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| Outram Formation Stratigraphic range: Early Ordovician ~485–470 Ma | |
|---|---|
| Type | Formation |
| Underlies | Skoki Formation |
| Overlies | Survey Peak Formation |
| Thickness | Up to 443 metres (1453 ft)[1] |
| Lithology | |
| Primary | Limestone, siltstone |
| Other | Shale, chert |
| Location | |
| Coordinates | [ ⚑ ] : 51°52′54″N 116°52′31″W / 51.88167°N 116.87528°W |
| Region | Canadian Rockies |
| Country | |
| Type section | |
| Named for | Mount Outram |
| Named by | J.D. Aitken and B.S. Norford[2] |
The Outram Formation is a stratigraphic unit of Early Ordovician age that is present on the western edge of the Western Canada Sedimentary Basin in the Canadian Rockies of Alberta and British Columbia.[3] It was named for Mount Outram in Banff National Park by J.D. Aitken and B.S. Norford in 1967.[2] The Outram Formation is fossiliferous and includes remains of trilobites and other marine invertebrates, as well as stromatolites and thrombolites.[1][2]
The Outram Formation formed as a shallow and at times emergent marine shelf along the western shoreline of the North American Craton during Early Ordovician time.[2][3] It consists primarily of nodular limestone, calcareous quartzose siltstone, limestone pebble-conglomerate, and brown shale. Nodules of grey chert occur throughout the formation.[1][2]
The Outram is present in the Rocky Mountains of Alberta and British Columbia. Its thickness and shale content increase toward the west.[1][2] It overlies the Survey Peak Formation and underlies the Skoki Formation.[4] Both contacts are gradational.[1][2]
The Outram Formation contains several genera of trilobites, as well as brachiopods, conodonts, gastropods, sponges, echinoderms, bivalves, gastropods, stromatolites, thrombolites, oncolites, rare graptolites, and others.[1][2]