Doig Formation
Encyclopedia
The Doig Formation is a stratigraphical
unit of middle Triassic
age
in the Western Canadian Sedimentary Basin
.
It takes the name from Doig River
, a tributary of the Beatton River
, and was first described in the Texaco N.F.A. Buick Creek No. 7 well (located north-west of Fort St. John
, east of the Alaska Highway
) by J.H. Armitage in 1962. .
siltstone
and dark calcareous shale
.
Nodular phosphate
s occur at the base of the formation. Porous
sandstone
channels and bars are present locally towards the top of the formation in the northern areal.
is extracted from the Doig Formation in the western Montney trend
and in the Peace River Arch
.
foothills it thins towards the north and east. It occurs in the sub-surface in north-western Alberta
, north-eastern British Columbia
and southern Yukon
, from 53ºN and 118ºW to the Canadian Rockies.
overlain by the Halfway Formation of the Schooler Creek Group
. The contact is marked by a dolomitic
bed and a chert
and quartz
conglomerate
bed. Westwards it is overlain by newer Jurassic beds. It conformably overlays the Montney Formation
, which rests under the phosphate
pellet bed located in the base of the Doig.
The formation correlates with the lower Llama Member of the Sulphur Mountain Formation in the southern ranges of the Canadian Rockies
, with the Whistler Member of the Whitehorse Formation in the Muskwa Ranges
, and with the Toad Formation in the upper Liard River
area.
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 middle Triassic
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided. It spans the time between 245 ± 1.5 Ma and 228 ± 2 Ma...
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 Doig River
Doig River
Doig River is a river in Alberta and northern British Columbia, Canada.It originates on the northern fringes of Peace River Country in northern Alberta, south of the Chinchaga Wildland Park, in the Halverson Ridge of the Clear Hills, then flows westwards into British Columbia...
, a tributary of the Beatton River
Beatton River
The Beatton River is a tributary of the Peace River, flowing generally east, then south through north-eastern British Columbia, Canada. The river rises at Pink Mountain, about 10 km west of the Alaska Highway hamlet of the same name, and flows 240 km generally east, then south, draining into the...
, and was first described in the Texaco N.F.A. Buick Creek No. 7 well (located north-west of Fort St. John
Fort St. John, British Columbia
The City of Fort St. John is a city in northeastern British Columbia, Canada. A member municipality of the Peace River Regional District, the city covers an area of about 22 km² with 22,000 residents . Located at Mile 47, it is one of the largest cities along the Alaska Highway. Originally...
, east of the Alaska Highway
Alaska Highway
The Alaska Highway was constructed during World War II for the purpose of connecting the contiguous U.S. to Alaska through Canada. It begins at the junction with several Canadian highways in Dawson Creek, British Columbia and runs to Delta Junction, Alaska, via Whitehorse, Yukon...
) by J.H. Armitage in 1962. .
Lithology
The Doig Formation is composed of argillaceousArgillaceous minerals
Argillaceous minerals may appear silvery upon optical reflection and are minerals containing substantial amounts of clay-like components . Argillaceous components are fine-grained aluminosilicates, and more particularly clay minerals such as kaolinite, montmorillonite-smectite, illite, and...
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 dark calcareous 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...
.
Nodular phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
s occur at the base of the formation. Porous
Porosity
Porosity or void fraction is a measure of the void spaces in a material, and is a fraction of the volume of voids over the total volume, between 0–1, or as a percentage between 0–100%...
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,...
channels and bars are present locally towards the top of the formation in the northern areal.
Hydrocarbon production
Natural gasNatural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
is extracted from the Doig Formation in the western Montney trend
Montney Formation
The Montney Formation is a stratigraphical unit of Middle Triassic age in the Western Canadian Sedimentary Basin in British Columbia and Alberta....
and in the Peace River Arch
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...
.
Distribution
The Doig Formation reaches a maximum thickness of 190 metres (623.4 ft) in the Canadian RockiesCanadian 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...
foothills it thins towards the north and east. It occurs in the sub-surface in north-western 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...
, north-eastern 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...
and southern Yukon
Yukon
Yukon is the westernmost and smallest of Canada's three federal territories. It was named after the Yukon River. The word Yukon means "Great River" in Gwich’in....
, from 53ºN and 118ºW to the Canadian Rockies.
Relationship to other units
The Doig Formation is unconformablyUnconformity
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...
overlain by the Halfway Formation of the Schooler Creek Group
Schooler Creek Group
The Schooler Creek Group is a stratigraphical unit of Ladinian to Norian age in the Western Canadian Sedimentary Basin.It was named for Schooler Creek, a left tributary of the Williston Lake, and was first described north-west of Fort St. John in the Pacific Fort St. John No. 16 and Southern...
. The contact is marked by a dolomitic
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
bed and a 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 quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
conglomerate
Conglomerate (geology)
A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...
bed. Westwards it is overlain by newer Jurassic beds. It conformably overlays the Montney Formation
Montney Formation
The Montney Formation is a stratigraphical unit of Middle Triassic age in the Western Canadian Sedimentary Basin in British Columbia and Alberta....
, which rests under the phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
pellet bed located in the base of the Doig.
The formation correlates with the lower Llama Member of the Sulphur Mountain Formation in the southern ranges of 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...
, with the Whistler Member of the Whitehorse Formation in the Muskwa Ranges
Muskwa Ranges
The Muskwa Ranges are a group of mountain ranges in northern British Columbia, Canada. They are part of the Northern Rockies section of the Rocky Mountains and are bounded on their west by the Rocky Mountain Trench and on their east by the Rocky Mountain Foothills...
, and with the Toad Formation in the upper Liard River
Liard River
The Liard River flows through Yukon, British Columbia and the Northwest Territories, Canada. Rising in the Saint Cyr Range of the Pelly Mountains in southeastern Yukon, it flows southeast through British Columbia, marking the northern end of the Rocky Mountains and then curving northeast back...
area.