Unit Name: Blackley Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Middle Devonian (397.5 - 385.3 ma)
Age Justification: Spores are the only fossils recovered so far from the Blackley.
Province/Territory: Northwest Territories
Originator: Tozer and Thorsteinsson, 1964; redefined by Embry and Klovan, 1976.
Type Locality:
Canrobert Hills of western Melville Island, 11 km northwest of the northeast corner of Blackley Haven.
Distribution:
Present on western Melville, Prince Patrick and western Banks Islands; up to 700 m thick.
Locality Data:
Thickness(m): Maximum 700.
Lithology:
Characterized by rhythmically interbedded, very fine-grained sandstone, siltstone and shale. The resistant, sandstone-siltstone units, 10 cm to 2 m thick, have abrupt basal contacts and a variety of sole markings. The shale units are up to 15 m thick and consist of medium grey, silty shale. The strata are arranged in Bouma cycles and are interpreted to have been deposited by turbidity currents.
Relationship:
Conformably overlies the Ibbett Bay or Kitson Formation and conformably overlain by the Cape de Bray Formation.
History:
The Blackley was originally defined as a member of the Weatherall Formation. Embry and Klovan (1976) gave it formation status because it is lithologically dissimilar from the type Weatherall Formation and is a mappable unit both on the surface and in the subsurface.
Other Citations:
Tozer and Thorsteinsson, 1964; Embry and Klovan, 1976; Christie and McMillan, 1994; Harrison, 1995.
References:
Embry, A.F. and Klovan, J.E., 1976. The Middle-Upper Devonian clastic wedge of the Franklinian Geosyncline; Bulletin of Canadian Petroleum Geology, vol. 24, no. 4, pp. 485-639.
Tozer, E.T. and Thorsteinsson, R., 1964. Western Queen Elizabeth Islands, Arctic Archipelago: Geological Survey of Canada, Memoir 332, 242 p.
Source: CSPG Lexicon of Canadian Stratigraphy, Volume 1, Arctic Archigelage (District of Franklin); R.L. Christie, A.F. Embry, G.A. Van Dyck (editor)
Contributor: A.F. Embry; K. Dewing
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 31 Mar 2009