Morrissey Formation
| Morrissey Formation Stratigraphic range: Late Jurassic (Portlandian) |
|
|---|---|
| Type | Geological formation |
| Unit of | Kootenay Group |
| Sub-units | Moose Mountain Member Weary Ridge Member |
| Underlies | Mist Mountain Formation |
| Overlies | Fernie Formation |
| Thickness | up to 80 metres (260 ft) |
| Lithology | |
| Primary | sandstone |
| Other | siltstone, mudstone, coal |
| Location | |
| Coordinates | 50°30′N 114°59′W / 50.500°N 114.983°W |
| Region |
 British Columbia Alberta
|
| Country |
 Canada
|
| Type section | |
| Named for | Morrissey Ridge |
| Named by | D.W. Gibson |
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 Morrissey Formation is the basal unit of the Kootenay Group. It consists of massive, cliff-forming, fine- to coarse-grained sandstone, with minor beds and lenses of conglomeratic sandstone, and rare beds of siltstone, carbonaceous mudstone, and coal. The sequence coarsens upward and, in most areas, it can be subdivided into two members. The lower portion, called the Weary Ridge Member, consists of orange-brown weathering, slightly argillaceous, calcareous sandstone with rare siltstone and mudstone interbeds. The upper portion, called the Moose Mountain Member, consists of hard, medium grey to brownish grey weathering, siliceous sandstone with rare beds of carbonaceous mudstone and coal. The contact between the two members is abrupt but conformable.
The Morrissey sediments were derived from newly rising mountain ranges to the west and transported eastward by river systems. They were deposited along the edge of the Western Interior Seaway in extensive littoral, deltaic and beach environments. Thin beds of carbonaceous mudstone and coal near the top of the formation may have been deposited in interdune, lacustrine or swale environments.
...
Wikipedia