Set answer questions

How are headlands and bays formed? [4 marks]

Before, the coast was discordant and had bands of soft and hard rock. The soft rock is less resistant so is more affected by abrasion and hydraulic action so it erodes faster than the more resistant, hard rock. The more resistant rock juts out to sea and forms headlands, the headlands shelter the bay from the wind causing wave refraction, so the waves that hit the bay are weaker and carry more sediment which builds up onto the bay causing a beach to form. To form the wave-cut platform abrasion and hydraulic action form a wave cut notch .The front of the headland is affected by freeze thaw and carbonation, this leads to rockfall occurring which causes the cliff to retreat leaving a wave-cut platform.

How are spits formed? [6 marks]

The prevailing wind direction causes waves to push their swash at an angle and backwash at a right angle; this process is called longshore drift. Longshore drift continues down the beach carrying sediment, when the coastline changes direction the longshore drift continues past the headland , into the estuary , and it creates a long and thin ridge created by sediment deposition called a spit. The secondary wind direction can cause the direction of the spit to change into a hook. The waves can’t get past the hook so the area of water behind is sheltered, material is deposited here and salt-marshes and mud-flats form.

How are bars formed ?

A bar is formed when a long-shore drift continues moving sediment until two headlands are connected with a lagoon behind.

why do i need a fourth flashcards

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