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TitreStorms and shoreline retreat in the southern Gulf of St. Lawrence
AuteurForbes, D L; Parkes, G S; Manson, G K; Ketch, L A
SourceStorms and their significance in coastal morpho-sedimentary dynamics2; par Stone, G W (éd.); Orford, J D (éd.); Marine Geology vol. 210, 2004 p. 169-204, https://doi.org/10.1016/j.margeo.2004.05.009
LiensAbstract - Résumé
Année2004
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 2002183
ÉditeurElsevier BV
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1016/j.margeo.2004.05.009
Mediapapier; en ligne; numérique
Formatspdf
ProvinceÎle-du-Prince-Édouard
SNRC11E/09; 11E/10; 11E/11; 11E/12; 11E/13; 11E/14; 11E/15; 11E/16; 11F/12; 11F/13; 11K/04; 11K/05; 11K/12; 11K/13; 11L; 11M/01; 11M/02; 11M/03; 11M/04; 11N/04; 12H/09; 12H/10; 12H/15; 12H/16; 12I/01; 12I/08; 12I/09; 12I/16; 12P/01; 12P/02
Lat/Long OENS -65.0000 -61.5000 47.2500 45.5000
Sujetstempêtes; trangressions; régressions; changements du niveau de la mer; variations du niveau de la mer; milieu côtièr; érosion côtière; sediments; dépôts de tempête; glace marine; climat; onde de marée; variations du littoral; littoraux; levés photogrammétriques; méthodes photogrammétriques; dunes; érosion; géologie marine; sédimentologie; stratigraphie; Nature et environnement
Illustrationslocation maps; photographs; aerial photographs; bathymetric profiles; graphs; bar graphs
ProgrammeLe Fonds d'action pour le changement climatique (FACC)
Résumé(disponible en anglais seulement)
Storms play a major role in shoreline recession on transgressive coasts. In the southern Gulf of St. Lawrence (GSL), southeastern Canada, long-term relative sea-level rise off the North Shore of Prince Edward Island has averaged 0.3 m/century over the past 6000 years (>0.2 m/century over 2000 years). This has driven long-term coastal retreat at mean rates >0.5 m/a but the variance and details of coastal profile response remain poorly understood. Despite extensive sandy shores, sediment supply is limited and sand is transferred landward into multidecadal to century-scale storage in coastal dunes, barrier washover deposits, and flood-tidal delta sinks. Charlottetown tide-gauge records show mean relative sea-level rise of 3.2 mm/a (0.32 m/century) since 1911. A further rise of 0.7±0.4 m is projected over the next 100 years. When differenced from tidal predictions, the water-level data provide a 90-year record of storm-surge occurrence. Combined with wind, wave hindcast, and sea-ice data, this provides a catalogue of potentially significant coastal storms. We also document coastal impacts from three recent storms of great severity in January and October 2000 and November 2001. Digital photogrammetry (1935-1990) and shore-zone surveys (1989-2001) show large spatial and temporal variance in coastal recession rates, weakly correlated with the storm record, in part because of wave suppression or coastal protection by sea ice. Large storms cause rapid erosion from which recovery depends in part on local sand supply, but barrier volume may be conserved by washover deposition. Barrier shores with dunes show high longshore and interdecadal variance, with extensive multidecadal healing of former inlet and overwash gaps. This reflects recovery from an episode of widespread overwash prior to 1935, possibly initiated by intense storms or groups of storms in the latter half of the 19th century. With evidence from the storms of 2000-2001, this points to the importance of storm clustering on scales of weeks to years in determining erosion vulnerability, as well as the need for a long-term, large-scale perspective in assessing coastal stability. The expected acceleration in relative sea-level rise, together with projections of increasing storm intensity and greatly diminished winter ice cover in the southern GSL, implies a significant increase in coastal erosion hazards in future.
GEOSCAN ID213961