Ma Butte Formation
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| Ma Butte Formation | |
|---|---|
| Stratigraphic range: | |
| Type | Geological formation |
| Unit of | Blairmore Group |
| Underlies | Crowsnest Formation |
| Overlies | Beaver Mines Formation |
| Thickness | up to 132 metres (430 ft) |
| Lithology | |
| Primary | Sandstone, siltstone, mudstone |
| Other | Conglomerate, bentonite, tuff |
| Location | |
| Region | Alberta |
| Country | Canada |
| Type section | |
| Named for | Ma Butte |
| Named by | J.R. McLean |
| Year defined | 1980[1] |
The Ma Butte Formation is a stratigraphic unit of Early Cretaceous (Albian) age in the Western Canada Sedimentary Basin.[2] It was named for Ma Butte, a mountain north of Coleman, Alberta, by J.R. McLean in 1980.[1] It is present in the foothills of southwestern Alberta and it contains plant fossils.[1][3]
The Ma Butte Formation is a unit of the Blairmore Group. It consists primarily of fine-grained sandstones interbedded with siltstones and mudstones. Some coarser grained sandstones and conglomerate beds are also present. Beds of bentonite and tuff increase upward toward the contact with the overlying Crowsnest Formation. The sandstones of the Ma Butte Formation are quartzose, in contrast with the feldspathic sandstones of the underlying Beaver Mines Formation.[1][3]
Distribution and thickness
The Ma Butte Formation is present in the southern foothills of Alberta as far north as the Red Deer River. It has a maximum reported thickness of 132 metres (430 ft) near the Bow River.[3]