Unit Name: Chinchaga Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Eifelian - Givetian (397.5 - 385.3 ma)
Province/Territory: Alberta; British Columbia; Northwest Territories

Originator: Law, J., 1955a.

Type Locality:
The type section is in the California Standard 2-22-117-5W6M well, in northwestern Alberta, between 1,670 and 1,732 m (5,475 and 5,680 ft).

From zero at the margins of the Peace River and Tathlina uplifts to 76 m (250 ft). Extends from the Fort Nelson area of northeastern British Columbia across northern Alberta between the Peace River and Tathlina uplifts; extends into southern District of Mackenzie on to the southwest, northeast and north flanks of the Tathlina Uplift. Thickens westward to the north of the Tathlina Uplift.

The type section consists of anhydrite and cryptocrystalline dolomite underlain by quartz sandstone with argillaceous and anhydritic cement; anhydrite and anhydritic dolomite, greenish grey dolomitic shale containing quartz sand grains at base. The formation grades eastward to anhydrite with minor amounts of salt and interbedded cryptocrystalline dolomite overlying basal sandstone and shale. It includes a higher proportion of sand and shale in the vicinity of the Tathlina and Peace River uplifts. No fossils have been found in the unit.

The Chinchaga is the lower half of Crickmay's Member 3. It overlies Precambrian and basal, detrital red beds on the flanks of the Peace River and Tathlina uplifts; rests on the Cold Lake Formation in northern Alberta, and, where present in southern District of Mackenzie, on the flanks of the Tathlina Uplift. It grades laterally into the Contact Rapids Formation of Saskatchewan and is equivalent to part of the Ashern Formation of that province, and to the Landry-Manetoe Formation, the overlying Headless, and part of the Nahanni formations of southern District of Mackenzie. Elsewhere it rests on basal Devonian red beds. It is overlain in the northern Alberta subsurface by the Keg River Formation; in the northeastern Alberta outcrop area by the Little Buffalo Formation; and in the adjacent Great Slave Lake area by the Lonely Bay and Pine Point formations.

Other Citations:
Belyea and Norris, 1962; Douglas, 1968; Govett, 1961; Law, 1955; Norris, 1963, 1965; Sherwin, 1962.

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; D.W. Morrow
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 11 May 2004