Purcell Supergroup
The Purcell Supergroup is composed primarily of argillites, carbonate rocks, quartzites, and mafic igneous rocks of late Precambrian (Mesoproterozoic) age. It is present in an area of about 15,000 km2 (5,800 sq. mi.) in southwestern Alberta and southeastern British Columbia, Canada, and it extends into the northwestern United States where it is called the Belt Supergroup. It was named for the Purcell Mountains of British Columbia by R.A. Daly in 1912. Fossil stromatolites and algal structures are common in some of the Purcell Supergroup rocks, and the Sullivan ore body at Kimberley, British Columbia, a world-class deposit of lead, zinc, and silver, lies within the Alderidge Formation in the lower part of the Purcell.
| Purcell Supergroup | |
|---|---|
| Stratigraphic range: | |
| Type | Geological supergroup |
| Sub-units | Many |
| Underlies | Windermere Supergroup |
| Overlies | Canadian Shield |
| Area | 15,000 km2 (5,800 sq. mi.) |
| Thickness | more than 10,000 m (3,200 ft) |
| Lithology | |
| Primary | Argillite, dolomite, quartzite |
| Other | Limestone, igneous rocks |
| Location | |
| Region | Alberta British Columbia |
| Country | Canada |
| Type section | |
| Named for | Purcell Mountains |
| Named by | R.A. Daly, 1912. |
Spectacular outcrops of Purcell and Belt Supergroup rocks can be seen in Glacier National Park in northwestern Montana and Waterton Lakes National Park in southwestern Alberta.