Unit Name: Sulphur Mountain Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Early Triassic (251 - 245 ma)
Province/Territory: Alberta; British Columbia

Originator: Mountjoy, 1960; emended by Gibson, 1968.

Type Locality:
Designated by Warren (1945) in the Spray River Gorge, at the south end of Sulphur Mountain, Banff National Park, Alberta. The section (described by Gibson, 1968) begins in the first intermittent stream gully downstream from the junction of Goat Creek and Spray Rivers and terminates at the south end of the Spray River Gorge. NTS 82O/4, Banff.

The Sulphur Mountain Formation occurs throughout the Rocky Mountain Foothills and eastern front ranges between the United States border and the Pine River of northeastern British Columbia. The recorded thickness ranges from 87 m (285 ft) near Picklejar Lakes south of Bow River, Alberta to 557 m (1,827 ft) on West Burnt River, south of Pine River, northeastern British Columbia (Gibson, 1968, 1974).

Locality Data:
Thickness(m): Minimum 87, Maximum 557.

Dark grey to rusty brown weathering siltstone, silty dolostone and silty, carbonaceous shale divisible into four members which, in ascending order are the Phroso Siltstone, Vega Siltstone (including Mackenzie Dolomite lentil), Whistler and Llama (Gibson, 1968).

The unit is conformably overlain by pale grey to yellow to buff weathering sandstone, dolostone and intraformational and/or solution breccia of the Whitehorse Formation or laterally equivalent Charlie Lake Formation; it disconformably overlies sandstone, chert and cherty dolostone of the Permian Ishbel Group or Fantasque Formation, or the Mississippian Rundle Group. In some eastern exposures it is disconformably overlain by the Jurassic Fernie Formation. The Sulphur Mountain Formation is laterally equivalent to the Grayling, Toad and Liard formations of the Sikanni Chief, Peace and Pine River areas of the northeastern British Columbia Foothills; the Montney, Doig, and Halfway formations of the subsurface Peace River Plains of Alberta and British Columbia (Gibson, 1975).

Originally named by Warren (1945) as the Sulphur Mountain Member of the Spray River Formation, and subsequently raised to formation status by Mountjoy (1960) and Manko (1960) in the Jasper and Rock Lake areas of Alberta. The type section was amended to include additional younger strata by Gibson (1968).

Other Citations:
Gibson, 1968, 1974, 1975; Manko, 1960; Mountjoy, 1960; Warren, 1945.

Gibson, D.W., 1968. Triassic stratigraphy between the Athabasca and Smoky Rivers of Alberta; Geological Survey of Canada, Paper 67-65.
Gibson, D.W., 1974, Triassic Rocks of the Southern Canadian Rocky Mountains, Geological Survey of Canada, Bulletin 230.
Gibson, D.W., 1975. Triassic rocks of the Rocky Mountain Foothills and Front ranges of northeastern British Columbia and west-central Alberta; Geological Survey of Canada, Bulletin 247, 42 p.
Manko, E.M., 1960. The Triassic of the Rock Lake area. In: Rock Lake Ellion, R.H.J. (Ed.). Edmonton Geol. Soc., 2nd Ann. Field Trip Guidebook, p. 24-42.
Mountjoy, E.W., 1960. Structure and stratigraphy of the Miette and adjacent areas, eastern Jasper National Park, Alberta; University of Toronto, Unpublished Ph.D. thesis, 249 p. + 23 plates in map folder.
Warren, P.S., 1945. Triassic faunas in the Canadian Rockies. Am. J. Sci, v. 243.

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: 24 Mar 2009