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Published byErnest Kelley Modified over 9 years ago
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Deposited Landforms © Karen Devine 2010
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Deposited Landforms The sediments found in waves are derived from: a) a)erosion of the coast b) b)transportation by rivers c) c)being carried off the sea floor. © Karen Devine 2010
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Deposited Landforms The main landforms caused by deposition are: a) a)beaches b) b)spits c) c)bars d) d)sand dunes e) e)tombolos. © Karen Devine 2010
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Beaches Beaches are the main depositional features along a coast. They are formed by constructive waves and shrunk by destructive waves. © Karen Devine 2010
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Sand Dunes Sand dunes are formed when the sediments deposited by wave action dry and are blown to the rear of the beach. © Karen Devine 2010
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Type of Sand Dunes There are many different types of dunes such as: a) a)foredunes: located closest to the waves b) b)parallel dunes: formed by a multitude of foredunes which have been stabilised by vegetation. c) c)Parabolic dunes: are curved dunes made where there is abundant sand. The horns point upwind and are covered by vegetation. d) d)Backdunes: formed at the rear of the beach and covered by vegetation. © Karen Devine 2010
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Sand Dunes All sand dunes need vegetation to stabilise them and prevent erosion by wind. All vegetation must be very hardy and be able to withstand strong salty winds, human intervention and storms. © Karen Devine 2010
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Sand Dunes When vegetation is removed a dune blowout can occur. This causes a totally denuded dune. © Karen Devine 2010
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Sand Bars Coastal deposition also forms sand bars offshore to the beach. Sand bars form when a wave loses velocity and deposits sediments before reaching the beach. © Karen Devine 2010
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Spits When longshore drift deposits sediments on a tangent to the beach a spit is formed. © Karen Devine 2010
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Tombolos Spits can link an island to the mainland and these deposits are known as tombolos. © Karen Devine 2010
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Lagoons When spits enclose a body of water away from the ocean, a lagoon is formed. Lagoons may be brackish or fresh water. © Karen Devine 2010
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Lagoons Lagoons form the basis of nature’s wetland systems. © Karen Devine 2010
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Question Time? Using Google Images find pictures of all the different types of sand dunes mentioned on Slide 6. © Karen Devine 2010
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