CGRG Bibliography of Canadian Geomorphology
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Author : Giles, P.T.
Date : 2003.
Title : Comparisons of the morphology of three relict foredune plains in the southern Gulf of St. Lawrence, Canada.
Publication : Joint Annual Meeting of the Canadian Quaternary Association and the Canadian Geomorphology Research Group. Halifax, Nova Scotia, June 8-12, 2003.
Issue :
Page(s) :
Abstract
A relict foredune plain is a series of sub-parallel ridges created by seaward progradation of successive foredunes. Sediment supply conditions, relative sea level changes, and coastal setting influence the development and morphology of a relict foredune plain. Post-glacial conditions in the Gulf of St. Lawrence during the Holocene epoch meant that sediment supply was high and the nature of relative sea level changes was highly localized. Three relict foredune plains in the southern Gulf of St. Lawrence region were examined in this study. Basin Head is on the Northumberland Strait coast on the eastern end of Prince Edward Island; Les Sillons and Dune de l'Est are both on the east-facing coast of Îles de la Madeline, Québec. The morphology of each relict foredune plain is described and interpreted in the context of relative sea level change and local coastal setting. Cross-sectional transect profiles and aerial photograph interpretations are used in this investigation. A previous study at Basin Head showed a rise in late-Holocene relative sea level (Palmer, 1978), and the rising trend in the relict foredune plain is attributed to that factor. By analogy, Les Sillons is interpreted to have been created during similar rising sea level conditions. In contrast, the relict foredune plain at Dune de l'Est has a complex morphology that reflects two distinct stages of evolution, a spit-washover stage, followed by a progradational ridge stage. It lacks a distinct rising trend in cross-sectional profile, and therefore it appears to have been created at an earlier stage of relative sea level history. Local coastal setting is invoked as the explanation for the difference in periods of development of Les Sillons and Dune de l'Est. While Les Sillons developed in the lee of a protective sand barrier that formed on the west-facing coast, the Dune de l'Est relict foredune plain formed in the sheltered environment provided by an existing bedrock island.
Bibliography of Canadian Geomorphology