Snake Indian Formation

The Snake Indian Formation is a stratigraphic unit of Middle Cambrian age that is present on the western edge of the Western Canada Sedimentary Basin in the northern Canadian Rockies of Alberta and British Columbia.[3] It was named for Snake Indian River in Jasper National Park by E.W. Montjoy and J.D. Aitken in 1978. The type locality was established on Chetamon Mountain.[1]

Snake Indian Formation Stratigraphic range: Middle Cambrian ~509–500 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Formation
Underlies	Eldon Formation, Titkana Formation
Overlies	Gog Group
Thickness	Up to 610 metres (2000 ft)[1][2]
Lithology
Primary	Shale
Other	Limestone, siltstone
Location
Coordinates	53°03′07″N 118°11′57″W
Region	Canadian Rockies
Country	Canada
Type section
Named for	Snake Indian River
Named by	E.W. Montjoy and J.D. Aitken[1]

Lithology and deposition

The Snake Indian Formation was deposited in shallow marine environments along the western shoreline of the North American Craton during Middle Cambrian time. It is a thick sequence of shale and calcareous shale with interbeds of limestone and siltstone. Mudcracks in the basal shales indicate that there were periods of subaerial exposure during the early stages of deposition.[1]

Distribution and stratigraphic relationships

The Snake Indian Formation is present in the northern Canadian Rockies of Alberta and British Columbia where it reaches thicknesses of up to about 610 metres (2000 ft). It uncomformably overlies the Gog Group, and is conformably overlain by the Titkana Formation in the north and the Eldon Formation in the south. It is equivalent to the Mount Whyte, Cathedral, and Stephen Formations of the southern Canadian Rockies.[1][2][4]

Paleontology

The Snake Indian Formation is fossiliferous and includes the remains of several genera of Middle Cambrian trilobites, as well echinoderms, other marine invertebrates, and stromatolites.[1][2]

References

1. Montjoy, E.W. and Aitken, J.D. 1978. Middle Cambrian Snake Indian Formation (new), Jasper Region, Alberta. Bulletin of Canadian Petroleum Geology, vol. 26, no. 3, p. 343-361.
2. 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.
3. Slind, O.L., Andrews, G.D., Murray, D.L., Norford, B.S., Paterson, D.F., Salas, C.J., and Tawadros, E.E., Canadian Society of Petroleum Geologists and Alberta Geological Survey (1994). "The Geological Atlas of the Western Canada Sedimentary Basin (Mossop, G.D. and Shetsen, I., compilers), Chapter 8: Middle Cambrian and Early Ordovician Strata of the Western Canada Sedimentary Basin". Retrieved 2018-07-13.CS1 maint: multiple names: authors list (link)
4. Alberta Geological Survey. "Alberta Table of Formations, May 2019" (PDF). Alberta Energy Regulator. Retrieved 24 March 2020.