UK Physical Evolving Landscape Flashcards
1
Q
Geology
A
Concerned with the solid Earth, rocks of which is composed, and the process by which they change over time
2
Q
Characteristics of sedimentary
A
- Layers
- Fossils
- Variety of colour
3
Q
Characteristics of igneous
A
- NO fossils
- Formed by molten rock
- Crystals
4
Q
Characteristics of metamorphic
A
- High heat and pressure
- May have crystals
Made by other rocks
5
Q
Formation of sedimentary
A
Deposited material that have been compacted over time
6
Q
Formation of igneous
A
- Made from magma underground or above
- Cools slowly or quickly
- Intrusive or extrusive
7
Q
Formation of metaomorphic
A
High heat and pressure
8
Q
What is mechanical weathering (freeze-thaw weathering)?
A
- Water enters the cracks in the rocks during day
- When temp drops below 0 water in crack freezes and expands by 10%
- Makes cracks larger, eventually pieces of rock break off
9
Q
Chemical weathering
A
Rainwater is slighly acidic - wears away rock
10
Q
Biological weathering
A
Plants/animals wear away rocks eg roots growing in cracks
11
Q
2 types of erosion
A
Abrasion and plucking
12
Q
Abrasion (erosion)
A
As glacier moves downhill, it begins to scrape the rock underneath like sandpaper, leaving striations (scratches)
13
Q
Plucking
A
Rocks become frozen into bottom and sides of glacier, as glacier moves, it plucks frozen rocks
14
Q
3 things that can happen after a glacier
A
Melt, erratics, drumlins
15
Q
Melt (after glacier)
A
Glacier melts = flood = ribbon lakes and misfit streams
16
Q
Erratics
A
Large rocks depositied by the glacier, can be carried from an area of diff geology, far away
17
Q
Drumlins
A
Mounds of deposited glacial moraine that are visible when glacier melts.
They have a steep and sloping side
18
Q
Tees-Exe line
A
Divides highland and lowland, highland areas are above line
19
Q
Relief
A
Way landscape changes in height
20
Q
4 types of erosion
A
Hydraulic action
Attritioon
Solution
Abrasion
21
Q
Hydraulic action
A
Water forced into cracks, pressure leads to erosion
22
Q
Attrition
A
Rocks bash into one another and soften each other - caused by longshore drift
23
Q
Abrasion
A
Sand and pebbles thrown with force
24
Q
Solution
A
Chemicals lead to break down of rocks
25
Discordant coastline
Soft rock easilt eroded, hard rock erodes slowly, layers are perpendicular to sea
26
Features of discordant coastline
Headlands (hard) and bays (soft)
27
Cove
Hard rock is eroded after many yrs and reaches soft rock which is eroded
28
Concordant coastline
Erosion through hard, then soft, then hard - parallel to coastline
29
Mass movement
downhill movement of sediment because of gravity eg rockfall, landsclide, mud slide, slumping
30
Formation of a stump
1. Faults in headlands
2. abrasion and hydraulic action erode to make a cave
3. cave is widened and deepened
4. sea cuts through to form an arch
5. sea arodes food of the arch and widens it
6. roof of arch collapses due to heavy
7. part of former cliff is isolated as a stack
8. stack eroded, might be undercut and collapse
9. stump is remains of eroded stack
31
order of a stump formation
* crack
* cave
* arch
* stack
* stump
32
Wave cut platform formation
1. Erosion at base of cliff
2. Sea weakens bottom of cliff = wave cut notch
3. notch gets larger, top becomes heavy
4. top falls due to gravity therefore a retreat
5. Process repeats forming new wave cut notches
6. gently sloping land at the base of the retreating cliff = wave cut platform
7. over time, as cliff erodes, it becomes wider
33
Waterfall formation
1. soft rock eroded quicker than hard by hydraulic action and abrasion = creates a step
2. erosion continues, hard rock undercut forming an overhang
3. abrastion and hydraulic action erode to create a plunge pool
4. gets bigger, increasing size of overhand until hard rock is no longer supporting - collapses
5. oricess continues and waterfall retreats upstream
6. steep sided valley is left where waterfall once was - called a gorge
34
How are V shaped valleys formed?
