Fort Simpson Formation
{{Infobox Rockunit
| name = Fort Simpson Formation
| image =
| caption =
| type = Geological formation
| age = {{Fossil range|Late Devonian|Late Devonian|Late Devonian}}
| period = Late Devonian
| prilithology = Shale
| otherlithology =
| namedfor = Fort Simpson, Northwest Territories
| namedby = A.E. Cameron, 1918
| region = Alberta
British Columbia
Northwest Territories
| country = Canada
| coordinates = {{coord|61|07|30|N|120|22|30|W|name=Briggs Turkey Lake No. 1|display=inline,title}}
| unitof =
| subunits =
| underlies = Jean Marie Member of the Redknife Formation
| overlies = Muskwa Member of the Horn River Formation
| thickness = up to {{convert|1000|m|ft|-1}}
| extent =
| area =
| map =
| map_caption =
}}
The Fort Simpson Formation is a stratigraphic unit of Devonian age in the Western Canadian Sedimentary Basin.
It takes the name from the settlement of Fort Simpson, and was first described in well Briggs Turkey Lake No. 1 (located south-east of Fort Simpson) by A.E. Cameron in 1918.Cameron, A.E., 1918. Explorations in the vicinity of Great Slave Lake. Geological Survey of Canada, Summary Report, 1917, Part C, p. 21-27.
Lithology
The Fort Simpson Formation is composed of grey shale and mudstone.
{{Cite web|url=http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:005169
|title=Fort Simpson Formation
|author=Lexicon of Canadian Geologic Units
|accessdate=2009-03-01}}
The shale can be calcareous, silty or sandy.
Distribution
The Fort Simpson Formation reaches a thickness of over {{convert|1000|m|ft|-1}} in the sub-surface of the Mackenzie River plain. It extends from northern Alberta to south-western northwest Territories and in north-eastern British Columbia (north of Peace River Arch).
Relationship to other units
The Fort Simpson Formation is overlain by the Jean Marie Member of the Redknife Formation in its eastern reaches, and progressively by the Kakisa Formation, Trout River Formation or Tetcho Formation towards the west. It is conformably underlain by the Muskwa Member of the Horn River Formation.
It is replaced by the Besa River Formation in the Liard River area. It is equivalent to the Imperial Formation to the north, the Tathlina Formation, Twin Falls Formation and Hay River Formation to the east, and the Woodbend Group in Alberta.
References
{{reflist}}
{{Western Canadian Sedimentary Basin|Fort_Nelson=yes|Northwest_Plains=yes}}
Category:Geologic formations of Alberta
Category:Geologic formations of British Columbia
Category:Geologic formations of the Northwest Territories
Category:Devonian southern paleotropical deposits
Category:Shale formations of Canada