Headlands, Bays, and Wave-Cut Platforms

The formation of coastal landforms is a dynamic process driven by erosion and deposition. This page explores the development of headlands, bays, and wave-cut platforms.

Formation of Headlands and Bays

Headlands and bays form along discordant coastlines where rocks of varying resistance are positioned perpendicular to the shore. Over thousands of years, differential erosion occurs as softer rocks erode more quickly than harder ones.

Vocabulary: Discordant coast - A coastline where rock types are positioned at right angles to the shore.

Wave refraction concentrates energy on headlands while dispersing it in bays. This process further accentuates the formation of these distinct features.

Highlight: Wave refraction plays a crucial role in shaping headlands and bays by focusing erosive power on protruding landforms.

Wave-Cut Platform Formation

Wave-cut platforms develop through a series of erosional processes at the base of cliffs. Waves continually attack the cliff between high and low water marks, causing erosion through hydraulic power and abrasion.

Definition: Hydraulic power - The force exerted by waves as they crash against the shore, causing erosion.

As the cliff base erodes, an overhang forms. Eventually, this overhang becomes unstable and collapses, leading to cliff retreat. This cycle repeats, gradually creating a wave-cut platform where the cliff once extended.

Example: The formation of a wave-cut platform can be observed at many coastal locations, such as the chalk cliffs of Dover in England.

Beach Formation

Beaches form in the area between the lowest spring tide level and the highest storm wave reach. They are typically composed of material deposited on wave-cut platforms and can consist of sand, shingle, pebbles, mud, or silt.

Sandy beaches often develop in sheltered bays where low-energy, constructive waves transport material onshore. The swash (incoming wave) is stronger than the backwash (retreating water), resulting in net deposition.

Vocabulary: Swash - The rush of water up the beach face after a wave breaks.

Shingle beaches, characterized by larger pebbles and stones, form under stronger wave conditions. These beaches typically have steeper profiles with distinct ridges across their surface.