1. downward erosion by river
2. soil saturaed with rain water, soft rock cut through
3. likely to slide into river - mass movement
4. overtime v shaped made
35
How are U shaped valleys formed
* glaciers
* melts, glacier widens and deepnds valley due to abrasion and steep sides from freeze thaw
36
interlocking spurs
* as river erodes the landscape in the upper course, it winds and bends to avoid areas of hard rock
* because rivers lack the power to erode laterally so have enough to wind around
37
meander
large bends in the river in middle and lower courses
38
tributary
smaller river meets big river and meet at a confluence
39
where is the river basin
mountain upland
40
watershed
area of high land forming edge of a river basin
41
source
where river starts
42
mouth
river meets sea
43
confluence
where 2 rivers meet
44
channel
where river flows
45
drainage basin
area of land drained by a river and its tributaris
46
Soil creep
* gravity
* happens with cold soil
* slow
* small scale
47
slumping
* heavy rain
* on steeper valleyes
* larg scale + area
48
saltations
bounce smaller pebbles along with the waves
49
traction
roll boulders on sea bed (large)
50
suspension
light material carried by the movement of the water
51
solution
minerals dissolved in water, colour change
52
Coastal management
1. sea wall
2. groynes
3. rip rap
4. marsh creation
5. beach noursihment
6. dune regeneration
53
Sea wall
* walls stop erosion
* expensive
* ugly
* long time made
54
groynes
* slow down longshore drift
* traps sand/shingle
* may cause erosion down drift
* wood not long lasting
* Absorbs huge amounts of wave energy
55
riprap
* easy to build
* looks natural
* more expensive
56
marsh creation
* soft
* hooded coastal areas by the sea become salt marshes
* creates wildlife and habitats
* land will be lost
57
beach nourishment
* soft
* move sand from sea to beach so it cant erode land
* not expensive
* erosion not stopped
* regulary have to move sand
58
dune regeneration
* soft
* absorb impact from sea
* cheap
* damaged in storms
* marram grass planting time consuming
59
4 coastal management strategies
* nothing
* hold the line - build defences
* managed realignment - allowing shore line to move naturally but slower
* adcance the line, new defenses built extending the coastline into the sea
60
spit formation
1. long shore drift drops sediment at the distal end of a cliff
2. spit stops water moving, still drops sand, starts to form land
3. a diff prevailing wind comes and causes a curve calls a hook which is the end of a spit
61
Bar formation
1. Beach, sea and an old bay
2. longshort drift causes sediment to be desosited across the gap between the beach and the bay
62
beach reprofiling
* changing the shape of the beach so that it absorbs more wave energy
* create a gently sloping profile
63
Advantages of the do nothing approach to coastal erosion
can invest more money into important areas where it should be proected for settlements and tourism
good for the environment
cheapest option
64
physical vs chemical weathering
physical = just breaks down into smaller bits
chemical = breaks down into the components it was made out of
65
name types of physical/mechanical weathing
freeze-thaw and salt crytallisation
66
what is salt crystallisation
* crack in rock
* salt water enters crack
* when sea water evaporates, salt is left
* over time crystalls build up and cause rock to crack
67
carbonation
* rain water = naturally acidic and reacts with chemicals in rock
68
oxidation
* iron is susceptibale to this
69
hydration
* rocks with a high clay content
* absorb water
* makes them swell
* then break up into separate elements
70
hydrolysis
* Hydrogen in rock reacts with water
* causing minerals to chemically break down
71
4 types of chemical weathering processes
* oxidation
* hydrolysis
* hydration
* carbonation
72
What angle does longshore drift leave the beach at?
90 defrees
73
key words related to longshore drift
* prevailing wind
* fetch
* swash
* backwash
* 90
* zig zag movement
* deposition of sediment
74
4 ways in which matieral is carried (based on size)
* Traction
* suspension
* saltation
* solution
75
Define a beach
An accumulation of eroded material transported and depositied by sea
76
Why do waves lose energy during longshore drift?
