Rundle Group Explained

Rundle Group
Type:Geological formation
Period:Mississippian
Prilithology:Limestone
Otherlithology:Chert
Namedfor:Mount Rundle
Namedby:R.J.W. Douglas, 1953
Region:,
Country: Canada
Coordinates:51.1302°N -115.4777°W
Subunits:Debolt, Shunda, Pekisko, Mount Head, Livingstone, Turner Valley, Prophet
Underlies:Fernie Formation, Belloy Formation
Overlies:Banff Formation
Thickness:up to 741m (2,431feet)[1]

The Rundle Group is a stratigraphical unit of Mississippian age in the Western Canadian Sedimentary Basin.

It takes the name from Mount Rundle (itself taking the name from Robert Terrill Rundle), and was first described in outcrops at the northern side of the mountain in Banff National Park by R.J.W. Douglas in 1953.[2]

Lithology

The Rundle Group consists of massive limestone interbedded with dark argillaceous limestone. Chert nodules are observed in the shaley beds, and crinoids and brachiopods are observed in the clean massive beds.[1] Dolimitization is observed in the Elkton Member of the Turner Valley Formation.

Distribution

The Rundle Group reaches a maximum thickness of 741feet at Tunnel Mountain. It thins out toward east and north and is completely eroded or absent in east central and only the lower part occurs in southern Alberta.[1]

Relationship to other units

The Rundle Group is disconformably overlain by the Rocky Mountain Formation in the front ranges of the Canadian Rockies and by the Fernie Formation in the foothills and by Cretaceous beds in the prairies. It conformably overlies the Banff Formation.[1]

The Rundle Group can be correlated with the Mission Canyon Formation in southern Saskatchewan, northeastern Montana and North Dakota.

Subdivisions

The Rundle Group comprises the Mount Head Formation and Livingstone Formation in the Rocky Mountains; by the Turner Valley Formation, Shunda Formation and Pekisko Formation in the foothills and plains. It is equivalent to the Debolt Formation and Prophet Formation in north-eastern British Columbia and west-northern Alberta.[1] Debolt, Shunda and Pekisko Formations are staked in the Fort Nelson area.

Canadian Rockies

Lithology Max.
Thickness
Reference
Wileman Member - silty dolomite
Baril Member - ooid grainstone, dolomite
Salter Member - dolomite, boundstone and wackestone, ooid grainstone, anhydritechert
Loomis Member - massive grainstone
Marston Member - microcrystalline dolomite, boundstone, breccia, ooid limestone, shale, marlstone
Opal Member - grainstone, subordinate marlstone, chert packstone and wackestone, shale, marlstone, breccia
Carnarvon Member - wackestone to packstone, shale interbeds
7.6-1NaN-1
39-1NaN-1
67-1NaN-1
101-1NaN-1
68-1NaN-1
161-1NaN-1
90-1NaN-1
[3]
crinoidal limestone, massive limestone, thin argillaceous limestone beds, dolomite 452-1NaN-1[4]

Foothills and plains

Lithology Max.
Thickness
Reference
110-1NaN-1[5]
122-1NaN-1[6]
134-1NaN-1[7]

Deep basin

Lithology Max.
Thickness
Reference
Upper Debolt - crystalline dolomite, anhydrite, micritic limestone
Lower Debolt - cherty bioclastic (crinoidal) limestone, argillaceous in the north
366-1NaN-1[8]
chert, skeletal to ooid limestone, shale, marlstone, dolomite 760-1NaN-1[9]

Notes and References

  1. Web site: Rundle Group. . 2009-02-12.
  2. Douglas, R.J.W., 1953b. Carboniferous stratigraphy in the southern Foothills of Alberta; Alberta Soc. Petrol. Geol., 3rd Ann. Field Conf. Guidebook, p. 66–88.
  3. Web site: Mount Head Formation. . 2009-02-12.
  4. Web site: Livingstone Formation. . 2009-02-12.
  5. Web site: Turner Valley Formation. . 2009-02-12.
  6. Web site: Shunda Formation. . 2009-02-12.
  7. Web site: Pekisko Formation. . 2009-02-12.
  8. Web site: Debolt Formation. . 2009-02-12.
  9. Web site: Prophet Formation. . 2009-02-12.