Unit Name: Hume Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Eifelian - Givetian (397.5 - 385.3 ma)
Age Justification: Well-preserved fauna of brachiopods, corals, conodonts and trilobites. Lower Hume beds contain a fauna characterized by Schuchertella nevadensis, whereas the upper Hume is characterized by Spinulicosta stainbrooki and the uppermost few feet of beds contain Leiorhynchus castanea.
Province/Territory: Northwest Territories

Originator: Bassett, 1961.

Type Locality:
Type section at the front of Mackenzie Mountains on the east branch of the Hume River at 65 deg 20'30"N and 129 deg 58'W.

Distribution:
122 m (400 ft) thick at the type section and extends throughout the northern Mackenzie Mountains and Mackenzie Plain. The Hume thickens slightly westward to about 160 m (525 ft). Generally it is of remarkably uniform thickness.

Lithology:
A relatively resistant thin upper part composed of light grey, thin to thick-bedded fossiliferous limestone overlies a recessive brownish-grey to medium grey argillaceous and fossiliferous limestone with abundant interbeds of brown to dark grey calcareous shale. Further west in the Mackenzie Mountains the lower part weathers greyish-green and yellowish-orange.

Relationship:
The Hume Fm conformably overlies the Landry, Gossage and Bear Rock formations and is conformably overlain by the Hare Indian shale. Previously the Hume Fm was thought to rest disconformably on the Bear Rock Fm and at some places, such as at Rouge Mountain River, this may be true, but the overall relationship appears to be one of conformity. Southward, the upper part of the Hume passes to the Nahanni Fm and the lower part passes to the Headless Fm. Northward, the Hume passes to the Blue Fiord Fm of the Arctic Archipelago. Westward, the Hume passes to the Road River shales. The Ebbutt Member of the Willow Lake Fm extends northeastward from the type section into the lower Hume Fm. A.W. Norris (1968) demonstrated a disconformable contact between the Hume Fm and the overlying Canol Fm. It is laterally equivalent to the Keg River Fm. The Hume and overlying Hare Indian formations are time equivalents of the upper part of the Ogilvie Fm.

Other Citations:
Aitken and Cook, 1974a; Aitken et al., in press; Balkwill and Yorath, 1970a, 1970b; Bassett, 1961; Braun, 1978; Caldwell, 1964; Chatterton, 1978; Cook and Aitken, 1971; Copper, 1978; Hume and Link, 1945; Law, 1971; Lawrence, 1973; Lenz and Pedder, 1972; A.W. Norris, 1967a, 1967b, 1968; Tassonyi, 1969; Uyeno, 1978; Uyeno and Mason, 1975.

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: D.C. Pugh; L.V. Hills; D.W. Morrow
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 29 Apr 2003