Exshaw Formation

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Exshaw Formation Stratigraphic range: Late Famennian to Middle Tournaisian PreЄ Є O S D C P T J K Pg N
Type	Geological formation
Sub-units	Lower and Upper Exshaw
Underlies	Banff Formation
Overlies	Wabamun Formation, Kotcho Formation, Palliser Formation
Thickness	up to 50 metres (160 ft)^[1]
Lithology
Primary	Shale
Other	Siltstone
Location
Coordinates	51°05′29″N 115°09′29″W / 51.09139°N 115.15806°W / 51.09139; -115.15806 (Exshaw Formation)Coordinates: 51°05′29″N 115°09′29″W / 51.09139°N 115.15806°W / 51.09139; -115.15806 (Exshaw Formation)
Region	Alberta
Country	Canada
Type section
Named for	Exshaw, Alberta
Named by	Warren, 1937

The Exshaw Formation is a stratigraphical unit of Mississippian age in the Western Canadian Sedimentary Basin.

It takes the name from the hamlet of Exshaw, Alberta, and was first described in outcrops on the banks of Jura Creek, north of Exshaw by P.S. Warren in 1937.^[2] The formation is late Famennian to middle Tournaisian, and includes the Devonian-Carboniferous limit. The strata were deposited during the Hangenberg event, an anoxic period associated with the Late Devonian extinction.

Lithology

The Exshaw Formation is composed of black shale in the lower part, and siltstone and limestone in the upper part, ^[1] The upper part is missing in central Alberta and northern Alberta.

Distribution

The Exshaw Formation has a thickness of 46.7 metres (150 ft) at its type locality in the Canadian Rockies.^[1] It occurs from the prairies of northern Montana to southern Northwest Territories. A hiatus is observed in the Peace River Arch.

Relationship to other units

The Exshaw Formation is unconformably overlain by the Banff Formation and unconformably underlain by the Wabamun Formation in Alberta, the Kotcho Formation in north-eastern British Columbia and the Palliser Formation in the Canadian Rockies and foothills.^[1]

It is equivalent to the lower and middle members of the Bakken Formation in east-southern Alberta, southern Saskatchewan, Montana and North Dakota.

References

↑ 1.0 1.1 1.2 1.3 Lexicon of Canadian Geologic Units. "Exshaw Formation". Retrieved 2009-03-01.
↑ Warren, P.S., 1937. Age of the Exshaw shale in the Canadian Rockies. American Journal of Science, Series 5, volume 33, pages 454-457.

v t e 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

Northeastern Plains	Bearpaw FM Belly River GRP Lea Park FM La Biche GRP Viking FM Joli Fou FM Colony SS Mannville GRP McLaren MBR Grand Rapids FM Waseca SS Sparky SS Gen. Petr. SS Clearwater FM Rex SS Lloydminster SS Wabiskaw MBR Cummings MBR McMurray FM Dina MBR Banff FM Exshaw FM Wabamun FM Winterburn FM Woodbend GRP Grosmont FM Irteton FM Cooking Lake FM Beaverhill Lake GRP Elk Point GRP Canadian Shield

Southern Alberta Plains	Cypress Hills FM Porcupine Hills FM Ravenscrag FM Edmonton GRP Belly River GRP Oldman FM Foremost FM Pakowki FM Milk River FM Colorado GRP Mannville GRP Ellis GRP Swift FM Rierdon FM Sawtooth FM Rundle GRP Banff FM Exshaw FM Bakken FM Wabamun FM Crowfoot FM Nisku FM Ireton FM Leduc FM Cooking Lake FM Beaverhill Lake GRP Elk Point GRP Canadian Shield

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