The Pika Formation is a

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers ( strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostr ...

unit of

Middle Cambrian Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (disambiguation) * Middle Brook (disambiguation) * Middle Creek ...

age that is present on the western edge of the

Western Canada Sedimentary Basin The Western Canadian Sedimentary Basin (WCSB) underlies of Western Canada including southwestern Manitoba, southern Saskatchewan, Alberta, northeastern British Columbia and the southwest corner of the Northwest Territories. This vast sedimentary ...

in the

Canadian Rockies The Canadian Rockies (french: Rocheuses canadiennes) or Canadian Rocky Mountains, comprising both the Alberta Rockies and the British Columbian Rockies, is the Canadian segment of the North American Rocky Mountains. It is the easternmost par ...

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...

and

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost Provinces and territories of Canada, province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include ...

. It was named for

Pika Peak Pika Peak is a mountain located between Mount Richardson and Ptarmigan Peak in Banff National Park, Alberta, Canada The mountain was named in 1928 after the pika, the small "rock rabbit" that inhabits alpine regions. The Lake Louise Mountain R ...

near Lake Louise in

Banff National Park Banff National Park is Canada's oldest national park, established in 1885 as Rocky Mountains Park. Located in Alberta's Rocky Mountains, west of Calgary, Banff encompasses of mountainous terrain, with many glaciers and ice fields, dense conif ...

by C.F. Deiss in 1939. It is

fossil 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 ...

iferous and preserves several genera of

trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the ...

s.Melzak, A. and Westrop, S.R. 1994. Mid-Cambrian (Marjuman) from the Pika Formation, southern Canadian Rocky Mountains, Alberta. Canadian Journal of Earth Sciences, vol. 31, p. 969-985.

Outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Features Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficia ...

s of the Pika Formation can be seen in Banff and

Jasper National Park Jasper National Park is a national park in Alberta, Canada. It is the largest national park within Alberta's Rocky Mountains spanning . It was established as a national park in 1930 and declared a UNESCO World Heritage Site in 1984. Its locatio ...

s.Leckie, D.A. 2017. Rocks, ridges and rivers – Geological wonders of Banff, Yoho, and Jasper National Parks. Brokenpoplars, Calgary, Alberta, 217 pp. .

Lithology and deposition

The Pika Formation consists primarily of dark-weathering, thin-bedded

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an a ...

mudstone with thin

dolomitized Dolomitization is a geological process by which the carbonate mineral dolomite is formed when magnesium ions replace calcium ions in another carbonate mineral, calcite. It is common for this mineral alteration into dolomite to take place due to e ...

partings. There are minor intervals of

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especia ...

near the base. The Pika was deposited in shallow marine environments along the western margin of the

North American Craton North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' is ...

during

time.Aitken, J.D. 1966. Middle Cambrian to Middle Ordovician cyclic sedimentation, southern Rocky Mountains of Alberta. Bulletin of Canadian Petroleum Geology, vol. 14, no. 6, p. 405-441.Aitken, J.D. 1997. Stratigraphy of the Middle Cambrian platformal succession, southern Rocky Mountains. Geological Survey of Canada, Bulletin 398, 322 p.

Distribution and stratigraphic relationships

The Pika Formation is present in the Rocky Mountains of Alberta and British Columbia, from south of

Mount Assiniboine Mount Assiniboine, also known as Assiniboine Mountain, is a pyramidal peak mountain located on the Great Divide, on the British Columbia/Alberta border in Canada. At , it is the highest peak in the Southern Continental Ranges of the Canadian Ro ...

to the Kakwa area in the north. It thickens westward, reaching a maximum thickness of about 361 metres (1,184 feet) near the Chaba River, and thins to zero in the subsurface of the Alberta plains. It is in gradational contact with the underlying

Eldon Formation The Eldon Formation is a stratigraphic unit that is present on the western edge of the Western Canada Sedimentary Basin in the southern Canadian Rockies of southwestern Alberta and southeastern British Columbia. It is a thick sequence of massi ...

in the south,

Titkana Formation The Titkana Formation is a stratigraphic unit of Middle Cambrian age that is present on the western edge of the Western Canada Sedimentary Basin in the northern Canadian Rockies of Alberta and British Columbia. It was named for Titkana Peak ...

in the north, and the

Earlie Formation The Earlie Formation is a stratigraphic unit of Middle Cambrian age in the Western Canada Sedimentary Basin that is present beneath the plains of Alberta and eastern Saskatchewan. It was named for Earlie Lake in the County of Vermilion River ...

in the east. In the mountains it is overlain by the

Arctomys Formation The Arctomys Formation is a stratigraphic unit of late Middle Cambrian age. It is present on the western edge of the Western Canada Sedimentary Basin in the Canadian Rockies of Alberta and British Columbia. It was named for Arctomys Peak near Mo ...

; the contact is abrupt and may be unconformable. In the plains to the east it is unconformably overlain by the Sullivan Formation or, farther east, by the

Deadwood Formation The Deadwood Formation is a geologic formation of the Williston Basin and Western Canada Sedimentary Basin. It is present in parts of North and South Dakota and Montana in the United States, and in parts of Alberta, Saskatchewan, and southwestern ...

References

{{Western Canadian Sedimentary Basin, Canadian Rockies=yes Cambrian Alberta Cambrian British Columbia Cambrian System of North America Western Canadian Sedimentary Basin Geologic formations of Alberta Geologic formations of British Columbia Mudstone formations Limestone formations of Canada Dolomite formations