Rundle Group

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

Rundle Group
Stratigraphic range: Middle to Late Mississippian PreꞒ Ꞓ O S D C P T J K Pg N
The massive limestone beds form outcrops at the top of Mount Rundle
Type	Geological formation
Sub-units	Debolt, Shunda, Pekisko, Mount Head, Livingstone, Turner Valley, Prophet
Underlies	Fernie Formation, Belloy Formation
Overlies	Banff Formation
Thickness	up to 741 metres (2,430 ft)^[1]
Lithology
Primary	Limestone
Other	Chert
Location
Coordinates	51°07′49″N 115°28′40″W / 51.13020°N 115.47765°W / 51.13020; -115.47765 (Rundle Group)
Region	Alberta,  British Columbia
Country	Canada
Type section
Named for	Mount Rundle
Named by	R.J.W. Douglas, 1953

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 741 feet (230 m) 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

Sub-unit	Age	Lithology	Max. Thickness	Reference
Mount Head Formation	Visean	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 m (20 ft) 39 m (130 ft) 67 m (220 ft) 101 m (330 ft) 68 m (220 ft) 161 m (530 ft) 90 m (300 ft)	^[3]
Livingstone Formation	Tournaisian to Visean	crinoidal limestone, massive limestone, thin argillaceous limestone beds, dolomite	452 m (1,480 ft)	^[4]

Foothills and plains

Sub-unit	Age	Lithology	Max. Thickness	Reference
Turner Valley Formation	Visean	crinoidal limestone and crystalline dolomite; two porous intervals are separated by a middle tight unit; diagenetically dolomitized in west southern Alberta; Lower porous zone is defined as Elkton Member	110 m (360 ft)	^[5]
Shunda Formation	Tournaisian to Visean	argillaceous limestone and dolomite, siltstone, sandstone, shale, breccia, anhydrite	122 m (400 ft)	^[6]
Pekisko Formation	Tournaisian	Upper Pekisko - lithographic limestone Lower Pekisko - massive crinoidal limestone	134 m (440 ft)	^[7]

Deep basin

Sub-unit	Age	Lithology	Max. Thickness	Reference
Debolt Formation	Meramecian	Upper Debolt - crystalline dolomite, anhydrite, micritic limestone Lower Debolt - cherty bioclastic (crinoidal) limestone, argillaceous in the north	366 m (1,200 ft)	^[8]
Prophet Formation	middle Tournaisian to late Visean	chert, skeletal to ooid limestone, shale, marlstone, dolomite	760 m (2,490 ft)	^[9]

References

1. Lexicon of Canadian Geologic Units. "Rundle Group". Retrieved 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. Lexicon of Canadian Geologic Units. "Mount Head Formation". Retrieved 2009-02-12.
4. Lexicon of Canadian Geologic Units. "Livingstone Formation". Retrieved 2009-02-12.
5. Lexicon of Canadian Geologic Units. "Turner Valley Formation". Retrieved 2009-02-12.
6. Lexicon of Canadian Geologic Units. "Shunda Formation". Retrieved 2009-02-12.
7. Lexicon of Canadian Geologic Units. "Pekisko Formation". Retrieved 2009-02-12.
8. Lexicon of Canadian Geologic Units. "Debolt Formation". Retrieved 2009-02-12.
9. Lexicon of Canadian Geologic Units. "Prophet Formation". Retrieved 2009-02-12.