Unit Name: Morrissey Formation
Unit Type: Lithostratigraphic
Usage: Currently in use
Age Interval: Portlandian (146 - 142 ma)
Province/Territory: Alberta; British Columbia
Originator: Gibson, D.W., 1979.
On the west side, near the south end of Morrissey Ridge, 8 km (5 mi) north of Morrissey Creek, 16 km 110 mill southeast of Fernie, British Columbia. NTS Maps 82G/6 Elko and 82G/7 upper Flathead Valley.
The Morrissey Formation is recognized throughout the Rocky Mountain Foothills and parts of the eastern front ranges of southwestern Alberta and south-eastern British Columbia between the United States border and North Saskatchewan River. The formation ranges in measured thickness from a minimum of 20 m (66 ft) near Moose Mountain, Alberta to a maximum of 80 m (262 ft) near Mist Mountain and Highwood Pass (Gibson, 1979, 1985).
A coarsening-upward sequence of medium dark to brownish grey to orange-brown weathering, very fine- to coarse-grained sandstone with rare carbonaceous mudstone and coal; subdivided into two members, the lower less well-indurated, orange-brown to brownish grey slightly argillaceous-carbonaceous lithofacies called the Weary Ridge Member, and an upper, generally darker grey weathering, better indurated, more siliceous sandstone lithofacies called the Moose Mountain Member.
The unit conformably overlies Upper Jurassic strata of the Fernie Formation, and is conformably overlain by coal bearing strata of the Mist Mountain Formation. Northward, beyond the North Saskatchewan River the Morrissey Formation grades laterally into an alternating succession of siltstone, sandstone, mudstone and shale of the lower Nikanassin Formation (Gibson, 1979). The Morrissey Formation is lithologically similar to and occurs at a similar stratigraphic level as the "Brown sand" in the subsurface of the Alberta Foothills near Turner Valley. It is uncertain whether the "Brown sand" is equivalent to all of the Morrissey or to only the Moose Mountain or Weary Ridge Member. The "Brown sand'' of the subsurface has been arbitrarily assigned to and informally considered part of the Fernie Formation (Spivak, 1954). Gibson (1979, 1985) recently suggested that the "Brown sand" be considered part of the Morrissey Formation and the Kootenay Group. Correlation of the Morrissey with strata south of the Canada-United States border in Montana is uncertain (Gibson, 1985).
Long recognized massive, cliff forming sandstone designated the base of the Kootenay Group (McEvoy, 1902; Cairnes, 1914; Rose, 1917).
Cairns, 1914; Gibson, 1977, 1979, 1985; McEvoy, 1902; Rose, 1917; Spivak, 1954.
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.W. Gibson
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 19 Dec 2008