DEPOSITIONAL
LANDFORMS
ABIN V ARKKATTU
Spit
• A Spit is a long, narrow
accumulation of sand or
shingle, one end attached to
the land the other projecting
out to ...
Spit
• As the fetch & prevailing winds
are from the south west, in this
diagram, longshore drift will be
moved eastward al...
Spit (Salt Marsh)
• Behind the spit a quiet
tranquil lagoon forms &
sediment (brought in both by
sea currents & from river...
Hooked (Recurved) Spit
• Occasionally storms
come in from the south
east or east & move
sediment in a different
direction ...
Hooked (Recurved) Spit
The hooks & salt Marsh are well
displayed on the slide above.
Animation
Double Spit
• Formed from a breach
of a pre existing spit
or bar.
• Usually by a river or
storm.
• Christchurch Harbour,
D...
Barrier Beach (Bar)
• The spits growth is limited
by river currents scouring
its end & transporting
sediment out to sea. I...
Barrier Island
• These are formed by rising sea level.
As the sea rose at the end of the last ice
age large quantities of ...
Barrier Island
Wave Refraction
• As waves approach the
coastline, they come in
contact with the sea bed &
slow down, this happens
first o...
Tombolo
• The waves are refracted
around the island & set up 2
opposing LSD directions.
• These merge behind the
island & ...
Tombolo
• Hafun Penninsula,
Somalia
• St. Ninian Island,
Western Scotland.
LSD
LSD
Cuspate Foreland
• A complex structure formed in a variety of ways
• Deposition behind a spit.
• LSD in 2 directions (Tomb...
Bayhead Beach
• In bays there is little
energy (wave
refraction).
• Sediment that drifts
in is trapped & a
beach develops....
Depositional landforms
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Depositional landforms

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Depositional landforms

  1. 1. DEPOSITIONAL LANDFORMS ABIN V ARKKATTU
  2. 2. Spit • A Spit is a long, narrow accumulation of sand or shingle, one end attached to the land the other projecting out to sea or across a river estuary. Many spits have hooked or curved ends. They are formed where longshore drift moves large quantities of sand & shingle along the coast & where the coastline suddenly changes direction to leave a shallow sheltered area of water. In the diagram X to Y represents the original coastline. Da Nong, Vietnam
  3. 3. Spit • As the fetch & prevailing winds are from the south west, in this diagram, longshore drift will be moved eastward along the coastline. At headland X the coastline changes direction & shingle will be deposited in water sheltered by the headland (B). Further deposition of sand enables the feature to build up to sea level (C) & extends its length (D). The spits growth is limited by river currents scouring its end & transporting sediment out to sea.Spurn point.
  4. 4. Spit (Salt Marsh) • Behind the spit a quiet tranquil lagoon forms & sediment (brought in both by sea currents & from rivers) is deposited there. Eventually the sediment builds up to sea level & a Salt marsh forms.
  5. 5. Hooked (Recurved) Spit • Occasionally storms come in from the south east or east & move sediment in a different direction forming the curve or hook (E).When the wind returns to normal the spit resumes its growth eastward (F). Sand is blown on land (G), forming sand dunes. • Hurst Castle Spit, Hants.
  6. 6. Hooked (Recurved) Spit The hooks & salt Marsh are well displayed on the slide above. Animation
  7. 7. Double Spit • Formed from a breach of a pre existing spit or bar. • Usually by a river or storm. • Christchurch Harbour, Dorset • Laudhelm Beach, Maine.
  8. 8. Barrier Beach (Bar) • The spits growth is limited by river currents scouring its end & transporting sediment out to sea. If there is no river the spit may grow across the estuary and form a Bar. • Slapton Sands, Devon
  9. 9. Barrier Island • These are formed by rising sea level. As the sea rose at the end of the last ice age large quantities of sediment (beach) were pushed upward in front of the rising sea level (bulldozerisation), forming a ridge or island. • The barriers move inland by “overwash” as sediment is eroded off the seaward side of the barrier & redeposited on the landward side. • North Carolina, USA.
  10. 10. Barrier Island
  11. 11. Wave Refraction • As waves approach the coastline, they come in contact with the sea bed & slow down, this happens first off the headlands. • The wave is still in deep water off the bays. • The wave is therefore bent. • The energy is concentrated on the headlands (erosion) • Energy is dissipated in the bays (deposition) Click Here
  12. 12. Tombolo • The waves are refracted around the island & set up 2 opposing LSD directions. • These merge behind the island & sand is deposited linking the mainland & the island • Goat Island, California • San Antonia, Costa Rica
  13. 13. Tombolo • Hafun Penninsula, Somalia • St. Ninian Island, Western Scotland. LSD LSD
  14. 14. Cuspate Foreland • A complex structure formed in a variety of ways • Deposition behind a spit. • LSD in 2 directions (Tombolo) • Dungeness, Kent.
  15. 15. Bayhead Beach • In bays there is little energy (wave refraction). • Sediment that drifts in is trapped & a beach develops. • Pett Levels, Kent.
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