Unit Name: Swan River Formation
Unit Type: Lithostratigraphic
Usage: Currently in use
Age Interval: Albian (112 - 99.6 ma)
Province/Territory: Manitoba; Saskatchewan
Originator: Wickenden, R.T.D., 1945.
Exposures along the Swan River, east of Swan River, Manitoba, between Secs. 3 and 6, Twp. 37, Rge. 26WPM.
The name Swan River has been applied only in the vicinity of the Manitoba escarpment and in the neighbouring subsurface of eastern Saskatchewan and southern Manitoba. Its thickness is highly variable, ranging from near zero around the Virden area of Manitoba (Bannatyne, 1970), to a maximum of about 150 m (492 ft) in some areas west of the Manitoba escarpment. Due to incomplete exposure its thickness along the escarpment is not precisely known.
Thickness(m): Minimum 0, Maximum 150.
Mainly a fine grained sand or sandstone, with silts and light to dark grey clays. In the type locality the lowest exposures are of kaolinitic clays and silts associated with minor amounts of fine grained sand, pyrite nodules and carbonized plant fragments. The upper type beds consist of fine, clean sands with interbedded dark clay and are distinguished by flaser bedding and a variety of biogenic sedimentary structures. The uppermost sands are richly glauconitic (up to 25 per cent).
The lower contact is not exposed, but in the subsurface the Swan River oversteps in succession, from the southwest to the northeast rocks of Jurassic, Devonian, Silurian and Ordovician age. At the type locality the upper contact with dark shale of the Ashville Formation is sharp and locally scoured. In eastern Saskatchewan the Swan River-Ashville contact maintains a fairly constant stratigraphic position, but towards the escarpment in southeastern Manitoba the contact rises markedly. The formation correlates westwards with the Cantuar and Pense formations of the Mannville Group in Saskatchewan, with the Mannville Group of southern and central Alberta, and with a part of the Blairmore Group of the Alberta Foothills. Southward it correlates with the Lakota Sandstone, Fuson Shale and Fall River Sandstone in North Dakota.
The rank of the Swan River has been changed from group to formation by McNeil and Caldwell (1981).
Bannatyne, 1970; Hansen, 1955; McLearn and Wickenden, 1936; McNeil and Caldwell, 1983; Price, 1963; Wickenden, 1945.
McNeil, D.H. and Caldwell, W.G.E., 1981. Cretaceous rocks and their Foraminifera in the Manitoba escarpment. Geol. Assoc. Can., Spec. Paper 21
Wickenden, R.T.D., 1945. Mesozoic stratigraphy of the eastern plains, Manitoba and Saskatchewan; Geological Survey of Canada, Memoir 239, 87 p.
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.L. Price; D.H. McNeil
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 24 Mar 2009