The Redknife Formation is a

stratigraphic unit A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features ( facies) that characteriz ...

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

age Age or AGE may refer to: Time and its effects * Age, the amount of time someone has been alive or something has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

in the

Western Canadian Sedimentary Basin The Western Canada Sedimentary Basin (WCSB) underlies of Western Canada including southwestern Manitoba, southern Saskatchewan, Alberta, northeastern British Columbia and the southwest corner of the Northwest Territories. This vast sedimentary b ...

. It takes the name from Redknife River, a tributary of the

Mackenzie River The Mackenzie River (French: ; Slavey language, Slavey: ' èh tʃʰò literally ''big river''; Inuvialuktun: ' uːkpɑk literally ''great river'') is a river in the Canadian Canadian boreal forest, boreal forest and tundra. It forms, ...

, and was first described in the banks of the Trout River, north of

Trout Lake, Northwest Territories Sambaa K'e (Slavey language: "place of trout"; formerly Trout Lake) is a "Designated Authority" in the Dehcho Region of the Northwest Territories, Canada. The community is located near the Alberta border, east of Fort Liard, on the shore of the ...

, at Table Rock Rapids by Belyea and McLaren in 1962.

Lithology

The Redknife Formation is divided into the Jean Marie Member (base) and an upper unnamed

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

unit. The Jean Marie Member is composed of argillaceous,

silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension (chemistry), suspension with water. Silt usually ...

y and

dolomitic Dolomite () is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally The term is also used for a sedimentary carbonate rock composed mostly of the mineral dolomite (see Dolomite (rock)). An alternative name sometimes ...

fossiliferous limestone Fossiliferous limestone is a type of limestone that contains noticeable quantities of fossils or trace fossil, fossil traces. If a particular type of fossil dominates, a more specialized term can be used as in "Ames Limestone, Crinoidal", "Coral ...

. The carbonates are massive east of

Fort Nelson A fortification (also called a fort, fortress, fastness, or stronghold) is a military construction designed for the defense of territories in warfare, and is used to establish rule in a region during peacetime. The term is derived from Lati ...

and west of the

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

border. The upper Redknife consists of calcareous

shales Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g., kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

with silty limestone and

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeabil ...

interbeds. To the south and east, the shales grade into limestone and siltstone, and it becomes dolomitic in the

Peace River The Peace River () is a river in Canada that originates in the Rocky Mountains of northern British Columbia and flows to the northeast through northern Alberta. The Peace River joins the Athabasca River in the Peace-Athabasca Delta to form the ...

arch. The Redknife formation contains common

coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...

and

brachiopod Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...

fossils.

Oil/gas production

Gas Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such as ...

is produced from the Jean Marie Member in the Greater Sierra filed east of

Fort Nelson, British Columbia Fort Nelson is a community in northeast British Columbia, Canada, within the Northern Rockies Regional Municipality (NRRM). It held town status prior to 6 February 2009, when it amalgamated with the former Northern Rockies Regional District to ...

Distribution

The Redknife Formation occurs in outcrops in the southern

Northwest Territories The Northwest Territories is a federal Provinces and territories of Canada, territory of Canada. At a land area of approximately and a 2021 census population of 41,070, it is the second-largest and the most populous of Provinces and territorie ...

and in the sub-surface in north-eastern

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

, also reaching into north-western

. The maximum thickness of the upper shales is , and the lower carbonates are up to . The Jean Marie Member is found in outcrops south of the

between

Kakisa Kakisa (Slavey language: ''K’agee''; ''between the willows'') is a "Designated Authority" in the South Slave Region of the Northwest Territories, Canada. The community is located on Kakisa Lake, and is southeast of Fort Providence. Original ...

and Blackstone River. It grades westwards into the

facies In geology, a facies ( , ; same pronunciation and spelling in the plural) is a body of rock with distinctive characteristics. The characteristics can be any observable attribute of rocks (such as their overall appearance, composition, or con ...

of the Fort Simpson Formation. East of the Peace River Arch it turns into the

carbonate A carbonate is a salt of carbonic acid, (), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word "carbonate" may also refer to a carbonate ester, an organic compound containing the carbonate group ...

s of the Kakisa Formation.

Relationship to other units

The Redknife Formation is conformly overlain by the Kakisa Formation and overlies the Tathlina Formation in

northern Alberta Northern Alberta is a geographic region located in the Canadian province of Alberta. An informally defined cultural region, the boundaries of Northern Alberta are not fixed. Under some schemes, the region encompasses everything north of the ce ...

and the Fort Simpson Formation in

and

. The Fort Simpson Formation replaces the Redknife Formation to the west. The Redknife Formation can be correlated with the Nisku Formation and upper part of the Ireton Formation in

central Alberta Central Alberta is a region located in the Canadian province of Alberta. Central Alberta is the most densely populated rural area in the province. Agriculture and energy are important to the area's economy. Geography Central Alberta is bordered ...

Subdivisions

The Jean Marie Member is designated as the lower part of the Redknife Formation where it is represented by massive

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

or silty

s. The Jean Marie Member was deposited during the

Frasnian The Frasnian is one of two faunal stages in the Late Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Givetian Stage and followed by the Famennian Stage. Major reef-building was under way during ...

age. It is named for the

Jean Marie River Jean Marie River (Slavey language: ''Tthets’ek’ehdeli'' "water flowing over clay") is a "Designated Authority" in the Dehcho Region of the Northwest Territories, Canada. The community is located on the Jean Marie River where it joins the M ...

References

Geologic formations of British Columbia Geologic formations of Alberta Geologic formations of the Northwest Territories Devonian southern paleotropical deposits Upper Devonian Series Devonian British Columbia Devonian Alberta Devonian Northwest Territories Shale formations of Canada Limestone formations of Canada Siltstone formations of Canada Dolomite formations of Canada {{Canada-geologic-formation-stub