Figure 10.40: These long, dark lines on the Aletsch glacier in Switzerland are examples of
medial and lateral moraines. ( 13 )
glacier is retreating. This means that is there is less ice in the glacier this year than there
was the year before (Figure10.41).
Figure 10.41: These photographs of the Grinnell Glacier in Glacier National Park were taken
over an almost 70 year period. The glacier is clearly visible and well developed in 1938. From
1981 through 2005, the amount of glacial ice has decreased and the meltwater forming the
lake has increased. In 2005, icebergs are further evidence of glacial melting. ( 32 )
When glaciers melt more than they flow forward, they deposit all the big and small bits
of rocky material they have been carrying. In general, all these unsorted deposits of rock,
formed directly by the ice, are calledglacial till.If you live in an area where glaciers once
were, you may have seen large boulders in the woods or even in the middle of a field. If