On the origin of the small moraines of Upper Hat Creek Valley

Numerous small linear moraines occur in Upper Hat Creek valley, British Columbia. The ridges lie transverse to the axis of the valley. They are, upon average, 1000 feet (305 m.) long, 8 feet (2.4 m.) high, and spaced 130 feet (40 m.) apart. Their profile is asymmetrical, with a steeper proximal slope. The alignment of a-axes of pebbles in the till is transverse to the moraine crest, regardless of the orientation of the crest with respect to the direction of regional ice movement. The dip of the pebbles is in the direction of the surface slope, however, it is less than the slope on the proximal side and greater than the slope on the distal side. The Hat Creek moraines form an extensive system of push moraines, deposited during the retreat of the last ice sheet. During the winter, a slight readvance of the glacier pushed the ablation moraine of the previous summer into a ridge along the ice front. The ridge was not overridden by the ice. Therefore, the asymmetry of a simple push moraine was maintained. During the subsequent ablation season the moraine was isolated from the retreating ice margin. The next winter's readvance rarely extended as far as the previous ridge, thereby preserving the moraines.Arts, Faculty ofGeography, Department ofGraduat