Unit Name: Naiset Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Middle Cambrian (513 - 499 ma)
Province/Territory: Alberta; British Columbia
Originator: Deiss, 1940a
Type Locality:
Naiset Point, at 50 deg 53'45"N, 115 deg 39'W, near Mount Assiniboine, British Columbia.
Distribution:
145 m (476 ft) thick at the type section; 212 m (695 ft) thick at nearby Wedgewood Peak. Rapid northeastward pinch-out is evident. Naiset equivalents at Mount Stephen are 108 m (354 ft). The known exposures are few; all lie west of the Kicking Horse Rim (Aitken, 1971).
Locality Data:
Thickness(m): Typical 145.
Lithology:
Mainly laminated, thin-bedded shale and siltstone, with gravity slides and penecontemporaneous folds. Lenses of sandstone, conglomerate and, locally lime mudstone occur at the base. Minor beds of oolitic and oncoidal limestone are present near the top.
Relationship:
The Naiset lies unconformably on Gog Group beds and is overlain by the Cathedral Formation at a gradational, interbedded contact. The northeastward pinch-out is partly by onlap onto the unconformity and partly by facies change to limestones of the Cathedral Formation. The Naiset dips westward and disappears from view within a few kilometres of the type locality. Equivalent strata to the east of the Kicking Horse Rim are assigned to the Mount Whyte Formation.
References:
Deiss, C. F., 1939a. Cambrian formations of southwestern Alberta and southeastern British Columbia; The Geological Society of America (GSA), GSA Bulletin, vol. 50, no. 6 (June), pp. 951-1019.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: L.V. Hills; J.D. Aitken
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 28 Mar 2014