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 composition of sand is dependent on the geographical area where the sand is located. Most sands are composed of small land sediment particles, minerals, rocks and organic matter that has been eroded and ground down over many years. For this reason, sand composition varies greatly.Full Answer >
Uluru began to form over 550 million years ago when sand, eroding from the Peterman Ranges, built up into thick deposits. Some 50 million years later, these deposits were compressed into sandstone by the weight of a sea that eventually disappeared. Within another 100 million years, geological events caused the sandstone to tilt almost 90 degrees, resulting in Uluru.Full Answer >
A barrier island is a long, thin stretch of sand deposited parallel to the mainland. One side of a barrier island faces the ocean, while the other side faces an estuary, bay or lagoon that separates the island from the mainland. Barrier islands are popular tourist attractions and contain fragile ecosystems with distinct habitats and wildlife. Due to their location, barrier islands serve as protection from storms for the mainland.Full Answer >
Some of the constructive forces that shape and create landforms are crustal deformation, deposition of sediment and volcanic eruptions. The flow of heat through the Earth's crust and the movement of tectonic plates and magma account for some of the more spectacular crustal deformations. The transportation, or deposition, of sedimentary particles by wind, water and glaciers results in the creation of dunes, deltas and other topographical features.Full Answer >