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.
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
The Himalaya Mountains were formed from a collision of tectonic plates. The mountain formation primarily occurred in three phases that began about 50 million to 70 million years ago and most recently occurred about 600,000 years ago. The tectonic plates still are moving, and the mountain range continues to rise; the movement occurs at a rate of about 2 centimeters per year.Full Answer >
The world's largest peninsula is the Arabian Peninsula. The Arabian Peninsula is located in Southwest Asia and contains the countries of Jordan, Iraq, Kuwait, Bahrain, Qatar, United Arab Emirates, Oman, Yemen and Saudi Arabia.Full Answer >
The Esa'ala Cave System is a fictional cave in Papua New Guinea. It was featured in the 2011 movie "Sanctum." The caving scenes in the movie were actually filmed at the Cave of Swallows in central Mexico, while the above-ground scenes were filmed in Australia.Full Answer >
Silt deposits at river mouths form landmasses called deltas, which are essentially small areas of wetlands. Deltas form when rivers empty their water and sedimentary materials into secondary bodies of water such as oceans, lakes and other rivers. Deltas may also empty on land, although this occurs much less frequently.Full Answer >