The Fernie 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: lithostrati ...

unit of

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

age Age or AGE may refer to: Time and its effects * Age, the amount of time someone or something has been alive or has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

. It is present in the western part 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 western

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 northeastern

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

.Poulton, T.P., Tittemore, J. and Dolby, G. 1990. Jurassic strata of northwestern (and west-central) Alberta and northeastern British Columbia. Bulletin of Canadian Petroleum Geology 38A: 159-175. It takes its name from the town of

Fernie, British Columbia Fernie is a city in the Elk Valley area of the East Kootenay region of southeastern British Columbia, Canada, located on BC Highway 3 on the western approaches to the Crowsnest Pass through the Rocky Mountains. Founded in 1898 and incorpora ...

, and was first defined by W.W. Leach in 1914.Leach, W.W., 1914. Blairmore map-area, Alberta;

Geological Survey of Canada The Geological Survey of Canada (GSC; french: Commission géologique du Canada (CGC)) is a Canadian federal government agency responsible for performing geological surveys of the country, developing Canada's natural resources and protecting the en ...

, Summary Report 1912, p. 234. with Map 107A,

Blairmore, Alberta Blairmore is a community in the Rocky Mountains within the Municipality of Crowsnest Pass in southwest Alberta, Canada. It was formerly incorporated as a town prior to 1979 when it amalgamated with four other municipalities to form Crowsnest Pas ...

, Scale: 1 inch to 2 miles

Depositional history

The Fernie Formation consists of marine sediments that were deposited in the

Sundance Sea The Sundance Sea was an epeiric sea that existed in North America during the mid-to-late Jurassic Period of the Mesozoic Era. It was an arm of what is now the Arctic Ocean, and extended through what is now western Canada into the central western ...

. Deposition took place throughout most of the Jurassic period, starting during the

Hettangian The Hettangian is the earliest age and lowest stage of the Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (My ...

stage in some parts of northeastern British Columbia and continuing until the mid-Tithonian, as determined from its fossil assemblages, including

ammonites Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...

molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant taxon, extant species of molluscs are recognized. The number of fossil sp ...

and

microfossil A microfossil is a fossil that is generally between 0.001 mm and 1 mm in size, the visual study of which requires the use of light or electron microscopy. A fossil which can be studied with the naked eye or low-powered magnification, ...

s.Stott, D.F. 1998. Fernie Formation and Minnes Group (Jurassic and lowermost Cretaceous), northern Rocky Mountain foothills, Alberta and British Columbia. Geological Survey of Canada, Bulletin 516. The sediments were sourced from the east during the deposition of the lower and middle units of the Fernie, where the coarser

facies In geology, a facies ( , ; same pronunciation and spelling in the plural) is a body of rock with specified characteristics, which can be any observable attribute of rocks (such as their overall appearance, composition, or condition of formatio ...

occur in the eastern part of the formation. In the uppermost Fernie, the coarsest material is found in the west, however, indicating a shift to sources in the west and south.Glass, D.J. (editor) 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba. Canadian Society of Petroleum Geologists, Calgary, 1423 p. on CD-ROM. .

Lithology

The Fernie Formation is composed primarily of brown and dark gray to black

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, especial ...

s that range from massive with

conchoidal fracture Conchoidal fracture describes the way that brittle materials break or fracture when they do not follow any natural planes of separation. Mindat.org defines conchoidal fracture as follows: "a fracture with smooth, curved surfaces, typically slig ...

to laminated and highly fractured or papery. Phosphatic

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

and

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

, including

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...

, occur locally in the lower parts of the

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondar ...

;

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, p ...

coquina Coquina () is a sedimentary rock that is composed either wholly or almost entirely of the transported, abraded, and mechanically sorted fragments of the shells of mollusks, trilobites, brachiopods, or other invertebrates. The term ''coquina'' ...

s and oolitic limestone interbeds can occur in the center;

glauconitic Glauconite is an iron potassium phyllosilicate ( mica group) mineral of characteristic green color which is very friable and has very low weathering resistance. It crystallizes with a monoclinic geometry. Its name is derived from the Greek () m ...

sandstone and

can be present in the upper parts.

Distribution

The Fernie Formation reaches a maximum thickness of near Mount Allan in Alberta, and typically is about 70 to 150m (230 to 492 ft) thick. It thins toward the east, disappearing at about the

longitude Longitude (, ) is a geographic coordinate that specifies the east–west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter l ...

Calgary Calgary ( ) is the largest city in the western Canadian province of Alberta and the largest metro area of the three Prairie Provinces. As of 2021, the city proper had a population of 1,306,784 and a metropolitan population of 1,481,806, makin ...

. The formation is exposed in

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 superficial ...

s in the

Kootenay Kootenay, Kootenai, and Kutenai may refer to: Ethnic groups *The Kutenai, also known as the Ktunaxa, Kootenai, or Kootenay, an indigenous people of the United States and Canada **Kutenai language, the traditional language of the Kutenai **Ktunaxa ...

region of southeastern

, in the foothills and front ranges of 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 part ...

in southwestern Alberta, and as far north as the

Peace River Country The Peace River Country (or Peace Country; french: Région de la Rivière-de-la-paix) is an aspen parkland region centring on the Peace River in Canada. It extends from northwestern Alberta to the Rocky Mountains in northeastern British Columbia, ...

in northeastern British Columbia.

Relationship to other units

The Fernie Formation is conformably overlain by the Morrissey Formation in the south, by the

Nikanassin Formation The Nikanassin Formation is a stratigraphic unit of Late Jurassic (Portlandian) to Early Cretaceous (Barremian) age.Poulton, T.P., Tittemore, J. and Dolby, G. 1990. Jurassic strata of northwestern (and west-central) Alberta and northeastern Britis ...

central Alberta Central Alberta is a region located in the Canadian province of Alberta. Central Alberta is the most densely populated rural area in the province. Agriculture and energy are important to the area's economy. Geography Central Alberta is bordere ...

and by the Monteith Formation in northeastern

. It rests disconformably on

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

units in the west, and

unconformably An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...

on upper

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

units such as the Schooler Creek Group and the

Montney Formation The Montney Formation is a stratigraphical unit of Lower Triassic age in the Western Canadian Sedimentary Basin in British Columbia and Alberta. It takes the name from the hamlet of Montney and was first described in Texaco's Buick Creek No. 7 w ...

farther east.

Subdivisions

The Fernie Formation has the following subdivisions from top to base:

References