Unit Name: Corner Brook Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Early Ordovician (485.4 - 470 ma)
Age Justification: Schuchert and Dunbar (1934) reported a few specimens of gastropods and cephalopods which indicated an Early Ordovician age.
Province/Territory: Newfoundland & Labrador

Originator: McKillop, 1963; Lilly, 1963.

Type Locality:
Humber Gorge, western Newfoundland (NTS 12 A/13).

Distribution:
The formation is 450 m thick. It has been mapped from north of Goose Arm (NTS 12 H/4) to south of Humber Gorge (NTS 12 A/13).

Lithology:
A lower sequence of intercalated limestones and dolostones, a middle limestone with minor dolostones, and an upper dolostone unit with some limestones. The carbonates are metamorphosed. The limestones contain some fossils and may be stromatolitic.

Relationship:
The Corner Brook Formation conformably overlies the Upper Cambrian to Lower Ordovician Hughes Brook Formation and may be disconformably (Walthier, 1949a) overlain by the Middle Ordovician Table Head Group, although this is disputed by McKillop (1963). This formation is probably equivalent to the Boat Harbour (informal), Catoche, and Aguathuna (informal) formations of the Great Northern Peninsula (NTS 12 I, 12 P) and Port au Port Peninsula (NTS 12 B/10, 11). The St. George Group includes the Watts Bight (informal), Boat Harbour (informal), Catoche, Aguathuna (informal) formations, the Corner Brook Formation, and the Brent Island and Southern Arm limestones. The Hughes Brook Formation would no longer be placed in the group as defined by Knight (1977, 1978) and James et al., (1980).

History:
The carbonates of the Humber Arm area were only briefly described by Schuchert and Dunbar (1934) and mapped in preliminary studies by Walthier (1949a). The Corner Brook Formation was mapped and named by McKillop (1963) and Lilly (1963). The formation, as was defined by these authors, is equivalent to a major part of the St. George Group, as it is defined by Knight (1978, 1980b) and James et al. (1980).

Other Citations:
Brückner, 1966; James et al., 1980; Knight, 1977, 1978, 1980b; Lilly, 1963; McKillop, 1963; Schuchert and Dunbar, 1934; Walthier, 1949a.

Source: CSPG Lexicon of Canadian Stratigraphy, Volume 6, Atlantic Canada; G.L. Williams, L.R. Fyffe, R.J. Wardle, S.P. Colman-Sadd, Boehner, R.C. (editor)
Contributor: I. Knight
Entry Reviewed: Yes
Name Set: Lithostratigraphic Lexicon
LastChange: 29 Apr 2003