Physical Weathering Processes

Freeze-Thaw Weathering

Freeze-thaw weathering occurs mainly with rocks that contain cracks and in locations where temperatures drop below freezing point regularly. As seen in the diagram, any rainfall in the cracks freezes when temperatures drop, expanding by up to ten times its size. Repeated freezing and thawing of rainwater in the crack will continue to put pressure on the rock and will eventually break it apart. This is a form of physical weathering; the rock is broken down but there is no change in the chemical composition of the rock.

Exfoliation:

Exfoliation is most common in locations where there is a hot climate and a large diurnal temperature range. As shown in the diagram, repeated heating and cooling puts pressure on the surface of the rock and the rock is broken down in layers from its surface. This is a form of physical weathering; the rock is broken down but there is no change in the chemical composition of the rock.