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Flashcards in Coasts Deck (49):
1

What is longshore drift?

Material being transported along the coast

2

How does longshore drift work?

Waves follow prevailing wind. Hit coast at oblique angle. Swash carries material on beach in direction of wind, backwash carries material off beach at 90 degrees.

3

What are the 4 processes of transportation?

Traction, saltation, solution and suspension

4

What is traction?

Large particles (boulders) pushed along sea bed by force if water

5

What is saltation?

Pebble sized particles bounced along sea bed by force of water

6

What is suspension?

Small particles (silt/clay) carried along in sea water

7

What is solution?

Soluble materials dissolve in sea water and carried along

8

What is deposition?

When material carried by sea water is dropped on coast

9

When do coasts build up?

When amount of deposition is higher than amount of erosion

10

How is amount of deposition increased?

When lots of erosion elsewhere on coast - lots of material available.

When lots of transportation of material into an area

11

What do low eve energy waves do?

(Slow) lots of deposition, less erosion

12

What do constructive waves do?

Deposit more than erode. Break up on beach, build up beaches

13

When are constructive waves created?

In calm weather

14

What are the characteristics of constructive waves?

Stronger swash than backwash. Less powerful than destructive. Low, long wavelength. Low frequency (6-8 per minute).

15

What is transportation?

The movement of material

16

What is longshore drift?

Material being transported along the coast

17

How does longshore drift work?

Waves follow prevailing wind. Hit coast at oblique angle. Swash carries material on beach in direction of wind, backwash carries material off beach at 90 degrees.

18

What are the 4 processes of transportation?

Fractions, saltation, solution and suspension

19

What is traction?

Large particles (boulders) pushed along sea bed by force if water

20

What is saltation?

Pebble sized particles bounced along sea bed by force of water

21

What is suspension?

Small particles (silt/clay) carried along in sea water

22

What is solution?

Soluble materials dissolve in sea water and carried along

23

What is deposition?

When material carried by sea water is dropped on coast

24

When do coasts build up?

When amount of deposition is higher than amount of erosion

25

How is amount of deposition increased?

When lots of erosion elsewhere on coast - lots of material available.

When lots of transportation of material into an area

26

What do low eve energy waves do?

(Slow) lots of deposition, less erosion

27

What do constructive waves do?

Deposit more than erode. Break up on beach, build up beaches

28

When are constructive waves created?

In calm weather

29

What are the characteristics of constructive waves?

Stronger swash than backwash. Less powerful than destructive. Low, long wavelength. Low frequency (6-8 per minute).

30

What is transportation?

The movement of material

31

What is weathering?

Erosion of rocks in situ

32

What is erosion?

Wearing away of moving rocks

33

What are 3 examples of biological weathering?

Vegetation roots break up rocks.

Bird ps excrete on rocks - acidic.

Rabbit burrows loosen soil making inundation by water easier.

34

What is rainwater?

Carbonic acid (weak)

35

What is mechanical weathering?

Breakdown of rocks without changing chemical composition

36

What is chemical weathering?

Breakdown of rocks by changing chemical composition

37

What is carbonation?

Rainwater (carbonic acid) dissolves rocks e.g. Limestone or clay

38

What is freeze thaw weathering?

Temp alternatives above/below freezing. Frozen water expands in cracks and contracts when it thaws. Repeated expansion widens cracks/breaks rock.

39

What is hydration?

Rocks like clay swell and expand in rainwater (carbonic acid)

40

What is mass movement?

Shifting in rocks and loose materials down a slope when gravity acting ok slope is greater than force supporting it.

41

What is oxidation?

Some rocks react with air and break down

42

What does mass movement cause?

Coasts to retreat rapidly

43

What is sliding?

Material shifts in one sheer vertical piece (straight line), often quickly

44

When is mass movement most likely?

When material is full of water (lubricant)

45

What is slumping?

Water soaks through permeable top layer of sand and collects above impermeable layer. Lubricated layer causes slumping on a curved axis.

46

What do destructive waves do?

Carry out erosional processes

47

When do destructive waves occur?

When wave energy is high and wave has travelled over a long fetch

48

What are the characteristics of destructive waves?

High frequency (10-14 per min).
High and steep.
Short wavelength.
Backwash more powerful than swash.

49

How are destructive waves created?

In storm conditions when wind is powerful and blowing over long time.