]] and was established by J. Law in 1955, based on [[core sample|core]] from a [[oil well|well]] (California Standard Steen River 2-22-117-5W6M) that was drilled north of Zama Lake.<ref name=lexicon/><ref name=Law>Law, J. 1955. Rock units of northwestern Alberta. Journal of the Alberta Society of Petroleum Geologists, v. 3, no. 6, p. 81-83.</ref>

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 dolomite. 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 dolomite. The Bistcho Member at the top is a fragmental carbonate unit.<ref name=McCamis />

==Relationship to other units==
The Muskeg Formation is [[unconformity|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]].<ref name=lexicon /><ref name=Glass /> 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.<ref name=Mossop10 />

==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 [[permeability (earth sciences)|impermeable]] anhydrite and halite beds of the formation act to seal the reservoirs.<ref name=McCamis />

==References==
{{reflist}}
{{Western Canadian Sedimentary Basin|Northwest_Plains=yes}}

[[Category:Geologic formations of Alberta]]
[[Category:Geologic formations of British Columbia]]
[[Category:Dolomite formations of Canada]]
[[Category:Limestone formations of Canada]]

Muskeg Formation - Revision history

imported>Volcanoguy: removed Category:Dolomite formations; added Category:Dolomite formations of Canada using HotCat