Unit Name: Adams Sound Formation
Unit Type: Lithostratigraphic
Rank: Formation
Status: Formal
Usage: Currently in use
Age Interval: Neohelikian ? (1269 - 1000 ma)
Age Justification: A radiometric date of 903 ± 140 m.y. for the underlying volcanics suggests a Neo-Helikian age for the Adams Sound Formation.
Province/Territory: Nunavut
Originator: Blackadar, 1970.
Type Locality:
Cliffs along Adams Sound, northern Baffin Island.
Distribution:
Up to 520 m on Borden Peninsula (Jackson et al., 1978b). East of Milne inlet the formation thins to 50 m (Ianelli 1979). The formation has been estimated to exceed 610 m (Jackson et al., 1978b) and even 1220 m (Blackadar, 1970). On Bylot Island the formation reaches a thickness of 560 m (Jackson and Davidson, 1975). The main outcrop area of the Adams Sound Formation lies between Strathcona Sound and Fabricius Fiord on western Borden Peninsula.
Locality Data:
Thickness(m): Maximum 1220.
Lithology:
The dominant lithology is white to reddish-brown quartz arenite with minor subarkoses and quartz-pebble orthoconglomerates near the base and siltstone beds near the top. Sedimentary structures suggest a fluvial origin with a predominant current direction toward the northwest. Conglomerate-based fining-upward cycles are found in the lower part, whereas coarsening-upward cycles characterize the transitional upper contact (Geldsetzer, 1973b). The formation has been subdivided into three members by Jackson et al. (1978b) and into five members by Ianelli (1979).
Relationship:
Rests abruptly, but conformably, on volcanics of the Nauyat Formation and transgresses onto Aphebian basement gneisses near and east of Milne Inlet. The formation grades upward into dominantly black, fine clastics of the Arctic Bay Formation and the Fabricius Fiord Formation by a series of coarsening-upward cycles. This transition reflects a change from a fluvial into a coastal-mudflat environment. The formation is probably equivalent to the Fury and Hecla Formation (Blackadar, 1970) about 350 km south of Borden Peninsula.
History:
The Adams Sound Formation was originally referred to as the Upper Quartzite Member of the Eqalulik Group (Blackadar, 1956; Lemon and Blackadar, 1963).
References:
Blackadar, R.G., 1956. Geological reconnaissance of Admiralty Inlet, Baffin Island, Arctic Archipelago: Geological Survey of Canada, Paper 55-6, 25 p.
Blackadar, R.G., 1970. Precambrian geology northwestern Baffin Island, District of Franklin: Geological Survey of Canada, Bulletin 191, 89 p.
Geldsetzer, H., 1973b. The tectono-sedimentary development of an algal-dominated Helikian succession on northern Baffin Island, N.W.T., pp. 99-126: in Aitken, J.D. and Glass, D.J. (eds. ), Canadian Arctic Geology, Proceedings of the Symposium on the Geol
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.
Lemon, R.R.H. and Blackadar, R.G., 1963. "Admiralty Inlet area, Baffin Island, District of Franklin"; Geological Survey of Canada, Memoir 328, 84 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: 10 Feb 2009