Sand spits form after sudden changes in the shape of a coastline. This causes longshore drifts that deposit sediment in the direction of the drift, rather than along the coastline. Sand spits appear as fingers of land projecting from the coast.Know More
Longshore drifts occur when prevailing winds blow at an angle to the coastline. The drifts carry sediment to the shore. When the shoreline suddenly changes direction the sediment continues to drift, eventually being deposited when currents become weaker. Wave refraction generates a hook in the shape of the spit. This hooked land area creates a shallow protected body of water. Salt marshes form within this protected body.
The continual erosion of sand spits combined with the continual deposition of sediment makes sand pits unstable land forms. Increased amounts of sediment may increase the rate of deposition behind the sand spit. When events such as storms create an imbalance between deposition and erosion, the shape of the sand pit can change dramatically. Sand pits that become large enough to completely block off a bay of water they are called bars. The water behind a bar is known as a lagoon. Many sand spits occur at the mouth of a river.Learn more about Landforms
The Center for Earth and Environmental Science describes that floodplains are formed as rivers erode their own banks. Floodplains are the flat lands that lie adjacent to a river; they encompass the area that floods when the river's water level rises. As the river flows, it washes material downstream. When a flood occurs, this material is resuspended in the water and added to the floodplain.Full Answer >
Islands form in several ways. The most common events that lead to island formation are volcanic activity and continental drift. Islands also form due to erosion, buildup of sediment and coral that grows enough to penetrate the surface of the water.Full Answer >
When a volcano surfaces just above sea level, erosion from waves can create a plateau called a guyot, that eventually sinks below sea level. Guyots sinks as a result of both erosion and the tectonic plates that the ocean floor rests on slowly moving apart.Full Answer >
Streams form when downhill running water creates a channel capable of carrying water. Most streams begin as temporary rivulets that only have water after a rainfall.Full Answer >