Banff Formation
Encyclopedia
The Banff Formation is a stratigraphical
unit of Devonian
age
in the Western Canadian Sedimentary Basin
.
It takes the name from the town of Banff, Alberta
, and was first described on the north-west slope of Mount Rundle
, near Banff by E.M. Kindle in 1924..
and marlstone in the base, chert
and limestone
in the middle, sandstone
, siltstone
and shale
at the top.
in southern Alberta
and the Kootenays
region of British Columbia
to north-eastern British Columbia, northern Alberta
and the District of Mackenzie
in the Northwest Territories
. In its southern area, the thickness ranges from 400 feet (121.9 m) in the Rocky Mountains
to 150 feet (45.7 m) in the sub-surface of the prairies. In the north, it ranges from 450 feet (137.2 m) in the Peace River Country
to 450 feet (137.2 m) in northern Alberta.
The age of the formation ranges from late Famennian
to Tournaisian
.
in the Canadian Rockies
, the Wabamun Formation
in central Alberta
, the Exshaw Formation
in southern Alberta
and in the Fort Nelson
area. It is overlain by the Pekisko Formation and the Livingstone Formation in north-central and southern Alberta respectively, and it is followed by the Shunda Formation in north-eastern British Columbia. An unconformity
is observed between Banff and the Rundle Group
in outcrop
.
The Banff Formation is equivalent to the Lodgepole Formation in Montana
. It can be correlated with the Besa River Formation
in north-eastern British Columbia. In the southeastern Rocky Mountains
, part of the formation passes laterally into the Pekisko Formation.
Stratigraphy
Stratigraphy, a branch of geology, studies rock layers and layering . It is primarily used in the study of sedimentary and layered volcanic rocks....
unit of Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
age
Geochronology
Geochronology is the science of determining the age of rocks, fossils, and sediments, within a certain degree of uncertainty inherent to the method used. A variety of dating methods are used by geologists to achieve this, and schemes of classification and terminology have been proposed...
in the Western Canadian Sedimentary Basin
Western Canadian Sedimentary Basin
The Western Canadian Sedimentary Basin is a vast sedimentary basin underlying 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...
.
It takes the name from the town of Banff, Alberta
Banff, Alberta
Banff is a town within Banff National Park in Alberta, Canada. It is located in Alberta's Rockies along the Trans-Canada Highway, approximately west of Calgary and east of Lake Louise....
, and was first described on the north-west slope of Mount Rundle
Mount Rundle
Mount Rundle is a mountain in Banff National Park overlooking the towns of Banff and Canmore, Alberta. The mountain was named by John Palliser in 1858 after Reverend Robert Rundle, who had visited the Banff area during the 1840s....
, near Banff by E.M. Kindle in 1924..
Lithology
The Banff Formation is composed of shaleShale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
and marlstone in the base, chert
Chert
Chert is a fine-grained silica-rich microcrystalline, cryptocrystalline or microfibrous sedimentary rock that may contain small fossils. It varies greatly in color , but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements...
and limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
in the middle, sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
, siltstone
Siltstone
Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystones.- Description :As its name implies, it is primarily composed of silt sized particles, defined as grains 1/16 - 1/256 mm or 4 to 8 on the Krumbein phi scale...
and shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
at the top.
Distribution
The Banff Formation extends from the 49th parallel49th parallel north
The 49th parallel north is a circle of latitude that is 49 degrees north of the Earth's equatorial plane. It crosses Europe, Asia, the Pacific Ocean, North America, and the Atlantic Ocean....
in southern Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
and the Kootenays
Kootenays
The Kootenay Region comprises the southeastern portion of British Columbia. It takes its name from the Kootenay River, which in turn was named for the Ktunaxa First Nation first encountered by explorer David Thompson.-Boundaries:The Kootenays are more or less defined by the Kootenay Land...
region of British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
to north-eastern British Columbia, northern Alberta
Northern Alberta
Northern Alberta is a region located in the Canadian province of Alberta.Its primary industry is oil and gas, with large heavy oil reserves being exploited at the Athabasca Oil Sands and Wabasca Area in the east of the region...
and the District of Mackenzie
District of Mackenzie
The District of Mackenzie was a regional administrative district of Canada's Northwest Territories. The district consisted of the portion of the Northwest Territories directly north of British Columbia, Alberta, and Saskatchewan on Canada's mainland....
in the Northwest Territories
Northwest Territories
The Northwest Territories is a federal territory of Canada.Located in northern Canada, the territory borders Canada's two other territories, Yukon to the west and Nunavut to the east, and three provinces: British Columbia to the southwest, and Alberta and Saskatchewan to the south...
