2.Coastal Erosion & Deposition

Question 1

Constructive Waves

Answer 1

• happen at low frequency
• long and low
• overtime form gently sloping beaches
• constructive waves deposit material on coasts as backwash less powerful that swash

Question 2

Destructive Waves

Answer 2

• responsible for erosional processes
• high frequency (10-15 per min)
• circular motion so waves break at a greater height
• destructive waves remove material from coasts as swash less powerful than backwash

Question 3

Abrasion

Answer 3

Where pieces of rock are picked up by waves and hit against the bead, beach or cliffs which wears them away over time

Question 4

Attrition

Answer 4

Where pieces of bedload are hit against one another causing them to break apart and become smaller and more rounded

Question 5

Corrosion

Answer 5

When there is a chemical reaction between the seawater and susceptible rocks like limestone

Question 6

Hydraulic Power

Answer 6

• causes the breakdown of cliffs due to the force of water being compressed into cracks of rock
• repeated action of the water forced in and out of the cracks in the rock leads to surrounding cliff

Question 7

Spits

Answer 7

• when coast changes direction at and estuary, longshore drift continues to move sediment across the inlet
• the rives doesn’t let spit completely join to the coast on the other side as river has energy to move sediment
• spits are long fingers of sand sticking out from one side in a coastline that have been curved by secondary winds

Question 8

Bars

Answer 8

• bar is formed when a spit grows across a bay

- lagoons often form behind bars

Question 9

Beaches

Answer 9

• made by constructive waves moving and depositing sand or shingle inland
• more gently sloping beach tends to be formed from sand than steeper pebbles beaches

Question 10

Tombolos

Answer 10

If a spit stretches across the mainland and joins an offshore island, this causes a Tombolo to form

Question 11

Cuspate Forelands

Answer 11

• form when sediment is deposited across a bay caused by longshore drift transporting sediment in two directions
• leads to formation of two spits which eventually meet, resulting in trapping of sediment until eventually new land is formed

Question 12

Sediment Cell Concept

Answer 12

• describes a closed system operated by sources, transfers and sinks driven by erosion, transportation and deposition processes
• the uk has 11 key sediment cells and sub-cells, each with its own shoreline management plan

Question 13

Mechanical Weathering

Answer 13

• when rocks are broken down without their chemical composition being changes
• salt weathering is the main type of mechanical weathering affecting coasts

Question 14

Biological Weathering

Answer 14

• when rocks are broken down by living things

- the activity of animals near the coast is also an example of biological weathering

Question 15

Chemical Weathering

Answer 15

• when rocks are broken down because of their chemical composition being changed
• carbon weathering is a a type of chemical weathering that takes place when it’s warm and wet