The Earth Contents

3. Weathering

Ice crystallization weathers rock

In temperate regions the most effective physical weathering process is the crystallisation of ice within small fractures. This mechanism starts with the penetration of moisture into small cracks in the rock surface, which allows water to build up during warmer spells of weather, and then to freeze in the cracks in colder weather. The freezing causes expansion and the force exerted in the crack by the expanding ice crystals is sufficient to prise open the crack, widening it and extending it deeper into the rock. Ultimately the cracks become extensive enough to shear away a block from the rock face, which falls to the cliff base to create a talus cone.

Ice crystallisation weathers rock

How does ice crystallisation weather rock?