Yeoman Formation

Unit Name: Yeoman Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Late Ordovician (460.9 - 443.7 ma)
Province/Territory: Saskatchewan

Originator: Saskatchewan Geological Society, Lower Paleozoic Names and Correlations Committee, 1958.

Type Locality:

Shell Yeoman 6-32-8-16W2M well, in Saskatchewan, between 2,450.0 and 2,524.1 m (8,038 and 8,281 ft).

Distribution:

Extends across the Williston Basin to erosional limits near the margins of the basin. Maximum thickness of approximately 180 m (590 ft) is present in North Dakota.

Lithology:

Predominantly light brown to tan, mottled, sparsely fossiliferous biomicrites, partially or wholly dolomitized. In the central portion of the Williston Basin yellowish to brownish grey, burrowed, mottled, fossiliferous and bioclastic dolomitized mudstones and wackestones are present in the upper portion of the formation.

Relationship:

Unconformably overlies the Deadwood Formation in the western portion of the Williston Basin. Elsewhere it overlies the Winnipeg Formation with apparent disconformity. It is conformably overlain by the Herald Formation. The Yeoman Formation correlates with the lower portion of the Red River Formation (Dog Head, Cat Head and Selkirk members).

History:

Originally defined by the Saskatchewan Geological Society as the Yeoman Beds, a marker-defined unit equivalent to the Lower Red River of Porter and Fuller (1958), with a type section between 2440.8 and 2524.1 m (8008 and 8281 ft) in the Shell Yeoman 6-32 well. Kent (1960) recognized the Yeoman as a stratigraphic member of the Red River Formation and re-defined the top of the unit to coincide with the base of an overlying sequence of argillaceous carbonates; in the Yeoman well the top of the type section was changed to 2450 m (8038 ft). Kendall (1976) raised the unit to formation status.

References:

Kendall, A.C., 1976. The Ordovician carbonate succession (Bighorn Group) ot southern Saskatchewan. Saskatchewan Dept. Min. Res., Rept. 180.

Kent, D.M., 1960. The evaporites of the Upper Ordovician strata in the northern part of the Williston Basin, Saskatchewan Department of Mineral Resources (SDMR), Saskatchewan Industry and Resources (SIR) Report no. 46, 45 p., 2 tables, 5 plates, 7 figures. 3 cross sections, 1 panel diagram, in pocket.

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.

Porter, J.W. and Fuller, J G.C.M., 1959. Lower Paleozoic rocks of northern Williston Basin and adjacent areas. Amer. Assoc. Petrol. Geol. Bull., v. 43, p. 124-189.

Porter, J.W. and Fuller, J.G.C.M., 1958. Succession of lower Paleozoic rocks in the northern part of the Williston Easin. In: 2nd International Williston Basin Symposium. North Dakota. Geol. Soc., p. 33-39.

Saskatchewan Geological Society, 1958. Report of the Lower Paleozoic Names and Correlation Committee, Regina.

Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: F.M. Haidl
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 29 Jan 2009