The Rundle Group is a stratigraphic 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.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.
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. Dolomitization is observed in the Elkton Member of the Turner Valley Formation.
Distribution The Rundle Group reaches a maximum thickness of 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.
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.
The Rundle Group can be correlated with the Mission Canyon Formation in southern Saskatchewan, northeastern Montana and North Dakota.
Subdivisions The Rundle Group includes 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. Debolt, Shunda and Pekisko formations are staked in the Fort Nelson area.
Canadian Rockies Sub-unit Age Lithology Max.thickness ReferenceMount Head Formation Visean Wileman Member - silty dolomiteBaril Member - ooid grainstone, dolomiteSalter Member - dolomite, boundstone and wackestone, ooid grainstone, anhydrite chertLoomis Member - massive grainstoneMarston Member - microcrystalline dolomite, boundstone, breccia, ooid limestone, shale, marlstoneOpal Member - grainstone, subordinate marlstone, chert packstone and wackestone, shale, marlstone, brecciaCarnarvon Member - wackestone to packstone, shale interbeds Livingstone Formation Tournaisian to Visean crinoidal limestone, massive limestone, thin argillaceous limestone beds, dolomite
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 Shunda Formation Tournaisian to Visean argillaceous limestone and dolomite, siltstone, sandstone, shale, breccia, anhydrite Pekisko Formation Tournaisian Upper Pekisko - lithographic limestoneLower Pekisko - massive crinoidal limestone
Deep basin Sub-unit Age Lithology Max.thickness Reference Debolt Formation Meramecian Upper Debolt - crystalline dolomite, anhydrite, micritic limestoneLower Debolt - cherty bioclastic (crinoidal) limestone, argillaceous in the north Prophet Formation middle Tournaisian to late Visean chert, skeletal to ooid limestone, shale, marlstone, dolomite
References