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TitleRetreat pattern of glaciers controls the occurrence of turbidity currents on high?latitude fjord deltas (eastern Baffin Island)
AuthorNormandeau, AORCID logo; Dietrich, P; Hughes Clarke, J; Van Wychen, W; Lajeunesse, P; Burgess, DORCID logo; Ghienne, J -F
SourceThe Arctic: an AGU joint special collection; Journal of Geophysical Research, Earth Surface vol. 124, 2019 p. 1-13, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20180178
PublisherAmerican Geophysical Union (AGU)
Mediapaper; on-line; digital
File formatpdf (Adobe® Reader®); html
ProvinceNunavut; Northern offshore region
NTS16E; 16F; 16K; 16L; 16M; 16N; 26H; 26I; 26J; 26O; 26P; 27; 37E; 37G; 37H; 38A; 38B; 38C; 47P; 48A; 48D
AreaBaffin Island; Baffin Bay; Conn River; Clephane Bay; Pangnirtung Fjord; Southwind Fjord; Dexterity Fjord; Oliver Sound; Canadian Arctic Archipelago
Lat/Long WENS -84.0000 -60.0000 74.0000 65.0000
Subjectsmarine geology; surficial geology/geomorphology; environmental geology; geophysics; Nature and Environment; glaciology; oceanography; climate; glaciers; ice sheets; deglaciation; ice retreat; turbidity currents; coastal environment; fiords; deltas; glacial erosion; sediment transport; sediment dispersal; surface waters; rivers; drainage systems; hydrologic environment; watersheds; bathymetry; geophysical surveys; acoustic surveys, marine; sedimentary structures; proglacial lakes; ice scours; statistical analyses; marine sediments; modelling; ice flow; hydrodynamics; ecosystems; carbon; remote sensing; satellite imagery; Climate change; glaciofluvial sediments; marine deltaic sediments; lacustrine deltaic sediments; ice-contact deltas
Illustrationslocation maps; geoscientific sketch maps; satellite images; plots; tables; models
ProgramPublic Safety Geoscience Marine Geohazards
Released2019 05 31
AbstractGlacier and ice sheet mass loss as a result of climate change is driving important coastal changes in Arctic fjords. Yet limited information exists for Arctic coasts regarding the influence of glacial erosion and ice mass loss on the occurrence and character of turbidity currents in fjords, which themselves affect delta dynamics. Here we show how glacial erosion and the production of meltwaters and sediments associated with the melting of retreating glaciers control the generation of turbidity currents in fjords of eastern Baffin Island (Canada). The subaqueous parts of 31 river mouths along eastern Baffin Island were mapped by high?resolution swath bathymetry in order to assess the presence or absence of sediment waves formed by turbidity currents on delta fronts. By extracting glaciological and hydrological watershed characteristics of these river mouths, we demonstrate that the presence and areal extent of glaciers are a key control for generating turbidity currents in fjords. However, lakes formed upstream during glacial retreat significantly alter the course of sediment routing to the deltas by forming temporary sinks, leading to the cessation of turbidity currents in the fjords. Due to the different deglaciation stages of watersheds in eastern Baffin Island, we put these results into a temporal framework of watershed deglaciation to demonstrate how the retreat pattern of glaciers, through the formation and filling of proglacial lakes, affects the turbidity current activity of deltas.
Summary(Plain Language Summary, not published)
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 glacial erosion/ice mass loss has dramatic consequences on nearshore sedimentary environments and associated ecosystems. Here, we show how the behavior 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. 644 glacio-hydrological watersheds of eastern Baffin Island were then modelled and allowed us to predict the location of density flows presently occurring in fjords. Our results greatly improve our understanding of modern density flows and nearshore fjord hydrodynamic in high-latitude coasts in response to retreating glacier behaviour in a warming climate.

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