The Ishbel Group is a stratigraphic unit of Permian age in the Western Canadian Sedimentary Basin . It is present in the Canadian Rockies of Alberta and British Columbia . First defined by A. McGugan in 1963,[ 2] Mount Ishbel of the Sawback Range in Banff National Park , and parts of the group were first described in the vicinity of the mountain at Ranger Canyon and Johnston Canyon .[ 3]
Lithology
The Ishbel Group is composed of carbonate rocks (limestone and dolomite ) and sandstone , with minor chert and siltstone .
[ 1] [ 3] Phosphoria Formation to the south in United States.[ 3]
Paleontology
Among the fossils that have been found in the Ishbel Group are corals , bryozoa , crinoids , and conodonts ,[ 3] productid , chonetid and spiriferid brachiopods , omphalotrochid gastropods , and edestid elasmobranch fish.[ 4]
Distribution
The Ishbel Group reaches a maximum thickness of up to about 425 metres (1400 ft). It is present in the front ranges of the Canadian Rockies as far north as the Peace River .[ 1] [ 3]
Subdivisions
Sub-unit Age Lithology
Max.
Reference
Kindle Formation Asselian to early Artinskian siltstone , shale 200 m (660 ft)
[ 5]
Belloy Formation Permian limestone , dolomite , and sandstone 274 m (900 ft)
[ 6]
Fantasque Formation Permian spicular chert, shale , and siltstone
55 m (180 ft)
[ 7]
Mowitch Formation Roadian to Wordian sandstone with gypsum
76 m (250 ft)
[ 8]
Ranger Canyon Formation Roadian to Wordian dark chert , silicified sandstone, evaporite minerals
30 m (100 ft)
[ 9]
Ross Creek Formation late Sakmarian to Artinskian
shaly siltstone , calcareous siltstone , silty carbonate , phosphatic coquinas
143 m (470 ft)
[ 10]
Telford Formation Asselian to Sakmarian sandy limestone and dolomite
259 m (850 ft)
[ 11]
Johnston Canyon Formation late Sakmarian to Artinskian
phosphatic siltstone , calcareous siltstone , and silty limestone and dolomite
57 m (190 ft)
[ 12]
Belcourt Formation Asselian to Sakmarian silty dolomite with chert
130 m (430 ft)
[ 13]
Relationship to other units
The Ishbel Group is disnconformably overlain by the Spray River Group and unconformably overlies the Tunnel Mountain Formation and the Kananaskis Formation .[ 1] Phosphoria Formation of Montana , Idaho , Wyoming , and Utah .[ 3]
References
^ a b c d
Lexicon of Canadian Geologic Units . "Ishbel Group" . Retrieved 2010-01-01 .
^ McGugan, A., 1963. A Permian brachiopod and fusulinid fauna from Elk Valley, British Columbia, Canada. Journal of Paleontology , v. 37, p. 621-627.
^ a b c d e f Glass, D.J. (editor) 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba. Canadian Society of Petroleum Geologists, Calgary, 1423 p. on CD-ROM. ISBN 0-920230-23-7 .
^ Journal of Paleontology. "Biostratigraphy and faunas of the Permian Ishbel Group, Canadian Rocky Mountains" . Retrieved 2010-01-10 . ^ Lexicon of Canadian Geologic Units . "Kindle Formation" . Retrieved 2010-01-09 .^ Lexicon of Canadian Geologic Units . "Belloy Formation" . Archived from the original on 2012-07-08. Retrieved 2010-01-09 .^ Lexicon of Canadian Geologic Units . "Fantasque Formation" . Retrieved 2010-01-09 .^ Lexicon of Canadian Geologic Units . "Mowitch Formation" . Retrieved 2010-01-09 .^ Lexicon of Canadian Geologic Units . "Ranger Canyon Formation" . Retrieved 2010-01-09 .^ Lexicon of Canadian Geologic Units . "Ross Creek Formation" . Retrieved 2010-01-09 .^ Lexicon of Canadian Geologic Units . "Telford Formation" . Retrieved 2010-01-09 .^ Lexicon of Canadian Geologic Units . "Johnston Canyon Formation" . Retrieved 2010-01-09 .^ Lexicon of Canadian Geologic Units . "Belcourt Formation" . Retrieved 2010-01-09 .
