Theme 1 - Landform Process and Change Flashcards
1
Q
fluvial?
A
referring to a river and it landforms
2
Q
erosion?
A
the wearing away of the land
3
Q
transportation?
A
movement of material by the flow of water
4
Q
deposition?
A
dropping of the material carried by the river
5
Q
bed load?
A
material carried by the river being bounced or rolled along its bed
6
Q
meander?
A
a bend in the river formed by lateral erosion
7
Q
why do river landforms change over time?
A
due to fluvial erosion, transportation and deposition
8
Q
erosional processes of the river channel? 3
A
~abrasion
~hydraulic action
~solution
9
Q
abrasion (river channel)?
A
stones and material carried by the river hitting the river bed and banks, wearing them away
10
Q
hydraulic action?
A
the sheer force of water hitting the river bed and banks compressing air in gaps in the soil and rock which causes material to be washed away
11
Q
solution?
A
slightly acidic river water dissolves chalk and limestone rocks which are made from calcium carbonate
12
Q
erosional processes of the river bed load? 2
A
~attrition
~abrasion
13
Q
attrition?
A
stones carried by the river collide together and are broken down becoming rounder and smaller
14
Q
abrasion (bed load)?
A
stones and material carried by the river hitting the river bed and banks become eroded and turn smaller and rounder
15
Q
when does deposition happen?
A
when the speed of flow is too slow for it to carry the load
16
Q
where does deposition happen? 3
A
~where there is a lack of rainfall, so there is less water moving
~on the inside of a meander, as water here is moving slower
~at the mouth of the river, where the river water flows against the direction of the sea
17
Q
river transportation? 4
A
~suspension
~traction
~saltation
~solution
18
Q
suspension?
A
fine, light material is held up and carried within the rivers flow, this is called suspended load
19
Q
traction?
A
large boulders and rocks are rolled along the river bed, load carried is called bedload
20
Q
saltation?
A
small pebbles and stones are bounced along the river bed, this load is lifted then dropped alternatively
21
Q
solution (transportation)?
A
minerals are dissolved in water, this s a chemical change affecting rocks such as chalk, load transported is called the solute load
22
Q
examples of river landforms? 5
A
~meanders
~floodplains
~gorges
~waterfalls
~v - shaped valleys
23
Q
where are v-shaped valleys found?
A
upper course of a river where the river is usually small and the land is steep
24
Q
what creates the v-shape valley? 2 processes
A
~vertical erosion
~weathering
25
how is a v-shaped valley formed?
~water flows down a steep slope in a river
~flowing water carries sediment and starts to erode the sides of the valley
~over time the continuous erosion deepens and widens the valley creating a v shaped cross-section
processes used - hydraulic action, abrasion
26
waterfall?
water falling from a higher level to a lower level due to a change in rock structure or as a result of glacial erosion
27
gorge?
a steep sided narrow valley formed by a retreating waterfall
28
floodplain?
a flat piece of land on either side of a river forming the valley floor
29
vertical erosion?
erosion of the river channel that results n its deepening rather than widening
30
interlocking spurs?
hard resistant rocks that a river cannot easily erode and therefore the river goes around them
31
weathering processes that help develop a v shaped valley?
~freeze thaw
~biological weathering
32
what two ways can waterfalls be created?
~glacial erosion
~differential erosion
33
steps on how glacial erosion formed waterfalls?
~glaciers move slowly down slopes and valleys carrying rocks and sediments
~as the glaciers move it erodes the land beneath through plucking and abrasion
~eroded material is transported by glaciers
~when the glacier reaches a steep cliff or a change in slope, it starts to melt, and the water flows over the edge
~water flows in a waterfall creating a plunge pool
34
how are waterfalls formed by differential erosion?
~hard resistant rock is undercut by erosion of the soft rock
~the water falls over the hard rock lip and splashes against the soft rock on the back wall
~soft resistant rock is eroded on the wall causing it to move back
~a plunge pool is formed by the force of water and is deepened by abrasion
~the overhang collapses due to lack of support and the pull of gravity
~gradually the waterfall retreats upstream, leaving a steep sided gorge
35
when is a gorge formed?
when a waterfall collapses and retreats upstream
36
slip off slope?
a bank of gently sloping deposited material found on the inside bend of a meander
37
where are meanders usually found?
middle and lower course of a river valley
38
what are meanders caused by?
erosion on the outside of the bank and deposition on the inside of the bank
39
feature of a meander?
~fastest flow outside bend
~slowest flow inside bend
~shallow water inside bend
~deep water outside bend
~deposition inside bend
~erosion outside bend
40
what happens to a floodplain when a river floods?
it gets covered with water
41
what is commonly found on floodplains?
meanders
42
where are floodplains found?
middle and lower course of a river
43
3 types of weathering?
~physical
~biological
~chemical
44
2 types of physical weathering?
~freeze thaw action
~salt crystal growth
45
2 types of biological weathering?
~plant roots
~burrowing animals
46
freeze thaw steps?
~rainwater enters crack in cliff
~temp drops and water freezes and expands making the crack bigger
~temps rise water melts and more water flows in crack
~process repeats until the rock falls off
47
salt crystal growth steps?
~seawater left on rock
~water evaporates leaving salt behind
~salt crystals grow and exert pressure on rock
~rocks broken apart
48
plant roots steps?