. In its southern area, the thickness ranges from 400 feet (121.9 m) in the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
to 150 feet (45.7 m) in the sub-surface of the prairies. In the north, it ranges from 450 feet (137.2 m) in the Peace River Country
Peace River Country
The Peace River Country is an aspen parkland region around the Peace River in Canada. It spans from northwestern Alberta to the Rocky Mountains in northeastern British Columbia, where the region is also referred to as the Peace River Block.- Geography :The Peace River Country includes the...
to 450 feet (137.2 m) in northern Alberta.
The age of the formation ranges from late Famennian
Famennian
The Famennian is one of two faunal stages in the Late Devonian epoch. It lasted from 374.5 ± 2.6 million years ago to 359.2 ± 2.5 million years ago. It was preceded by the Frasnian stage and followed by the Tournaisian stage and is named after Famenne, a natural region in southern Belgium.It was...
to Tournaisian
Tournaisian
The Tournaisian is in the ICS geologic timescale the lowest stage or oldest age of the Mississippian, the oldest subsystem of the Carboniferous. The Tournaisian age lasted from 359.2 ± 2.5 Ma to 345.3 ± 2.1 Ma...
.
Relationship to other units
The Banff Formation is overlies the Palliser FormationPalliser Formation
The Palliser Formation is a stratigraphical unit of Famennian age in the Western Canadian Sedimentary Basin. found in the ranges of the Canadian Rockies and foothills....
in the Canadian Rockies
Canadian Rockies
The Canadian Rockies comprise the Canadian segment of the North American Rocky Mountains range. They are the eastern part of the Canadian Cordillera, extending from the Interior Plains of Alberta to the Rocky Mountain Trench of British Columbia. The southern end borders Idaho and Montana of the USA...
, the Wabamun Formation
Wabamun Formation
The Wabamun Formation is a stratigraphical unit of Famennian age in the Western Canadian Sedimentary Basin.It takes the name from Wabamun Lake, and was first described in the Anglo Canadian Wabamun Lake No...
in central Alberta
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...
, the Exshaw Formation
Exshaw Formation
The Exshaw Formation is a stratigraphical unit of Mississippian age in the Western Canadian Sedimentary Basin.It takes the name from the hamlet of Exshaw, Alberta, and was first described in outcrops on the banks of Jura Creek, north of Exshaw by P.S. Warren in 1937. The formation is of late...
in southern Alberta
Southern Alberta
Southern Alberta is a region located in the Canadian province of Alberta. As of the year 2004, the region's population was approximately 272,017. The primary cities are Lethbridge and Medicine Hat...
and in the Fort Nelson
Fort Nelson, British Columbia
Fort Nelson is a town of approximately 5000 residents in British Columbia's northeastern corner. It is the administrative centre of the newly formed Northern Rockies Regional Municipality, a first for BC. The majority of Fort Nelson's economic activities have historically been concentrated in the...
area. It is overlain by the Pekisko Formation and the Livingstone Formation in north-central and southern Alberta respectively, and it is followed by the Shunda Formation in north-eastern British Columbia. An unconformity
Unconformity
An unconformity is a buried erosion 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 of time before deposition of the younger, but the term is used to describe...
is observed between Banff and the Rundle Group
Rundle Group
The Rundle Group is a stratigraphical unit of Mississippian age in the Western Canadian Sedimentary Basin.It takes the name from Mount Rundle , and was first described in outcrops at the northern side of the mountain in Banff National Park by R.J.W...
in outcrop
Outcrop
An 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 deposits are covered by a mantle of soil and vegetation and cannot be...
.
The Banff Formation is equivalent to the Lodgepole Formation in Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
. It can be correlated with the Besa River Formation
Besa River Formation
The Besa River Formation is a stratigraphical unit of Devonian age in the Western Canadian Sedimentary Basin.It takes the name from Besa River, a tributary of the Prophet River, and was first described in outcrop near the Muskwa River, in the Muskwa Ranges by F.A. Kidd in 1963.-Lithology:The Besa...
in north-eastern British Columbia. In the southeastern Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
, part of the formation passes laterally into the Pekisko Formation.