Winterburn Group

The Winterburn Group is a stratigraphical unit of Frasnian age in the Western Canadian Sedimentary Basin.

Winterburn Group
Stratigraphic range: Frasnian
TypeGeological formation
Sub-unitsNisku Formation, Calmar Formation, Graminia Formation, Blue Ridge Member
UnderliesWabamun Group
OverliesIreton Formation
Thicknessup to 150 metres (490 ft)[1]
Lithology
Primarydolomite, limestone, siltstone
OtherAnhydrite, shale
Location
Coordinates53.3451°N 113.6949°W / 53.3451; -113.6949 (Winterburn Group)
Region Alberta
Country Canada
Type section
Named forWinterburn, Edmonton
Named byImperial Oil Limited, 1950

It takes the name from Winterburn area located west of Edmonton, and was first described in well P.A. Pyrcz No. 1 by Imperial Oil Limited in 1950.[2]

Lithology

The Winterburn Group is composed of silty dolomite, evaporite, argillaceous limestone, red and green siltstone, anhydrite, silty dolomite and siltstone. Pinnacle reefs develop in the Nisku Formation. [1]

Hydrocarbon production

Oil is produced from the Nisku Formation in the Pembina oil field.

Distribution

The Winterburn Group reaches a maximum thickness of 150 metres (490 ft) west of the Leduc reef system. In central Alberta it is 30 to 70m thick. It thins out over the Peace River Arch, and disappears in north-eastern British Columbia.[1]

Subdivisions

The Winterburn Group is composed, from bottom to top, of the Nisku, Calmar and Graminia Formations. The Graminia Formation includes the carbonate Blue Ridge Member west of the Rimbey-Meadowbrook reef trend.

Sub-unitAgeLithologyMax.
Thickness		Reference
Graminia FormationFrasniansilty dolomite, anhydrite, siltstone
Blue Ridge Member:[3] silty dolomite, siltstone		18.3 m (60 ft) [4]
Calmar FormationFrasniandolomitic shale and siltstone, anhydrite13.4 m (40 ft) [5]
Nisku FormationFrasniancrystalline dolomite, dolomitic siltstone, green shale, anhydrite.100 m (330 ft) [6]

Relationship to other units

The Winterburn Group is conformably overlain by the Wabamun Group and overlays the Ireton Formation, except in the Peace River Arch, where it rests on the Precambrian basement.[1]

It is correlated with the Birdbear Formation and part of the Three Forks Group in Saskatchewan, with the Southesk Formation and Alexo Formation in the Canadian Rockies and with the Redknife Formation and Kakisa Formation in north-eastern British Columbia.

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References
  1. Lexicon of Canadian Geologic Units. "Winterburn Group". Archived from the original on 2013-02-21. Retrieved 2009-03-01.
  2. Geological Staff, Imperial Oil Limited, Western Division, 1950. Devonian Nomenclature in Edmonton Area, Alberta, Canada. Bulletin of the American Association of Petroleum Geologists, Vol. 34, No. 9, pp. 1807-1825.
  3. Lexicon of Canadian Geologic Units. "Blue Ridge Formation". Archived from the original on 2012-07-08. Retrieved 2011-04-02.
  4. Lexicon of Canadian Geologic Units. "Graminia Formation". Retrieved 2009-12-31.
  5. Lexicon of Canadian Geologic Units. "Calmar Formation". Archived from the original on 2012-07-07. Retrieved 2009-12-31.
  6. Lexicon of Canadian Geologic Units. "Nisku Formation". Archived from the original on 2012-07-10. Retrieved 2009-12-31.
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