~plants grow on top of cliff
~roots push into cracks of rocks
~rocks broken apart
49
burrowing animals steps?
~small animals burrow through soil and into cracks in the rock
~rock is broken apart
50
type of chemical weathering?
carbonation
51
carbonation steps?
~rainwater enters cracks on the cliff face
~the weak acid reacts with carbonates in the limestone
~cracks get bigger
52
slope processes?
processes involved in moving material from the cliffs on to the beach
53
weathering?
breakdown of rocks in place by elements of the weather
54
mass movement?
when soil, rocks or stones move down a slope
55
examples of mass movement? 2
~rockfalls
~landslides
56
what causes rockfalls on cliffs?
as waves erode the base of the cliff, a large section collapses
57
coastal erosion processes and what part they erode? 4
erode cliff
~hydraulic action
~abrasion
~solutions
erode beach material
~abrasion
~attrition
58
how does hydraulic action erode coasts?
waves crash into cliffs, trapping and compressing air in the cracks which break up the rocks
59
how does abrasion erode coasts?
waves hurl sand and pebbles against the cliff, which wears the land away
60
how does solution erode coasts?
salt water dissolves rocks made of calcium carbonate
61
how does attrition erode coasts?
pebbles are rolled back and forth, they collide with each other which makes them smaller and rounder, eventually turning into sand
62
sediment?
material carried by the sea
63
longshore drift?
process by which sediment is moved along the coastline
64
process of longshore drift?
swash - pushed up the beach at the same angle as the wind
backwash - moves straight down the beach due to the pull of gravity
65
what is a headland and how is it formed?
a headland is an area of land that juts into the sea and is formed due to harder, more resistant rock being eroded more slowly
66
how is a bay formed?
a bay is formed between the headlands due to softer, less resistant rock which erodes more quickly, beaches often form in sheltered bays
67
bay?
a recessed area of coastline often found between two headlands
68
wave cut platform?
a coastal landform made of a rocky shelf in front of a cliff
69
wave cut notch?
a slot with overhanging rocks that has been cut into the bottom of a cliff by wave action
70
bedding plane?
clearly seen layers of rock in a cliff face
71
how are wave cut platforms made?
~as waves pound the base of the cliff, hydraulic action and abrasion cut a wave cut notch into the base of the cliff
~with continued erosion the wave cut notch will make the cliff unstable and collapse due to gravity
~material from the cliff will then be moved by the sea, and in doing so abrasion will smooth the surface of the wave cut platform left behind
72
how are arches and stacks formed?
~two caves on either sides of a headland erode by abrasion and hydraulic action backwards until they cut through the back wall, this creates an ARCH
~weathering erodes the roof of the arch and wave cut notches erode the base of the arch to make it wider
~eventually the roof will collapse to leave a rock pillar called a STACK
73
swash?
movement of water up the beach as a wave breaks
74
backwash?
flow of water back into the sea after a wave has broken on to the shore
75
beach?
created by deposition and lies between the high water mark and low water mark
76
spit?
sand or shingle beach that is joined to the land but projects outwards into the sea in the direction of the prevailing wind
77
offshore bar?
an area of deposition that is slightly off the coastline in the estuary of a river
78
how is a spit formed?
~longshore drift carries sediment along a coastline, swash brings material on shore, backwash removes material
~this continues in a zigzag movement along the coast
~if the coast changes direction, material will continue to be deposited in the original direction in a shallow sea
~the built up material is a SPIT
79
offshore bars?
ridges of sand or shingle running parallel to the coast in an offshore zone
80
how are offshore bars formed?
destructive waves erode sediment and backwash transport it off the coast and deposit the material
81
example of a sand dune?
Ynyslas sand dunes
82
rock pool?
a pool of seawater between shoreline rocks
83
how are sand dunes formed?
sand dunes are formed by wind blown sand, when wind moves across a flat, sandy surface it lifts and transports loose grains of sand, as the wind slows down, it drops the sand creating dunes
84
what happens at high and low tide to rocks pools?
high - covered by the sea
low - some seawater remains forming the rock pools
85
cavern?
large underground cave which has been created due to enlargement of joints in carboniferous limestone
86
sink hole?
a hole in the ground caused by a collapse of the surface layer, often found in carboniferous limestone areas where caverns are present
87
what factors affect the rates of landform change? 3
~geology
~climate
~human activity
88
how can geology affect the rate of landform change?
they type of rock being eroded and the way in which rock types are laid down
~hard rock takes much longer to erode then soft rock
89
concordant coastline?
rocks are formed parallel to the sea so that erosion rates along the coastline are even
90
discordant coastline?
rocks are formed at right angles to the sea and so erosion rates vary along the coastline
91
how does climate affect the rate of landform change? 3
coasts - prevailing wind affects the angle at which the waves break on to the coastline, therefore the direction of erosion and transportation
rivers - the more flowing water in a river the higher the erosion rates - in UK during winter months as most rainfall
extreme weather events - a powerful storm can change the coasts overnight as it causes destructive waves
92
fetch?
distance waves have travelled before breaking onshore
93
how does human activity affect the rate of landform change?
~intended human activity includes management strategies to reduce erosion impacts of both river and coastal landforms
94
how are meanders managed?
using gabions, cages filled with rock which absorb the power of water reducing erosion on the outside bend
95
groyne?
a low wall or barrier on a beach built at right angles to the sea to restrict longshore drift
