Elk Point Group Stratigraphic range: Early to Middle Devonian |
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Type | Geological formation |
Sub-units | Upper and Lower Elk Point Group |
Underlies | Beaverhill Lake Group, Manitoba Group |
Overlies | Precambrian to Silurian formations |
Thickness | up to 610 metres (2,000 ft) |
Lithology | |
Primary | Dolomite, halite, anhydrite |
Other | Limestone, shale, potash |
Location | |
Coordinates | 53°54′19″N 110°37′49″W / 53.9053°N 110.6304°WCoordinates: 53°54′19″N 110°37′49″W / 53.9053°N 110.6304°W |
Region | Northern plains |
Country | Canada United States |
Type section | |
Named for | Elk Point |
Named by | J.R. McGehee |
The Elk Point Group is a stratigraphic unit of Early to Middle Devonian age in the Western Canada and Williston sedimentary basins. It underlies large area that extends from southern boundary of the Northwest Territories in Canada to North Dakota in the United States. It has been subdivided into numerous formations, many which host major petroleum and natural gas reservoirs.
The formations of the Elk Point Group are composed primarily of carbonate rocks (dolostone and limestone) and evaporitic rocks (halite, anhydrite and potash), with lesser amounts of dolomitic mudstone and shale.
Some of the carbonate formations of the Elk Point Group contain rich assemblages of marine invertebrate fossils, including many species of brachiopods, gastropods, bivalves, cephalopods, crinoids, ostracods and corals. The evaporitic formations are unfossiliferous or contain a few spores and algal remains.