Unit Name: Mattson Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: late Visean, V3 - POSSIBLE early Namurian (332 - 320.7 ma)
Age Justification: Palynomorphs and other plant remains are the predominant fossils, but in the upper Mattson pelmatozoans, brachiopods, bryozoans and other invertebrate fossils are locally common.
Province/Territory: British Columbia; Northwest Territories; Yukon Territory

Originator: Patton, 1958.

Type Locality:
North side of Jackfish Gap, Yohin Ridge, 31 km (19 mi) west of Nahanni Butte, southwest District of Mackenzie (61 deg 06'N, 123 deg 59'W).

Distribution:
Widely distributed in the Liard and Labiche ranges Tlogotsho Plateau of the southern Mackenzie Mountains, District of Mackenzie, in the Liard Plateau and Beaver River Basin of the Yukon, and northeast British Columbia. Recorded thicknesses range between 0 and 1,412 m (0 and 4,630 ft, 935 m (3,068 ft) at the type section), thickest near the Yukon-District of Mackenzie border. To the east of the Mackenzie Mountains it thins to zero in part due to post-depositional erosion and in part to depositional thinning.

Lithology:
Chiefly sandstones fine- to medium-grained, submature to mature, and siliceous to calcareous and dolomitic with thin intervals of shale, limestone, dolomite and minor amounts of chert and coal. Much of the Mattson is subdivided into three informal members. Sandstones in the upper member's upper half are largely chertarenites and subchertarenites; whereas quartzarenites predominate elsewhere. In the northeast the lower member consists mainly of coarsening-up cycles of sandstone and shale, but southwestward sandstone turbidites become predominant. Fining-up cycles of sandstone and shale dominate the middle member, and the upper member comprises both fining- and coarsening-up cycles of sandstone and shale that are separated by intervals of carbonates and chert. Tabular and ripple cross-bedding dominate the fining-up cycle, and the coarsening-up cycles are characterized by horizontal stratification and ripple, tabular and trough cross-bedding.

Relationship:
Conformably overlies the Flett, Golata and Besa River formations, intertongues southwestward with the Besa River, and is unconformably overlain by the Kindle and Belloy (B.C.) formations and Fort St. John Gp. In northeast British Columbia, much of the Stoddart Gp is equivalent to the Mattson and occurs in the same lithosome. It is equivalent to the upper part of the Mount Head Fm and Etherington Fm of southwestern Alberta.

Other Citations:
Bamber and Mamet, 1978; Bamber et al., 1968; Braman and Hills, 1977a, 1977b; Douglas, 1976a, 1976b; Douglas and D.K. Norris, 1959, 1960, 1977a, 1977b; Gabrielse and Blusson, 1969; Harker, 1961, 1963; Laudon and Chronic, 1947, 1949; Nassichuk and Bamber, 1978; Patton, 1958; Pelzer, 1966; Richards, in prep.

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: B.C. Richards; P.A. Monahan; L.V. Hills; D.R. Braman
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 28 Jun 2004