3.4

• What is cliff-foot erosion?

  Cliff-foot erosion occurs when waves erode the base of a cliff, weakening it and leading to undercutting, instability, and eventually collapse.
• What is abrasion in coastal erosion?

  Abrasion, or corrosion, occurs when sediment picked up by waves scrapes against and wears down the cliff face, contributing to erosion.
• What is corrosion in coastal erosion?

  Corrosion happens when weak acids in seawater dissolve alkaline rocks (e.g., chalk) or cement bonds, gradually breaking down the cliff material.
• What is attrition in coastal erosion?

  Attrition is the process by which rock particles are gradually reduced in size and become rounder and smoother through repeated impact and abrasion as they are moved by waves and currents.
• How does hydraulic action contribute to cliff erosion?

  Hydraulic action is the force of waves compressing air and water into cracks in the cliff, causing the rock to weaken and break apart.
• How do waves and lithology affect coastal erosion?

  The type and size of waves, along with the lithology (rock type) of the coast, influence erosion rates. Destructive waves, especially in winter, are more powerful and cause more erosion.
• What is differential erosion?

  Differential erosion occurs when areas of weaker rock, such as cracks or joints, are eroded more quickly than more resistant rock, leading to uneven erosion along the coastline.
• How do resistant and weak rocks affect coastal landforms?

  Resistant rocks, such as granite, form cliffs and headlands, while weaker rocks, like shale or boulder clay, erode more quickly, forming lowlands, bays, and inlets.
• How much has the Holderness Coast eroded in the last century?

  At Holderness, weak boulder clays have eroded by 120 meters in the last century
• How much has the granite at Land's End eroded in the last century?

  Resistant granites at Land's End have only eroded by 10 cm in the same period.
• How do wave-cut notches and platforms form?

  When waves break against a cliff, erosion concentrates near the high-tide line, forming a wave-cut notch. As the notch enlarges, the cliff above becomes unstable, eventually collapsing and forming a wave-cut platform.
• What happens to a cliff as wave-cut notches continue to erode?

  As wave-cut notches deepen and the cliff retreats, the area left behind forms a shoreline platform or wave-cut platform.
• What type of cliffs have the steepest profiles?

  The steepest cliffs are found where rock strata are vertical or horizontal or have almost vertical joints.
• What is the process of arch formation?

  Arches form when caves on both sides of a headland erode and connect, or when a single cave is eroded through a headland, eventually becoming a large opening.
• How do stacks form from arches?

  When the top of an arch collapses due to erosion, it leaves behind an isolated pillar of rock known as a stack.
• What happens to stacks over time?

  Stacks continue to erode until they collapse, and eventually, only a stump remains, often submerged at high tide and visible only at low tide.
• What is a stump?

  A stump is the remnant of a stack that has been eroded down to a small, isolated rock, often only visible at low tide.
• How do caves, arches, stacks, and stumps form in coastal erosion?

  These features form when rocks like limestone, with natural faults and joints, are eroded by hydraulic action and abrasion. Caves form first, then when caves connect or erode through headlands, arches form. Arches collapse, leaving stacks, which erode further into stumps.