Unit Name: Frobisher-Alida Beds
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Osagian (348 - 340 ma)
Age Justification: Brindle (1960) found the Frobisher-Alida Beds to contain an extremely rich coral-brachiopod-mollusca fauna containing some 59 species and 37 genera. He identified the assemblage as being lower to middle Osagean.
Province/Territory: Manitoba; Saskatchewan; North Dakota

Originator: Saskatchewan Geological Society, 1956.

Type Locality:
These beds were named from the Frobisher (incorporated in Steelman field) and Alida oil fields, Saskatchewan, where the first discovery of oil in the upper (April, 1954) and lower (November, 1954) parts, respectively of this sequence were made. Fuzesy (1960) recommended that the standard reference section for this unit be the interval between 1,268.6 and 1,382.9 m (4,162 and 4,537 ft) in the Imperial Workman 3-8-1-32W1M well.

Distribution:
A complete section occurs in the Imperial Workman No. 3-8 well, in Lsd. 3, Sec. 8, Twp. 1, Rge. 32W1M between 1,269 and 1,383 m (4,162 and 4,537 ft). The unit varies from 65.5 to 123 m (215 to 403 ft) in thickness, and is recognized in southeastern Saskatchewan, extreme southwestern Manitoba and north-central and central North Dakota.

Lithology:
The beds consist of fossiliferous-fragmental to algal, oolitic and pisolitic limestones. Patchily distributed lenticular sandstones occur in the middle of the unit and there are at least three evaporitic intervals, Gainsborough, Winlaw and Hastings. The former is in the upper portion of the Alida Beds and the latter two respectively near the base and top of the Frobisher Beds.

Relationship:
The top of the Frobisher-Alida beds was established at the top of the argillaceous dolomitic limestone immediately subjacent to the Midale beds, and the base is at the top of the MC-2 marker bed in the Tilston. Brindle (1960) interpreted the base of the Charles to occur within the Frobisher-Alida at approximately the level of the Gainsborough Evaporite. He correlated the Frobisher-Alida with the Pekisko Formation of Alberta. These beds correlate as well with a series of beds that lie beneath the State "A" marker in North Dakota; included in this sequence are the Landa, Wayne, Glenburn, Mohall, Sherwood and Bluell Beds (Harris et al., 1966).

Other Citations:
Brindle, 1960; Harris, et al., 1966; Saskatchewan Geological Society, 1956.

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.M. Kent
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 18 May 2004