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A Late Pleistocene Low Sea-Level Stand of the Southeast Canadian Offshore

  • Gordon B. J. Fader
Part of the NATO ASI Series book series (ASIC, volume 256)

Abstract

A widespread, submarine, low sea-level stand is interpreted to occur at a present depth of 110–120m across the Scotian Shelf and is dated at 15 ka BP. Evidence in support of this position includes: 1) absence of fine-grained muddy sediments above and their abundance below 110m; 2) the distribution of well-sorted sand and rounded gravel clasts above the low sea-level position in contrast to the widespread occurrence of angular clasts below; 3) the occurrence of terraces cut into both bedrock and glacial sediments at 110–120m water depth; 4) the occurrence of unconformities on glacial sediments dated from 40-15 ka BP which exist as erosional remnants above the low sea-level position; 5) the distribution of continuous deposits of till below and its general absence above the low sea-level stand; 6) the relative distribution of relict versus modern iceberg furrows at the seabed above and below the low sea-level stand; and 7) the occurrence of a subaerially desiccated crust above 110m water depth and its absence below. The low sea-level position occurs at approximately the same depth across the outer continental shelf. This suggests that the glaciers had retreated from the shelf before the maximum lowering and that differential warping has not occurred since its formation, otherwise the low stand would be discontinuous. It also supports the idea that for the offshore area of the southeast Canadian continental shelf, glacial isostatic rebound was largely over by the time the low sea-level stand was formed.

