Unit Name: Fantasque Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Permian (299 - 251 ma)
Age Justification: Sparsely fossiliferous - no fossils have been described from the chert member; E.D. Kindle (1944) reports a sparse brachiopod fauna of probable Permian age from talus of the upper sandstone member.
Province/Territory: British Columbia; Northwest Territories; Yukon Territory
Originator: Named by Harker, 1961, with more complete discussion in Harker, 1963, from a section described by E.D. Kindle, 1944.
Type Locality:
Southwest side of Mount Merrill, on the north side of Beaver River, 60 deg 07'N, 124 deg 45'W. Note that no formalized type section description is given by either Harker or Kindle.
Distribution:
The type section thickness of 55 m (180 ft) appears to be close to the maximum for the Southern Yukon - Northern B.C. area in which the formation has been described. The formation thins to zero to the north and east due to truncation by the pre-Mesozoic unconformity.
Lithology:
Type section consists of 46 m ( 150 ft) of chert "in beds that vary from 0.3 to 3 m (1 to 10 ft) or more in thickness. The beds are separated by layers of shale from 2.5 to 7.6 cm (1 to 3 in) thick". This chert member is overlain by "about 9 m (30 ft) of calcareous sandstone".
Relationship:
Douglas and D.K. Norris (1959) map the Fantasque as map unit 9, and infer an unconformable relationship with the underlying Mattson Fm. The upper contact is the pre-Mesozoic unconformity, so that the Fantasque may be overlain by Triassic, Jurassic (?), or Cretaceous beds. Rock units of Permian age bounded by a major regional unconformity below and by the pre-Mesozoic unconformity above are widespread in Western Canada. Hovdebo (1962) proposed the name Chowade Group for such a unit in the Rocky Mountains to the north of the Peace River; the Belloy Fm of Halbertsma (1959) has been applied extensively in the subsurface of northeastern B.C. and northern Alberta. Equivalent to Ranger Canyon chert and Mowitch sandstone of Ishbel Gp of Southern and Central Alberta Foothills and Rockies.
Other Citations:
Douglas and D.K. Norris, 1959; Harker, 1961, 1963; Halbertsma, 1959; Hovdebo, 1962; E.D. Kindle, 1944; McGugan and Rapson, 1963; Pelzer, 1966.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 2, Yukon Territory and District of Mackenzie; L.V. Hills, E.V. Sangster and L.B. Suneby (editor)
Contributor: P.A. Monahan; E.E. Pelzer
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 28 Jun 2004