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TitleTerrain controls on the occurrence of coastal retrogressive thaw slumps along the Yukon Coast, Canada
AuthorRamage, J L; Irrgang, A M; Herzchuh, U; Morgenstern, A; Couture, NORCID logo; Lantuit, H
SourceJournal of Geophysical Research, Earth Surface vol. 122, 2017.,
Alt SeriesNatural Resources Canada, Contribution Series 20170021
Mediapaper; on-line; digital
File formatpdf
ProvinceYukon; Northern offshore region
NTS117D; 117C/01; 117C/08; 117C/09; 117C/16
AreaHerschel Island; Yukon Coast; Beaufort Sea
Lat/Long WENS-141.0000 -137.0000 69.6667 69.0000
SubjectsNature and Environment; slumps; permafrost; ground ice; ice conditions; ice disintegration features; coastal environment; coastal studies; coastal erosion; coastal management; slope stability; slope failures
Illustrationslocation maps; tables; satellite images; plots; schematic diagrams
ProgramClimate Change Geoscience Coastal Infrastructure
Released2017 09 08
AbstractRetrogressive thaw slumps (RTSs) are among the most active landforms in the Arctic; their number has increased significantly over the past decades. While processes initiating discrete RTSs are well identified, the major terrain controls on the development of coastal RTSs at a regional scale are not yet defined. Our research reveals the main geomorphic factors that determine the development of RTSs along a 238 km segment of the Yukon Coast, Canada. We (1) show the current extent of RTSs, (2) ascertain the factors controlling their activity and initiation, and (3) explain the spatial differences in the density and areal coverage of RTSs. We mapped and classified 287 RTSs using high-resolution satellite images acquired in 2011. We highlighted the main terrain controls over their development using univariate regression trees model. Coastal geomorphology influenced both the activity and initiation of RTSs: active RTSs and RTSs initiated after 1972 occurred primarily on terrains with slope angles greater than 3.9° and 5.9°, respectively. The density and areal coverage of RTSs were constrained by the volume and thickness of massive ice bodies. Differences in rates of coastal change along the coast did not affect the model. We infer that rates of coastal change averaged over a 39 year period are unable to reflect the complex relationship between RTSs and coastline dynamics. We emphasize the need for large-scale studies of RTSs to evaluate their impact on the ecosystem and to measure their contribution to the global carbon budget.
Summary(Plain Language Summary, not published)
Retrogressive thaw slumps (RTSs) are landforms in the Arctic caused by thawing ground ice. This research examines a 235 km coastal segment of the Yukon Coastal Plain, Canada, to see how geomorphology controls the development of RTSs. We mapped and classified the RTSs using satellite images from 2011 and then used statistical analyses to determine the main geomorphic controls. The results show that slope angle affected both the initiation and the level of activity of the slumps, while the presence of massive ground ice within permafrost affected the number and extent of them. Coastal erosion appears to affect them only indirectly by maintaining good conditions for reactivation.

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