Keywords

Nova Scotia Sand Ridge Glacial Sediment Scotian Shelf Outer Continental Shelf 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Amos, C.L. in press. Quaternary sediments and bedforms of the Scotian Shelf observed from the submersible Pisces IV. Spec. Publ. G.S.C.Google Scholar
  2. Amos, C.L. and Knoll, R.G. 1987. The Quaternary sediments of Banquereau, Scotian Shelf. Geological Society of America Bulletin, v. 99, p. 244–260.CrossRefGoogle Scholar
  3. Belknap, D.F., Shipp, R.C. and Kelley, J.T. 1986. Depositional setting and Quaternary stratigraphy of the Sheepscot Estuary, Maine: a preliminary report. Géographil Physique et Quaternaire, v. 6, p. 55–69.Google Scholar
  4. Boyd, R. and Penland, S. 1984. Shoreface translation and the Holocene stratigraphic record: examples from Nova Scotia, the Mississippi Delta, and eastern Australia. Marine Geology, v. 60, p. 391–412.CrossRefGoogle Scholar
  5. Brookes, I.A. 1977. Radiocarbon age of Robinson’s Head moraine, west Newfoundland, and its significance for postglacial sea-level changes. Canadian Journal of Earth Sciences, v. 14, p. 2101–2120.CrossRefGoogle Scholar
  6. Bruun, P. 1983. Beach scraping — is it damaging to beach stability? Coastal Engineering, v. 7, p. 167–173.CrossRefGoogle Scholar
  7. Fader, G.B. in press. Submersible observations of iceberg furrows and sand ridges, Grand Banks of Newfoundland. G.S.C Spec. Paper.Google Scholar
  8. ___, King, L.H. and MacLean, B. 1977. Surficial geology of the eastern Gulf of Maine and Bay of Fundy. Geological Survey of Canada, Paper 76-17; Marine Sciences Paper 19, 23 p.Google Scholar
  9. ___ and King, L.H. 1981. A reconnaissance study of the surficial geology of the Grand Banks of Newfoundland. Current Research Part A, Geological Survey of Canada, Paper 81-A, p. 45–81.Google Scholar
  10. ___ and Miller, R.O. 1986. A reconnaissance study of the surficial and shallow bedrock geology of the southeastern Grand Banks of Newfoundland. In Current Research, Part B, Geological Survey of Canada Paper 86-1B, p. 591–604.Google Scholar
  11. Forbes, D.L. 1987. Shoreline Sediment Distribution. In Coastal Sediments 87, v. 1, p. 694–709.Google Scholar
  12. Grant, D.R. 1971. Glacial deposits, sea-level changes and pre-Wisconsin deposits in southwest Nova Scotia, Geological Survey of Canada Paper 71-B, p. 110–113.Google Scholar
  13. Hutchins, R.W. 1974. Computer simulation of a transiently excited underwater sound projector. Ocean’ 74, Proc. in. Conf. on Engineering in the Ocean Environment, Halifax, Nova Scotia, 2, p. 115–119.Google Scholar
  14. ___, McKeown, D.L. and King, L.H. 1976. A deep tow high resolution seismic system for continental shelf mapping. Geoscience Canada, v. 3, p. 95–100.Google Scholar
  15. James, N.P. and Stanley, D.J. 1968. Sable Island Bank of Nova Scotia: Sediment dispersal and recent history. American Association of Petr. Geol. Bull., 52, p. 2208–2230.Google Scholar
  16. King, C.A. 1972. Beaches and Coasts, Second Edition, Edward Arnold Publ., London, U.K., 570 p.Google Scholar
  17. King, L.H. 1967. Use of conventional echo-sounder and textural analyses in delineating sedimentary facies — Scotian Shelf. Canadian Journal of Earth Sciences, v. 4, p. 691–708.CrossRefGoogle Scholar
  18. ___ 1970. Surficial geology of the Halifax — Sable Island map-area. Geological Survey of Canada Marine Science Paper 1. 16 pp.Google Scholar
  19. ___ 1980. Aspects of regional surficial geology related to site investigation requirements — Eastern Canadian Shelf. In Offshore Site Investigation, D.A. Ardus (ed). Graham Trotman Ltd., London, 291 p.Google Scholar
  20. ___ and Fader, G.B.J. 1986. Wisconsinan glaciation of the continental shelf-southeastern Atlantic Canada. Geological Survey of Canada Bulletin 363, 72 pp.Google Scholar
  21. Letson, J.R.J. 1980. Sedimentology of southwestern Mahone Bay. Unpublished M.Sc. thesis, Dalhousie University, Halifax, N.S.Google Scholar
  22. Lewis, C.F.M. et al. in press. Estimating iceberg scouring rates for the Grand Banks of Newfoundland, in POAC’ 87, Fairbanks, Alaska.Google Scholar
  23. McKeown, D.L. 1975. Evaluation of the Huntec (’70) Hydrosonde Deep Tow Seismic System, B.I.O. Report BI-R-75-4.Google Scholar
  24. Piper, D.J.W. et al. 1986. Quaternary Geology. In M.J. Keen and G.L. Williams (eds), Geology of Canada. G.S.C. Spec. Report.Google Scholar
  25. Quinlan, G. and Beaumont, C. 1981. A comparison of observed and theoretical postglacial relative sea level in Atlantic Canada. Canadian Journal of Earth Sciences, v. 18, p. 1146–1163.CrossRefGoogle Scholar
  26. ___ and ____ 1982. The deglaciation of Atlantic Canada as reconstructed from the postglacial relative sea-level record. Canadian Journal of Earth Sciences, v. 19, p. 2232–2246.CrossRefGoogle Scholar
  27. Scott, D.B. and Medioli, F.S. 1982. Micropaleontological documentation for early Holocene fall of relative sea level on the Atlantic coast of Nova Scotia. Geology, v. 10, p. 278–281.CrossRefGoogle Scholar
  28. Scott, D.B. and Greenburg, D.A. 1983. Relative sea-level rise and tidal development in the Fundy tidal system. Canadian Journal of Earth Sciences, v. 20, p. 1554–1564.CrossRefGoogle Scholar
  29. Segall, M.P., Buckley, D.E., and Lewis, C.F.M. 1987. Clay mineral indicators of geological and geochemical subaerial modification of near-surface tertiary sediments on the Northeastern Grand Banks of Newfoundland. Geological Survey of Canada Contribution #40186, 31 p.Google Scholar
  30. Sonnichsen, G., Fader, G.B.J., and Miller, R.O. 1987. Compilation of seabed sample data from the Scotian Shelf, the Western Grand Banks of Newfoundland and adjacent areas. G.S.C. Open File 1430.Google Scholar
  31. Stanley, D.J., Drapeau, G. and Cok, A.E. 1968. Submerged terraces on the Nova Scotian Shelf. Annals of Geomorphology, v. 7, p. 85–94.Google Scholar

Copyright information

© Kluwer Academic Publishers 1989

Authors and Affiliations

  • Gordon B. J. Fader
    • 1
  1. 1.Atlantic Geoscience Centre Geological Survey of CanadaBedford Institute of OceanographyDartmouthCanada

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