Minnes Group

Minnes Group
Stratigraphic range: Mesozoic
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Minnes Group; Stratigraphic range: Mesozoic PreЄ Є O S D C P T J K Pg N
Type	Group
Sub-units	Gorman Creek Formation ; Bickford Formation ; Monach Formation ; Beattie Peaks Formation ; Monteith Formation
Underlies	Cadomin Formation
Overlies	Fernie Formation
Thickness	maximum 2,100 m (6,890 ft)
Lithology
Primary	Sandstone
Other	Siltstone, mudstone, coal
Location
Coordinates	54°09′45″N120°04′00″W / 54.1625°N 120.0667°W Coordinates: 54°09′45″N120°04′00″W / 54.1625°N 120.0667°W
Region	British Columbia ; Alberta
Country	Canada
Type section
Named for	Mount Minnes, British Columbia
Named by	W.H. Ziegler and S.A.J. Pocock [1]

Last updated April 25, 2019

The Minnes Group, originally named the Minnes Formation,^[1] is a geologic unit of latest Jurassic to earliest Cretaceous age in the Western Canada Sedimentary Basin.^[2] It is present in the northern foothills of the Canadian Rockies and the adjacent plains in northeastern British Columbia and west-central Alberta.^[3] Its strata include natural gas reservoirs and minor coal deposits.^[4] Fossil dinosaur tracks have been described from one of its formations.^[5]

The Late Jurassic is the third epoch of the Jurassic period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.

The Early Cretaceous or the Lower Cretaceous, is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 146 Ma to 100 Ma.

The Western Canadian Sedimentary Basin (WCSB) is a vast sedimentary basin underlying 1,400,000 square kilometres (540,000 sq mi) of Western Canada including southwestern Manitoba, southern Saskatchewan, Alberta, northeastern British Columbia and the southwest corner of the Northwest Territories. It consists of a massive wedge of sedimentary rock extending from the Rocky Mountains in the west to the Canadian Shield in the east. This wedge is about 6 kilometres (3.7 mi) thick under the Rocky Mountains, but thins to zero at its eastern margins. The WCSB contains one of the world's largest reserves of petroleum and natural gas and supplies much of the North American market, producing more than 16,000,000,000 cubic feet (450,000,000 m³) per day of gas in 2000. It also has huge reserves of coal. Of the provinces and territories within the WCSB, Alberta has most of the oil and gas reserves and almost all of the oil sands.

Stratigraphy and lithology

The strata of the Minnes Group were originally described as the Minnes Formation^[1] which was revised to group status by D.F. Stott.^[4] Stott subdivided the group into four formations in the north as shown below. South of the Pine River the upper three formations are not readily divisible and those beds are included in the Gorman Creek Formation.^[4]^[3]

The Gorman Creek Formation is a geologic formation of Early Cretaceous (Valanginian) age in the Western Canada Sedimentary Basin that consists primarily of nonmarine sediments. It is present in the northern foothills of the Canadian Rockies and the adjacent plains in northeastern British Columbia. Plant fossils and dinosaur tracks have been described from its strata.

North:

Formation	Age	Lithology	Maximum Thickness	Reference
Bickford Formation	Early Cretaceous (Valanginian)	interbedded sandstone, siltstone, and mudstone, with minor coal seams	400 m (1,310 ft)	^[4]
Monach Formation	Early Cretaceous (Valanginian)	quartzose sandstone, minor coal	350 m (1,150 ft)	^[4]
Beattie Peaks Formation	Early Cretaceous (Valanginian)	mudstone, siltstone, argillaceous sandstone	460 m (1,510 ft)	^[4]
Monteith Formation	Late Jurassic (Tithonian) to Early Cretaceous (Berriasian)	quartzose to argillaceous sandstone, with minor conglomerate, siltstone, mudstone, coal	600 m (1,970 ft)	^[4]

South:

Formation	Age	Lithology	Maximum Thickness	Reference
Gorman Creek Formation	Early Cretaceous (Valanginian)	argillaceous sandstone, siltstone, carbonaceous mudstone, and coal	1,200 m (3,940 ft)	^[4]
Monteith Formation	latest Jurassic (Tithonian) to Early Cretaceous (Berriasian)	quartzose to argillaceous sandstone, with minor conglomerate, siltstone, mudstone, coal	600 m (1,970 ft)	^[4]

