A 100-km wide slump along the upper slope of the Canadian Arctic was likely preconditioned for failure by brackish pore water flushing

Marine Geology
By: , and 

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Abstract

Exploration of the continental slope of the Canadian Beaufort Sea has revealed a remarkable coalescence of slide scars with headwalls between 130 and 1100 m water depth (mwd). With increased depth, the scars widen and merge into one gigantic regional slide scar that is more than 100 km wide below ~1100 mwd. To understand the development of these features, five sites were investigated with an Autonomous Underwater Vehicle, which provided 1-m bathymetric grids and Chirp profiles, and surveyed with a Remotely Operated Vehicle. The morphologies are consistent with retrograde failures that occurred on failure planes located between 30 and 75 m below the modern seafloor. At issue is whether the continental slope in this area is preconditioned for failure. While rapid sedimentation during glacial periods, and the presence of shallow gas cannot be ruled out, given the geological environment, it is unclear that they are primary preconditioning factors. Evidence of widespread flushing of the slope with brackish waters, and observed flows of brackish water within slide scars, suggest fluid venting and overpressure may play a role in the development of the extensive slope failures seen along this margin. The impact of pore water salinity changes at the depth of the failure plane on slope stability has not been considered in marine settings previously.

Publication type Article
Publication Subtype Journal Article
Title A 100-km wide slump along the upper slope of the Canadian Arctic was likely preconditioned for failure by brackish pore water flushing
Series title Marine Geology
DOI 10.1016/j.margeo.2021.106453
Volume 435
Year Published 2021
Language English
Publisher Elsevier
Contributing office(s) Pacific Coastal and Marine Science Center
Description 106453, 16 p.
Country Canada
Other Geospatial Arctic Sea, Canadian Beaufort Sea
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