4.3A Coastal Features

Question 1

How does geological structure and rock type influence erosional landforms?

Answer 1

Hard rock coasts are smooth sands with steep and high cliffs behind them. While soft rock coasts are rough sand and crumbling soil with little to no beaches.

Question 2

Why are some rocks weaker than others

Answer 2

Other than different types of rocks joints and faults will weaken a rock

Question 3

What are Joints

Answer 3

Joints are small, usually vertical, cracks found in many rocks.

Question 4

What are faults

Answer 4

Faults are larger cracks caused by past tectonic movements where rocks have moved.

Question 5

What is a discordant coastline

Answer 5

Discordant coastlines are coastlines that alternate between hard and soft rock with hard rocks containing headlands and soft rocks containing bays

Question 6

How are caves, arches, stacks and stumps formed.

Answer 6

Due to erosion a headlands side and base erodes until it forms a cave. The base on the other side starts to erode until the other side collapses. Further erosion takes place until the roof collapses leaving a stack. After further erosion the the stack collapses into a stump. This process then continues.

Question 7

Explain wave cut platforms

Answer 7

Erosional processes such as hydraulic action and abrasion start to erode. A wave cut notch will be formed in the inter tidal zone. The cliff is now unsupported and overhangs the wave cut notch. The cliff collapses and a rocky platform is left underneath. The cliff retreats and the sequence continues over and over again leaving a large flat rocky platform.

Question 8

Transport of sediment/solution

Answer 8

This happens within the water. When very small chalk/limestone is dissolved within the water.

Question 9

Transport of sediment/suspension

Answer 9

This occurs within water when small particles are light enough to be suspended within the water.

Question 10

Transport of sediment/traction

Answer 10

This happens on the seabed when large pebbles are being rolled along the seabed

Question 11

Transport of sediment/Saltation

Answer 11

This occurs on the seabed when medium/ heavy particles are hopping/bouncing along the seabed

Question 12

What is Long shore drift

Answer 12

Prevailing wind direction from the SW causes waves to approach beach at the same direction as the wind. Swash moves sediment up the beach in the same direction as the wind. Backwash moves sediment down the beach at a right angle due to gravity. The next wave picks up the sediment and moves it towards the beach. This process continues on

Question 13

What is a spit

Answer 13

A spit is a very shallow, long and thin body with either 1 or many curves. The edges are all sand while the middle is grass. The development is when sediment is deposited off the coast.

Question 14

How is a spit formed

Answer 14

A spit is formed when there is a sudden curve in the coastline causing long shore drift to drop off sediment. After a while a wind from a different angle causes the spit to curve back. This creates shelter causing a salt marsh. The spit cannot develop too far as it cannot travel across deep water.

Question 15

Landforms of deposition

Answer 15

The most common deposition landform is a beach. These are found in bays because they are sheltered from strong winds and destructive waves. These are found where there are constructive waves because there is more swash than backwash and they deposit material.

Question 16

Coastal bars and lagoons

Answer 16

A lagoon is formed when a bay causes a sudden change in the coastline causing long shore drift to grow a spit which eventually connects to the other side creating a bar which closes of the bay causing it to become a lagoon