Unit Name: Midas Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Early Cambrian (542 - 513 ma)
Province/Territory: British Columbia
Originator: Holland, S.S., 1954; Sutherland-Brown, A., 1963; Campbell, R.B., et al., 1973.
Type Locality:
Reference Section: Headwaters of Dome Creek, northern Cariboo Mountains (53 deg 36'N, 121 deg 01'W), British Columbia.
Distribution:
The Midas Formation crops out in numerous discontinuous localities in the Cariboo Mountains, and is poorly exposed due to its recessive character. It is 148 m (485 ft) thick at its reference section at Dome Creek, thinning to about 100 m (328 ft) at Zig Zag Ridge near the Southern Rocky Mountain trench, and becoming thinner and sandier eastward.
Lithology:
The Midas Formation is a recessive weathering, dark argillaceous unit comprising shale and siltstone with minor sandstone. Shales are silty, dark grey to black and weather orange-brown. Sandstones are texturally immature and commonly horizontally burrowed. Ichnofossils include Planolites, Scolicia and an unnamed radiating burrow structure.
Relationship:
The Midas Formation is in sharp, although in detail gradational contact with the underlying Yanks Peak Formation. It grades upward into the silty to sandy limestone of the overlying Mural Formation. The Midas Formation is correlative with the uppermost McNaughton Formation of the Rockies, as each directly underlies the Mural Formation.
History:
The type locality of the Midas Formation at Yanks Peak is in a zone of intense structural deformation. As with the two underlying formations there is doubt that the type section represents the Midas Formation of current usage (Campbell et al., 1973).
Other Citations:
Campbell et al., 1973; Holland, 1954; Sutherland-Brown, 1963; Young, 1972a, 1979.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 4, western Canada, including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba; D.J. Glass (editor)
Contributor: M.R. McDonough
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 04 May 2004