coastal landforms

Question 1

Formation of Coastal Spits -Deposition

Answer 1

1) Swash moves up the beach at the angle of the prevailing wind.
2) Backwash moves down the beach at 90° to the coastline, due to gravity.
3) Longshore Drift transports material along the beach.
4) Deposition causes the beach to extend, until reaching a river estuary.
5) Change in prevailing wind direction forms a hook.
6) Sheltered area behind spit encourages deposition, salt marsh forms.

Question 2

Formation of Bays and Headlands

Answer 2

1) Waves attack the coastline.
2) Softer rock is eroded by the sea quicker forming a bay, calm area causes deposition.

3) More resistant rock is left jutting out into the
sea. This is a headland and is now more vulnerable to erosion.

Question 3

formation of a coastal stack

Answer 3

a large crack is enlarged by the pressure on/off hydraulic action

the crack grow into a notch and then a cave as desctructive waves erode headland

cave becomes larger. wave refraction draws waves to all sides of the headland, so caves may form back to back

the sea breaks through the back if the caves, forming a natural arch. the base of the arch is widened as notches form

weathering such as freeze thaw continues to weaken the top of the arch, making it less stable

the top of the arch eventually collapse

this leaves a polar of detached rock called a stack

notches form at the base of the stack which eventually makes it unstable

the stack will eventually topple into the sea, leaving only its base. this stump is normally only visible at a low tide

Question 4

Describe how a wave-cut platform is formed?

Answer 4

The sea attacks the base of the cliff-forming a wave-cut notch.

The notch increases in size causing the cliff to collapse.

The backwash carries the rubble towards the sea forming a wave-cut platform.

The process repeats and the cliff continues to retreat.

Question 5

• formation of sand dunes

Answer 5

at the back of the beach, sand blown inland can build up to form dunes

embryo dunes form around obstacles

dunes develop and are stabilised by vegitation to form fore dunes and tall yellow dunes

decomposing vegetation makes sand more fertile and a wider range of plants colonise the back dunes

ponds can form in depressions

Question 6

• define and describe beaches

Answer 6

beaches are deposits of sand and shingle

sandy beaches are mainly found in sheltered bays and are created by constructive waves

along high energy coasts sand is washed aqay leaving behind a pebble beach

Question 7

describe longshore drift

Answer 7

1. Waves approach the beach at an angle
2. As waves break the swash carries material up the beach at the same angle
3. The backwash carries material straight back down the beach under gravity
4. This causes the material to move along the beach in a zig-zag pattern

Question 8

How is a bar formed?

Answer 8

Longshore drift carries sediment along from a headland, depositing sediment further out from the headland. Over time, this line of sediment joins two headlands together; a bar is formed, cutting the bay off from the sea.