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).

Distribution:
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.

Lithology:
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).

Relationship:
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).

References:
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