WAVE DEPOSITION
Waves carry a variety of materials, including sand, rock fragments, dead coral, and shells. Often, this material is deposited on a shoreline, where it forms a beach. A beach is any area of the shoreline made up of material deposited by waves. Some beach material is also deposited by rivers. The colors and textures of beaches vary. They vary because the type of material found on a beach depends on its source.
When waves erode material from the shoreline, longshore currents can transport and deposit this material offshore, which creates landforms in open water. A sandbar is an underwater or exposed ridge of sand, gravel, or shell material. A barrier spit is an exposed sandbar that is connected to the shoreline. Cape Cod, Massachusetts is an example of a barrier spit. A barrier island is a long, narrow island usually made of sand that forms offshore parallel to the shoreline.
WIND DEPOSITION
Wind eventually drops all the material it carries. The amount and the size of particles the wind can carry depend on the wind speed. The faster the wind blows, the more material and the heavier the particles it can carry. As wind speed slows, heavier particles are deposited first.
Wind can deposit extremely fine material. Thick deposits of this windblown, fine-grained sediment are known as loess (LOH ES). Loess feels like the talcum powder a person may use after a shower. Because wind carries fine-grained material much higher and farther than it carries sand, loess deposits are sometimes found far away from their source.
When the wind hits an obstacle, such as a plant or a rock, the wind slows down. As it slows, the wind deposits, or drops, the heavier material. The material collects, which creates an additional obstacle. This obstacle causes even more material to be deposited, forming a mound. Eventually, the original obstacle becomes buried. The mounds of wind-deposited sand are called dunes. Dunes are common in sandy deserts and along the sandy shores of lakes and oceans. Dunes can be found on Cumberland Island, Georgia.
ICE DEPOSITION (GLACIERS)
As a glacier melts, it drops all the material it is carrying. Glacial drift - all material carried and deposited by glaciers. Glacial drift is divided into two main types, till and stratified drift.
Unsorted rock material (rock material of different sizes—from large boulders to fine sediment)that is deposited directly by the ice when it melts is calledtill. When the glacier melts, the unsorted material is deposited on the surface of the ground. The most common till deposits are moraines.
When a glacier melts, streams form that carry rock material away from the shrinking glacier. A glacial deposit that is sorted into layers based on the size of the rock material is called stratified drift. Streams carry sorted material and deposit it in front of the glacier. Sometimes, a block of ice is left when a glacier retreats. As the ice melts, sediment builds up around the block of ice, and a depression called a kettle forms. Kettles commonly fill with water to form lakes or ponds.
DEPOSITION BY GRAVITY (MASS MOVEMENT)
Although you can’t see it, the force of gravity is also an agent of deposition. Materials that are carried during slow mass movements (creep) and rapid mass movements (mudflows, lahars, rock falls, and landslides) are deposited once the movement stops.