Coastal Systems and Landscapes 3

Some coastal landforms are caused by erosion:

Cliffs and wave-cut platforms:

• Cliffs - form as the sea erodes the land. They retreat due to the action of waves and weathering.
• Weathering and wave erosion cause a notch to form at the high water mark - a cave is formed.
• Rock above becomes unstable and collapses.
• Wave-cut platforms are flat surfaces left behind.

Headlands and bays:

• Form where there are bands of alternating hard rock and soft rock at right angles to the shoreline.
• Soft rock is eroded quickly forming a bay. The harder rock is protruding out to sea; the headland.

Caves, arches and stacks:

• Cliff profile features.
• Weak areas in rock are eroded to form caves.
• Caves on the opposite sides of a narrow headland may eventually join up to form an arch.
• When an arch collapses, it forms a stack.

Some coastal landforms are caused by deposition:

Beaches:

• Form when constructive waves deposit sediment on the shore.
• Shingle beaches are steep and narrow; have large particles.
• Sand beaches are wide and flat; have small particles.
• Berms - ridges of sand and pebbles found at high tide marks.
• Runnels - grooves in the sand running parallel to the shore, formed by backwash draining to the sea.
• Cusps - crescent-shaped indentations that form on beaches of mixed sand and shingle.

Spits:

• Longshore drift - deposits material across the river mouth, leaving a bank of sand and shingle sticking out into the…