How can glaciers cause disposition?

Answer 1

When glaciers move as they grow, they grind the ground and rock underneath them. These pieces are pushed forward while they grow. When they final begin to melt, the water that is in the glaciers flows out from underneath them. This often carried sand and small bits of gravel. As they melted further and faster, larger gravel and stones wash out. Finally very large rocks and boulders are left behind. All of these are called deposition.