Unit Name: Nation River Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Late Devonian (385.3 - 359.2 ma)
Age Justification: Palynomorphs including Acanthotriletes, Ancyrospora, Archaeoperisaccus Archaeozonotriletes, Auroraspora, Calamospora, Camptozonotriletes, Convolutispora, Corystisporites, Cristatisporites, Diaphanospora. Foveosporites, Hymenozonotriletes, Hystricosporites, Leiotriletes, Leiozonotriletes, Lophozonotriletes, Lycospora, Pustulatisporites, Raistrickia, Retusotriletes and Samarisporites have been recovered from the Nation River by Scott and Doher (1967).
Province/Territory: Yukon Territory; Alaska

Originator: Brooks and E.M. Kindle, 1908.

Type Locality:
Central eastern Alaska, Nation River.

Distribution:
1,524-1,829 m ? (5,000-6,000 ft ?). Thickness generally not given. It occurs in east central Alaska and in the Yukon only in the northwest corner of the Dawson map area.

Lithology:
Chert-pebble conglomerate, chert quartz arenite, siltstone, mudstone, shale and pebbly mudstone. Sedimentary structures include flute casts, groove casts, load casts, small scale cross-stratification, uncommon medium to large scale cross-stratification, convolute lamination current ripple marks, slump structures, sandstone dykes, possible dish structures, oriented plant debris, locally trace fossils, channelling at the base of sandstone and conglomerate beds, amalgamated bedding, graded bedding and thick, massive, ungraded sandstone and conglomerate. A variety of turbidite? Bouma sequences are present (Nilsen et al., 1976). In the northwest corner of the Dawson map area, brown shale, impure brown sandstone and minor chert pebble conglomerate are assigned to the Nation River (Cairnes, 1914; L. H. Green, 1972, map-unit 13a).

Relationship:
In east central Alaska, it overlies the Calico Bluff Fm and is overlain unconformably by the Tahkandit Fm. It is similar to the Kanayut conglomerate of the Brooks Range and the Imperial Fm of the eastern Yukon and western District of Mackenzie and the Crystal Peak Fm, central Yukon. It is possible that some of the strata mapped as Nation River may belong to the Cretaceous Monster Fm (L.H. Green, 1972).

Other Citations:
Brabb and Churkin, 1964a, 1964b, 1969; Brooks and E.M. Kindle, 1908; Brosgé et al., 1962; Cairnes, 1914; R.B. Campbell, 1967; Churkin and Brabb, 1965; Gabrielse, 1967a; L.H. Green, 1972; Laudon et al., 1966; Mertie, 1930, 1933, 1937; R.C. Moore et al., 1944; Nilsen et al., 1976; Scott and Doher, 1967; Wedow, 1954.

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: L.V. Hills; A.W. Norris
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 29 Jun 2004