|
View Paper
CONTRASTING PATTERNS OF THERMO-EROSION GULLIES FORMED IN SYNGENETIC ICE WEDGE POLYGONAL TERRAINS ON BYLOT ISLAND, EASTERN CANADIAN ARCTIC: CASE STUDIES FROM THREE DIFFERENT SEDIMENTARY ENVIRONMENTS
Session: Characterization of Permafrost State and Variability II / Caractérisation et variabilité du pergélisol II
Audrey Veillette, Département de Géographie, Université de Montréal, Montréal, QC, CAN; Centre d'Études Nordiques, Université Laval, Québec, QC, CAN (Canada)
Daniel Fortier, Département de Géographie, Université de Montréal, Montréal, QC, CAN (Canada)
Etienne Godin, Département de Géographie, Université de Montréal, Montréal, QC, CAN (Canada)
Ice wedge polygonal terrains, typical of Arctic permafrost geosystems, are vulnerable to thermo-erosional gullying and thermokarst. Gullies located on Bylot Island (NU) have distinct shapes and dynamics on factors such as their age, alluvial activity level, water balance and nature of the sedimentary environment. In this paper we focus on the contrasts differencing gullies observed in aeolian sands, colluvium/alluvium and peaty-loess deposits. Polygons areas, ice wedges size and consequently gully shapes were distinct for each environment: the peaty-loess-zone had medium-sized polygons and generally larger ice wedges, which erosion resulted in well-developed multi-channel gullies. The aeolian sands-zone had smaller polygons and thinner ice wedges, where quasi-linear gullies were formed. The colluvium/alluvium-zone had large polygons with large primary ice wedges. The erosion was concentrated, very active, and essentially restricted to the primary ice wedges. The role of the ice wedges geometry and size in the evolution of the gullies was major, putting thermo-erosion gullies as distinct landforms from gullies found in warmer, non-permafrost zones.
|
