Glacial landforms are deposits of sediments produced by the advance and retreat of glaciers. As a glacier forms and advances, large amounts of rock and soil are picked up and incorporated into the base of the ice. In alpine glaciers, erosion along valley walls may also contribute sediment build-up on the top of the glacier. The continual flow of the glacier carries these materials forward until they reach the end of the glacier, where they are deposited when the toe of the glacier melts away. If the sediments are deposited directly from the ice, they are called till. Till consists of a range of unconsolidated and usually unstratified materials in a range of sizes, from clay to large boulders. Sediments may also be transported and deposited by glacial melt water and are termed glaciofluvial deposits.

A distinct deposit of till is called a moraine. Because till...