Till is a type of sediment that is directly deposited by glaciers or ice sheets. It is composed of a mixture of different-sized particles, including clay, silt, sand, gravel, and boulders. Till is often found in moraines, which are ridges of sediment that are deposited at the edges of glaciers or ice sheets.

Till can be classified into two main types: lodgement till and ablation till. Lodgement till is deposited when glaciers or ice sheets move over the ground and deposit sediment directly onto the underlying surface. Ablation till is deposited when glaciers or ice sheets melt and release their sediment load.

Till is an important source of information about the past movement of glaciers and ice sheets. By studying the composition and distribution of till, scientists can learn about the direction of ice flow, the thickness of glaciers and ice sheets, and the timing of past glacial advances and retreats.

Till is also a valuable resource for construction materials. The different-sized particles in till make it a versatile material that can be used for a variety of purposes, including road construction, building construction, and landscaping.