The Beaver Mines Formation is a

stratigraphic unit A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features ( facies) that characteriz ...

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

(

Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

) age in the

Western Canada Sedimentary Basin The Western Canada 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 ba ...

that is present in southwestern

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

and southeastern

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

. It was established by G.B. Mellon in 1967 who named it for the hamlet of

Beaver Mines Beaver Mines is a hamlet in southern Alberta, Canada within the Municipal District of Pincher Creek No. 9. It is located in the foothills of the Canadian Rockies on Highway 507, approximately west of Pincher Creek. History The community wa ...

, Alberta. It contains a variety of plant fossils.

Lithology

Fine- to coarse-grained greenish-grey

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

interbedded with greenish-grey

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.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

and

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. Although its permeabil ...

, and lesser amounts of conglomerate,

bentonite Bentonite ( ) is an Absorption (chemistry), absorbent swelling clay consisting mostly of montmorillonite (a type of smectite) which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably greater swelli ...

, and

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock co ...

. Some conglomerate beds contain pebbles of volcanic origin. Minor

argillaceous Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin, Al2 Si2 O5( OH)4), sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces. Clay mineral ...

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

is present at the top in some areas. The sandstones are

feldspathic Feldspar ( ; sometimes spelled felspar) is a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagiocla ...

, in contrast to the

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

ose sandstones of the overlying Ma Butte Formation.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. .

Environment of deposition and paleontology

The Beaver Mines Formation was deposited in

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...

and fluvial channel environments by

meander A meander is one of a series of regular sinuous curves in the Channel (geography), channel of a river or other watercourse. It is produced as a watercourse erosion, erodes the sediments of an outer, concave bank (cut bank, cut bank or river cl ...

ing river systems.Taylor, D.R. and Walker, R.G. 1984. Depositional environments and paleogeography of the Albian Moosebar Formation and adjacent fluvial Gladstone and Beaver Mines Formations, Alberta. Canadian Journal of Earth Sciences, vol. 21, p. 698-714. It contains a variety of plant fossils including remains of

fern The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

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

s, cycadeoids,

Ginkgo ''Ginkgo'' is a genus of non-flowering seed plants, assigned to the gymnosperms. The scientific name is also used as the English common name. The order to which the genus belongs, Ginkgoales, first appeared in the Permian, , and ''Ginkgo'' is n ...

s and extinct

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

s, but remains of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s do not appear until the overlying Ma Butte Formation.Bell, W.A. 1949. Lower Cretaceous floras of western Canada. Geological Survey of Canada, Memoir 285, 331 p.McLean, 1980. Lithostratigraphy of the Lower Cretaceous coal-bearing sequence, foothills of Alberta. Geological Survey of Canada, Paper 80-29.

Distribution and thickness

The Beaver Mines Formation is present in the southern foothills of southwestern Alberta and southeastern British Columbia and extends as far north as the Clearwater River where it grades into the Gates Formation of the

Luscar Group The Luscar Group is a geologic unit of Early Cretaceous age in the Western Canadian Sedimentary Basin, Western Canada Sedimentary Basin that is present in the foothills of southwestern Alberta. It is subdivided into a series of formation (stratigr ...

.Langenberg, C.W. and McMechan, M.E. 1985. Lower Cretaceous Luscar Group (revised) of the northern and north-central foothills of Alberta. Bulletin of Canadian Petroleum Geology, vol. 33, p. 1-11. It reaches a maximum thickness of about at Ma Butte north of the

Crowsnest Pass Crowsnest Pass (sometimes referred to as Crow's Nest Pass, ) is a low mountain pass across the Continental Divide of the Canadian Rockies on the Alberta–British Columbia border. Geography The pass is located in southeast British Columbia an ...

Relationship to other units

The Beaver Mines Formation is part of the

Blairmore Group 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 fo ...

. It disconformably overlies the Gladstone Formation and grades into the Gates Formation of the

north of the Clearwater River. It is disconformably overlain by the Ma Butte Formation in the southern foothills and by the Blackstone Formation north of the

Red Deer River The Red Deer River is a river in Alberta and a small portion of Saskatchewan, Canada. It is a major tributary of the South Saskatchewan River and is part of the larger Saskatchewan / Nelson River, Nelson system that empties into Hudson Bay. T ...

. To the east, it is correlated with the upper part of the

Mannville Group The Mannville Group is a stratigraphic unit of Cretaceous age in the Western Canadian Sedimentary Basin. It takes the name from the town of Mannville, Alberta, and was first described in the ''Northwest Mannville 1'' well by A.W. Nauss in 1945. ...

References

{{reflist Western Canadian Sedimentary Basin Geologic formations of Alberta Cretaceous Alberta Geologic formations of British Columbia Cretaceous British Columbia Albian Stage

Lithology

Environment of deposition and paleontology

Distribution and thickness

Relationship to other units

See also

References