Depositional landforms

Why does deposition happen

When waves or currents lose energy and can no longer transport sediment

What’s long shore drift

Waves approach the coastline at an angle. Sediment is zig zagged across the beach and transported along the coast

What are depositional landforms

Beaches, bays, deltas, tombolos, salt marsh, on shore bar, spits bars,

How is a beach formed

Waves break and slow down due to friction, the waves spills up the beach putting sediment on the beach. Smash slows down, dropping pebbles then sand.

How do landforms continue to change in a beach

Storm beach, bigger pebbles thrown to the top of the beach.

Berm(ridges)

Cusps, semi circle in dents ( sediment pulled away by rip current)

Seasonal - summer beach gets steeper and winter beach gets flatter due to high energy waves

How’s a spit formed

Longshore drift zig zagged sediment along the coast. Coast changes direction, waves slow down in sheltered area

What’s a spit

A long narrow beach extending from land across bay or estuary eg berullus spit Nile delta

How can a spit continue to change

If direction of wind changes the end bands/curves round (recurved end)

In sheltered area behind spit fine silt deposits and forms salt marsh

How does a bar form

A bar is a narrow beach from one side of a bay. Spit forms, lsd and deposition grow spit.the end of the spit rejoins mainland eg mandala bar Nile delta.

Continue to change as lagoon can dry up and bars can be breached by storm waves

How does a tombolo form

A tombolo is a narrow beach connecting an offshore island to the mainland. Wave refraction around an island, waves loose energy, sediment is deposited, building a beach linking to mainland

How does a salt marsh form

Waves break/ refract into calm water, friction slows waves completely, deposition of fine silts. It can continue to change as plants colonise salt marsh roots strength silts