MORPHOLOGY, FREQUENCY AND MAGNITUDE OF ACTIVE-LAYER DETACHMENT SLIDES, FOSHEIM PENINSULA, ELLESMERE ISLAND, N.W.T.

• Main Author: Antoni G. Lewkowicz
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Ellesmere Island; Eureka; Fosheim Peninsula
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.518.7450; http://pubs.aina.ucalgary.ca/cpc/cpc5-111.pdf

Hundreds of active-layer detachment slides are present on the Fosheim Peninsula both above and below the marine limit within a 50 km radius of Eureka These landslides occur in silty or sandy materials on slopes from 2->40 ° and range up to 700 m in length and 150 m in width. Length distributions are positively skewed and modal values are 20-40 m. Typical scar depths are 03-0.5 m and since these represent the position of the thaw front in mid- to late summer, slope failure occurs at this time. Minimum estimates of downslope movement of soil materials by active-layer detachment sliding in three locations range &om 6 to 60 mm yr l for the upper 0.5 m of the active layer. These rates correspond to volumetric transport of 30-300 cm3 cm-1 yrl and indicate that this geomorphic process is at least as important as solifluction. Unequal responses at three sites to a particularly warm period in the summer of 1988 suggest that where active-layer detachment slides are already common, climatic warming might initially induce additional failures. More frequent external triggers will not affect long-term activity rates, however, unless internal slope processes such as weathering and moisture migration are also influenced by climatic change. Sur la Pdninsule Fosheim, au-dessus et au-dessous de la limite marine se trouvent des centaines de ruptures du mollisol B l'indrieur d'un rayon de 50 lun de Eureka. Ces glissernents de terrain se produisent