Exposed rocks along the coastline can be broken down by the processes of weathering.
Freeze-thaw weathering occurs when rocks are porous (contain holes) or permeable (allow water to pass through it).
- Water enters cracks in the rock.
- When temperatures drop, the water freezes and expands causing the crack to widen.
- The ice melts and water makes its way deeper into the cracks.
- The process repeats itself until the rock splits entirely.
- Plant roots can get into small cracks in the rock.
- As the roots grow, the cracks become larger.
- This causes small pieces of rock to break away.
Rainwater and seawater can be a weak acid. If a coastline is made up of rocks such as limestone or chalk, over time they can become dissolved by the acid in the water.