The Mist Mountain Formation is a geologic

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 ...

of latest Jurassic to earliest Cretaceous age in the Western Canada Sedimentary Basin that is present in the southern and central Canadian Rockies. It was named for

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 along the western spur of

Mist Mountain Mist Mountain is a mountain located alongside Highway 40 in the Canadian Rockies of Alberta, Canada. It reaches an elevation of and is visible from Alberta Highway 40 and the Sheep River. The mountain was named in 1884 by George M. Dawson. ...

in Alberta by D.W. Gibson in 1979. The Mist Mountain Formation contains economically important

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when ...

seams that have been mined in southeastern

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, ...

and southwestern

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 ...

.Gibson, D.W. 1979. The Morrissey and Mist Mountain formations - newly described lithostratigraphic units of the Jura-Cretaceous Kootenay Group, Alberta and British Columbia. Bulletin of Canadian Petroleum Geology 27: 183-208.

Lithology

The Mist Mountain Formation consists of interbedded light to dark grey siltstone, silty shale, mudstone, and

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 ...

, with localized occurrences of

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 ...

- and

quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tec ...

-pebble conglomerate and conglomeratic sandstone, as well as a series of economically important coal seams.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, 1 CD-ROM. .

Environment of deposition

The Mist Mountain Formation is part of the

Kootenay Group The Kootenay Group, originally called the Kootenay Formation, is a geologic unit of latest Jurassic to earliest Cretaceous age in the Western Canada Sedimentary Basin that is present in the southern and central Canadian Rockies and foothills. ...

, an eastward-thinning wedge of sediments derived from the erosion of newly uplifted mountains to the west. The sediments were transported eastward by river systems and deposited in a variety of fluvial channel,

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...

, swamp,

coastal plain A coastal plain is flat, low-lying land adjacent to a sea coast. A fall line commonly marks the border between a coastal plain and a piedmont area. Some of the largest coastal plains are in Alaska and the southeastern United States. The Gulf Co ...

and

deltaic A river delta is a landform shaped like a triangle, created by deposition of sediment that is carried by a river and enters slower-moving or stagnant water. This occurs where a river enters an ocean, sea, estuary, lake, reservoir, or (more rarel ...

environments along the western edge of the

Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, and the Western Interior Sea) was a large inland sea that split the continent of North America into two landmasses. The ancient sea ...

.Gibson, D.W. 1985. Stratigraphy, sedimentology and depositional environments of the coal-bearing Jurassic-Cretaceous Kootenay Group, Alberta and British Columbia. Geological Survey of Canada, Bulletin 357, 108 p.

Thickness and distribution

The Mist Mountain Formation is present in the front ranges and foothills of the southern and central Canadian Rockies. It extends from the Canada–US border to north of the

North Saskatchewan River The North Saskatchewan River is a glacier-fed river that flows from the Canadian Rockies continental divide east to central Saskatchewan, where it joins with the South Saskatchewan River to make up the Saskatchewan River. Its water flows event ...

. It thins eastward, ranging from thick near

Elkford Elkford is a district municipality in the southeast region of the Canadian province of British Columbia in the Rocky Mountain range. It is north of the junction at Sparwood, on provincial Highway 43. Outdoor recreational activities take place ...

, British Columbia, to less than in the eastern foothills in Alberta. Farther to the east it was truncated by pre- Aptian erosion.

Relationship to other units

The Mist Mountain Formation is the middle unit of the Kootenay Group. It rests conformably on the cliff-forming sandstones of the Moose Mountain Member of the Morrissey Formation, and is conformably overlain by the Elk Formation. In the eastern foothills, the Elk Formation has been removed by erosion and the Mist Mountain Formation is unconformably overlain by the

Cadomin Formation The Cadomin Formation is a stratigraphic unit of Early Cretaceous (Barremian to Aptian) age in the western part of the Western Canada Sedimentary Basin. It is extends from southeastern British Columbia through western Alberta to northeastern Bri ...

. North of the

, the Mist Mountain Formation grades into the Nikanassin Formation. Correlation south of the Canada–United States border is uncertain.

