Naiset Formation
The Naiset Formation is a stratigraphic unit of Middle Cambrian age. It is present on the western edge of the Western Canada Sedimentary Basin in the southern Rocky Mountains of British Columbia. It consists primarily of siliciclastic rocks, and was named for Naiset Point near Mount Assiniboine by C.E. Deiss in 1940.[1][2]
| Naiset Formation Stratigraphic range: Middle Cambrian ~509–500 Ma | |
|---|---|
| Type | Formation |
| Underlies | Cathedral Formation |
| Overlies | Gog Group |
| Thickness | Up to about 212 m (695 feet)[1] |
| Lithology | |
| Primary | Shale, siltstone |
| Other | Sandstone, conglomerate, limestone |
| Location | |
| Coordinates | 50°53′45″N 115°39′00″W |
| Region |  |
| Country | .svg.png.webp){kind=small} |
| Type section | |
| Named for | Naiset Point |
| Named by | C.E. Deiss, 1940[2] |
Thickness and lithology
The Naiset Formation ranges in thickness from about 100 to 212 m (328 to 695 ft), and was deposited in a deep-water marine environment. It consists primarily of thin-bedded shale and siltstone. There are minor beds of sandstone, conglomerate, and calcareous mudstone at the base, and minor beds of oolitic and oncolitic limestone near the top.[1]
Distribution and relationship to other units
The Naiset Formation is present in Rocky Mountains of southeastern British Columbia. It unconformably overlies the Gog Group. It is overlain by the Cathedral Formation, and the contact is gradational. Equivalent strata to the east of the Kicking Horse area are assigned to the Mount Whyte Formation.[1][3]
References
- Glass, D.J. (editor) 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba, p. 849. Canadian Society of Petroleum Geologists, Calgary, 1423 p. on CD-ROM. ISBN 0-920230-23-7.
- Deiss, C.E. 1940. Lower and Middle Cambrian stratigraphy of southwestern Alberta and southeastern British Columbia. Geological Society of America Bulletin, vol. 51, p. 731-794.
- Aitken, J.D. 1997. Stratigraphy of the Middle Cambrian platformal succession, southern Rocky Mountains. Geological Survey of Canada, Bulletin 398, 322 p.