Holocene Mass Movements in a Canadian High Arctic Lake, East Lake, Melville Island

Alexandre Normandeau1, Gabriel Joyal1, Patrick Lajeunesse1, Pierre Francus2, Scott F Lamoureux3 and François Lapointe4, (1)Université Laval, Département de géographie, Québec, QC, Canada, (2)Inst Nat Recherche Sci, Québec, QC, Canada, (3)Queen's University, Geography, Kingston, ON, Canada, (4)Inst Nat Recherche Sci, GEOTOP, Québec, QC, Canada

Contact First Author: Alexandre Normandeau; alexandre.normandeau@nrcan-rncan.gc.ca

Previously Published Material: The same abstract will be presented at the conference: Submarine Mass Movements and Their Consequences in New Zealand. The results are under consideration for the publication in the conference book.

Abstract ID#: 34182

 

English Abstract:
East Lake, located at Cape Bounty (Melville Island, Canadian High Arctic), was mapped using a high-resolution swath bathymetric sonar and a 12 kHz sub-bottom profiler, allowing imaging for the first time the widespread occurrence of mass movement deposits (MMDs) in a High Arctic Lake. MMDs are mostly located on steep slopes not influenced by high sedimentation rates. The marine to lacustrine transition in the sediment favours the generation of mass movements where the underlying massive mud appears to act as a slip surface for the overlying varved deposits. Based on acoustic stratigraphy and backscatter intensity data, we have identified at least 2 to 3 events that triggered failures in the lake during the last 2000 years. Based on the proximity of the lake to the Byam-Martin Seismic Zone, the location of the MMDs far from sediment input and the possible correlation between a turbidite layer in a sediment core and a recorded earthquake, seismicity could be responsible for sediment failures in the lake basin.
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