tread

A tread in geology refers to the flat surface of a river terrace, which was once a floodplain. River terraces are landforms found in valleys, representing former floodplains where a river flowed at a higher elevation than its current channel. They consist of a tread and a scarp, which is a steep slope connecting the tread to a lower surface.1

Terraces are important for understanding a river valley's history, as their presence indicates changes in controlling factors like climate or tectonic activity. The tread itself is typically underlain by sediment deposited by the river. The term "tread" can also refer to the part of a tire or shoe that contacts the ground.12