<P> Long, sinuous glacial deposits are called eskers . Eskers are composed of sand and gravel that was deposited by meltwater streams that flowed through ice tunnels within or beneath a glacier . They remain after the ice melts, with heights exceeding 100 meters and lengths of as long as 100 km . </P> <P> Very fine glacial sediments or rock flour is often picked up by wind blowing over the bare surface and may be deposited great distances from the original fluvial deposition site . These eolian loess deposits may be very deep, even hundreds of meters, as in areas of China and the Midwestern United States of America . Katabatic winds can be important in this process . </P> <P> Large masses, such as ice sheets or glaciers, can depress the crust of the Earth into the mantle . The depression usually totals a third of the ice sheet or glacier's thickness . After the ice sheet or glacier melts, the mantle begins to flow back to its original position, pushing the crust back up . This post-glacial rebound, which proceeds very slowly after the melting of the ice sheet or glacier, is currently occurring in measurable amounts in Scandinavia and the Great Lakes region of North America . </P> <P> A geomorphological feature created by the same process on a smaller scale is known as dilation - faulting . It occurs where previously compressed rock is allowed to return to its original shape more rapidly than can be maintained without faulting . This leads to an effect similar to what would be seen if the rock were hit by a large hammer . Dilation faulting can be observed in recently de-glaciated parts of Iceland and Cumbria . </P>

Explain the behavior and activity of a retreating glacier