Basal melt-out till from snout area of Aktineq GlacierLocation: Southeast side of snout of Aktineq Glacier (B-17), Bylot Island, Nunavut, Canada, ca. 40 km WNW of Pond Inlet; 72° 53' N, 78° 55' W
This image shows the basal debris load of Aktineq Glacier in a section cut by its lateral meltwater channel in 1990. Because the glacier's front retreats by melting down and back, once the melting descends into the 2 (Ø) m - thick, debris-charged basal part of the glacier, the first debris released insulates the frozen base, preserving it beneath a layer of diamicton or other sediment until meltwater cuts through it, as in this example. The surface diamicton is basal melt-out till, but retains no structures related to the basal structure of the glacier. The frozen debris below, however, if melted out slowly, might retain structures such as those that can be seen in this natural cross-section. Even though the basal ice looks heavily charged with debris, it is probably more than 50% ice by volume. Images 0136, 0138, and 0158 are from the same general location and show other views of the same process.
Updated 03/30/2010 AW