The Nikanassin 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 ...

Late Jurassic The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...

(

Portlandian The Portland Group (defining the Portlandian) is a Late Jurassic (Tithonian) lithostratigraphic group (a sequence of rock strata) in South East England. The name is derived from the Isle of Portland in Dorset where the strata are exposed and ha ...

) to

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

(

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 125.77 Ma (million years ago) and 121.4 ± 1.0 Ma (Historically, this stage was placed at 129.4 million to approximately 125 million years ago) It is a ...

) age.Poulton, T.P., Tittemore, J. and Dolby, G. 1990. Jurassic strata of northwestern (and west-central) Alberta and northeastern British Columbia. Bulletin of Canadian Petroleum Geology 38A: 159-175. It is present along the western edge of the

Western Canada 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 ba ...

in western

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 ...

and northeastern

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 ...

. Its name was first proposed by D.B. Dowling in 1909 (Coal Fields South of Grand Trunk Pacific Railway, in the foothills of the Rocky Mountain, Alberta Page 140 paragraph 4 " to this it is proposed to give the name Nikanassin, from the Cree word meaning outer range" Also it is noted on the map by D.B. Dowling.(Geological Survey of Canada. Incorrect info follows: It was named by B.R. MacKay in 1929Mackay, B.R., 1929a. Mountain Park Sheet, West of Fifth Meridian, Alberta;

Geological Survey of Canada The Geological Survey of Canada (GSC; , CGC) is a Canadian federal government agency responsible for performing geological surveys of the country developing Canada's natural resources and protecting the environment. A branch of the Earth Science ...

, "A" Series Map 208A, Scale: 1:63360 (1 Inch to 1 Mile). for the Nikanassin Range of the front-central ranges of the

Canadian Rockies The Canadian Rockies () or Canadian Rocky Mountains, comprising both the Alberta Rockies and the British Columbian Rockies, is the Canadian segment of the North American Rocky Mountains. It is the easternmost part of the Canadian Cordillera, w ...

(''Nikanassin'' means "first range" in

Cree The Cree, or nehinaw (, ), are a Indigenous peoples of the Americas, North American Indigenous people, numbering more than 350,000 in Canada, where they form one of the country's largest First Nations in Canada, First Nations. They live prim ...

). Mackay did not designate a type locality for the formation, although he described

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 ...

s near the hamlet of Brûlé, north of the

Yellowhead Highway The Yellowhead Highway () is a major interprovincial highway in Western Canada that runs from Winnipeg west to Graham Island off the coast of British Columbia via Saskatoon and Edmonton. It stretches across the four western provinces of Britis ...

outside of

Jasper National Park Jasper National Park, in Alberta, Canada, is the largest national park within Alberta's Rocky Mountains, spanning . It was established as Jasper Forest Park in 1907, renamed as a national park in 1930, and declared a UNESCO world heritage site ...

Depositional history

The Nikanassin Formation grades from marine sediments at the base to coastal and continental at the top. The sediments were derived from newly uplifted mountains to the west and deposited along the western margin of the

Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, or the Western Interior Sea) was a large inland sea (geology), inland sea that existed roughly over the present-day Great Plains of ...

, which is represented by the marine shales of the Fernie Formation.

Lithology

The Nikanassin consists primarily of marine

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

s interbedded with dark grey

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 ...

s. The sandstones are dark grey, hard, mostly quartzose, and fine- to medium-grained. In the foothills the upper beds are nonmarine and include thin

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...

beds and carbonaceous shales. There are no commercially significant coal beds.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. .

Thickness and distribution

The Nikanassin thickens northward from the foothills near the

North Saskatchewan River The North Saskatchewan River is a glacier-fed river that flows from the Canadian Rockies continental divide east to central Saskatchewan, where it joins with the South Saskatchewan River to make up the Saskatchewan River. Its water flows event ...

, reaching a maximum of about near Brûlé. From there it thins toward the east and north. It extends into the southernmost part of northeastern British Columbia, where it transitions into the

Minnes Group The Minnes Group, originally named the Minnes Formation, is a geologic unit of latest Jurassic to earliest Cretaceous age in the Western Canada Sedimentary Basin. It is present in the northern foothills of the Canadian Rockies and the adjacent ...

Relationship to other units

The Nikanassin is roughly equivalent to the Kootenay Group of the southern Alberta foothills and the

north of northeastern British Columbia. It conformably overlies and interfingers with the "Passage Beds" at the top of the Fernie Formation. A major period of regional erosion occurred after the deposition of the Nikanassin, removing some of the uppermost Nikanassin strata prior to the deposition of the overlying conglomerates of the Cadomin Formation. The contact between the two formations is thus sharp and

unconformable An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval ...

References

{{Western Canadian Sedimentary Basin, Northwest_Plains=yes Geologic formations of Alberta Jurassic Alberta Cretaceous Alberta Geologic formations of British Columbia Jurassic British Columbia Cretaceous British Columbia Sandstone formations of Canada Shale formations of Canada Coal formations Western Canadian Sedimentary Basin