Glaciers shape landforms through erosion by scraping and plucking rocks and sediment as they move. As glaciers advance, they pick up debris from the valley floor and sides, and as they retreat, they leave behind piles of rocks and sediment known as moraines. The constant movement of glaciers also grinds against the bedrock below, carving out valleys, cirques, and other distinctive landforms through the process of glacial erosion.
