They are submerged or partly exposed ridges of sand or coarse material. Destructive waves erode sand from beach with their backwash and deposit it offshore. Offshore bars or sandbars act both as sediment sinks and sediment input stores.
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Spit-Spurnhead
Sediment is moved along the coast by a process called longshore drift. When there is a change in the coastline (e.g. at a river mouth) the waves spread out. Waves then lose energy and deposit sediment forming a bar. As the bar builds out from the sho
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Compound spit-Hurst Castle Spit
A number of recurred ridges or minor spits along their landward side, possibly marking the position where they terminated in the past.
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Tombolo-Chesil Beach
Where a spit that joins an island to the mainland is known as a tombolo.
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Barrier Beaches and Islands
Where a beach or spit extends across a bay to join two headlands. This is a barrier beach. They can also trap water behind them to form lagoons (Slapton Ley, Devon).
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Sand Dunes
Sand deposited by longshore drift is moved up the beach by the wind. Sand trapped by driftwood or berms is colonised by plants and grasses (marram). The vegetation stabilises the sand and encourages more sand to accumulate there, forming embryo dunes
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Salt Marshes
Salt marshes form in areas of sheltered water. As silt and mud are deposited by the river or the tide mudflats develop. The mudflats are colonised by vegetation that can survive the high salt levels and long periods of submergence.
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Other cards in this set
Card 2
Front
Sediment is moved along the coast by a process called longshore drift. When there is a change in the coastline (e.g. at a river mouth) the waves spread out. Waves then lose energy and deposit sediment forming a bar. As the bar builds out from the sho
Back
Spit-Spurnhead
Card 3
Front
A number of recurred ridges or minor spits along their landward side, possibly marking the position where they terminated in the past.
Back
Card 4
Front
Where a spit that joins an island to the mainland is known as a tombolo.
Back
Card 5
Front
Where a beach or spit extends across a bay to join two headlands. This is a barrier beach. They can also trap water behind them to form lagoons (Slapton Ley, Devon).
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