CGRG Bibliography of Canadian Geomorphology
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Author : Clarke, S.A.; and Lewkowicz, A.G.
Date : 1998
Title : Influence of climate fluctuations on solifluction: an experimental study.
Publication : Permafrost, Seventh International Conference, June 23-27, Yellowknife, Canada. Edited by: A.G. Lewkowicz and M. Allard. Université Laval, Centre d'études nordiques, Collection Nordicana.
Issue : 57:
Page(s) :
Abstract
Solifluction is one of the most important mass movement processes within the active layer in permafrost environments (Egginton and French, 1985). Given an incomplete understanding of the relationship between solifluction rates and climate, it is difficult to effectively predict future rate changes as a result of climate fluctuations. The objective of this experiment was to simulate climate change and to directly examine the effect on solifluction. The experimental site is located in continuous permafrost in the valley of Hot Weather Creek on the Fosheim Peninsula, Ellesmere Island. Five electro-mechanical meters (Lewkowicz, 1992) anchored in permafrost and thermocouple cables were installed close together on a planar portion of an 8° colluvial slope in 1992-93. The meters and cables were multiplexed to a data logger which acquired ground temperature and soil movement data continuously from August 1993 until August 1997. The soil at the site consists of a sandy silt (clay < 8%) with a liquid limit of 29% and a plasticity index of 12%. During the summer of 1996, one meter was warmed using polyethylene (B), one wetted by manual watering of the slope (D), one treated to a combination of these treatments (A), one cooled by shading (E) and the last left as a control (C). The climatic treatments were successful in manipulating active layer conditions in 1996, as maximum thaw depths ranged from 72 cm at meter A to 54 cm at meter E. The control meter (C) thawed to a depth of 64 cm. The increase in thaw depth had an impact on movement throughout the soil profile. Between January 1, 1996 and January 1, 1997, the blocks at Meter A indicated the greatest amount of downslope movement (Figure 1). The maximum amount of movement recorded, 34 mm, was at a depth of 26 cm, while movement at the other meters ranged between 12 and 16 mm at the same depth. Very little movement was measured at 66 cm (1 to 7 mm) at meters B, C and D, whereas meter A indicated 22 mm. Measurements of meter height above the ground surface suggest that much of meter A’s movement may have occurred as a result of soil settlement, as the increased thaw depth allowed for the melting of an ice-rich zone. Between June 26 and August 9, soil surrounding meter A settled approximately 58 mm, whereas that surrounding meter E heaved approximately 10 mm. The detailed nature of the data collected has highlighted the importance of considering both vertical and downslope movement throughout the soil profile when examining solifluction.
Bibliography of Canadian Geomorphology