Once material is incorporated into a glacier it may be carried many miles downstream before it is released in the ablation zone. Some material may ride on top of the ice after falling from the valley sides. This type of material is called morainal debris . Trails of morainal debris can be seen on top of many glaciers as it is carried downstream by the glacier. Trails of debris in the middle of the glacier are called medial moraines , those along the sides of the glacier are called lateral moraines .
Glaciers usually deposit their load in the ablation zone where ice is melting.
If the glacier dumps the material in an unsorted mixture, this is called till . Till is also deposited at the bottom of the glacier as ice melts. Sediment that is deposited on top of a glacier and then reworked a bit by water and as landslides is called supraglacial sediments . Gravel, sand, and silt sorted by water and deposited by streams in front of the glacier is called outwash . Some of this finer material may be picked up by the wind and later deposited as loess .