Coastal landforms

Question 1

Beaches

Answer 1

A landform of deposition created when constructive waves (swash is stronger than backwash) lose their energy and drop sediment in bays

Question 2

What 3 things should you talk about when you describe the characteristics of a beach

Answer 2

• shingle (rocks, pebbles), sand
• beach profile (beach gradient)
• sand dunes

Question 3

Beach profile

Answer 3

gradient of the beach from the back of the beach to the sea

Question 4

Berm

Answer 4

ridge found on the beach profile, due to storm tides/high tides

Question 5

Why do beach profiles change?

Answer 5

• a sandy beach has a gentle sloping profile whereas a shingle beach can be much steeper
• the size of the material is larger at the top of the beach due to high energy storm waves carrying large sediment
• The smallest material is found nearest the water as the waves break here and break down the rock through attrition

Question 6

Sand dunes

Answer 6

landforms of deposition formed when the wind carries sediment, loses energy then drops it at the back of beaches

Question 7

what is the first sand dune formed called

Answer 7

embryo dune

Question 8

what species grow on a fore dune

Answer 8

pioneer species

e.g: Marram Grass

Question 9

where does rainwater collect with the water table (fresh water)

Answer 9

dune slack

Question 10

what happens at the grey dune

Answer 10

soil is created as grass dies back
new vegetation
(e.g: Heather)

Question 11

a) what can now grow at the mature dunes
b) why can they grow
c) how do they benefit the dunes

Answer 11

a) Trees
(e. g: Oak Tree, Ash Tree)
b) There is enough soil
c) Roots stabilise the dunes

Question 12

headlands and bays

Answer 12

• discordant coastline
• alternating band of hard rock and soft rock
• the soft rock is eroded faster by hydraulic action (water and air in forced into the cliffs causing them to expand and break off)
• the soft rock forms bays
• beaches are formed by deposition due to constructive waves
• headlands are formed at the hard rock
• when the hard rock is eroded by hydraulic action and abrasion it forms arches, stacks, stumps (e.g: Old Harry)

Question 13

wave cut platform

Answer 13

wave cut platforms form at the base of a cliff at headlands
here the sea attacks the cliff base at low tide and high tide
this means the cliff is eroded backwards at it’s base
overtime a notch forms between low and high tide marks
the overhanging cliff collapses into the sea leaving a platform at the cliff base
this means the cliffs recede inland

Question 14

explain how a cave turns into an arch then stack then stump

Answer 14

Caves form because of hydraulic action (the power of the water forces air into the rocks causing them to expand and break) and also by abrasion (the seawater contains sand which rubs against the cracks in the cliff cliff causing the cracks to become a cave
This will carry on eroding on the inside until it breaks through forming an arch
The arch will gradually become bigger until it can no longer support the top of the arch.
The arch collapses it leaves the headland on one side and a stack the other.
The stack will be attacked by hydraulic action and abrasion and solution (dissolved chemicals in the sea water react with the rock causing it to dissolve)
Overtime due to gravity and erosion this will eventually collapse to form a stump.

Question 15

explain the process of longshore drift and how this creates a spit which leads to other depositional landforms

Answer 15

in the process of LSD, the swash moves up the beach at an angle determined by the prevailing wind
the backwash then moves back down the beach at a right angle due to gravity

when the coastline changes shape the waves lose their energy so deposits the sediment forming a spit

the change in wind direction causes the spit to have a hooked end

behind the spit, a lagoon and a marsh form lie sandbanks due to a lack of input from the sea