Coasts

Question 1

Coasts are systems, what makes up a system?

Answer 1

inputs, outputs, flows/transfers and stores

Question 2

What are the sources of energy in costal systems?

Answer 2

Wind, waves, tides, currents

Question 3

What is a high energy / low energy coast?

Answer 3

high energy coasts - have large powerful waves, caused by strong winds and long fetches.
Low energy coast - small gentle waves, caused by gentle winds and short fetches.

Question 4

What are inputs to a coastal system?

Answer 4

rivers, erosion, abrasion of shells, offshore deposits

Question 5

What is the difference between the sediment that enters the cell and sediment that leaves the cell?

Answer 5

sediment budget

Question 6

What are the types of erosion?

Answer 6

Abrasion, Hydraulic action, wave quarrying, solution, attrition, cavitation

Question 7

What is abrasion?

Answer 7

bits of rock smash against rocks and cliffs breaking them down and smoothening them

Question 8

What is hydraulic action?

Answer 8

Air in cracks compressed when waves crash in and the compression breaks the rock apart

Question 9

What is cavitation?

Answer 9

As waves recede compressed air expands which breaks rock

Question 10

what is wave quarrying?

Answer 10

The energy of a wave as it breaks against a cliff

Question 11

What is solution?

Answer 11

Soluble rock that gets dissolved by seawater.

Question 12

What is attrition?

Answer 12

Bits of rock in the water smash against each other

Question 13

What is sub-aerial weathering?

Answer 13

the gradual breakdown of rock by agents such as ice, salt, plant roots and acids. It weakens cliffs and makes them more vulnerable to erosion.

Question 14

What is salt weathering?

Answer 14

this is caused when salt water enters cracks in rocks at high tide and as the tide goes back out the water evaporates leaving salt crystals. these crystals expand and put pressure on the rock.

Question 15

What is freeze-thaw weathering?

Answer 15

this occurs in areas where temperatures fluctuate above and below zero, water enters cracks freezes and then expands

Question 16

What is wetting and drying?

Answer 16

Some rocks contain clay, when clay gets wet it expands and the pressure caused breaks fragments off the rock

Question 17

What is chemical weathering?

Answer 17

the breakdown of rock by changing its chemical composition

Question 18

What is mass movement?

Answer 18

The shifting of material downhill due to gravity, it includes landslides, slumping, rockfalls and mudflows.

Question 19

What causes mass movement?

Answer 19

unconsolidated rocks with little friction holding them up, heavy rain can saturate unconsolidated rock making it more likely to collapse.

Question 20

What are wave cut platforms?

Answer 20

A flat surface that is left behind when a cliff is eroded.

Question 21

How do headlands and bays form?

Answer 21

When hard and soft rock is perpendicular to the sea the soft rock erodes creating bays and the hard rock remains creating a headland.

Question 22

How are stacks formed?

Answer 22

1. weak areas in the rock begin to crack and form a cave.
2. caves on the opposite side of the headland meet and an arch is formed.
3. the arch collapses and a stack is left.
4. this will weather down to a stump eventually.