Unit Name: Moosebar Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: early Albian (112 - 108.8 ma)
Age Justification: Arcthoplites representative of the lower part of the generalized Arcthoplites or Beudanticeras affine Zone are of late Early Albian age. An Early to Middle Albian microfaunal assemblage of the Marginulinopsis collinsi-Verneuilinoides cummingensis subzone occurs in these beds (Caldwell et al., 1978; Stelck et al., 1956; Stott, 1968, 1982).
Province/Territory: Alberta; British Columbia
Originator: McLearn, 1923, p. 5B.
Type Locality:
Located at the southeastern end of Peace River canyon, 55 deg 58'N, 122 deg 06'N. Although McLearn indicated that the type section was on the north side of the canyon opposite Contact Point, Stott (1968, p. 48) described better exposures on the south side. Exposures on either side are now poor owing to the flooding that resulting from the construction of the lower dam on Peace River.
Distribution:
The unit occurs throughout the foothills of northeastern British Columbia south of Peace River (Stott, 1968, 1982) and extends as a thin tongue southeasterly into the Alberta Foothills (McLean, 1982; Langenberg and McMechan, 1985). The formation is about 289 m (950 ft) thick at its type location, but thins southeasterly along the foothills. It is only 43 an (141 ft) thick at Mount Torrens.
Lithology:
The formation consists of marine shale and siltstone. The basal shale is dark grey, rubbly to blocky and commonly concretionary. A thin bed of pebbles and glauconitic mudstone commonly marks the contact with the Gething Formation. The silt content increases in the upper beds, and silty mudstones and thin platy siltstone occur toward the top.
Relationship:
The formation lies abruptly on the Gething Formation, but is gradational into the overlying sandstones of the Gates Formation. It is equivalent to the Wilrich Member of the Spirit River Formation of the Peace River Plains and to the basal part of the Buckinghorse Formation between Peace and Tetsa rivers and part of the Garbutt Formation of the Liard River region.
History:
Defined by McLearn (1923, p. 5B) and later more precisely summarized (McLearn and Kindle, 1950, p. 74) as the lowest formation of the Fort St. John Group in the Pine and Peace River valleys, lying between the Gething Formation of the Bullhead Group and the Gates or Commotion formation above.
Other Citations:
Caldwell et al., 1976; Langenberg and McMechan, 1985; McLean, 1982; McLearn, 1923; McLearn and Kindle, 1950; Stelck et al., 1956; Stott, 1968, 1982.
References:
McLearn, F.H., 1923. Peace River Canyon Coal Area, British Columbia; Geological Survey of Canada, Summary Report 1922, Part B, pp. 1-46.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: D.F. Stott
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 28 May 2008