CGRG Bibliography of Canadian Geomorphology
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Author : Cockburn, J.; and Lamoureux, S.
Date : 2005.
Title : Identifying long term permafrost degradation impact on sedimentation rates in Arctic coastal margins.
Publication : Arctic Net 2005 Programme. Annual Scientific Meeting, December 13-16, 2005. Banff, Alberta
Issue :
Page(s) : 43.
Abstract
Future climate scenarios predict that the arctic hydrological cycle could be extended and that permafrost degradation due to warmer conditions could increase overall sediment loads in arctic streams and thus, increased sediment flux to coastal margins [Syvitski, 2002]. The impact of recent climate change on the arctic landscape, specifically sediment erosion and transfer along the coastal margins can be evaluated through analysis of coastal lake sedimentation trends. In this study, sedimentary records from two coastal lakes at Cape Bounty, on the southern coast of Melville Island, NU, are used to reconstruct the rates of sediment transport and erosion from this lowland permafrost environment. The sedimentary structure and characteristics of the annual sedimentary unit (varves) provide information regarding the type of sediment that is eroded from the watershed and delivered downstream. Furthermore, sedimentation rates can estimate permafrost degradation from these same regions by providing a quantitative measure of the material available for transfer and changes in base sediment yield or persistent increased sediment delivery. In the records from Cape Bounty, the sedimentation rate is higher in the last quarter of the 20th century compared with the rest of the century. In the context of the last 500 years, sedimentation rates remain highest during the 20th century. High resolution particle size determination of the sediments over the same period show mean grain size increased over the last half of the 20th century as well. These results suggest that higher sedimentation rates also coincide with larger mean grain size and may indicate that a combination of sediment availability and/or stream power processes have changed during the 20th century. Through evaluation of the long sediment records during known past periods of warmer and cooler temperatures, sediment accumulation rates for coastal margins can be predicted for future periods of warmer and cooler temperatures.
Bibliography of Canadian Geomorphology