Solifluction and related processes, eastern Banks Island, N.W.T.

Abstract

Mean surface soil movement measured over the period of 1971-1983 on eight relatively low angle (<10.degree.), well drained slopes on eastern Banks Island averaged 0.6 cm/year. Substantial variation in mean movement was recorded amongst the slopes. The variation relates to differences in soil moisture conditions, soil grain size, and the position of the measurement transect relative to the crest or base of the slope. The former two variables and therfore the rate of movement can change rapidly across any given slope, particularly when stripes are present. Three types of movement are identified by in the study area: (1) mud burst and flow, (2) classic solifluction, and (3) pluglike flow. The latter occurs along discrete shear planes located both within an at the base of the active layer. The existence of episodic and relatively rapid mass movement on these slopes suggests that long-term monitoring programs are necessary to adequately assess and measure slope movement.