Unit Name: Blue Mountain Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Maysvillian (453 - 447.5 ma)
Province/Territory: Ontario

Originator: Parks, 1928.

Type Locality:
Reference section is Manock Gas Syndicate well, lot 22, con. 2, Louth tp., Lincoln country; interval 1, 056-1, 309 feet (Sanford, 1961).

The outcrop area extends from Nottawasaga Bay southeastward to the Toronto area. The subsurface extent, however, is imperfectly known; the beds are undoubtedly present throughout the eastern part of the Ontario peninsula, but are not recognized in the western half (Sanford, 1961).

Locality Data:
Thickness(m): Minimum 9, Maximum 76.

Blue-grey, poorly fossiliferous, noncalcareous shale, fissile. In Toronto area, unit is predominantly brown to brown-grey shale (locally referred to as Rouge River Member) (Thurston et al., 1992).

Upper contact with the Georgian Bay Formation is gradational. Lower contact with the Collingwood Member of the Lindsay Formation is sharp. Where the Collingwood Member is absent, a phosphate lag marks the disconformable contact with the lower member of the Lindsay Formation (Thurston et al., 1992).

Parks, W.A., 1928. Faunas and stratigraphy of the Ordovician black shales and related rocks in southern Ontario, Proceedings and Transactions of the Royal Society of Canada, March 1928, Vol. 22, pp. 39-92
Sanford, B.V. 1961. Subsurface Stratigraphy of Ordovician Rocks in Southwestern Ontario 30, 31, 40, 41 (parts of), Geological Survey of Canada, Paper 60-26.
Thurston, P.C., Williams, H.R., Sutcliffe, R.H. and Stott, G.M. 1992. Geology of Ontario; Ontario Ministry of Northern Development and Mines, Ontario Geological Survey Special Volume 4, 1525 p.

Source: GSC file of geological names; T.E. Bolton and J. Dougherty (compiler)
Contributor: A.A. Coyne; Michael Pashulka
Entry Reviewed: No
Name Set: Lithostratigraphic Lexicon
LastChange: 07 Dec 2009