Unit Name: Muncho-McConnell Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Silurian - Devonian (443.7 - 359.2 ma)
Age Justification: Fossils are extremely rare in the Muncho-McConnell Formation. Well preserved fish originally reported as of Early Devonian age (Taylor and MacKenzie, 1970, p. 7) are now considered to be of Pridolian (latest Silurian) age. Apparently the Muncho-McConnell Formation spans the Silurian-Devonian boundary.
Province/Territory: British Columbia; Yukon Territory
Originator: Taylor, G.C., 1967; Taylor, G.C. and MacKenzie, W.S., 1970.
Type Locality:
Located on ridge north of the Alaska Highway, 4 km (2.5 mi) west of Toad River bridge at Mile 438, (km 701) directly overlying the type Nonda Formation. Geographical co-ordinates of the type section: 58 deg 48'N, 125 deg 37'W, British Columbia.
Distribution:
Recognized as far south as Pine Pass, where it onlaps the Peace River and Alberta arches, to Beaver River in southern Yukon. Thickens westerly from 60 m (197 ft) at mountain front to 350 m (1148 ft) in the Sentinel Ranges.
Lithology:
Recessive, light brown weathering, sandy, argillaceous, fine-crystalline dolomites at base, overlain by alternating medium and dark grey weathering, well bedded, finely crystalline dolomites. Local thin beds of orthoquartzite in upper part, with floating bimodal frosted sand grains in the dolomites; rare thin brown shale partings.
Relationship:
Disconformably overlies the Nonda Formation and is conformably overlain by the Wokkpash Formation in type area. South of Redfern Lake [Trutch (94G) map-area] is disconformably overlain by the Stone Formation. Further south the Muncho-McConnell pinches out against the Peace River Arch, and westward it passes to a shale facies.
History:
Laudon and Chronic (1949) named the Muncho and McConnell formations in northeastern British Columbia and designed type sections for them in the Sentinel Range east of the Alaska Highway near Mile 472. Later workers recognized that a fault cuts the type sections and moreover, were unable to recognize the same two-fold division of that interval. It became common practice to regard the interval as a single mappable unit. The hyphenated name was applied and a new type section designated revising the unit to formation status.
Other Citations:
Griffin, 1967; Laudon and Chronic, 1949; Norford et al., 1966; Taylor, 1967; Taylor and MacKenzie, 1970; Taylor and Stott, 1973.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: G.C. Taylor
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 29 Apr 2003