Dunes

Around the world along coasts and in deserts sand dunes have formed. The formation of sand dunes is known as psammosere. In order for dunes to develop along a coast there are four requirements: a sandy beach, onshore winds, a large tidal range, and an obstacle. The process begins with saltation, which is the movement of sand due to wind. Convection currents, which are created because the land heats faster than the sea and warm air rises, cause the wind. Once the sand is being blown onto the beach an obstacle is needed. This obstacle can range from a piece of seaweed to a pebble (See Figure 1, Step 1). The sand will begin to collect behind the obstacle as the wind speed ...