A wave-cut platform is formed through the erosional power of the sea acting on a coastline. According to the provided reference, wave-cut platforms form when destructive waves interact with the base of a cliff face, initiating a specific sequence of events.
The process described begins with destructive waves hitting directly against the cliff face. This forceful impact and subsequent action of the waves cause erosion that leads to the formation of an undercut at the base of the cliff. This undercut is typically located within the tidal zone, specifically between the high and low water marks, where wave action is most concentrated and effective.
This erosion is not caused by just one force, but mainly as a result of several key processes:
Key Erosional Processes
The reference highlights three primary types of erosion responsible for creating the undercut and subsequent notch:
- Abrasion: This occurs when the waves hurl rocks and pebbles against the cliff face. These materials act like sandpaper, wearing away the rock over time.
- Corrosion: Also known as solution, this is the chemical action of seawater on soluble rocks (like limestone) at the cliff base, dissolving them away.
- Hydraulic Action: This involves the sheer force of water and air. Waves crashing into cracks in the cliff compress the air within. When the wave retreats, the pressure is suddenly released, causing the air to expand explosively, widening the cracks. The force of the water itself can also loosen and remove rock fragments.
As these processes continue to erode the base of the cliff, the undercut deepens and develops into a prominent feature known as a wave-cut notch. The reference states that the creation of this wave-cut notch is the mechanism through which wave-cut platforms form.
Essentially, the relentless erosion at the base creates an unstable overhang (the cliff above the notch). As this notch enlarges, the overlying rock mass becomes unsupported and eventually collapses. This process of notch formation and subsequent collapse repeats over time, causing the cliff line to retreat landward. The relatively flat, rocky area left behind at the base of the retreated cliff, within the tidal zone, is the wave-cut platform.
| Erosional Process | Description |
|---|---|
| Abrasion | Rocks carried by waves grind against the cliff. |
| Corrosion | Chemical action of seawater dissolving soluble rocks. |
| Hydraulic Action | Force of waves and compressed air eroding cracks in the cliff. |
Thus, the formation of a wave-cut platform is intrinsically linked to the initial creation and subsequent enlargement of the wave-cut notch at the base of the cliff through the persistent action of destructive waves and the processes of abrasion, corrosion, and hydraulic action.
