Kootenay Group

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Kootenay Group
Stratigraphic range: Late Jurassic to Early Cretaceous
Type Group
Sub-units Elk Formation
Mist Mountain Formation
Morrissey Formation
Underlies Blairmore Group
Overlies Fernie Formation
Thicknessmaximum 1,335 m (4,380 ft)
Lithology
Primary Sandstone, siltstone, mudstone
Other Coal, conglomerate
Location
Region Canadian Rockies
CountryFlag of Canada (Pantone).svg  Canada
Type section
Named byD. W. Gibson, 1979 [1] [2]

The Kootenay Group, originally called the Kootenay Formation, [1] [2] is a geologic unit of latest Jurassic to earliest Cretaceous age in the Western Canada Sedimentary Basin that is present in the southern and central Canadian Rockies and foothills. [3] It includes economically important deposits of high-rank bituminous and semi-anthracite coal, [4] as well as plant fossils and dinosaur trackways. [2]

Contents

Stratigraphy and lithology

The strata of the Kootenay Group were originally described as the Kootenay Formation. [1] [5] D.W. Gibson revised the sequence as the Kootenay Group and defined it as encompassing the stratigraphic interval between the Jurassic Fernie Formation and the Lower Cretaceous Blairmore Group. He subdivided it into three formations as shown below and designated a type section for each of the formations, thus eliminating the need for a type section for the group. [2]

Formation Age Lithology Maximum
Thickness		Reference
Elk Formation earliest Cretaceous interbedded sandstone, siltstone, mudstone, conglomerate; rare thin coal seams590 m (1,940 ft) [2]
Mist Mountain Formation latest Jurassic to earliest Cretaceous interbedded sandstone, siltstone, mudstone, shale, and mineable coal seams; rare conglomerate 665 m (2,180 ft) [2]
Morrissey Formation latest Jurassic massive cliff-forming fine- to medium-grained sandstone 80 m (260 ft) [2]

Environment of deposition

The Kootenay Group is an eastward-thinning wedge of sediments derived from the erosion of newly uplifted mountains to the west. The sediments were transported eastward by river systems and deposited in a variety of river channel, floodplain, swamp, coastal plain, deltaic and shoreline environments along the western edge of the Western Interior Seaway. [2]

Paleontology

Fossils are rare in the Morrissey Formation, but the Mist Mountain Formation includes plant fossils and dinosaur trackways, and the Elk Formation includes plant fossils, trace fossils and bivalves. [2]

Thickness and distribution

The Kootenay Group is present in the front ranges and foothills of the Canadian Rockies in southeastern British Columbia and southwestern Alberta. It extends from the Canada–US border to north of the North Saskatchewan River. It has a maximum thickness of about 1,355 metres (4,450 ft), and it thins eastward. [6]

Relationship to other units

The Kootenay Group conformably overlies the marine shales of the Fernie Formation. In most areas it is disconformably overlain by the nonmarine strata of the Blairmore Group, although in some western areas the contact may be conformable. [6] [7]

North of the North Saskatchewan River the Kootenay Group grades into the Nikanassin Formation. To the south it may correlate with the upper part of the Morrison Formation in Montana. It was originally mis-correlated with the Kootenai Formation which underlies the Morrison. [6]

See also

Related Research Articles

<span class="mw-page-title-main">Nikanassin Formation</span>

The Nikanassin Formation is a stratigraphic unit of Late Jurassic (Portlandian) to Early Cretaceous (Barremian) age. It is present along the western edge of the Western Canada Sedimentary Basin in western Alberta and northeastern British Columbia. 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 for the Nikanassin Range of the front-central ranges of the Canadian Rockies. Mackay did not designate a type locality for the formation, although he described outcrops near the hamlet of Brûlé, north of the Yellowhead Highway outside of Jasper National Park.

