Gog Group

The Gog Group is a stratigraphic unit in the Western Canada Sedimentary Basin. It is present in the western main ranges of the Canadian Rockies in Alberta and British Columbia, and in the Cariboo Mountains and in the central Purcell Mountains in southwestern British Columbia.[2][3] It was named by C.F. Deiss in 1940 for a type locality near Mount Assiniboine.[1][4]

Gog Group Stratigraphic range: Early Cambrian) PreꞒ Ꞓ O S D C P T J K Pg N
Trace fossils in a slab from the Gog Group.
Type	Group
Sub-units	see text
Underlies	Mount Whyte Formation, Chancellor Group, Snake Indian Formation
Overlies	Miette Group
Thickness	up to 2,180 metres (7,150 ft)
Lithology
Primary	Quartzose sandstone, quartzite, conglomerate
Other	Siltstone, mudstone, limestone, dolomite
Location
Region	Alberta  British Columbia
Country	Canada
Type section
Named by	C.F. Deiss, 1940[1]

Lithology and environment of deposition

The Gog Group consists primarily of thick deposits of cross-bedded quartzose sandstone and quartzite, with minor quartzitic conglomerate and sub-arkosic sandstone. It also includes mudstone, siltstone, limestone and dolomite formations. The Gog sediments are thought to have been deposited in shallow marine environments on the subsiding margin of the North American craton (Laurentia).[2][3][5]

Stratigraphy

Subdivisions

The Gog Group is subdivided into the following formations:

Jasper area (north)

Formation	Age	Lithology	Maximum Thickness	Reference
Hota Formation	late Early Cambrian	arenaceous limestone	244 m (800 ft)	[2][4][6]
Mahato Formation	Early Cambrian	quartzose sandstone	240 m (790 ft)	[2][4][6]
Mural Formation	Early Cambrian	limestone, dolomite, shale, quartzose sandstone	545 m (1,790 ft)	[2][4][6]
McNaughton Formation	Early Cambrian	quartzose sandstone, quartzite, arkosic sandstone, conglomerate	600 m (1,970 ft)	[2][4][6]
Jasper Formation	Early Cambrian	arkosic sandstone, quartzite, conglomerate, argillite	500 m (1,640 ft)	[2][4][6]

Kicking Horse Pass area (south)

Formation	Age	Lithology	Max. Thickness	Reference
Peyto Formation	late Early Cambrian	limestone, dolomite	125 m (410 ft)	[2][4][6]
St. Piran Formation	Early Cambrian	quartzose sandstone	825 m (2,710 ft)	[2][4][6]
Lake Louise Formation	Early Cambrian	limestone, dolomite, shale, quartzose sandstone		[2][4][6]
Fort Mountain Formation	Early Cambrian	quartzose sandstone, quartzite, arkosic sandstone, conglomerate	510 m (1,670 ft)	[2][4][6]
Jasper Formation	Early Cambrian	arkosic sandstone, quartzite, conglomerate, argillite	500 m (1,640 ft)	[2][4][6]

Paleontology

Trace fossils such as Skolithos, Cruziana, Diplocraterion, Chondrites, Planolites, Rusophycus and others are abundant in the Gog Group sediments, and Early Cambrian trilobites of the genus Olenellus are found in the Peyto Formation limestones at the top of the Group.[2][5] Small archaeocyathid bioherms have been reported from the base of the Mahato Formation, and archaeocyathids, salterellids, primitive brachiopods and echinoderms have been reported from the Mural Formation.[4]

See also

• List of fossiliferous stratigraphic units in Alberta
• Big Rock (glacial erratic)
• Foothills Erratics Train

References

1. Deiss, C.F. 1940. Lower and Middle Cambrian stratigraphy of southwestern Alberta and southeastern British Columbia. Geological Society of America Bulletin, vol. 57, p. 731-794.
2. Hein, H. J., and M. E. McMechan (1994). Chapter 6 Proterozoic and Lower Cambrian Strata of the Western Canada Sedimentary Basin; in Geological Atlas of the Western Canada Sedimentary Basin, G.D. Mossop and I. Shetsen (comp.). Alberta, Canada: Canadian Society of Petroleum Geologists and Alberta Research Council.[Last accessed 28 June 2016].
3. Desjardins, P.R., Buatois, L.A., Pratt, B.E. and Mágano, M.G. 2010. Stratigraphy and sedimentary environments of the Lower Cambrian Gog Group in the southern Rocky Mountains of western Canada. Bulletin of Canadian Petroleum Geology, vol. 58, p. 403-439.
4. 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.
5. Hein, F.J. and Arnott, R.W. 1983. Precambrian Miette conglomerates, Lower Cambrian Gog quartzites and modern braided outwash deposits, Kicking Horse Pass area. Canadian Society of Petroleum Geologists Field Trip Guidebook, 1983, 46 p.
6. Alberta Geological Survey, 2013. "Alberta Table of Formations; Alberta Energy Regulator". Retrieved 2016-06-20.