Environment of deposition

The formations of the Minnes Group were deposited in marine and nonmarine environments within and adjacent to the Western Interior Seaway. Depositional settings ranged from shallow marine to shoreline, coastal plain, deltaic, river channel, floodplain, and swamp environments.^[4]

Western Interior Seaway A large inland sea from mid-Cretaceous to early Paleogene, splitting the continent of North America

The Western Interior Seaway was a large inland sea that existed during the mid- to late Cretaceous period as well as the very early Paleogene, splitting the continent of North America into two landmasses, Laramidia to the west and Appalachia to the east. The ancient sea stretched from the Gulf of Mexico and through the middle of the modern-day countries of the United States and Canada, meeting with the Arctic Ocean to the north. At its largest, it was 2,500 feet (760 m) deep, 600 miles (970 km) wide and over 2,000 miles (3,200 km) long.

A shore or a shoreline is the fringe of land at the edge of a large body of water, such as an ocean, sea, or lake. In physical oceanography, a shore is the wider fringe that is geologically modified by the action of the body of water past and present, while the beach is at the edge of the shore, representing the intertidal zone where there is one. In contrast to a coast, a shore can border any body of water, while the coast must border an ocean; in that sense a coast is a type of shore; however, coast often refers to an area far wider than the shore, often stretching miles into the interior.

A coastal plain is flat, low-lying land adjacent to a sea coast. One of the largest coastal plains is located in southeastern United States. The Gulf Coastal Plain of North America extends northwards from the Gulf of Mexico along the Lower Mississippi River to the Ohio River, which is a distance of about 981 miles (1,579 km).

Paleontology and age

The age of the Minnes Group strata has been determined from their fossil fauna, primarily species of the bivalve Buchia. Ammonites, plant fossils, palynomorphs, and microfossils have also been described from the Minnes Group.^[4] Dinosaur trackways are present on bedding surfaces in the Gorman Creek Formation of the Minnes Group near the Narraway River:

Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them. Usually the aim is correlation, demonstrating that a particular horizon in one geological section represents the same period of time as another horizon at some other section. The fossils are useful because sediments of the same age can look completely different because of local variations in the sedimentary environment. For example, one section might have been made up of clays and marls while another has more chalky limestones, but if the fossil species recorded are similar, the two sediments are likely to have been laid down at the same time.

Bivalvia, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. Bivalves as a group have no head and they lack some usual molluscan organs like the radula and the odontophore. They include the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. The shipworms bore into wood, clay, or stone and live inside these substances.

Ammonoids are an extinct group of 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 than they are to shelled nautiloids such as the living Nautilus species. The earliest ammonites appear during the Devonian, and the last species died out in the Cretaceous–Paleogene extinction event.

"More than 200 fossil footprints are preserved in at least 8 trackways... The majority of the footprints were made by small theropods, but the most dramatic trackway was made by a large biped whose feet were more than a half meter in length."^[6]
Theropoda or theropods are a dinosaur suborder that is characterized by hollow bones and three-toed limbs. They are generally classed as a group of saurischian dinosaurs, although a 2017 paper has instead placed them in the proposed clade Ornithoscelida as the closest relatives of the Ornithischia. Theropods were ancestrally carnivorous, although a number of theropod groups evolved to become herbivores, omnivores, piscivores, and insectivores. Theropods first appeared during the Carnian age of the late Triassic period 231.4 million years ago (Ma) and included the sole large terrestrial carnivores from the Early Jurassic until at least the close of the Cretaceous, about 66 Ma. In the Jurassic, birds evolved from small specialized coelurosaurian theropods, and are today represented by about 10,500 living species.

Thickness and distribution

The Minnes Group can be seen in outcrops in the northern foothills of the Canadian Rockies and is present beneath the adjacent plains from the Prophet River in northeastern British Columbia to the Berland River in west-central Alberta. It reaches a maximum thickness of 1,200 m (3,940 ft) in the foothills and thins eastward, reaching zero at its erosional edge.^[3]

An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth.