<span class="mw-page-title-main">Cadomin Formation</span>

The Cadomin Formation is a stratigraphic unit of Early Cretaceous age in the western part of the Western Canada Sedimentary Basin. It is extends from southeastern British Columbia through western Alberta to northeastern British Columbia, and it contains significant reservoirs of natural gas in some areas. It was named after the mining town of Cadomin, which is an acronym of "Canadian Dominion Mining".

Bullhead Group is a stratigraphic unit of Lower Cretaceous age in the Western Canada Sedimentary Basin of northeastern British Columbia and western Alberta. It was first defined by F.H. McLearn in 1918 as the Bullhead Mountain Formation, but later was upgraded to group status. It consists of the Cadomin and Gething Formations, although some early workers included the Bluesky Formation and others in the group.

<span class="mw-page-title-main">Fernie Formation</span>

The Fernie Formation is a stratigraphic unit of Jurassic age. It is present in the western part of the Western Canada Sedimentary Basin in western Alberta and northeastern British Columbia. It takes its name from the town of Fernie, British Columbia, and was first defined by W.W. Leach in 1914.

The Mist Mountain Formation is a geologic formation of latest Jurassic to earliest Cretaceous age in the Western Canada Sedimentary Basin that is present in the southern and central Canadian Rockies. It was named for outcrops along the western spur of Mist Mountain in Alberta by D.W. Gibson in 1979. The Mist Mountain Formation contains economically important coal seams that have been mined in southeastern British Columbia and southwestern Alberta.

<span class="mw-page-title-main">Edmonton Group</span>

Within the earth science of geology, the Edmonton Group is a Late Cretaceous to early Paleocene stratigraphic unit of the Western Canada Sedimentary Basin in the central Alberta plains. It was first described as the Edmonton Formation by Joseph Burr Tyrrell in 1887 based on outcrops along the North Saskatchewan River in and near the city of Edmonton. E.J.W. Irish later elevated the formation to group status and it was subdivided into four separate formations. In ascending order, they are the Horseshoe Canyon, Whitemud, Battle and Scollard Formations. The Cretaceous-Paleogene boundary occurs within the Scollard Formation, based on dinosaurian and microfloral evidence, as well as the presence of the terminal Cretaceous iridium anomaly.

The Ravenscrag Formation is a stratigraphic unit of early Paleocene age in the Western Canada Sedimentary Basin. It was named for the settlement of Ravenscrag, Saskatchewan, and was first described from outcrops at Ravenscrag Butte near the Frenchman River by N.B. Davis in 1918.

<span class="mw-page-title-main">Morrissey Formation</span>

The Morrissey Formation is a stratigraphic unit of Late Jurassic (Portlandian) age in the Western Canada Sedimentary Basin. It is named for outcrops on Morrissey Ridge, 16 kilometres (10 mi) southeast of Fernie, British Columbia, and is present in southeastern British Columbia and southwestern Alberta.

The Elk Formation is a stratigraphic unit of the Western Canada Sedimentary Basin that is present in southeastern British Columbia and southwestern Alberta. It is probably of Early Cretaceous age, but in some areas its strata could be as old as Late Jurassic. It includes minor thin coal beds and was named for outcrops near the now-abandoned Elk River coal mine east of Fernie, British Columbia.

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 plains in northeastern British Columbia and west-central Alberta. Its strata include natural gas reservoirs and minor coal deposits. Fossil dinosaur tracks have been described from one of its formations.

The Blairmore Group, originally named the Blairmore Formation, is a geologic unit of Early Cretaceous age in the Western Canada Sedimentary Basin that is present in southwestern Alberta and southeastern British Columbia. It is subdivided into four formations: Cadomin Formation, Gladstone, Beaver Mines and Ma Butte, all of which are defined by type sections, most of which contain plant fossils. In some areas the Blairmore contains significant reservoirs of natural gas.

The Beattie Peaks Formation is a geologic formation of Early Cretaceous (Valanginian) age in the Western Canada Sedimentary Basin that consists primarily of marine mudstone. It is present in the northern foothills of the Canadian Rockies and the adjacent plains in northeastern British Columbia.

