Unit Name: Torquay Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Famennian (372.2 - 358.9 ma)
Province/Territory: Manitoba; Saskatchewan

Originator: Christopher, J.E., 1961, p. 18.

Type Locality:
Compagnie Francaise des Petroles Torquay No. 1 well, in 8-32-3-11W2M, Saskatchewan, between 2,015.3 and 2,067.2 m (6,612 and 6,782 ft).

The thickness is consistently 45 to 50 m (148 to 164 ft), except in southwestern Saskatchewan, where it reaches a maximum of 65 m (213 ft), and in southeastern Saskatchewan, where it is locally reduced to 20 m (66 ft). The Torquay is present throughout much of the Williston Basin. Its northern limit is the west-northwest trending post Mississippian erosional edge in central Saskatchewan (south of Saskatoon).

Locality Data:
WELL 101083200311W200; FRENCH PETROLEUM TORQUAY NO 1. Thickness(m): Minimum 20, Maximum 65, Typical 50. Interval(m): From 2015.3, To 2067.2.

Dolomite and shale, with lesser amounts of anhydrite. Some brecciated fragments of dolomite occur scattered in the mudstone. Color ranges from greys and greens to reds and browns, depending on the degree of oxidation of the sediments. Weathered anhydrite is white. The formation is divided into 6 units.

The relationship to the underlying carbonates of the Birdbear Formation is probably unconformable in western Saskatchewan but conformable farther east (Kent, 1968a). The Torquay is conformably overlain by mudstones of the Big Valley Formation, or unconformably of black shales of the Bakken Formation. The Torquay is the lowest formation of the Three Forks Group. It is equivalent to the Stettler Member of Kents (1959) and the Potlatch Evaporite (restricted) of Wilson (1955). Equivalent strata in Alberta comprise the Crowfoot Formation.

This unit was formally called the Lyleton Formation (McCabe, 1967, 1971), and then informally called the Three Forks Formation by Martiniuk (1988) and LeFever et al. (1991a, b). The extensive work on this formation done by Nicolas (2012) recommends the nomenclature of Torquay Formation for this unit, which is the same nomenclature as that used by Saskatchewan.

Other Citations:
Christopher, 1961; Kent, 1968a; Kents, 1959; Wilson, 1955; McCabe, 1967; McCabe, 1971; Martiniuk, 1988; LeFever et al., 1991a; LeFever et al., 1991b; Nicolas, 2012;

Christopher, J.E., 1961. Transitional Devonian-Mississippian formations of southern Saskatchewan. Saskatchewan Dept. Min. Res. Rept. 66.
Kent, D.M., 1968a. The geology of the Upper Devonian Saskatchewan Group and equivalent rocks in western Saskatchewan and adjacent areas; Saskatchewan Department of Mineral Resources, Saskatchewan Industry and Resources (SIR) Report No. 99, 221 p., 8 tables, 21 plates, 3 figures. 9 maps, 2 panel diagrams, 14 cross sections, in pocket.
Kents, P., 1959. Three Forks and Bakken stratigraphy in west central Saskatchewan, Report - Department of Mineral Resources (Regina)(SDMR), vol. 37, 39 pp.
LeFever, J. A., Martiniuk, C. D. and Anderson, S. B. 1991b: Correlation cross-sections along the United States - Canada international border (North Dakota - Manitoba); Manitoba Energy and Mines and the Industrial Commission of North Dakota, Petroleum Open-File Report POF 12-91, 5 p.
LeFever, J. A., Martiniuk, C. D., Danscok, E. F. R. and Mahnic, P. A. 1991a: Petroleum Potential of the Middle Member, Bakken Formation, Williston Basin, in Christopher, J. E. and Haidl, F., eds., Williston Basin Sixth International Symposium, Special Publication Number 11: Regina, Saskatchewan, p. 74-94.
Martiniuk, C. D. 1988: Regional geology and petroleum potential of the Bakken Formation, southwestern Manitoba; Manitoba Energy and Mines, Petroleum Open File Report POF 8-88, 34 p.
McCabe, H. R. 1956: Lyleton and Amaranth Red Beds in southwestern Manitoba; University of Manitoba, Winnipeg, 133 p.
McCabe, H.R., 1971. "Stratigraphy of Manitoba, an introduction and review", in, Geoscience studies in Manitoba; Turnock, A.C. (Ed ). Geol. Assoc. Can, Spec. Paper 9, p. 167-187.
Nicolas, M. P. B. 2012: Stratigraphy and regional geology of the Late Devonian- Early Mississippian Three Forks Group, southwestern Manitoba (NTS 62F, part of 62G, K); Manitoba Innovation, Energy and Mines, Manitoba Geological Survey, Geoscientific Report GR2012-3, 92 p.
Wilson, J.L., 1955. Devonian correlations in northwestem Montana. 6th Ann. Field Conf., Billings Geol. Soc. Guidebook, p. 70-77.

Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: C.E. Dunn; K.R. Milner; Michelle Nicolas
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 13 Oct 2015