Unit Name: Contact Rapids Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Middle Devonian (397.5 - 385.3 ma)
Province/Territory: Alberta; Saskatchewan

Originator: Sherwin, D.F., 1962.

Type Locality:
Canadian Seaboard Ernestina Lake 10-13-60-4W4M, in Alberta between 938.2 and 982.7 m (3,076 and 3,222 ft).

The Contact Rapids Formation is 44.5 m (146 ft) thick at the type section and reaches 48.8 m (160 ft) in central Alberta. It is present in east-central and northeastern Alberta and in northwestern Saskatchewan north of the Meadow Lake Escarpment. In the western part of the Elk Point Basin it thickens to include Cold Lake Formation equivalents; near the Peace River Arch it includes thick feldspathic sandstone (Assineau Sandstone of Suska, 1960).

Grey to green, argillaceous dolomite and dolomitic shale, grading to red at the base.

The Contact Rapids overlies the Cold Lake Formation in the type area; in the western part, with the incorporation of Cold Lake equivalents it overlies the Ernestina Lake Formation. It is overlain by the Winnipegosis Formation in eastern Alberta and northwestern Saskatchewan (Keg River Formation in northwestern Alberta). It is laterally equivalent to the Chinchaga Formation of northern Alberta, northeastern British Columbia and southern Northwest Territories; further north and northwest to the Willow Lake and upper part of the Bear Rock formations, and to the Nahanni-Headess-Manetoe-Landry formations respectively. To the southeast, in Saskatchewan it grades into the Ashern Formation. It is probably equivalent to part of the Cedared and Mount Forster formations of southeastern British Columbia.

Other Citations:
Grayston, Sherwin and Allen, in: McCrossan and Glaister (Eds.), 1964; Hamilton, 1971; Norris, 1963; Norris, in: Carrigy and Kramers (Eds.), 1973; Sherwin, 1962; Suska, 1960.

Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: H.R. Balkwill
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 14 May 2004