Paleontology and age

Plant fossils from the Mist Mountain Formation include remains of

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...

cycad Cycads are seed plants that typically have a stout and woody (ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male o ...

s, cycadeoids,

ginkgo ''Ginkgo'' is a genus of non-flowering seed plants. The scientific name is also used as the English name. The order to which it belongs, Ginkgoales, first appeared in the Permian, 270 million years ago, and is now the only living genus with ...

s, and extinct conifers. No remains of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s have been reported.Bell, W.A. 1949. Lower Cretaceous floras of western Canada. Geological Survey of Canada, Memoir 285, 331 p. Indeterminate fossil

ornithischian Ornithischia () is an extinct order of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. The name ''Ornithischia'', or "bird-hipped", reflects this similarity and is derived from the Greek st ...

tracks are also known from the formation.Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.): The Dinosauria, 2nd ed., "Dinosaur distribution," pp. 517-607. Berkeley: University of California Press. 861 pp. . None of the fossils are sufficiently time-sensitive to

date Date or dates may refer to: *Date (fruit), the fruit of the date palm (''Phoenix dactylifera'') Social activity *Dating, a form of courtship involving social activity, with the aim of assessing a potential partner ** Group dating *Play date, a ...

the formation precisely.

Coal resources

Economically important

seams in the Mist Mountain Formation reach a maximum thickness of . Seams occur throughout the formation, and some of the seams near the base for the formation are regionally extensive. The formation was strongly folded and faulted during the

Laramide Orogeny The Laramide orogeny was a time period of mountain building in western North America, which started in the Late Cretaceous, 70 to 80 million years ago, and ended 35 to 55 million years ago. The exact duration and ages of beginning and end of the ...

, which brought the coal to surface in many places. This also produced localized thickening and thinning of the coal in some areas due to shearing and fault-repetition of the seams, especially in the cores of folds and flexures. A seam was thickened to in the core of an

anticline In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the ...

at Grassy Mountain near

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 ...

, and extreme thickening to occurred in a faulted syncline at

Corbin, British Columbia Corbin is a ghost town in British Columbia, Canada. It was a coal mining community located at the foot of Coal Mountain (elev. 6835 feet; 2083 metres), south of the Crowsnest Pass in the southern Canadian Rockies. Daniel Chase Corbin, president o ...

. Mist Mountain coal generally has a low sulphur content and

coal rank Coal analysis techniques are specific analytical methods designed to measure the particular physical and chemical properties of coals. These methods are used primarily to determine the suitability of coal for coking, power generation or for iron ...

typically ranges from high- to medium-volatile

bituminous Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term ...

in the south, and from low-volatile bituminous to semi-anthracite in the north. As of 2019, it is being produced from large

open-pit mines Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique of extracting rock or minerals from the earth from an open-air pit, sometimes known as a borrow. This form of minin ...

near Sparwood and

Elkford, British Columbia Elkford is a district municipality in the southeast region of the Canadian province of British Columbia in the Rocky Mountain range. It is north of the junction at Sparwood, on provincial Highway 43. Outdoor recreational activities take place ...

, and the majority of it is exported to international markets for use as

coking coal Metallurgical coal or coking coal is a grade of coal that can be used to produce good-quality coke. Coke is an essential fuel and reactant in the blast furnace process for primary steelmaking. The demand for metallurgical coal is highly coupled ...

. Mist Mountain coal was formerly mined in British Columbia near Fernie, Hosmer, and Corbin; at several locations in the

Crowsnest Pass Crowsnest Pass (sometimes referred to as Crow's Nest Pass, french: link=no, col du Nid-de-Corbeau) is a low mountain pass across the Continental Divide of the Canadian Rockies on the Alberta– British Columbia border. Geography The pass is ...

area of Alberta; and at Canmore, Alberta, in many cases by

underground mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic vi ...

methods.Smith, G.G. 1989. Coal Resources of the Rocky Mountain Front Ranges and Foothills, Chapter 6 in G.G. Smith, Coal Resources of Canada, Geological Survey of Canada, Paper 89-4, 146 p. .

References

{{Western Canadian Sedimentary Basin, Canadian Rockies=yes Geologic formations of Canada Upper Jurassic Series Stratigraphy of Alberta Cretaceous Alberta Cretaceous British Columbia Stratigraphy of British Columbia Lower Cretaceous Series of North America Ichnofossiliferous formations