ABSTRACT

A roadcut on the improved Kananaskis Forestry Trunk Road, near Fortress Mountain Junction, exposes the Pennsylvanian Spray Lakes Group (McGugan and Rapson, 1963) including the Lower Pennsylvanian Tunnel Mountain Formation (restricted, McGugan and Rapson, 1961), overlain disconformably by the Lower Middle Pennsylvanian (Lower Atokan, Bashkirian to Lower Moscovian) Kananaskis Formation (McGugan and Rapson, 1961) with Profusulinella cf. fittsi (Thompson), in turn disconformably overlain by the Lower Permian Johnston Canyon Formation, Ishbel Group (McGugan and Rapson, 1963). Considerable relief can be demonstrated on the disconformities involved. Reliable correlations can be made south to the Elk Valley and west and north to the type section of the Kananaskis Formation on Mount Chester and the well-known succession on Tunnel Mountain, Banff. East of the Kananaskis Valley on the Front Range, thin but laterally persistent Pennsylvanian and Permian "feather edge" condensates are developed toward the easterly shoreline, and rocks of these ages are absent in the Foothills subsurface farther east. The Kananaskis Formation is correlative with carbonate erosional remnants named the Hanington Formation (Bamber and Macqueen, 1979) with Profusulinella in northeastern British Columbia. Rocks of similar age, with Profusulinella, have been reported from Utah, Oklahoma, Texas, the Russian Platform and China.