How do sea stacks form?
• Why is the Totem Pole a “Fantastic Place” for climbers and others? How do sea stacks form? • The base of the cliff is subjected to constant erosion from the waves. The main types of coastal erosion are corrosion, attrition, solution and hydraulic action. • Over time the joints, faults and bedding planes in the base of the cliff become eroded and larger cracks appear. • The cracks become wider and weaker as the erosion continues, causing caves to form. Caves are often found on headlands because wave erosion is particularly strong here. In some cases the roofs of caves may be broken through to form blowholes. • When caves develop on opposite sides of a headland they will join up to form a natural arch, as the cliff is being eroded from both sides. • The arch continues to be eroded and will gradually become bigger and bigger until just a slim pillar is left, attached to the top of the cliff. • The top of the pillar collapses as it can no longer support the weight of the connecting rock,
