Unit Name: Banff Formation
Unit Type: Lithostratigraphic
Usage: Currently in use
Age Interval: late Famennian - Tournaisian (364.3 - 345.3 ma)
Age Justification: Biostratigraphy.
Province/Territory: Alberta; British Columbia; Northwest Territories
Originator: Kindle, 1924b; Warren, 1927.
Northwest end of Mount Rundle, near Banff; 51° 09'54"N, 115° 31'08"W; NTS 82O/4, southwestern Alberta (Warren, 1927; Macqueen and Bamber, 1967).
The Banff extends from the United States border in southern Alberta and southeastern British Columbia into southwestern District of Mackenzie (Macauley et al., 1964). At its structurally thickened stratotype it is 366 to 411 m (1,201 to 1,348 ft) thick (Macqueen and Bamber, 1967). The southern Banff thins slowly northeastward below the Rundle Group, ranging from more than 400 m (1,312 ft) in the Rocky Mountains to about 150 m (492 ft) on the plains. In the Peace River Embayment and farther northward the formation thins slowly below the Rundle from more than 450 m (1,476 ft) in the southwest to about 300 m (984 ft) in the northeast. Thinning is accompanied by a decrease in the proportions of chert and shale and a corresponding increase in that of limestone, siltstone and sandstone. Northeastward of the subcrop edge of the Rundle the Band is rapidly truncated beneath Mesozoic strata.
Thickness(m): Minimum 150, Maximum 450.
The Banff Formation was partly divided into a lower, middle and upper member by Clark (1949) and members A to F by (Richards et al., in press). In general the formation comprises a lower succession of shale and marlstone grading upward and eastward into spiculite, bedded chert and carbonates that pass into interbedded sandstone, siltstone, and shale. Member A, forming the basal Banff ranges in thickness from <8 m (26 ft) in southwestern Alberta to about 490 m (1,607 ft) in the northwest. The member consists of black to dark grey shale with subordinate turbiditic sandstone and silty to cherty carbonates. Member B, extending from southern Alberta into northeastern British Columbia gradationally overlies member A and ranges from 50 to 250 m (164 to 820 ft) in thickness. Member B, partly equivalent to the informal Clark's Member of Sikabonyi and Rodgers (1959) constitutes the middle Banff or most of the lower and middle Banff. Lower and southwestern facies are laminated to rhythmically bedded, cherty to argillaceous dark grey spiculite, siltstone, dolostone, lime mudstone and wackestone. These deposits grade upward and northeastward into medium bedded, cherty, dark grey, bryozoan-pelmatozoan lime packstone to wackestone. The latter pass into massive to cross-stratified, medium to light grey lime grainstone which is medium- to very thick-bedded. Member C is widely distributed on the interior Plains and in the eastern Cordillera from southern Alberta to east-central British Columbia. Normally less than 100 m (328 ft) thick, medium bedded member C gradationally overlies and passes southwestward into the more resistant upper member B. Southwestern occurrences of member C comprise medium grey, cherty, skeletal lime wackestone and packstone with subordinate shale, marlstone and dolostone. These deposits pass northeastward into medium grey, algal-peloid lime wackestone and fenestral, cryptalgal carbonates associated with shale, silty dolostone and anhydrite. Member D is present on the plains from southern Alberta into northeastern British Columbia and occurs locally in the Foothills of Alberta. It gradationally overlies member B or C and ranges in thickness from <40 m (131 ft) in the south to >135 m (443 ft) in the northwest. The thin- to medium-bedded member comprises interbedded light olive grey siltstone, silty to sandy carbonates, sandstone and dark grey to greenish grey shale. Small scale cross-bedding is common in eastern and upper member D. Member E, present in the eastern Cordillera of southwestern Alberta and the western part of the southern plains, generally conformably overlies member B and passes northeastward into the basal Pekisko Formation. This medium to thick bedded member is generally greater than 30 m (98 ft) thick. It contains rhythmically bedded turbidite-like beds, and consists of dark grey cherty, spiculitic, skeletal lime packstone and wackestone. Member F, correlative with the middle to upper Pekisko Formation and the basal Shunda Formation, overlies member E and occurs in the same areas. This medium- to thick-bedded member, less resistant and more argillaceous than member E comprises marlstone, rhythmically interbedded with dark grey dolostone and cherty, pelmatozoan wackestone to packstone. The member, generally more than 130 m (426 ft) thick in the northeast, thickens southwestward in the eastern front ranges. Most of the Banff is undivided in the southernmost interior plains and in the southernmost Rocky Mountains. The undivided Banff overlies member A and consists of dark grey, laminated to thin-bedded spicular chert and cherty lime mudstone to wackestone that grade upward into medium-bedded chert and cherty bryozoan-pelmatozoan limestone.
