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{{short description|Stratigraphic unit in Canada}}
{{Infobox Rockunit
| name = Nikanassin Formation
| image = Athabasca at Brule Lake.jpg
| caption = Nikanassin Formation near Brule
| type = [[Geological formation]]
| age = {{fossil range|146|Barremian|[[Portlandian]] to [[Barremian]]}}
| period = Mesozoic
| prilithology = [[Sandstone]], [[shale]]
| otherlithology = [[Coal]]
| namedfor = [[Nikanassin Range]]
| namedby = MacKay, 1929<ref name=named/>
| region = [[Western Canadian Sedimentary Basin|Western Canada Sedimentary Basin]]
| country = [[Canada]]
| coordinates = {{coord|53|17|21|N|117|52|34|W|name=Nikanassin Formation|display=inline,title}}
| unitof =
| subunits =
| underlies = [[Cadomin Formation]]
| overlies = [[Fernie Formation]]
| thickness = {{convert|400|m|ft|sp=us}} to 0
| extent =
| area =
| map =
}}
The '''Nikanassin Formation''' is a [[stratigraphic unit]] of [[Late Jurassic]] ([[Portlandian]]) to [[Early Cretaceous]] ([[Barremian]]) age.<ref name=Poulton>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. </ref> It is present along the western edge of the [[Western Canadian Sedimentary Basin|Western Canada Sedimentary Basin]] in western [[Alberta]] and northeastern [[British Columbia]].<ref name=Mossop18>{{Cite web|url=http://www.ags.gov.ab.ca/publications/wcsb_atlas/a_ch18/ch_18.html|title=The Geological Atlas of the Western Canada Sedimentary Basin, Chapter 18: Jurassic and Lowermost Cretaceous strata of the Western Canada Sedimentary Basin|author=Mossop, G.D. and Shetsen, I., (compilers), Canadian Society of Petroleum Geologists and Alberta Geological Survey|year=1994|accessdate=2013-08-01|url-status=dead|archiveurl=https://web.archive.org/web/20130326021000/http://www.ags.gov.ab.ca/publications/wcsb_atlas/a_ch18/ch_18.html|archivedate=2013-03-26}}</ref> 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 1929<ref name=named>Mackay, B.R., 1929a. Mountain Park Sheet, West of [[114th meridian west|Fifth Meridian]], Alberta; [[Geological Survey of Canada]], "A" Series Map 208A, Scale: 1:63360 (1 Inch to 1 Mile).</ref> for the [[Nikanassin Range]] of the front-central ranges of the [[Canadian Rockies]] (''Nikanassin'' means "first range" in [[Cree Language|Cree]]<ref name=bivuac>{{Cite web|url=http://www.bivouac.com/ArxPg.asp?ArxId=1032|title=Nikanassin Range|author=Bivuac.com|accessdate=2009-02-05}}</ref>). Mackay did not designate a [[type locality (geology)|type locality]] for the [[formation (stratigraphy)|formation]], although he described [[outcrop]]s near the hamlet of [[Brule, Alberta|Brûlé]], north of the [[Yellowhead Highway]] outside of [[Jasper National Park]].<ref name="Glass" /><ref name="lexicon" />

==Depositional history==
The Nikanassin Formation grades from marine sediments at the base to coastal and continental at the top.<ref name="Glass" /><ref name="lexicon" /> The sediments were derived from newly uplifted mountains to the west and deposited along the western margin of the [[Western Interior Seaway]], which is represented by the marine shales of the [[Fernie Formation]].<ref name="Mossop18" />

==Lithology==
The Nikanassin consists primarily of marine [[sandstone]]s interbedded with dark grey [[shale]]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]] beds and carbonaceous shales. There are no commercially significant coal beds.<ref name=Glass>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. {{ISBN|0-920230-23-7}}.</ref><ref name=lexicon>{{Cite web|url=http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:010770|title=Nikanassin Formation|author=[[Lexicon of Canadian Geologic Units]] |accessdate=2009-02-05}}</ref>

==Thickness and distribution==
The Nikanassin thickens northward from the foothills near the [[North Saskatchewan River]], reaching a maximum of about {{convert|400|m|ft|sp=us}} near [[Brule, Alberta|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]].<ref name="Glass" /><ref name="lexicon" />

==Relationship to other units==
The Nikanassin is roughly equivalent to the [[Kootenay Group]] of the southern Alberta foothills and the [[Minnes Group]] north of northeastern British Columbia. It conformably overlies and interfingers with the "Passage Beds" at the top of the Fernie Formation.<ref name="Glass" /><ref name="lexicon" />

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 [[conglomerate (geology)|conglomerates]] of the [[Cadomin Formation]]. The contact between the two formations is thus sharp and [[unconformity|unconformable]].<ref name="Mossop18" /><ref name="Glass" />

==References==
{{reflist}}
{{Western Canadian Sedimentary Basin|Northwest_Plains=yes}}

[[Category:Geologic formations of Alberta]]
[[Category:Jurassic Alberta]]
[[Category:Cretaceous Alberta]]
[[Category:Geologic formations of British Columbia]]
[[Category:Jurassic British Columbia]]
[[Category:Cretaceous British Columbia]]
[[Category:Sandstone formations of Canada]]
[[Category:Shale formations of Canada]]
[[Category:Coal formations]]
[[Category:Western Canadian Sedimentary Basin]]

Nikanassin Formation - Revision history

imported>The Space Enthusiast at 23:29, 25 June 2025