Longshore drift, gernated by waves advancing obliquely toward the shore, is one of the most important shoreline processes. Erosion along a coast tends to develop seacliffs by the undercutting action of waves and longshore currents. As a cliff recedes, a wave cut platform developes, until equilibrium is established between wave energy and the configration of the coast. Sediment transported by waves and longshore currents is deposited in areas of low energy to form beaches, spits, and barrier islands. Erosion and deposition alsong a coast ten to develop a staight or gently curving shoreline that is in equilibrium with th energy expended upon it.
Reefs grow in a special environment and form coasts that can evolve into atolls.
The worldwide rise in sea level associated iwth the melting of the Pleistocene glaciers drouwned many coasts between 15,000 and 20,000 years ago. Tides are produced by the gravitational attraction of the moon and exert a major local influence on shorelines. Tsunamis are waves generated by earth movements that cause disturbance of the sea floor. Wind is not an effective agent of erosion in most areas, but it can transport loose, unconsolidated fragments of sand and dust. Wind transports sand by saltation and surface creep.