Coasts

Question 1

Describe the term swash

Answer 1

Water breaking onto and moving up the shore is called the swash. It hits the shore at an angle determined by wind direction

Question 2

Describe the term backwash

Answer 2

Water returning back down the shore is called the backwash. It always moves down at right angle to the shore due to gravity

Question 3

Explain the process of hydraulic action

Answer 3

The force of waves compressing air into cracks and holes in the cliff breaking up the rocks

Question 4

Explain the process of corrasion (abrasion)

Answer 4

Results from large waves hurling materials against the cliff breaking the rocks

Question 5

Explain the process of attrition

Answer 5

When waves cause rocks and pebbles to bump into each other and break down into smaller particles

Question 6

Explain the process of solution (corrosion)

Answer 6

When salts and acids in seawater slowly dissolve cliffs

Question 7

Explain the formation of a cliff

Answer 7

A wave cut notch starts to form at the base of a cliff due to hydraulic action(explain). This expands to form a rock overhang due to abrasion(explain). The rock overhangs can no longer support its weight and collapses into the sea leaving a wave cut platform.

Question 8

Explain the formation of headlands and bays

Answer 8

Headlands and bays form at discordant coastlines which is where there is a mixture of hard rock(limestone) and soft rock(chalk). Hydraulic action and abrasion(explain) breakdown the soft rock faster than the hard rock leaving bays and headlands

Question 9

Explain the formation of caves, arches and stacks

Answer 9

Lines of weakness are enlarged by hydraulic action(explain) to form a cave -. The waves continue to expand the cave through corrasion(explain). The cave is eroded on both sides until the sea cuts through the headland to form a natural arch. Further wave erosion produces wave cut notches which widen the base of the arch. The roof of the arch becomes too heavy to be supported and collapses into the sea. This leaves an isolated pillar of rock called a stack.

Question 10

Explain the process of longshore drift

Answer 10

Swash brings materials up the beach at an angle dictated by the prevailing wind. Backwash moves the material back towards the sea at right angles to the beach, due to gravity. Longshore drift moves materials along a beach or out into a bay.

Question 11

Explain the formation of sand spits

Answer 11

Sand spits (long narrow ridges of sand or shingle) form where the coastline changes direction. Longshore drift transports sand and deposits it in a sheltered area. Deposited sand builds up over time until it is above sea level. This deposition continues until the beach extends into the sea to form a spit. Sand spits can also develop a hooked or curved end due to a change in prevailing wind/wave direction. Mud flats or salt marsh can develop in an area of calm water behind the spit.