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TitreThe behaviour of retreating glaciers controls sediment density flow activity in high-latitude fjords
AuteurNormandeau, A; Dietrich, P; Hughes Clarke, J; Van Wychen, W; Burgess, D; Lajeunesse, P; Ghienne, J -F
SourceISC2018 - 20th International Sedimentological Congress, abstract volume; 2018 p. 1
Année2018
Séries alt.Ressources naturelles Canada, Contribution externe 20180227
ÉditeurIAS
RéunionISC2018 - 20th International Sedimentological Congress; Québec, QC; CA; août 13-17, 2018
Documentsite Web
Lang.anglais
Mediapapier
Formatspdf
ProvinceNunavut; Région extracotière du nord
SNRC16; 25H; 25I; 25J; 25N; 25O; 25P; 26; 27; 37E; 37G; 37H; 38A; 38B
Lat/Long OENS -80.0000 -60.0000 73.0000 61.0000
Sujetsfjords; glaciers; retrait de la glace; transport des sediments; milieu côtièr; milieu sédimentaire; milieu littoral; hydrodynamique; climat; océanographie; milieux marins; deltas; structures sédimentaires; réseaux hydrographiques; milieu hydrologique; lacs glaciaires; écosystèmes; Changement climatique; hydrogéologie; géologie des dépôts meubles/géomorphologie; géologie marine; sédimentologie; géologie de l'environnement
ProgrammeRisques géo marines, Géoscience pour la sécurité publique
Diffusé2018 08 01
Résumé(disponible en anglais seulement)
Ice mass loss is driving important coastal morphodynamic changes in Arctic regions, from rapid coastal erosion to substantial prograding coastlines. Sediment supply delivered by rivers due to enhanced glacial erosion/ice mass loss has dramatic consequences on nearshore sedimentary environments and associated ecosystems. However, limited data exists in Arctic coasts on the influence of ice mass loss due to climate change in modifying the nearshore hydrodynamic of fjords. Here, we show how the behaviour of retreating glaciers and ice-mass loss influences the generation of density flows in eastern Baffin Island fjords, which has important consequences for bottom water renewal and nutrient and carbon fluxes to the marine environment. Through a detailed analysis of sediment waves formed by sediment density flows on 31 delta fronts mapped from 2003 to 2014 and by extracting their correlative glacio-hydrological drainage basin characteristics, we observed that the presence of glaciers controls the occurrence of density flows. However, lakes formed during glacial retreat, small or large, significantly alter the course of sediment routing to the deltas, leading to the interruption of density flow processes in fjords. Applying these results to 700 glacio-hydrological drainage basins of eastern Baffin Island allows us to predict the location of density flows presently occurring in fjords. These findings inform local communities and stakeholders on the locations where bottom-water renewal and organic carbon and nutrient transfer is more likely to occur, which has significant impacts on ecosystems. Our results greatly improve our understanding of modern density flows and fjord hydrodynamic in high-latitude coasts in response to retreating glacier behaviour in a warming climate.
Résumé(Résumé en langage clair et simple, non publié)
La bathymétrie de delta de fjords nous a permis d'identifier les facteurs qui contrôlent la présence de courants de turbidité dans les fjords. Ces résultats nous permettent ensuite de prédire où ces processus sédimentaires sont actifs le long de l'île de Baffin, contribuant à nos connaissances sur l'instabilité du plancher marin.
GEOSCAN ID311309