Exshaw Formation

Exshaw Formation
Exshaw Formation
Stratigraphic range: Late Famennian to Middle Tournaisian PreꞒ Ꞓ 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)
Lithology
Primary	Shale
Other	Siltstone, limestone
Location
Coordinates	51°05′29″N 115°09′29″W / 51.09139°N 115.15806°W
Region	Alberta
Country	Canada
Type section
Named for	Exshaw, Alberta
Named by	P.S. Warren, 1937

TypeGeological formation

Sub-unitsLower and Upper Exshaw

UnderliesBanff Formation

OverliesWabamun Formation, Kotcho Formation, Palliser Formation

The Exshaw Formation is a stratigraphic unit in the Western Canada Sedimentary Basin.^[3] It takes the name from the hamlet of Exshaw, Alberta, in the Canadian Rockies, and was first described from outcrops on the banks of Jura Creek north of Exshaw by P.S. Warren in 1937.^[2] The formation is of Late Devonian (late Famennian) to Early Mississippian (middle Tournaisian) age as determined by conodont biostratigraphy, and it straddles the Devonian–Carboniferous boundary.^[2]^[4]

The Exshaw strata were deposited in a marine setting during the Hangenberg event, an oceanic anoxic event associated with the Late Devonian extinction. The black shales of the Exshaw Formation are rich in organic matter and are one of the most important petroleum source rocks of the Western Canada Sedimentary Basin.^[5]

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v t e Western Canada 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

Exshaw Formation

Thickness and Distribution

Relationship to other units

References

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