Unit Name: Arctic Bay Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Neohelikian ? (1269 - 1000 ma)
Age Justification: A Neo-Helikian age as suggested for the underlying Adams Sound Formation seems probable.
Province/Territory: Nunavut
Originator: Blackadar, 1956.
Type Locality:
Lower part of cliffs at Arctic Bay, northwestern Baffin Island.
Distribution:
Thickness increases from 88 m at the type section (Jackson et al., 1978b) eastward to 770 m east of Milne Inlet (Ianelli, 1979); on Bylot Island, estimated to be 520 m (Jackson and Davidson, 1975). The formation is exposed mainly on Borden Peninsula.
Locality Data:
Thickness(m): Maximum 770.
Lithology:
The bulk of the formation consists of a marine, black to grey, fissile micaceous shale and siltstone with occasional interbeds of dense yellow-brown dolomite (mudstone). The lower part is characterized by coarsening-upward cycles with a strong quartz arenite component. The upper part is a succession of black to grey fine clastic rocks, dense yellow-brown dolomitic mudstones, brown quartz arenites and black stromatolitic dolomite. The quartz arenite-dolomite component becomes dominant upsection and eastward. The formation has been subdivided into five members by Jackson et al. (1978b) and into four members by Ianelli (1979).
Relationship:
The formation grades downward into the Adams Sound Formation through a series of coarsening-upward cycles; disconformably overlain by massive dolomites of the Society Cliffs Formation. The Arctic Bay grades laterally to the south into lower members of the Fabricius Fiord Formation, and is probably equivalent to the Autridge Formation, 350 km southward. The sedimentological character of the Arctic Bay Formation is similar to that of the underlying Eqalulik Group: the Arctic Bay appears to represent a late stage of an episode of clastic deposition that began with the quartz arenites of the Nauyat Group.
References:
Blackadar, R.G., 1956. Geological reconnaissance of Admiralty Inlet, Baffin Island, Arctic Archipelago: Geological Survey of Canada, Paper 55-6, 25 p.
Iannelli, Thomas R., 1979. "Stratigraphy and depositional history of some Upper Proterozoic sedimentary rocks on northwestern Baffin Island, District of Franklin, Contract 94843", in, Current Research, Part A, Precambrian Shield, Blackadar, R.G., Griffin, P.J., Dumych, H., and Neale, E.R.W. (Eds. and Compilers); Geological Survey of Canada, Paper 79-1A, pp. 45-56.
Jackson, G.D. and Davidson, A., 1975. Bylot Island Map-area, District of Franklin; Geological Survey of Canada, Paper 74-29, 12 p.
Jackson, G.D., Ianelli, T.R., Narbonne, G.M., and Wallace, P.J., 1978b. "Upper Proterozoic sedimentary and volcanic rocks of northwestern Baffin Island"; Geological Survey of Canada, Paper 78-14, 15 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: H.H.J. Geldsetzer; P.H. Davenport
Entry Reviewed: No
Name Set: Lithostratigraphic Lexicon
LastChange: 03 Mar 2009