Survey Peak Formation Explained

Survey Peak Formation
Type:	Formation
Age:	latest Cambrian to earliest Ordovician ~
Prilithology:	Limestone
Otherlithology:	Shale, mudstone, siltstone
Namedfor:	Survey Peak
Namedby:	J.D. Aitken and B.S. Norford^[1]
Region:	Canadian Rockies
Country:	Canada
Coordinates:	51.9546°N -116.8497°W
Underlies:	Outram Formation
Overlies:	Mistaya Formation, Lynx Group
Thickness:	Up to 519 metres (17023 ft)^[2]

The Survey Peak Formation is a stratigraphic unit of latest Cambrian to earliest Ordovician age. It 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 Survey Peak near Mount Erasmus in Banff National Park by J.D. Aitken and B.S. Norford in 1967. The Survey Peak Formation is fossiliferous and includes remains of trilobites and other marine invertebrates, as well as conodonts, stromatolites, and thrombolites.

Lithology and deposition

The Survey Peak Formation formed as a shallow and at times emergent marine shelf along the western shoreline of the North American Craton during latest Cambrian to earliest Ordovician time.^[4] It consists of limestones, calcareous shales and mudstones, and siltstones, and can be subdivided into four informal members: a basal siltstone, overlain in turn by a putty-colored calcareous shale, a limestone and shale unit, and a massive, cliff-forming limestone.

Distribution and stratigraphic relationships

The Survey Peak Formation is present in the Rocky Mountains of Alberta and British Columbia. It thickens westward. It overlies the Mistaya Formation or the top of the Lynx Group, and is overlain by the Outram Formation.^[5] The basal contact is conformable but abrupt. The top contact is gradational.

Paleontology

The Survey Peak Formation is considered to be one of the best exposed and most accessible fossiliferous examples of the Cambrian-Ordovician boundary in Canada. It includes several genera of trilobites, as well as brachiopods, conodonts, gastropods, echinoderms, stromatolites, thrombolites, rare graptolites, and others.

Notes and References

1. Aitken, J.D. and Norford, B.S. 1967. Lower Ordovician Survey Peak and Outram formations, southern Rocky Mountains of Alberta. Bulletin of Canadian Petroleum Geology, vol. 15, p. 150-207.
2. Glass, D.J. (editor) 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba. Canadian Society of Petroleum Geologists, Calgary, 1423 p. on CD-ROM. .
3. Web site: The Geological Atlas of the Western Canada Sedimentary Basin (Mossop, G.D. and Shetsen, I., compilers), Chapter 8: Middle Cambrian and Early Ordovician Strata of the Western Canada Sedimentary Basin. Slind, O.L., Andrews, G.D., Murray, D.L., Norford, B.S., Paterson, D.F., Salas, C.J., and Tawadros, E.E., Canadian Society of Petroleum Geologists and Alberta Geological Survey. 1994. 2018-07-13.
4. Aitken, J.D. 1966. Middle Cambrian to Middle Ordovician cyclic sedimentation, southern Rocky Mountains of Alberta. Bulletin of Canadian Petroleum Geology, vol. 14, no. 6, p. 405-441.
5. Web site: Alberta Geological Survey . Alberta Table of Formations, May 2019 . Alberta Energy Regulator . 24 March 2020.