Canadian Rockies mountain range in Canada

The Canadian Rockies or Canadian Rocky Mountains comprise the Canadian segment of the North American Rocky Mountains. They are the eastern part of the Canadian Cordillera, which is a system of multiple ranges of mountains which runs from the Canadian Prairies to the Pacific Coast. The Canadian Rockies mountain system comprises the southeastern part of this system, lying between the Interior Plains of Alberta and Northeastern British Columbia on the east to the Rocky Mountain Trench of BC on the west. The southern end borders Idaho and Montana of the United States. In geographic terms the boundary is at the Canada/US border, but in geological terms it might be considered to be at Marias Pass in northern Montana. The northern end is at the Liard River in northern British Columbia.

The Prophet River is a river in northern British Columbia, Canada. It is a tributary of the Muskwa River.

Relationship to other units

The Minnes Group was deposited conformably over the marine shales of the Fernie Formation, and was eroded prior to the deposition of the Cadomin Formation of the Bullhead Group which unconformably overlies it. The Minnes strata grade into those of the Nikanassin Formation to the south in Alberta.^[2]^[3]

Economic Resources

The Minnes Group contains natural gas reservoirs in the subsurface of the Peace River Plains and Deep Basin areas, where it is sometimes reported as "Nikanassin Formation". Coal seams and carbonaceous shales, which may have been the source for much of the gas, are also present in the Minnes Group, but none of the coal deposits have been found to be economically mineable.^[4]

Related Research Articles

The Scollard Formation is an Upper Cretaceous to lower Palaeocene stratigraphic unit of the Western Canada Sedimentary Basin in southwestern Alberta. Its deposition spanned the time interval from latest Cretaceous to early Paleocene, and it includes sediments that were deposited before, during, and after the Cretaceous-Paleogene (K-Pg) extinction event. It is significant for its fossil record, and it includes the economically important coal deposits of the Ardley coal zone.

The Nikanassin Formation is a stratigraphic unit of Late Jurassic (Portlandian) to Early Cretaceous (Barremian) age. It is present along the western edge of the Western Canada Sedimentary Basin in western Alberta and northeastern British Columbia. Its name was first proposed by D.B. Dowling in 1909 (Coal Fields South of Grand Trunk Pacific Railway, in the foothills of the Rocky Mountain, Alberta Page 140 paragraph 4 " to this it is proposed to give the name Nikanassin, from the Cree word meaning outer range" Also it is noted on the map by D.B. Dowling.(Geological Survey of Canada. Incorrect info follows: It was named by B.R. MacKay in 1929 for the Nikanassin Range of the front-central ranges of the Canadian Rockies. Mackay did not designate a type locality for the formation, although he described outcrops near the hamlet of Brûlé, north of the Yellowhead Highway outside of Jasper National Park.

The Cadomin Formation is a stratigraphic unit of Early Cretaceous age in the western part of the Western Canada Sedimentary Basin. It is extends from southeastern British Columbia through western Alberta to northeastern British Columbia, and it contains significant reservoirs of natural gas in some areas. It was named after the mining town of Cadomin, which is an acronym of "Canadian Dominion Mining".

Gething Formation is a stratigraphic unit of Lower Cretaceous (Aptian) age in the Western Canada Sedimentary Basin. It is present in northeastern British Columbia and western Alberta, and includes economically important coal deposits.

Bullhead Group is a stratigraphic unit of Lower Cretaceous age in the Western Canada Sedimentary Basin of northeastern British Columbia and western Alberta. It was first defined by F.H. McLearn in 1918 as the Bullhead Mountain Formation, but later was upgraded to group status. It consists of the Cadomin and Gething Formations, although some early workers included the Bluesky Formation and others in the group.

The Fernie Formation is a stratigraphic unit of Jurassic age. It is present in the western part of the Western Canada Sedimentary Basin in western Alberta and northeastern British Columbia. It takes its name from the town of Fernie, British Columbia, and was first defined by W.W. Leach in 1914.

The Mist Mountain Formation is a latest Jurassic to earliest Cretaceous geologic formation in the Western Canada Sedimentary Basin of southeastern British Columbia and southwestern Alberta. It was named for outcrops along a western spur of Mist Mountain in the Canadian Rockies of Alberta. It contains economically important coal reserves that are mined in southeastern British Columbia.

The Morrissey Formation is a stratigraphic unit of Late Jurassic (Portlandian) age in the Western Canada Sedimentary Basin. It is named for outcrops on Morrissey Ridge, 16 kilometres (10 mi) southeast of Fernie, British Columbia, and is present in southeastern British Columbia and southwestern Alberta.

