Increased precipitation drives mega slump development and destabilization of ice-rich permafrost terrain, northwestern Canada

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dc.contributor.author Kokelj, S.V.
dc.contributor.author Tunnicliffe, J.
dc.contributor.author Lacelle, D.
dc.contributor.author Lantz, T.C.
dc.contributor.author Chin, K.S.
dc.contributor.author Fraser, R.
dc.date.accessioned 2018-05-30T17:55:15Z
dc.date.available 2018-05-30T17:55:15Z
dc.date.copyright 2015 en_US
dc.date.issued 2015
dc.identifier.citation Kokelj, S.V., Tunnicliffe, J. Lacelle, D., Lantz, T.C., Chin, K.S. & Fraser, R. (2015). Increased precipitation drives mega slump development and destabilization of icerich permafrost terrain, northwestern Canada. Global and Planetary Change, 129, 56-68. http://dx.doi.org/10.1016/j.gloplacha.2015.02.008 en_US
dc.identifier.uri http://dx.doi.org/10.1016/j.gloplacha.2015.02.008
dc.identifier.uri http://hdl.handle.net/1828/9412
dc.description.abstract It is anticipated that an increase in rainfall will have significant impacts on the geomorphology of permafrost landscapes. Field observations, remote sensing and historical climate data were used to investigate the drivers, processes and feedbacks that perpetuate the growth of large retrogressive thaw slumps. These “mega slumps” (5–40 ha) are now common in formerly glaciated, fluvially incised, ice-cored terrain of the Peel Plateau, NW Canada. Individual thaw slumps can persist for decades and their enlargement due to ground ice thaw can dis- place up to 106 m3 of materials from slopes to valley bottoms reconfiguring slope morphology and drainage net- works. Analysis of Landsat images (1985–2011) indicate that the number and size of active slumps and debris tongue deposits has increased significantly with the recent intensification of rainfall. The analyses of high resolution climatic and photographic time-series for summers 2010 and 2012 shows strong linkages amongst temperature, precipitation and the downslope sediment flux from active slumps. Ground ice thaw supplies meltwater and sediments to the slump scar zone and drives diurnal pulses of surficial flow. Coherence in the timing of down valley debris tongue deposition and fine-scaled observations of sediment flux indicate that heavy rainfall stimulates major mass flow events. Evacuation of sediments from the slump scar zone can help to maintain a headwall of exposed ground ice, perpetuating slump growth and leading to larger disturbances. The development of debris tongue deposits divert streams and increase thermoerosion to initiate adjacent slumps. We conclude that higher rainfall can intensify thaw slump activity and rapidly alter the slope-sediment cascade in regions of ice-cored glaciogenic deposits. en_US
dc.description.sponsorship This work was supported by the NWT Cumulative Impact Monitoring Program, the Aurora Research Institute and theNWT Geoscience Office, Government of the Northwest Territories, by Natural Sciences and Engineering Research Council of Canada grants to D. Lacelle and T. Lantz, and by the Polar Continental Shelf Project. Institutional support from the Gwich’in Tribal Council, Gwich’in Renewable Resources Board and the Tetlit Gwich’in Renewable Resources Council is gratefully acknowledged. We thank Shawne Kokelj and Meg McCluskie from Water Research and Studies, Environment and Natural Resources, Government of the Northwest Territories for supplying data from the Peel Plateau Meteorological Station. The authors thank Kyle Rentmeister from the NWT Centre for Geomatics for the GIS work. Jaya Bastedo, Steven Tetlichi, Clifford Vaneltsi, Gina Vaneltsi and Billy Wilson supplied critical field and logistical support. We thank Larry Flysak, Environment Canada, for timely provision of unpublished Fort McPherson Airport precipitation data. en_US
dc.language.iso en en_US
dc.publisher Global and Planetary Change en_US
dc.subject climate change en_US
dc.subject ground ice en_US
dc.subject landscape change en_US
dc.subject mass wasting en_US
dc.subject permafrost en_US
dc.subject rainfall intensity en_US
dc.subject thaw slump en_US
dc.subject thermokarst en_US
dc.title Increased precipitation drives mega slump development and destabilization of ice-rich permafrost terrain, northwestern Canada en_US
dc.type Article en_US
dc.description.scholarlevel Faculty en_US
dc.description.reviewstatus Reviewed en_US

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