The Horn River Formation (also ''Horn River Shale'') 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 ...

(early

Givetian The Givetian is one of two faunal stages in the Middle Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Eifelian Stage and followed by the Frasnian Stage. It is named after the town of Givet in ...

to late

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 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 is a thick sequence of marine sediments that was first described in

outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth and other terrestrial planets. Features Outcrops do not cover the majority of the Earth's land surface because in most p ...

on the banks of the

Horn River The Horn River is a river in the Northwest Territories of Canada. It is a major tributary of the Mackenzie River. The river gives the name to the Horn River Formation, a shale deposit of the Western Canadian Sedimentary Basin. The Horn River Bas ...

, 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, ...

, in the

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 ...

(at the time

District of Mackenzie The District of Mackenzie was a regional administrative district of Canada's Northwest Territories. The district consisted of the portion of the Northwest Territories directly north of British Columbia, Alberta, and Saskatchewan on Canada's main ...

) by Whittaker in 1922, and it takes its name from that river. In 1963 it was redefined in the subsurface of the

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 ...

area of

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 ...

(well Fort Nelson a-95-J/94-J-10) by F.F. Gray and J.R. Kassube. It is significant for its

shale gas Shale gas is an unconventional natural gas that is found trapped within shale formations. Since the 1990s, a combination of horizontal drilling and hydraulic fracturing has made large volumes of shale gas more economical to produce, and ...

resources.

Lithology

The Horn River Formation is composed of dark

siliceous Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant ...

and

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcare ...

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 ...

, and

argillaceous Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin, Al2 Si2 O5( OH)4), sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces. Clay mineral ...

bituminous Bitumen ( , ) is an immensely viscous constituent of petroleum. Depending on its exact composition, it can be a sticky, black liquid or an apparently solid mass that behaves as a liquid over very large time scales. In American English, the m ...

limestone.

Stratigraphy

The Horn River Formation is included in the Beaverhill Lake Group. It is subdivided into the following members, from top to base: *

Muskwa Member The Muskwa Formation is a stratigraphic unit of Frasnian age in the Western Canadian Sedimentary Basin. It takes the name from Muskwa River, and was first described in the Western National Gas Fort Nelson a-95-J/94-J-10 well by F.F. Gray and J.R ...

: bituminous, mildly radioactive shale *

Otter Park Member The Horn River Formation (also ''Horn River Shale'') is a stratigraphic unit of Devonian (early Givetian to late Frasnian) age in the Western Canadian Sedimentary Basin. It is a thick sequence of marine sediments that was first described in outc ...

: grey calcareous shale *

Evie Member The Horn River Formation (also ''Horn River Shale'') is a stratigraphic unit of Devonian (early Givetian to late Frasnian) age in the Western Canadian Sedimentary Basin. It is a thick sequence of marine sediments that was first described in outc ...

: black silty limestone

Distribution

The Horn River Formation is present in the subsurface in northeastern British Columbia and extends to

Great Slave Lake Great Slave Lake is the second-largest lake in the Northwest Territories, Canada (after Great Bear Lake), List of lakes by depth, the deepest lake in North America at , and the List of lakes by area, tenth-largest lake in the world by area. It ...

in the Northwest Territories, where it outcrops. It reaches a maximum thickness of in the subsurface of the Fort Nelson area.

Relationship to other units

The Horn River Formation is overlain by the Fort Simpson Formation and underlain by the limestones of the Lonely Bay Formation, Nahanni Formation or Pine Point Formation. It is equivalent to the

Slave Point Formation The Slave Point Formation is a stratigraphic unit of Middle Devonian age in the Western Canadian Sedimentary Basin. It takes the name from Slave Point, a promontory on the north-west shore of the Great Slave Lake, and was first described in outc ...

. In the Northwest Territories it includes the

Muskwa Formation The Muskwa Formation is a stratigraphic unit of Frasnian age in the Western Canadian Sedimentary Basin. It takes the name from Muskwa River, and was first described in the Western National Gas Fort Nelson a-95-J/94-J-10 well by F.F. Gray and J.R ...

, and the Waterways Member of the

Hay River Formation The Hay River Formation is a geologic formation in Northwest Territories. It preserves fossils dating back to the Devonian period. See also * List of fossiliferous stratigraphic units in Northwest Territories This is a list of fossiliferous ...

. It includes the pinnacle

reef A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic component, abiotic (non-living) processes such as deposition (geol ...

s of the Horn Plateau Formation.

Hydrocarbon production

Shale gas Shale gas is an unconventional natural gas that is found trapped within shale formations. Since the 1990s, a combination of horizontal drilling and hydraulic fracturing has made large volumes of shale gas more economical to produce, and ...

is present in the siliceous shales of all three members of the Horn River Formation in northeastern British Columbia, and it is produced in the Greater Sierra oil field north of Fort Nelson. Horizontal drilling and

fracturing Fracture is the appearance of a crack or complete separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity sur ...

techniques are used to extract the gas from the low permeability shales. The original-gas-in-place volumes are estimated to be up to 500 Tcf, making it the third largest North American natural gas accumulation discovered prior to 2010. Companies involved in the extraction of natural gas from the Horn River Shale include

Ovintiv Ovintiv Inc. is a U.S. petroleum company based in Denver. The company was formed in 2020 through a restructuring of its Canadian predecessor, Encana. History On January 24, 2020, after receiving shareholder approval, the company completed th ...

EOG Resources EOG Resources, Inc. is an American energy company engaged in hydrocarbon exploration. It is organized in Delaware and headquartered in the Heritage Plaza building in Houston, Texas. The company is ranked 186th on the Fortune 500 and 337th on ...

, Stone Mountain Resources,

ExxonMobil Exxon Mobil Corporation ( ) is an American multinational List of oil exploration and production companies, oil and gas corporation headquartered in Spring, Texas, a suburb of Houston. Founded as the Successors of Standard Oil, largest direct s ...

, Quicksilver Resources, and

CNOOC Petroleum North America ULC CNOOC Petroleum North America ULC, formerly known as Nexen, is a Canadian oil and gas company based in Calgary, Alberta. Originally the Canadian subsidiary of US-based Occidental Petroleum (known as Canadian Occidental Petroleum or CanOxy), it ...

. Horn River gas contains 10-12% , much higher than the 2–4.5% of conventional natural gas. If this gas is processed normally about 500 million tonnes of will be released into the atmosphere.

Hydraulic fracturing in Canada

Massive hydraulic fracturing has been widely used in

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 ...

since the late 1970s. The method is currently used in development of the Cardium, Duvernay,

Montney Montney is an unincorporated locality located in British Columbia about north of Fort St. John, near Beatton Provincial Park. It lies at an elevation of , along the BC Rail tracks. The settlement gives the name to the Montney Formation, a ...

and

Viking Vikings were seafaring people originally from Scandinavia (present-day Denmark, Norway, and Sweden), who from the late 8th to the late 11th centuries raided, pirated, traded, and settled throughout parts of Europe.Roesdahl, pp. 9� ...

formations in

, Bakken formation in

Saskatchewan Saskatchewan is a Provinces and territories of Canada, province in Western Canada. It is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and to the south by the ...

and Horn River formations in

References

{{Shale gas Oil-bearing shales in Canada Natural gas fields in Canada Devonian British Columbia Devonian Northwest Territories Frasnian Stage Givetian Stage Geologic formations of British Columbia Devonian System of North America Geologic formations of the Northwest Territories Western Canadian Sedimentary Basin Limestone formations of Canada