Unit Name: Strathallen Beds
Unit Type: Lithostratigraphic
Usage: Currently in use
Age Interval: Kinderhookian - Osagian (359.2 - 340 ma)
Age Justification: Kent (1974) identified a limited coral-brachiopod fauna in the Strathallen Beds, much of which came from the rocks of the upper part of the unit. The fauna was thought to be of Kinderhookian and lower Osagean age.
Originator: Kent, D.M., 1974.
Named after the post office of Strathallen, 9.7 km (6 mi) southeast of the standard reference well for southwestern Saskatchewan, Sohio et al. Wood Mountain 9-18-3-3W3M. The unit occupies the interval between 1,777.3 and 2,017.8 m (5,831 and 6,620 ft) in that well.
A depositional thickness of the Strathallen Beds can be determined only where they are overlain by the Killdeer Beds. In that area the maximum thickness is about 261 m (856 ft); beyond the subcrop of the Killdeer the unit varies from 104 to 229 m (341 to 751 ft). The Strathallen Beds underlie all of southwestern Saskatchewan from 106 deg W to 110 deg W.
WELL 111091800303W300; SOHIO ET AL WOOD MOUNTAIN 9 18 3 3. Thickness(m): Maximum 261. Interval(m): From 1777.3, To 2017.8.
The lithology of the Strathallen Beds varies considerably. The lower portion is dominated by bituminous or argillaceous, laminated lime mudstones that can be recognized as far north as the Swift Current area. Beyond that area rocks at the same stratigraphic level are much less bituminous or argillaceous, but continue to be mainly lime mudstones. The upper portion includes nonargillaceous lime mudstones, wackestones and thick accumulations of crinoidal grainstones that Kent (1974) considered to represent crinoidal banks.
The Strathallen beds are separated from the overlying Killdeer by a 3 to 9 m (10 to 30 ft) thick interval of skeletal grainstone or lime mudstone with numerous partings of reddish brown or greyish red shale. The shaly nature of the interval gives a high natural radioactive response on the gamma ray log, which can be used to correlate the unit throughout its uneroded extent in southeastern Saskatchewan. This marker lies about 21 m (69 ft) above a second argillaceous interval that is less continuous in southwestern Saskatchewan, but can be correlated farther east with the marker bed at the top of the Midale. The Strathallen Beds rest unconformably on the Bakken Formation, and there is a clear indication of progressively deeper truncation of that formation toward the west. Kent (1974) considered the Strathallen Beds to be equivalent to most of the Mississippian sequence beneath the Ratcliffe Beds of southeastern Saskatchewan. The unit is correlative with the Lodgepole Formation and the lower Mission Canyon of Montana.
Kent, D.M., 1974. A stratigraphic and sedinnentological analysis of the Mississippian Madison Formation in southwestern Saskatchewan. Saskatchewan Dept. Min. Res., Rept. 141.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: D.M. Kent
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 27 Mar 2009