Geomorphology Flashcards

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1
Q

Agents of weathering

A
  • Water
  • Ice
  • Acids
  • Salts
  • Plants
  • Animals
  • Changes in temperature
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2
Q

Types of physical weathering

A
  • Temperature change
  • Freeze thaw/ Frost Shattering
  • Abrasion - Wind, Rain, Waves
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3
Q

Degree of chemical weathering depends on

A
  • Type of rock
  • Temperature
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4
Q

How acidic rain is made:

A
  • Fossil fuels are burnt up, releasing oxides such as nitrogen, carbon and sulphur into the atmosphere
  • These oxides combine with the moisture in the air, and form nitric acid, sulphuric acid, carbonic acid
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5
Q

Types of Biological weathering

A
  • Trees and other plants
  • Tiny organisms
  • Burrowing animals
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6
Q

Difference between weathering, erosion, deposition

A

Weathering: occurs on the spot
Erosion: weathered rocks or minerals are transported away
Deposition: comes to rest

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7
Q

Transporting agents

A
  • Gravity
  • Water
  • Wind
  • Ice
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8
Q

River valley sections

A
  • Upper Course (young)
  • Middle Course (aged/mature)
  • Lower Course (old)
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9
Q

Rivers goal

A

To erode all land to sea level

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10
Q

Agents of erosion

A
  • Rivers
  • Oceans
  • Winds
  • Glaciers
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11
Q

Meander is also called

A

River bend

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12
Q

Importance of rivers to man

A
  • For our survival: water
  • For food
  • Irrigation, watering our crops
  • Transportation
  • Energy, hydro electric power
  • Leisure
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13
Q

Characteristics of upper course

A
  • Closer to the source
  • Steep gradient
  • Small river and flows quickly
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14
Q

Features in upper course

A
  • V- shaped valleys
  • Interlocking spurs
  • Rapids
  • Waterfalls
  • Gorges and canyons
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15
Q

Types of erosion

A
  • Hydraulic action
  • Abrasion
  • Attrition
  • Solution
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16
Q

Types of transportation

A
  • Traction
  • Saltation
  • Suspension
  • Solution
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17
Q

V - shaped valleys

A

Deep valleys with steep sides

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18
Q

Interlocking spurs

A
  • Erosion outside the banks and vertical erosion
  • Results in ridges of high land (spurs) to project towards the river, decreasing in height towards the river
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19
Q

Waterfalls are commonly formed

A

When a river crosses a band of hard or resistant rock

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20
Q

White water shows

A

A lot of turbulence

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21
Q

What results in rapids

A

Friction that is caused

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22
Q

River’s velocity depends on

A
  • Gradient
  • Smoother the channel/path
  • Volume
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23
Q

Rapids

A

Steep slope, with rough river bed (uneven due to alternating bands of soft and hard rock)

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24
Q

Characteristics of Middle Course

A
  • Gradient not as steep as Upper Course
  • Lateral erosion (erosion of the banks) more effective than vertical
  • More wider, open appearance
  • Some deposition takes place
  • Meanders are common
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25
Q

Features in Middle Course

A
  • Meanders: river cliffs and slip-off slopes
  • Ox-bow lakes
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26
Q

Meanders with river cliffs and slip-off slopes

A
  • Outside banks are undercut creating river cliffs
  • Inside banks where water flows more slowly with deposition. Giving rise to gentler slopes/slip-off slopes
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27
Q

Ox-bow lakes

A
  • Sometimes meanders become so pronounced that only a narrow neck of land is left
  • When a river is in flood the neck breaks
  • Deposition then takes place sealing off the ends of the meander
28
Q

Characteristics in the lower course

A
  • Nearest the sea
  • Gradient is gentler
  • River flows slowly
  • Volume of water is greater
  • Transportation is mainly suspension and solution
  • Deposition is more important than erosion
29
Q

Features in a lower course

A
  • Floodplain
  • Levees
  • Braiding
  • Deltas
30
Q

Floodplains

A
  • Middle and lower course
  • Alluvium is deposited on valley floor
31
Q

Levees

A
  • River floods, depositing material on flood plains
  • Heavier/larger material are deposited near the river, lighter/smaller sediment is carried/deposited further away
  • After successful floods, natural embankments called levees are created
32
Q

