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Go to class jump.com. http://classjump.com/a/ailish/index.php. Coastal Deposition. When waves don’t have much energy they drop their load. This happens mainly when: A bay is sheltered (no wind to give the wave energy). The shore is sloped (harder for the wave to move uphill).
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Go to class jump.com http://classjump.com/a/ailish/index.php
When waves don’t have much energy they drop their load. This happens mainly when: • A bay is sheltered (no wind to give the wave energy). • The shore is sloped (harder for the wave to move uphill). How Deposition takes Place How is a bay formed ? Sheltered Bays + Gentle Slope = Deposition
Beaches and storm beaches • Spits • Bars • Lagoons • Tombolos Features of Coastal Deposition
Spit Lagoon Bar Tombolo Sheltered Bay Longshore drift
F A beach is the area between high tide and low tide and it consists of sand and shingle. • E Beaches are formed by constructive waves depositing material. When waves break the swash carries its load up the shore. The weak backwash drags some of the finer material down the shore. • ERosses Point, Co. Sligo Beaches
F A storm beach is a beach consisting of large rocks and stones above normal high tide level. E They are formed when the swash is strong enough to hurl the large stones up past the normal level of the beach where they remain. EGreystones, Co. Wicklow Killiney Beach, Co. Dublin Storm Beaches
Some material comes from the river system Cliffs Transportation of sediment by Longshore drift Destructive waves attack the coast Beach
The formation of a sea spit , sea bar , lagoon and tombolo Quickly revise beaches Learning Outcomes Tuesday 8th
Storm Beach Sandy Beach High tide mark Coarser Material Fine Material Low tide mark Silt
What other features can you see ? Headland Constructive Waves Storm Beach
Spit Lagoon Bar Tombolo Sheltered Bay Longshore drift
F A spit is a ridge of sand or shingle that is connected to the land at one end and extends into the bay or estuary at the other. E Sand spits are formed by longshore drift. When it reaches a bay or sheltered area the waves lose energy and deposit their load on the seabed. These deposits build up above the level of the water. As this continues a spit is formed. ETramore, Co. Waterford Clew Bay, Co. Mayo Spits
Spit stopped by a river estuary Salt Marsh behind a spit Curve caused by wind direction Headland (hard-rock) Direction of longshore drift Spit Change in wind direction Prevailing wind direction
http://www.ngfl-cymru.org.uk/vtc/transport_deposit/eng/Introduction/MainSessionPart3.htmhttp://www.ngfl-cymru.org.uk/vtc/transport_deposit/eng/Introduction/MainSessionPart3.htm
Spit Lagoon Bar Tombolo Sheltered Bay Longshore drift
F A bar is a narrow ridge of sand or shingle which seals off the mouth of a bay. E A bar is formed when a spit connects two headlands. E Our Lady’s Island Lake, Co. Wexford Sand Bars
F A lagoon is a body of water behind a sand bar. E As the bar connects two headlands it traps a body of water behind it called a lagoon. Over time this lagoon will dry or silt up. E Our Lady’s Island Lake, Co. Wexford Lough Gill, Co. Kerry Lagoon
Lagoon : Area of water cut off by a sand bar Old bay Sand Bar formed when a spit grows across a bay, joining the two headlands
http://www.youtube.com/watch?NR=1&v=3Y8AkkB3GdA&feature=endscreenhttp://www.youtube.com/watch?NR=1&v=3Y8AkkB3GdA&feature=endscreen
Spit Lagoon Bar Tombolo Sheltered Bay Longshore drift
F A tombolo is a ridge of sand or shingle connecting an island to the mainland. E A sand spit extends outwards from the mainland due to long shore drift and sometimes it links with an island. E The Sutton tombolo links Howth Head with the mainland. Tombolo
Beaches Marram Grass Storm Beach Sand Dunes