The Banff unconformably overlies the Palliser Formation in the central Rocky Mountains and commonly the Wabamun and older strata in the Peace River Embayment of west-central Alberta (Richards and Higgins, 1988; Richards, 1989). To the south the Banff generally unconformably overlies the Exshaw, but to the north the basal Banff becomes older northward as the Exshaw passes laterally into it. The Pekisko and Livingstone formations overlie the Banff (Macqueen et al., 1972; Chatellier, 1988) except in northeastern British Columbia, where an unnamed correlative of the Shunda Formation commonly overlies it. The Banff/Pekisko contact is erosional except on the southern interior plains and in the southeastern Cordillera, where it is gradational. Members E and F of the Banff pass laterally into the Pekisko Formation toward the northeast in the southeastern Cordillera (Moore, 1958; Richards, 1989). Basinward (generally southwestward) of the southwestern limit of the Pekisko the Livingstone overlies the Banff and passes basinward into it. The southern Banff is lithologically and stratigraphically equivalent to the Lodgepole Formation. Their arbitrary nomenclatural boundary lies along the Sweetgrass Arch in southeastern Alberta and along the 49th parallel. In northeastern British Columbia the Banff passes southwestward into the Besa River Formation (Bamber and Mamet, 1978). Northeast of the subcrop edge of the overlying Rundle Group Mesozoic strata unconformably overlie the Banff.
The name Banff series was introduced by McConnell (1887) for a thick succession of Devonian to Triassic strata near Banff, Alberta. Kindle (1924) restricted the Banff to include only the lower Banff shales of McConnell and called that unit the Banff Formation. Kindle (1924) and Warren (1927) included in the basal type Banff Formation a black shale unit and overlying siltstone unit that jointly constitute the Exshaw Formation. Warren (1937) restricted the Banff by designating the black shale unit the Exshaw Formation. Clark (1949) and Macqueen and Sandberg (1970) further restricted the Banff by placing the siltstone unit into the Exshaw.
Bamber, E.W. and Mamet, B.L., 1978. Carboniferous biostratigraphy and correlation, northeastern British Columbia and southwestern District of Mackenzie; Geological Survey of Canada, Bulletin 266, 65 p.
Clark, Leslie M., 1949. Geology of Rocky Mountain Front Ranges near Bow River, Alberta; American Association of Petroleum Geologists (AAPG), AAPG Bulletin, vol. 33, no. 4 (April), pp. 614-633.
Kindle, E.M., 1924b. Standard Paleozoic section of Rocky Mountains near Banff, Alberta; Pan-American Geologist, vol. 42, no. 2 (September), pp. 113-124.
Macauley, G., Penner, D.G., Procter, R.M., and Tisdall, W.H., 1964. Carboniferous; In: Geological history of western Canada, McCrossan, R.G. and Glaister, R.P. (Eds.), p. 89-102. Alberta Soc. Petrol. Geol.
Macqueen, R.W. and Bamber, E.W., 1967. "Stratigraphy of Banff Formation and lower Rundle Group (Mississippian), southwestern Alberta (Report, 3 plates and 9 figures)"; Geological Survey of Canada, Paper 67-47, 37 p. (including 3 plates).
Macqueen, R.W., Bamber, E.W., and Mamet, B.L., 1972. Lower Carboniferous stratigraphy and sedimentology of the southern Canadian Rocky Mountains. 24th Internat. Geol. Congress, Montreal, Quebec, Guidebook, Field Excursion C17.
Moore, P.F., 1958. Late Paleozoic stratigraphy in the Rocky Mountains and foothills of Alberta - a critical historical review; in, Jurassic and Carbonifenous of western Canada; Goodman, A.J. (Ed.). Amer. Assoc. Petrol Geol., p. 145-176.
Richards, B.C. and Higgins, A.C., 1988. Devanian-Carboniferous boundary beds of the Palliser and Exshaw formations at Jura Creek, Rocky Mountains, southwestern Alberta. In: Devonian of the World; McMillan, N.J., Embry, A.F. and Glass, D.J. (Eds.). Can. Soc. Petrol. Geol., Memoir 14, v. 2, p. 399-412.
Richards, B.C., 1989. Uppermost Devonian and Lower Carboniferous stratigraphy, sedimentation and diagenesis, southwestern District of Mackenzie and southeastern Yukon Territory (NTS 95B, C, F and G). Geol. Surv Can., Bulletin 390.
Warren, P.S., 1927. Banff area, Alberta; Geological Survey of Canada, Memoir 153.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: B.C. Richards
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 24 Jun 2009