Winterburn Group

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Winterburn Group
Stratigraphic range: Frasnian
Type Geological formation
Sub-units Nisku Formation, Calmar Formation, Graminia Formation, Blue Ridge Member
Underlies Wabamun Group
Overlies Ireton Formation
Thickness up to 150 metres (490 ft)[1]
Lithology
Primary Dolomite, limestone, siltstone
Other Anhydrite, shale
Location
Coordinates 53°20′42″N 113°41′42″W / 53.3451°N 113.6949°W / 53.3451; -113.6949 (Winterburn Group)Coordinates: 53°20′42″N 113°41′42″W / 53.3451°N 113.6949°W / 53.3451; -113.6949 (Winterburn Group)
Region  Alberta
Country  Canada
Type section
Named for Winterburn, Edmonton
Named by Imperial Oil Limited, 1950

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

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[edit]

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[edit]

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

Distribution[edit]

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[edit]

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-unit Age Lithology Max.
Thickness
Reference
Graminia Formation Frasnian silty dolomite, anhydrite, siltstone
Blue Ridge Member:[3] silty dolomite, siltstone
18.3 m (60 ft) [4]
Calmar Formation Frasnian dolomitic shale and siltstone, anhydrite 13.4 m (40 ft) [5]
Nisku Formation Frasnian crystalline dolomite, dolomitic siltstone, green shale, anhydrite. 100 m (330 ft) [6]

Relationship to other units[edit]

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.

References[edit]

  1. ^ a b c d Lexicon of Canadian Geologic Units. "Winterburn Group". 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". Retrieved 2011-04-02. 
  4. ^ Lexicon of Canadian Geologic Units. "Graminia Formation". Retrieved 2009-12-31. 
  5. ^ Lexicon of Canadian Geologic Units. "Calmar Formation". Retrieved 2009-12-31. 
  6. ^ Lexicon of Canadian Geologic Units. "Nisku Formation". Retrieved 2009-12-31.