How do wave-cut platforms form below sea cliffs?

A wave-cut platform is a gently sloping rock ledge that forms at the base of a sea cliff through the process of wave abrasion.21

The formation process occurs as follows:

• Notch Erosion: Waves batter the bedrock at the base of the cliff, gradually eroding a notch into the rock surface.23
• Cliff Collapse: As the notch deepens, the rock above it becomes unsupported and eventually collapses.2
• Platform Development: This cycle of erosion and collapse causes the cliff to retreat, leaving behind a flat or gently sloping bench that extends from the high-tide level to below the low-tide level.21

The rate and success of this process depend heavily on the rock type and structure; massive, resistant rocks like granite may inhibit platform formation, while the presence of a beach can protect the cliff base from direct wave attack, slowing or preventing the formation of a platform. If sea levels change over time, these platforms may be raised above the current water level, becoming known as marine terraces.23