Outram Formation

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]

Outram Formation
Stratigraphic range: Early Ordovician ~
TypeFormation
UnderliesSkoki Formation
OverliesSurvey Peak Formation
ThicknessUp to 443 metres (1453 ft)[1]
Lithology
PrimaryLimestone, siltstone
OtherShale, chert
Location
Coordinates51°52′54″N 116°52′31″W
RegionCanadian Rockies
Country Canada
Type section
Named forMount Outram
Named byJ.D. Aitken and B.S. Norford[2]

Lithology and deposition

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]

Distribution and stratigraphic relationships

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]

Paleontology

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]

References

  1. 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. ISBN 0-920230-23-7.
  2. 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.
  3. 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). "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". Archived from the original on 2016-07-01. Retrieved 2018-07-13.{{cite web}}: CS1 maint: multiple names: authors list (link)
  4. Alberta Geological Survey. "Alberta Table of Formations, May 2019" (PDF). Alberta Energy Regulator. Retrieved 24 March 2020.
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