Coastal Landforms - Depositional

define the 2 types of coastal landforms

erosional and depositional landforms

state the depositional landforms (of coastal landforms)

• beaches

• spits

• bars

describe the formation of beaches

beaches are made up from eroded material that has been transported from elsewhere and then deposited by the sea

• for this to occur, waves must have limited energy —> therefore often form in sheltered areas like bays

• constructive waves build up beaches as they have strong swash and a weak backwash

where are sandy beaches usually found?

usually found in bays —> where the water is shallow and the waves have less energy

where do pebble beaches often form?

often form where cliffs are being eroded and where the waves have more energy

what is the cross profile of a beach called?

beach profile

what does a beach profile have?

has lots of ridges —> which are called berms

define what berms are

they are ridges —> which show the lines of the high tide and the storm tides

where is larger material found on the beach?

and why?

larger material is found at the top of the beach —> due to the high energy storm waves carrying large sediment

where is smaller material found on beaches?

• and why?

the smallest material is found nearest the water as the waves break here and break down the rock through attrition

describe what splits are

splits are an extended stretch of sand or shingle jutting out into the sea from the land

where to splits occur?

occur when there is a change in the shape of the landscape or there is a river mouth

describe the formation of splits

1) sediment is carried by longshore drift

2) when the coastline changes shape —> deposition occurs —> a long thin ridge of material is deposited —> this is the split

3) a hooked end can form if there is a change in wind direction

4) waves cannot get past a spit —> therefore, the water behind a spit is very sheltered and so silts are deposited here to form salt marshes or mud flats

describe the formation of bars

1) sometimes a spit can grow across a bay —> and joins two headlands together —> this landform is known as a bar

what can form due to the formation of bars?

lagoons —> due to bars trapping lakes behind it

• however, lagoons are not permanent as may be filled up with sediment