scholarly journals An updated assessment of ground ice and permafrost geology-related observations based on seismic shothole drillers' log records, Northwest Territories and northern Yukon

2012 ◽  
Author(s):  
I R Smith ◽  
K Lesk-Winfield
Keyword(s):  
Northwest Territories ◽  
Ground Ice

Headwall retreat of ground-ice slumps, Banks Island, Northwest Territories

1987 ◽  
Vol 24 (6) ◽  
pp. 1077-1085 ◽  
Author(s):  
Antoni G. Lewkowicz
Keyword(s):  
Northwest Territories ◽  
Latent Heat ◽  
Field Measurements ◽  
Geometric Factor ◽  
Ground Ice ◽  
Model Based ◽  
Banks Island ◽  
Sand Hills ◽  
Ground Slope ◽  
The Relationship

The relationship between ice-face ablation and headwall retreat is described for three ground-ice slumps in the Sand Hills moraine, southwest Banks Island. Retreat exceeds ablation by a geometric factor that depends on the slope of the ice and the gradient of the surrounding terrain. Amounts of retreat predicted from ice-ablation calculations compare favourably with field measurements, except at the start of thermokarst activity in the spring or when the ground ice remains covered by debris for long periods.Long-term headwall retreat for slumps in southern Banks Island with different orientations and ice contents can be estimated using a model based on meteorological information. The model predicts headwall recession of 11 m/a for a ground-ice slump facing south and 8.8–9.3 m/a for one facing north, with inputs of a 35 °ice face, a ground slope of 5°, and a volumetric latent heat of 270 MJ/m3. These predictions are close to the maximum rates of retreat over a 10 year period as measured from air photographs.

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