The Eldon Formation is a stratigraphic unit 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 southern

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 part ...

of southwestern Alberta and southeastern British Columbia. It is a thick sequence of massive, cliff-forming limestones and

dolomite Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincor ...

s that was named for Eldon Switch on the

Canadian Pacific Railway The Canadian Pacific Railway (french: Chemin de fer Canadien Pacifique) , also known simply as CPR or Canadian Pacific and formerly as CP Rail (1968–1996), is a Canadian Class I railway incorporated in 1881. The railway is owned by Canadi ...

near

Castle Mountain Castle Mountain ( bla, Miistukskoowa) is a mountain located within Banff National Park in the Canadian Rockies, approximately halfway between Banff and Lake Louise. It is the easternmost mountain of the Main Ranges in the Bow Valley and sits ...

Banff National Park Banff National Park is Canada's oldest National Parks of Canada, national park, established in 1885 as Rocky Mountains Park. Located in Alberta's Rockies, Alberta's Rocky Mountains, west of Calgary, Banff encompasses of mountainous terrain, wi ...

by Charles Doolittle Walcott, who discovered the Burgess Shale fossils. The Eldon Formation was deposited during Middle Cambrian time, and it includes fossil stromatolites. The Eldon forms the scenic cliffs at the top of Castle Mountain, and can also be seen at

Mount Yamnuska Mount John Laurie is a mountain in the Canadian Rockies, located in Alberta's Municipal District of Bighorn No. 8. Various names Officially named Mount John Laurie in 1961, it is also known as Mount Laurie, or by the Nakoda name ''Mount Yamn ...

and other mountains in Banff and Yoho National Parks.

Lithology and deposition

The Eldon Formation is a thick sequence of cliff-forming carbonate rocks that was deposited during the Middle Cambrian time. It originally formed as limestone and calcareous

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

in the intertidal to supratidal zone along the western margin of the North American Craton.Aitken, J.D. 1971. Control of lower Paleozoic sedimentary facies by the Kicking Horse Rim, southern Rocky Mountains, Canada. Bulletin of Canadian Petroleum Geology, vol. 19, no. 3, p. 557-569. It was subsequently altered to

and

dolomitic Dolomite () is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally The term is also used for a sedimentary carbonate rock composed mostly of the mineral dolomite. An alternative name sometimes used for the dolomiti ...

in some areas.

Distribution and stratigraphic relationships

The Eldon Formation is present in the southern Rocky Mountains of southwestern Alberta and southeastern British Columbia. It reaches a maximum thickness of about 500 metres (1,640 feet) at

Mount Bosworth Mount Bosworth is located in the Canadian Rockies on the border of Alberta and British Columbia. The mountain is situated immediately northwest of Kicking Horse Pass and straddles the shared border of Banff National Park with Yoho National Park. ...

on the Alberta-British Columbia border. The Eldon conformably overlies the Stephen Formation, which hosts the fossils of the Burgess shale, in the south, and the Snake Indian Formation in the north. It is conformably overlain by the Pika Formation. The Eldon grades into 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, Al ...

to the east, the Chancellor Formation to the west, and the Titkana Formation to the north. It is probably equivalent to the Windsor Mountain Formation to the south.

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 Canada Stratigraphy of British Columbia