landforms of deposition ap
TRANSCRIPT
Landforms of Deposition
Learning objectives:• To understand how long shore drift can
create a depositional landform.• To increase awareness and
understanding of GCSE coursework processes.
This movement of sediment along the coastline is called longshore drift.
Direction of movement
swash
Backwash
Backwash is always at right angles to the beach
Longshore drift
The wind direction changes and moves the spit inland. In storm conditions the spit may be breached.
Why doesn’t the spit grow across the estuary to form a bar?
The river’s current stops deposition across the estuary.
Why is the spit curved?
Spit formation
Fetch - direction of prevailing winds (and therefore waves) in approaching the beach.
Direction of Long-Shore Drift.
Short term changes in wind and wave direction causing the curved ends to the spit.
Original Coastline
Salt Marsh
Fastest current at the centre of the river.
River Estuary
Spurn Head
Spurn Head
Spurn head
1. Long shore drift takes place in a southerly direction.
2. Where the coast line changes direction LSD continues and deposits sediment starting to form a spit.
3. As the spit has grown there have been a couple of hooked ends caused by a change in the wind direction.
4. The protected waters behind the spit have trapped sediement coming down the river and a salt marsh ecosystem has developed there.
Spurn Heads 2 lighthouses!
• The one in the sea was once part of the spit!