Kotcho Formation
| Kotcho Formation | |
|---|---|
| Stratigraphic range: | |
| Type | Geological formation |
| Underlies | Exshaw Formation |
| Overlies | Tetcho Formation |
| Thickness | up to 210.9 metres (690 ft)[1] |
| Lithology | |
| Primary | Shale |
| Other | Limestone |
| Location | |
| Coordinates | 60°09′18″N 121°18′16″W / 60.15500°N 121.30444°W |
| Region |  British Columbia Northwest Territories |
| Country |  Canada |
| Type section | |
| Named for | Kotcho Lake |
| Named by | H.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[edit]
The Kotcho Formation is composed of green-grey shale, locally bituminous, with thin argillaceous limestone beds or lenses.[1]
Distribution[edit]
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[edit]
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[edit]
- ^ a b c d Lexicon of Canadian Geologic Units. "Kotcho Formation". Retrieved 2009-03-01.
- ^ 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.