Type Formation Primary Slate | ||
Thickness Up to 140 metres (460 ft) | ||
The Perdrix Formation a geologic formation of Late Devonian (Frasnian) age in the Western Canada Sedimentary Basin. It named for Roche à Perdrix in Jasper National Park, Alberta, by P.E. Raymond in 1930. It was deposited in a marine basin and preserves marine fossils dating back to the Late Devonian period.
Contents
Lithology
The Perdrix Formation consists of black, bituminous shales. The upper portion includes nodules and thin nodular beds of argillaceous limestone that increase in frequency upwards and laterally toward the reefs of the Cairn Formation.
Thickness and Distribution
The Perdrix Formation is present as outcrops in the front and main ranges of the Canadian Rockies from Kakwa Lake in northeastern British Columbia to the Ram River area of Alberta. It is also recognized in the subsurface immediately adjacent to the mountain front. Thicknesses range from about 80 metres (260 ft) to 140 metres (460 ft).
Relationship to Other Units
The Perdrix Formation overlies the Maligne Formation or, where the Maligne is absent, the Flume Formation. It is conformably overlain by the Mount Hawk Formation and the contact is gradational. Laterally it interfingers with the Peechee Formation and the reefs of the Cairn Formation.
Paleontology
Tentaculids are ubiquitous in the Perdrix Formation, and brachiopods and pelecypods are present in the more limestone-rich portions.