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
Canyons are formed by wind and water erosion over a long period of time after a large hill, mountain or plateau is formed. The original land mass is formed by tectonic plates colliding and causing tectonic uplift, and the weakest of material is worn down over time to create a deep, narrow ravine called a canyon.Full Answer >
A strait is either formed by tectonic shifts or land that has subsided or been eroded. If a strait is created by people rather than geological forces, it is generally referred to as a canal.Full Answer >
Landforms are formed by movements of the earth, such as earthquakes, weathering, erosions and deposits. Many landforms are created by more than one of these processes. These are called polygenetic landforms.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 >