* very shallow sea
* they reach a sheltered area of coast
77
What wave builds beaches? Why?
constructive - swash stronger than backwash
78
4 sources of matieral that makes up a beach
* parts of cliff face
* detritus and sediment from rivers
* sea bed
* longshore drift
79
Where are the largest particles found on the beach and why?
At the back - carried by largest and strongest waves
80
What is a spit?
long narrow depositional coastal feature - end joiend to the land, one goes out to sea
81
3 preconditions to spit formation
* sea must be relatively shallow
* coastaline must change direction
* longshore drift must be moving material
82
What is a tombolo?
special type of bar that forms by longshore drift
* a spit that connects an island to the mainaland
83
What increases risk of river flooding
* impermeable structures
* houses built on floodplains - vegetation removed - no natural absorption
84
Flood walls - rivers
* hard engineering solution
* vertical hard walls build at either side of the river
* provides more space to store water
* concrete walls
85
Flood barriers
* larger scale solution
* go fully across channel
* cuz they protect against tidal surge
86
What are embankments/levees
* hard engineering
* increase holding capacity
* natural + man made
* triangular shape
* can burst
* made out of loose sediment - fragile
87
Why are meanders good for coping against floods?
* has more capacity than a straight channel
* slow down water - more time for water evaporation and absorption or seep down in river beds
88
interception
when water falls on objects like houses or trees
89
infiltration
water enters soil
90
percolationn
water moves through soil and into the underlying rock
91
3 functions of a river
* erode particles from bed and banks
* transport them
* deposit
92
load
material carried by river
93
What is abstraction?
process of taking water from rivers for human use
94
3 courses of a river
* upper stage - at the start/source - mountains
* middle
* lower - widest, close to sea
95
What can only be found in the upper course of a river
* interlocking spurs
* waterfalls
* gorges
96
When do waterfalls form?
river flows over an area of hard rock which sits above an area of soft rock
97
How is an oxbow lake formed?
1. erosion causes outside bends to get closer
2. until there is only a small bit of land left between bends
3. river breaks through this lland - mostly during a flood
4. river flows along shortest course
5. depostion eventually cuts of the meander
6. oxbow lake
98
Floodplain
* formed by erosion and deposition
* flat
* fertile soil
* prone to flooding
99
laterally
sideways
100
esturary
meeting point between river and sea - flat/fertile
101
delta
depositional feature made from material dropped by river (lost energy)
102
physical causes of flooding
* geology
* impermeable rock = surface run off
* rock type determined soil type
* weather prior storm - sunny = soild dry so infiltration will happen
* shape of river basin - rounder - water arrives at some time, narrow - takes more time to reach river channel
* type of precipiation - snow/misty rain
103
river basin
area surrounding river that all water runs into
104
Human causes of flooding
* deforestation - no interceptors
* urbanisation - impermeable
105
hydrograph
how a river responds to a rainfall event
x axis = time
y axis = precipitation + run off
106
parts of a hydrograph
* rising limb
* peak discharge
* recession limb
107
long and shallow gradeint for recession limb
long time to return to normal
108
what is the lag time on a hydrograph
diff between peak discharge and peak rainfall
109
shorter lag time
quicker it reaches and fills channel so increases likelihood of flooding
110
length of lag time factors
* rock type - permeability
* relief - steep shortens lag time
* vegetation - lengthens lag time
111
what is a course (river)
path of a river as it flows downhill
112
What does the long profile of a river show you?
how the gradient changes
113
What does the shape of the valley depend on?
on whether erosion or deposition is the dominant process
114
Upper course features
* steep gradient
* V shaped valley
* steep sides
* narrow and shallow channels
115
middle course features
* medium gradient
* gently sloping
* wide and deep channel
116
lower course features
* gentle gradient
* wide and deep channel
* almost flat
117
2 types of erosion
* vertical
* laternal
* they can happen at the same time but 1 is more dominant
118
vertical erosion
* upper course
* makes it V shaped - channel deepends
119
Lateral erosion
* widens channel
* lower course
* erodes horizontallly
120
How is a meander formed?
1. Current is faster on outer bends because river channel is deeper
2. this is why more erosion on outside of the bend - forming river cliffs
3. current is slower on the inside of the bend - as its shallower
4. so eroded material is deposited on the inside of the bend forming slip off slopes
