The Perdrix Formation is a geologic formation of

Late Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding ...

( Frasnian) age in the Western Canada Sedimentary Basin. It named for Roche à Perdrix in Jasper National Park,

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

, by P.E. Raymond in 1930. It includes

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

of marine animals.

Lithology

The Perdrix Formation was deposited in a marine basin and consists primarily of black,

bituminous Bitumen ( , ) is an immensely viscous constituent of petroleum. Depending on its exact composition, it can be a sticky, black liquid or an apparently solid mass that behaves as a liquid over very large time scales. In American English, the m ...

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

s. The upper portion includes nodules and thin nodular beds of argillaceous

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

that increase in frequency upwards and laterally toward the

reefs A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic (non-living) processes such as deposition of sand or wave eros ...

of the Cairn Formation.Glass, D.J. (editor) 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba, p. 925-926. Canadian Society of Petroleum Geologists, Calgary, 1423 p. on CD-ROM. .

Thickness and Distribution

The Perdrix Formation is present as

outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth and other terrestrial planets. Features Outcrops do not cover the majority of the Earth's land surface because in most p ...

s in the front and main ranges of the Canadian Rockies from the Kakwa Lakes area in northeastern

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

to the Ram River area of Alberta. It is also recognized in the subsurface immediately adjacent to the mountain front. Thicknesses range from about to .

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 common throughout the Perdrix Formation, and

brachiopod Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...

s and pelecypods are present in the more limestone-rich portions.

References

* {{Western Canadian Sedimentary Basin, Canadian Rockies=yes Devonian Alberta Devonian southern paleotropical deposits Frasnian Stage Geologic formations of Alberta Western Canadian Sedimentary Basin Fossiliferous stratigraphic units of North America Paleontology in Alberta Shale formations of Canada Limestone formations of Canada

Lithology

Thickness and Distribution

Relationship to Other Units

Paleontology

See also

References