Abstract

Analyses of 103 till fabrics taken from proximal and distal slopes of distinctive cross-valley moraines in the Isortoq Valley of north-central Baffin Island show variations in fabric pattern with respect to slope and location within the valley. Changes in dip patterns and fabric strengths are also associated with variations in moraine morphology. Four distinct morphological moraine types are delimited and are called simple-linear, s-shaped, hooked, and asymmetric. There is no gradation in type along a single moraine. Orientation and dip strength are found to vary with moraine type as well as between distal and proximal slopes. Dip patterns of elongate pebbles from proximal and distal sites are also shown to vary with slope, location within the valley and moraine type. These results indicate that the hooked, asymmetric, and simple-linear moraines are formed by either dissimilar processes or changes in intensity of the same process. S-shaped moraines differ morphologically from simple-linear but have the same fabric characteristics. The possibility of annual deposition is examined and concluded to be possible though in no sense proven. The cross-valley moraines are thought to form at the base of an ice cliff grounded in a glacial lake. The influx of summer meltwater provides a possible trigger mechanism and explains the association between the moraines and water-deposited kame features. The asymmetric moraines were deposited by overriding and pushing. Moraines at right angles to the ice cliff were formed by the squeezing of till into basal crevasses or melt-water tunnels.

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