This is where the glacier is gaining snow. Near the bottom is the ablation area , where the glaciers lose snow and ice. In the middle is the equilibrium . Crevasses are deep trenches formed by the glacier pulling apart, and moraines are the dark bands you can see in this picture, which carry rocky debris. Terminal moraines are big mounds of earth pushed up in front of the glacier as it moves forwards.
Lateral moraines are lines of pushed-up debris on the sides of glaciers.
We've already talked about moraines . But when the huge glacier passes over the land, it makes a lot of changes. There are things called tills , which are all the little bits of rocks and soil that are left behind as a glacier moves forward. Kettles are chunks of ice buried by the glacier that melt to form little lakes. Sometimes, the glacier drops out rocky material while it is still moving, and then goes over it, creating little hills called drumlins .