Braiding

A
  • Occurs when the river divides over various distances into two or more channels
  • Occurs when the river carries a large load/the volume of the river changes rapidly from season to season
33
Q

Deltas form under these conditions

A
  • River carries large amount of sediment
  • Sea is relatively calm (no waves or strong currents to carry sediment away)
  • Sea is not too deep
  • River flows slowly
  • Vertical difference between high tide and low tide (tidal range) is not too great
34
Q

Traction

A

In the upper course. Big rocks roll/slide down with the water

35
Q

Saltation

A

In the upper course. Pebbles (smaller) are bounced with the movement of the water

36
Q

Suspension

A

In the middle and lower course. Tiny grains of sand and silt/clay are held in the body of the water carried along with the flow.

37
Q

Solution

A

In middle and lower course. Minerals that are dissolved in water are carried along in solution

38
Q

Size of wave is determined by

A
  • Speed of wind
  • Length of time the wind has been blowing
  • Distance of sea it has travelled over (fetch)
39
Q

Hydraulic action: blow holes

A

Power of the waves forces air into cracks, compresses and blows the rock apart as the pressure is released

40
Q

Constructive waves

A
  • Build up beaches
  • Large swash
  • Lower than destructive waves
  • Longer wavelength
  • Made when the sea is calm
41
Q

Destructive waves

A
  • Much larger and powerful
  • Made during a storm
  • Travelled a long way
  • Stronger backwash
  • Short distance between peaks
  • Much taller
42
Q

Features of Coastal Erosion

A
  • Cliffs
  • Notches
  • Wavecut platforms
  • Headlands
  • Bays
  • Caves
  • Arches
  • Stacks
43
Q

Cliffs form where…

A

There is harder, more resistant rock (limestone/chalk)

44
Q

Wave erosion is strongest where…

A

The large waves break against the base of the cliff

45
Q

Headlands and bays are created by

A
  • Differential erosion and formed in alternating bands of different rock types
  • Meets the coast at right angles, softer rocks erode faster to form sheltered bays
  • Harder rocks are more resistant to form exposed headlands
46
Q

Long shore drift: transportation of particles along a coastline is influenced by:

A
  • Strength of waves
  • Angle at which waves strike the shoreline
47
Q

Spits form where:

A
  • The coastline changes direction
  • Longshore drift continues to move material along the beach
48
Q

Coastal methods of Transport

A

Longshore drift

49
Q

Coast: Features of deposition

A

Spits

50
Q

Longshore drift will…

A

Deposit material in the sea after the coastline has changed direction

51
Q

Spit cannot…

A

Develop right across the bay as a river’s estuary prevents build-up of sand

52
Q

Sand spits often have a…

A

Curved/hooked end

53
Q

Sand spits end is created by:

A
  • Secondary wind
  • Wave direction
    These causes waves to strike from a different direction
54
Q

Spits create…

A

An area of calmer water, sheltered by the spit from the waves. A lagoon can develop in this sheltered area.

55
Q

Lagoon is also called

A

Salt marsh or dry land

56
Q

Coastal landforms

A
  • Bays
  • Beaches
  • Capes
  • Caves
  • Headlands
  • Islands
  • Lagoons
  • Peninsulas
  • Reefs
  • Rocky shores
  • Sea cliffs
  • Tidal pools
57
Q

Peninsula

A
  • Connected by a thin land mass
  • Almost an island
  • Bordered by water on 3 sides
58
Q

Cape

A

Bordered by water on 2 sides

59
Q

Management of the coast

A
  • Hard Engineering
  • Soft Engineering
60
Q

Hard Engineering Examples

A
  • Sea walls = 75 years life span
  • Revetments = sloped structures
  • Groynes/Piers
  • Rock armour/rickrap
61
Q

Hard Engineering Advantages

A
  • Immediately stops erosion
  • Encourages deposition
62
Q

Hard Engineering Disadvantages

A
  • High impact on environment
  • Expensive
  • Less sustainable
  • Short term
63
Q

Soft Engineering Examples

A
  • Beach nourishment
  • Sand dune stabilisation
  • Managed realignment
64
Q

Soft Engineering Advantages

A
  • Long term
  • Cheaper
  • Low impact on environment
  • More sustainable
65
Q

Soft Engineering Disadvantages

A

Less effective against erosion and flooding