Unit Name: Devon Island Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Late Silurian - Early Devonian (422.9 - 397.5 ma)
Age Justification: Monograptid graptolites including Monograptus transgediens and Monograptus fanicus; brachiopods, crinoids and trilobites, including the Silurian-Devonian boundary guide fossil Warburgella rugulosa in the limestone interbeds.
Province/Territory: Nunavut
Originator: Thorsteinsson, 1963a.
Type Locality:
On the northwestern shore of Ptarmigan Lake on Devon Island, N.W.T.
Distribution:
85 m thick near Goose Fiord in southwest Ellesmere Island and ranges in thickness from 109 m to 305 m along the Douro Range of northwestern Devon Island. The Devon Island Formation is confined to northwestern Devon Island and to southwestern Ellesmere Island.
Lithology:
A light yellow-weathering, dark brown to black, silty, thinly laminated, somewhat fissile limestone and dolomite rich in noncalcareous organic matter (sapropel) forms most of the formation. The upper part becomes thicker bedded with some medium bedded intervals of silty dolomite. The Devon Island commonly is referred to as shale because of its fissility and organic content. Occasional thin beds of crinoidal lime wackestone occur throughout the formation.
Relationship:
Conformably overlies the Douro formation and underlies the Sutherland River Formation on Devon Island. On Ellesmere Island it is overlain by unnamed limestones and dolomites. It is laterally equivalent to Barlow Inlet and Sophia Lake Formations, and passes into Cape Phillips Formation to the north and west.
Remark:
First Published: Geological Survey of Canada Maps 20, 21-1959.
Other Citations:
Thorsteinsson, 1963a, in press; Greiner, 1963a; Morrow and Kerr, 1977; Mayr, 1978.
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: D.W. Morrow
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 29 Apr 2003