Glaciers, which are very large sheets of ice up to 2 miles in height, move
under the force of gravity because of their massive weight. As an ice sheet
moves through a valley or over bedrock below, huge quantities of sediments ranging
in size from fine clay to large boulders are ripped from valley walls and floors
then incorporated into the ice sheet itself. This Glacial Drift, embedded within
the ice sheet, travels quite a distance from its point of origin. Eventually,
upon the glacier's melting and retreat, sediments of all sizes are deposited
in unsorted mounds on top of bedrock that does not match the composition of
the individual fragments.
Is the arrow pointing to an example of weathering or erosion?
