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Kotcho Formation

Coordinates: 60°09′18″N 121°18′16″W / 60.15500°N 121.30444°W / 60.15500; -121.30444 (Kotcho Formation)
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Kotcho Formation
Stratigraphic range: Middle Famennian
TypeGeological formation
UnderliesExshaw Formation
OverliesTetcho Formation
Thicknessup to 210.9 metres (690 ft)[1]
Lithology
PrimaryShale
OtherLimestone
Location
Coordinates60°09′18″N 121°18′16″W / 60.15500°N 121.30444°W / 60.15500; -121.30444 (Kotcho Formation)
Region British Columbia
 Northwest Territories
Country Canada
Type section
Named forKotcho Lake
Named byH.R. Belyea, D.J. McLaren, 1962

The Kotcho Formation is a stratigraphical unit of middle Famennian age in the Western Canadian Sedimentary Basin.

It takes the name from Kotcho Lake and was first described in the Imperial Island River No. 1 by H.R. Belyea and D.J. McLaren in 1962.[2]

Lithology

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The Kotcho Formation is composed of green-grey shale, locally bituminous, with thin argillaceous limestone beds or lenses.[1]

Distribution

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The Kotcho Formation reaches a maximum thickness of 210.9 metres (690 ft).[1]It is up to 30 metres (100 ft) thick in the Fort Nelson area, and thins down southwards, disappearing completely on the northern flank of the Peace River Arch.

Relationship to other units

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The Kotcho Formation is overlain by the Exshaw Formation and conformably overlays the Tetcho Formation.[1]

To the east, it grades into the upper Wabamun Group carbonate, and to the south-west into the Palliser Formation. To the east it is replaced by the Besa River Formation shale.

References

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  1. ^ a b c d Lexicon of Canadian Geologic Units. "Kotcho Formation". Retrieved 2009-03-01.
  2. ^ Belyea, H.R. and McLaren, D.J., 1962. Upper Devonian formations, southern pan of Northwest Territories, northeastern British Columbia and northwestern Alberta. Geological Survey of Canada, Paper 61-29.