Erosion and sea level change

Question 1

Define ‘weathering’

Answer 1

The gradual breakdown of rock in situ or close to the ground surface in three different types; mechanical, biological or chemical.

Question 2

Define ‘mass movement’

Answer 2

The movement of weathered material down a slope as a result of gravity

Question 3

Define ‘rotational landslide’

Answer 3

The downward movement of a mass on a concave/ curved slip surface

Question 4

Define ‘translational landslide’

Answer 4

The downward movement of material along a fault, joint or bedding plane said to be translational when the slip surface is straight

Question 5

Define ‘block slide’

Answer 5

A translational slide of mass consisting and moving as a single unit of a few closely related units

Question 6

Define ‘rock fall’

Answer 6

Similar to a block fall on slopes of over 40 degrees when material either bounces down the slip surface or falls vertically to form scree at the foot of the slope

Question 7

Define ‘topple’

Answer 7

The forward rotation of a mass generally occurring around an axis

Question 8

Define ‘debris flow’

Answer 8

A moving mass of loose soil, mud, soil and rock made weak by saturation that travels down a slope by the influence of gravity, at least 50% of the moving material must be the size of sand particles or larger

Question 9

Define ‘debris avalanche’

Answer 9

When an unstable slope collapses and so the material is transported away from the slip surface and may slide over underlying rocks

Question 10

Define ‘earthflow’

Answer 10

A downward flow of saturated fine grain material as an intermediate stage between a creep and mudflow

Question 11

Define ‘creep’

Answer 11

Slow downward movement of weathered material indicated by slow but persistent tilting of trees

Question 12

Define ‘lateral spread’

Answer 12

Rapid movement of material as a result of liquefaction

Question 13

Define ‘carbonation’

Answer 13

The mixing of water with CO2 to form carbonic acid which reacts with minerals in the rocks

Question 14

Define ‘oxidation’

Answer 14

The reaction of a substance with oxygen e.g. iron forms iron oxide which weakens the rock

Question 15

Define ‘hydrolysis’

Answer 15

A chemical reaction of rock minerals with water e.g. feldspar in granite and rainwater forms clay

Question 16

Define ‘freeze-thaw weathering’

Answer 16

When water enters a crack or joint expands 10% when it freezes exerting pressure on the rock causing the crack to widen

Question 17

Define ‘exfoliation’

Answer 17

Mechanical weathering in which curved plates of rock are weathered away from the rock below to form exfoliation domes along joints in layers

Question 18

Define ‘aeoliation’

Answer 18

Referring to the wind

Question 19

Define ‘burrowing’

Answer 19

When birds e.g. puffins and animals burry into the cliff

Question 20

Define ‘roots’

Answer 20

Plant roots grow into cracks into the slip surface and forces them to break wider when they thicken

Question 21

Give some factors affecting erosion rates
MM
HA
J
W
H/S R
G

Answer 21

Mass movement
Human activity 
Jointing
Weathering 
Hard/ Soft rocks 
Geology

Question 22

Give some factors affecting erosion rates 
C/D
SA
WR
P
C
F

Answer 22

Concordant/ Discordant 
Sub-aerial marine processes
Wave refraction
Permeability 
Climate 
Fetch

Question 23

Give some factors that affect morphology 
F
CF
ER
H/D
CP

Answer 23

Folds
Coastal features 
Erosion rate 
Haff/ Dalmation 
Cliff profile

Question 24

Give some factors that affect morphology 
BP/ J 
F
C/D
G

Answer 24

Bedding planes/ joints
Faults
Concordant/ Discordant
Geology

Question 25

Describe salt crystallisation

Answer 25

The growth of sea salt crystals in cracks and pore spaces can exert a breaking force but less effective than freeze-thaw.

Question 26

What’s the difference between flows and slides?

Answer 26

Flows are wet and fast

Slides are dry and fast

Question 27

Describe soilfluction

Answer 27

Occurs mainly in tundra areas where the ground is frozen when the top layer thaws, the under layer remains frozen so saturated land flows over the subsoil

Question 28

Give the flowchart of how sub-aerial processes affect the coastline

Answer 28

Rainfall - Saturated cliff - Heavier - Gravity causes cliff to fail - Slump - Bottom of the slump is eroded - Unstable cliff - Slumps again

Question 29

President of Kiribati bought (1) of land on one of the (2) islands to grow food, source water and take refuge there. Sea levels are rising at (3)/yr and most of the land is less than (4). Sea levels are rising due to (5)

Answer 29

1 - 20km squared 
2 - Fijian 
3 - 1.2cm
4 - 1m above sea level 
5 - thermal expansion

Question 30

How much would the sea level rise if the Alpine glaciers, Greenland and Antarctica ice sheets melt?

Answer 30

AG - 0.6m
G - 7.3m
A - 56.6m

Question 31

Give three ways in which sea level falls

Answer 31

• sea level falls and land rises or subsides at a slower pace
• land rises and sea level remains fixed
• the sea rises but the land rises at a greater pace

Question 32

Give three ways in which sea level rises

Answer 32

• sea level falls and land subsides at a greater pace
• sea level remains fixed whilst land subsides
• sea level rises and land subsides, stays still or rises at a slower pace

Question 33

What is the difference between eustatic and isostatic sea level change?

Answer 33

Eustatic - global change

Isostatic - local change e.g. ice sheets squashes the land and then rises again when the ice melts

Question 34

Why is land rising in the N and W of England?

Answer 34

It was covered by an ice sheet so is rising due to isostatic recovery

Question 35

Why is land sinking in the S and E of England?

Answer 35

The weight of the sediment in the Thames Estuary causes the crust to sink and relative sea levels to rise due to isostatic change and rising sea level due to global warming