Dunvegan Formation Stratigraphic range: Cenomanian |
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Dunvegan Sandstone
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Type | Geological formation |
Underlies | Smoky Group |
Overlies | Fort St. John Group (Shaftesbury Formation) |
Thickness | up to 380 feet (120 m) |
Lithology | |
Primary | Sandstone |
Other | Shale |
Location | |
Coordinates | 55°55′14″N 118°37′55″W / 55.92043°N 118.63203°WCoordinates: 55°55′14″N 118°37′55″W / 55.92043°N 118.63203°W |
Region | Northeast British Columbia Northwest Alberta |
Country | Canada |
Type section | |
Named for | Dunvegan, Alberta |
Named by | George Mercer Dawson, 1881 |
The Dunvegan Formation is a stratigraphical unit of Cenomanian age in the Western Canadian Sedimentary Basin.
It takes the name from the settlement of Dunvegan, Alberta, and was first described in an outcrop on Peace River near Dunvegan by George Mercer Dawson in 1881.
The Dunvegan Formation is composed of marine, and deltaic sandstone with thin shale interbeds in the Peace River Country. East of Dunvegan, Alberta it is of marine origin, and in its western reaches in British Columbia it was deposited in a continental facies, where the sandstone becomes more conglomeratic. During Dunvegan time, a brackish water environment was present in the Wapiti River area and south of Grande Prairie, where the formation is porous.
The Dunvegan Formation had an initial established recoverable oil reserve of 9.9 million m³, with 3.1 million m³ already produced as of 2008.Gas reserves totaled 18.7 million m³, with 4.5 million m³ already produced.
The Dunvegan Formation is 180 feet (50 m) thick in its type locality in Peace River Country and up to 380 feet (120 m) in the sub-surface of the Canadian Rockies foothills. It occurs south of Fort Nelson and the Liard River in north-east British Columbia, thins out south of the Peace River Country. South of the Athabasca River, the Dunvegan grades laterally into the Blackstone Formation.