Coasts 3 - Coastal landforms

Question 1

What are the 9 coastal landforms?

Answer 1

1) Cliffs ad wave cut platforms
2) Headlands and bay6s
3) Caves, arches, stacks and stumps
4) Spits
5) Beaches
6) Barrier islands
7) Sand dunes
8) Eustarine mudflats and salt marshes
9) Offshore bars and tomobolos

Question 2

How do cliffs and common coastal landforms form?

Answer 2

As the sea erodes the land, overtime cliffs retreat due to the action of waves and weathering

Question 3

What does weathering and wave erosion cause

Answer 3

A notch to form at the high water mark, eventually forming a cave

Question 4

What happens to the rock above the cave

Answer 4

It becomes unstable with nothing to support it and it collapses

Question 5

What are wave cut platforms

Answer 5

Flat surfaces left behind when a cliff is eroded

Question 6

When are headlands and bays formed

Answer 6

When there’s bands of alternating hard and soft rock at right angles to the shoreline

Question 7

What happens to the rock in the formation of headlands and bays?

Answer 7

The soft rocks is eroded quickly forming a bay and the hard rock is eroded less and sticks out as a headland

Question 8

What is it called if landforms are found in cliffs?

Answer 8

Profile features

Question 9

How are caves formed?

Answer 9

Joints are eroded to form caves

Question 10

What is a joint?

Answer 10

Weak areas in the rock

Question 11

How are arches formed?

Answer 11

Caves on opposite sides of narrow headlands join up to form an arch

Question 12

When does a stack occur?

Answer 12

When an arch collapses

Question 13

when do beaches form?

Answer 13

Constructive waves deposit sediment on the shore

Question 14

What are shingle beaches like?

Answer 14

Steep and narrow and made up of larger particles that pile up at steep angles

Question 15

What are sand beaches like?

Answer 15

Smaller particles are wide and flat

Question 16

What is found at a high tide?

Answer 16

beams and ridges of sand and pebbles

Question 17

What runs parallel to the shore

Answer 17

Runnels and grooves in the sand

Question 18

How are runnels and grooves formed?

Answer 18

Backwash draining to the sea

Question 19

What are cusps?

Answer 19

Crescent shaped indentations that form on beaches and are mixed sand and shingle

Question 20

When do spits form?

Answer 20

Where the coast changes direction suddenly

Question 21

How does longshore drift affect a spit?

Answer 21

It continues to deposit material across the river mouth and leaves a bank of sand and shingle sticking out In the sea

Question 22

What is a straight spit?

Answer 22

Grows roughly parallel to the coast - known as a simple spit

Question 23

What happens when there’s changes to wind and wave direction

Answer 23

Leads to a spit having a curved end known as a recurved end

Question 24

What happens when there’s several recurved ends

Answer 24

They’re abandoned and the waves turn to their original direction

Question 25

When do spits have multiple recurved ends?

Answer 25

From several periods of growth

Question 26

What are these called?

Answer 26

Compound spits

Question 27

What happens to the area behind a spit?

Answer 27

It’s sheltered from waves and develops into mudflats and salt marshes

Question 28

When are bars formed?

Answer 28

When a spit joins 2 headlands together

Question 29

Where do bars form?

Answer 29

Across a bay or river mouth

Question 30

What forms behind a bar

Answer 30

A lagoon

Question 31

When else can bars form?

Answer 31

Off the coast when material moves towards the coast as sea levels rise

Question 32

When is it an offshore bar?

Answer 32

When they’re partially submerged by the sea

Question 33

What is a tombolo?

Answer 33

A bar that connects the shore to an island (often a stack)

Question 34

How are St Nina’s Isle joined with a larger island?

Answer 34

By a tombolo

Question 35

What is a barrier island?

Answer 35

Long, narrow islands of sand or gravel that run parallel to the shore and are detached from it

Question 36

Where do barrier islands tend to form

Answer 36

When there’s a good supply of sediment, a gentle slope offshore, powerful waves and a small tidal range

Question 37

What’s 1 theory for how barrier islands form?

Answer 37

After the last ice age, when ice melts it causes rapid sea level rise. The rising waters flooded the land behind beaches and transported sand offshore where its deposited in shallow water forming islands

Question 38

What’s the other theory for how barrier islands form

Answer 38

They were originally bars, attached to the coast, which were eroded in sections causing beaches in the bar

Question 39

When does a lagoon form

Answer 39

Behind barrier islands where the coast is sheltered from wave action

Question 40

Where are barrier islands found?

Answer 40

On many coastlines, including the East coast of the USA

Question 41

When are sand dunes formed?

Answer 41

When sand deposited by longshore drift is moved up the beach by wind

Question 42

How are sand dunes formed (3 steps)

Answer 42

1) Sand trapped by driftwood or Berns us colonised by plants and grasses
2) The vegetation stabilises the sand encouraging more sand to accumulate there and form embryo dunes
3) Overtime, the oldest dunes migrate inland and newer embryo dunes are formed, they can reach heights of 10m

Question 43

Where do mudflats and salt marshes form?

Answer 43

Sheltered, low energy environments like river estuaries or behind spits

Question 44

When do mudflats develop?

Answer 44

Slit and mud are deposited by river or tide

Question 45

How are mudflats colonised?

Answer 45

By vegetation that can survive high salt levels and long periods of submergence by the tide

Question 46

What do plants of to salt marshes

Answer 46

Trap more mud and slit and gradually build upwards to create an area of salt marsh that remains exposed for ages in-between tides

Question 47

What does erosion by tidal currents or streams do?

Answer 47

Form channels in the surface of mudflats and salt marshes maybe perminantly flooded or dry at low tide