The Elk Formation is a stratigraphic unit of the Western Canada Sedimentary Basin that is present in southeastern British Columbia and southwestern Alberta. It is probably of Early Cretaceous age, but in some areas its strata could be as old as Late Jurassic. It includes minor thin coal beds and was named for outcrops near the now-abandoned Elk River coal mine east of Fernie, British Columbia.

The Coalspur Formation is an Upper Cretaceous to lower Palaeocene stratigraphic unit of the Western Canada Sedimentary Basin in the foothills of southwestern Alberta. Its deposition spanned the time interval from latest Cretaceous (Maastrichtian) to early Palaeocene, and it includes sediments that were deposited before, during, and after the Cretaceous-Paleogene (K-Pg) extinction event. It includes the economically important coal deposits of the Coalspur Coal Zone, as well as nonmarine plant and animal fossils.

The Blairmore Group, originally named the Blairmore Formation, is a geologic unit of Early Cretaceous age in the Western Canada Sedimentary Basin that is present in southwestern Alberta and southeastern British Columbia. It is subdivided into a series of formations, most of which contain plant fossils. In some areas it contains significant reservoirs of natural gas.

The Beattie Peaks Formation is a geologic formation of Early Cretaceous (Valanginian) age in the Western Canada Sedimentary Basin that consists primarily of marine mudstone. It is present in the northern foothills of the Canadian Rockies and the adjacent plains in northeastern British Columbia.

The Monach Formation is a geologic formation of Early Cretaceous (Valanginian) age in the Western Canada Sedimentary Basin that consists primarily of sandstone. It is present in the northern foothills of the Canadian Rockies and the adjacent plains in northeastern British Columbia.

The Monteith Formation is a geologic formation of Early Cretaceous (Valanginian) age in the Western Canada Sedimentary Basin that consists primarily of sandstone. It is present in the northern foothills of the Canadian Rockies and the adjacent plains in northeastern British Columbia and west-central Alberta.

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 mountains and foothills of southeastern British Columbia and southwestern Alberta. It includes economically important deposits of high-rank bituminous and semi-anthracite coal, as well as plant fossils and dinosaur trackways.

The Bickford Formation is a geologic formation of Early Cretaceous (Valanginian) age in the Western Canada Sedimentary Basin that consists primarily of nonmarine sediments. It is present in the northern foothills of the Canadian Rockies in northeastern British Columbia.

The Luscar Group is a geologic unit of Early Cretaceous age in the Western Canada Sedimentary Basin that is present in the foothills of southwestern Alberta. It is subdivided into a series of formations, some of which contain economically significant coal deposits that have been mined near Cadomin and Luscar. Coal mining in those areas began in the early 1900s and continues near Luscar as of 2016.

The Whitehorse Formation is a geologic formation of Late Triassic age. It is present on the western edge of the Western Canada Sedimentary Basin in western Alberta and northeastern British Columbia. It was first described as a member of the Spray River Formation by P.S. Warren in 1945, who named for Whitehorse Creek, a tributary of the McLeod River south of Cadomin, Alberta. It was later raised to formation status.

The geology of Alberta encompasses parts of the Canadian Rockies and thick sedimentary sequences, bearing coal, oil and natural gas, atop complex Precambrian crystalline basement rock.

References

1 2 3 Ziegler, W.H. and Pocock, S.A.J. 1960. The Minnes Formation. In: Second Annual Field Trip Guidebook, Rock Lake, August 1960. Edmonton Geological Society, p. 43-71.
1 2 Mossop, G.D. and Shetsen, I. (compilers), Canadian Society of Petroleum Geologists and Alberta Geological Survey (1994). "The Geological Atlas of the Western Canada Sedimentary Basin, Chapter 18: Jurassic and Lowermost Cretaceous strata of the Western Canada Sedimentary Basin" . Retrieved 2016-06-20.CS1 maint: Multiple names: authors list (link)
1 2 3 4 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. ISBN 0-920230-23-7.
1 2 3 4 5 6 7 8 9 10 11 12 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.
↑ 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. ISBN 0-520-24209-2.
↑ Currie, P.J. 1991. Dinosaur footprints of western Canada. In: Dinosaur tracks and traces, D.D. Gillette and M. Lockley (eds.), p. 294. Cambridge University Press, ISBN 9780521407885, 476 p.