The Monach Formation is a geologic formation of Early Cretaceous (Valanginian) age in the Western Canada Sedimentary Basin that consists primarily of sandstone. It is present in the northern foothills of the Canadian Rockies and the adjacent plains in northeastern British Columbia.

The Monteith Formation is a geologic formation of Early Cretaceous (Valanginian) age in the Western Canada Sedimentary Basin that consists primarily of sandstone. It is present in the northern foothills of the Canadian Rockies and the adjacent plains in northeastern British Columbia and west-central Alberta.

The Gorman Creek Formation is a geologic formation of Early Cretaceous (Valanginian) age in the Western Canada Sedimentary Basin that consists primarily of nonmarine sediments. It is present in the northern foothills of the Canadian Rockies and the adjacent plains in northeastern British Columbia. Plant fossils and dinosaur tracks have been described from its strata.

The Bickford Formation is a geologic formation of Early Cretaceous (Valanginian) age in the Western Canada Sedimentary Basin that consists primarily of nonmarine sediments. It is present in the northern foothills of the Canadian Rockies in northeastern British Columbia.

The Luscar Group is a geologic unit of Early Cretaceous age in the Western Canada Sedimentary Basin that is present in the foothills of southwestern Alberta. It is subdivided into a series of formations, some of which contain economically significant coal deposits that have been mined near Cadomin and Luscar. Coal mining in those areas began in the early 1900s and continues near Luscar as of 2016.

The Gladstone Formation is a stratigraphic unit of Early Cretaceous (Aptian) age in the Western Canada Sedimentary Basin. It is present in the foothills of southwestern Alberta and is named for outcrops along Gladstone Creek, a tributary of the Castle River south of the Crowsnest Pass.

The Ma Butte Formation is a stratigraphic unit of Early Cretaceous (Albian) age in the Western Canada Sedimentary Basin. It was named for Ma Butte, a mountain north of Coleman, Alberta, by J.R. McLean in 1980. It is present in the foothills of southwestern Alberta and it contains plant fossils.

The Glenogle Formation or Glenogle Shale is a stratigraphic unit of Ordovician age. It is present on the western edge of the Western Canada Sedimentary Basin in southeastern British Columbia. It consists primarily of black shale and was named for Glenogle Creek in the Kicking Horse River area by L.D. Burling in 1923.

References

  1. 1 2 3 Gibson, D. W. 1979. The Morrissey and Mist Mountain formations – newly described lithostratigraphic units of the Jura-Cretaceous Kootenay Group, Alberta and British Columbia. Bulletin of Canadian Petroleum Geology 27: 183–208.
  2. 1 2 3 4 5 6 7 8 9 Gibson, D. W. 1985. Stratigraphy, sedimentology and depositional environments of the coal-bearing Jurassic-Cretaceous Kootenay Group, Alberta and British Columbia. Geological Survey of Canada, Bulletin 357, 108 p.
  3. ↑ Mossop, G. D. and Shetsen, I. (compilers), Canadian Society of Petroleum Geologists and Alberta Geological Survey (1994). "The Geological Atlas of the Western Canada Sedimentary Basin, Chapter 18: Jurassic and Lowermost Cretaceous strata of the Western Canada Sedimentary Basin" . Retrieved 2016-06-20.{{cite web}}: CS1 maint: multiple names: authors list (link)
  4. ↑ Mossop, G. D. and Shetsen, I. (compilers), Canadian Society of Petroleum Geologists (1994). "The Geological Atlas of the Western Canada Sedimentary Basin, Chapter 33: Coal Resources of the Western Canada Sedimentary Basin" . Retrieved 2016-06-20.{{cite web}}: CS1 maint: multiple names: authors list (link)
  5. ↑ Cairnes, D. D., 1908. Moose Mountain district of southern Alberta. Geological Survey of Canada Publication No. 968.
  6. 1 2 3 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.
  7. ↑ Alberta Geological Survey, 2013. "Alberta Table of Formations; Alberta Energy Regulator" . Retrieved 1 May 2018.
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