Deposited Landforms © Karen Devine 2010

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

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

Beaches   Beaches are the main depositional features along a coast.   They are formed by constructive waves and shrunk by destructive waves. © Karen Devine 2010

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

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

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

Sand Dunes   When vegetation is removed a dune blowout can occur.   This causes a totally denuded dune. © Karen Devine 2010

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

Spits   When longshore drift deposits sediments on a tangent to the beach a spit is formed. © Karen Devine 2010

Tombolos   Spits can link an island to the mainland and these deposits are known as tombolos. © Karen Devine 2010

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

Lagoons   Lagoons form the basis of nature’s wetland systems. © Karen Devine 2010

Question Time?  Using Google Images find pictures of all the different types of sand dunes mentioned on Slide 6. © Karen Devine 2010