Sediment dynamics in paired High Arctic lakes revealed from high-resolution swath bathymetry and acoustic stratigraphy surveys

High Arctic lakes are commonly used for paleoclimatic reconstructions because they are particularly sensitive to climate variability. However, the processes leading to sediment deposition and distribution in these lakes are often poorly understood. Here for the first time in the Canadian High Arctic...

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Bibliographic Details
Published in:Journal of Geophysical Research: Earth Surface
Main Authors: Normandeau, A., Lamoureux, S. F., Lajeunesse, P., Francus, Pierre
Format: Article in Journal/Newspaper
Language:English
Published: 2016
Subjects:
Earth and Environmental Sciences
SUBMARINE MASS MOVEMENTS
ST-LAWRENCE ESTUARY
ENVIRONMENTAL-CHANGE
LACUSTRINE VARVES
CONTINENTAL-SLOPE
RIVER-DELTA
CAPE BOUNTY
CANADA
RECORD
ISLAND
Arctic
Canada
Cape Bounty
permafrost
Melville Island
Online Access:https://biblio.ugent.be/publication/8761150
http://hdl.handle.net/1854/LU-8761150
https://doi.org/10.1002/2016JF003873
https://biblio.ugent.be/publication/8761150/file/8761151
Description
Summary:High Arctic lakes are commonly used for paleoclimatic reconstructions because they are particularly sensitive to climate variability. However, the processes leading to sediment deposition and distribution in these lakes are often poorly understood. Here for the first time in the Canadian High Arctic, we present original data resulting from swath bathymetry and subbottom surveys carried out on two lakes at Cape Bounty, Melville Island. The results reveal the dynamic nature of the lakes, in which mass movement deposits and bedforms on the deltas reflect frequent slope instabilities and hyperpycnal flow activity. The analysis of the mass movement deposits reveals that small blocky debris flows/avalanches, debris flows, and a slide occurred during the Holocene. These mass movements are believed to have been triggered by earthquakes and potentially by permafrost thawing along the shoreline. Altogether, these mass movement deposits cover more than 30% of the lake floors. Additionally, the river deltas on both lakes were mapped and reveal the presence of several gullies and bedforms. The presence of gullies along the delta front indicates that hyperpycnal flows generated at the river mouth can transport sediment in different trajectories downslope, resulting in a different sediment accumulation pattern and record. The dynamic nature of these two lakes suggests that further analysis on sedimnt transport and distribution within Arctic lakes is required in order to improve paleoclimatic reconstructions.

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