Chapter 5-8 Flashcards
(99 cards)
1
Q
How are igneous rocks formed?
A
When magma or lava cools down.
2
Q
How was sedimentary rock formed?
A
Sedimentary rock was formed when existing rocks, plant and animal life were worn down and compressed to form rocks. This mainly happens under water.
3
Q
How are metamorphic rocks formed?
A
When existing rocks are changed by great heat and/or pressure.
4
Q
What are some examples of sedimentary rock?
A
- sandstone
- limestone
5
Q
How is sandstone formed, what are its uses and where can you find it?
A
- Sandstone is formed when layers of sand are compressed and cemented into sandstone by pressure.
- sandstone is used in buildings and in road surfaces
- you can find sandstone in Macgillycuddy’s creek in Co. Kerry
6
Q
How is limestone formed, what are it’s uses and where can you find it?
A
- limestone is formed from the layers of shells and bones at the bottom of the sea. The weight of these layers compresses the shells and bones into limestone.
- limestone is used in buildings, roads and cement
- limestone covers about 40% of Ireland but you can also find it in the burren
7
Q
What are examples of metamorphic rocks?
A
- marble
- quartzite
8
Q
How was marble formed, what is it used for and where can you find it?
A
- Marble was formed when limestone was changed by great heat and pressure.
- used in sculptures, kitchen worktops and headstones
- Connemara marble
9
Q
What are the three rock groups?
A
- igneous
- sedimentary
- metamorphic
10
Q
How is quarzite formed, when is it used and where are examples of it?
A
- quarzite is formed when sandstone is changed by a great heat or pressure
- quarzite is used in glass-making and road surfaces
- sugarloaf mountain
11
Q
What are some examples of metamorphic rock?
A
- marble
- quarzite
- slate
12
Q
What is the extraction of rocks and minerals?
A
The way in which the rocks and minerals are mined or taken out of the earth
13
Q
Open-cast mining/quarrying
A
Used when the rocks and minerals are close to the surface, used for sand, gravel and limestone
14
Q
Shaft mining
A
Used to extract rocks and minerals that are deeper underground e.g coal
15
Q
Advantages of quarrying
A
- provides employment both in the extraction and the transport industry
- raw materials used in industry e.g sand and gravel in construction
- the local council gets money from the quarry companies
- local roads are improved for heavy traffic
16
Q
Disadvantages of quarrying
A
- noise pollution from heavy lorries and from blasting in the quarries
- parts of the countryside are destroyed
- loss of farmland
- old, abandoned quarries are quite dangerous when flooded
17
Q
What is denudation?
A
The wearing down of the surface of the earth, it is done by weathering and erosion
18
Q
What is weathering?
A
The breakdown of rock, usually by the forces of weather. The broken rock lies where is has been broken. There are 2 types; mechanical and chemical
19
Q
What is erosion?
A
The wearing away of rock, the transportation of that rock and its deposition. Erosion is carried out by rivers, the sea, glaciers and wind
20
Q
What is mechanical weathering?
A
Mechanical weathering occurs when rocks are broken apart by physical force applied by frost and plants etc.
21
Q
Where does freeze-thaw action occur?
A
In colder climates or high up in mountains, occurs when:
- temp rises above and falls below 0
- where there is precipitation
22
Q
What is scree?
A
Broken rock pieces that lay at the bottom of slopes after freeze-thaw action has occurred
23
Q
What is an example of mechanical weathering in a hot climate?
A
Exfoliation
24
Q
Where does exfoliation occur?
A
In hot climates where the different between the temperatures during the day and the night are high
25
How does exfoliation work?
The outer layer of rock is heated during the day and it expands, the rock then contracts during the cold nights. This continues day after day until eventually the outer layer of rock cracks away from the inner layers
26
What is chemical weathering?
Chemical weathering occurs when a chemical change in the rocks causes them to dissolve
27
What is carbonation?
Limestone is dissolved by carbon dioxide in rainwater
28
How does carbonation occur?
When rain falls it takes in carbon dioxide from the air, the carbon dioxide acts like a weak acid to open cracks and joints in the limestone by dissolving the limestone
29
Where can the effects of carbonation be seen?
The burren Co. Clare
30
What does it mea that limestone in permeable?
This means rainwater can pass through it
31
What is a karst landscape?
A landscape formed from the dissolution of soluble rocks, it is characterised by underground features such as caves
32
What is a limestone pavement?
The bare surface of the limestone divided into blocks
33
What are clints?
The blocks of limestone that form the limestone pavement
34
What are grimes?
The gaps between the blocks. Joints in the rock are opened wider by the process of carbonation
35
What are swallow holes/sink holes?
Opening in the surface of the limestone through which the rivers disappear underground
36
What are the surface features of a karst landscape?
- limestone payments (clints+grikes)
| - swallow holes
37
What are the underground features of a karst landscape?
–stalactites
- stalagmites
- pillars/columns
38
What are stalactites?
Cone-shaped deposits of minerals that hand down from the ceiling of a limestone cave
39
How are stalactites formed?
They are formed when water drops containing dissolved limestone (calcite) form on the roof of the cave When the water evaporates, it leaves behind calcite. Over time these deposits develop into stalactites
40
What are stalagmites?
Cone-shaped deposits of minerals that are built up from the floor of a limestone cave
41
What are pillars/columns?
A feature formed when stalactites and stalagmites join together
42
What is a case study for a conflict between different interest groups?
The Mullaghmore Visitor centre
43
What was the Mullaghmore Visitor Centre conflict?
In the 1990's there was a proposal to build a visitor centre, along with a restaurant and carpark in the middle of the burren, but after the idea was met with strong opposition the centre was eventually not built
44
What were the arguments for building the Mullaghmore visitor centre?
* there would be more jobs for local people in building the centre and as tour guides
* the centre would cause more money for the locals as the visitors would buy locally made produce
* the centre would make the Burren a more interesting place to visit and it would draw greater numbers of visitors than before
* there was no other industry in the locality to provide employment
* the site of the centre was a disused quarry, this centre would make good use of an abandoned site
45
Arguments against the building of the Mullaghmore centre
* tourists walking in the Burren would damage the rare flora (Mediterranean and Artic-Alpine plants)
* pollution from extra traffic would damage plant life and wider roads would destroy the unique landscape
* the limestone would be damaged by extra tourists walking over it
* historical sites such as the Poulnabrone Dolmen could also be damaged
* it would be better to build the centre in a local village where other services could benefit
46
What is mass movement?
The movement of loose earth materials (soil, stones,mud) called regolith down a slope under the influence of gravity
47
What factors influence mass movement?
* slope: the steeper the slope the more likely mass movement will occur
* water: rainfall will make the soil heavier and easier to move downhill- it will act as a lubricant
* lack of vegetation: the roots and plants hold the soil, so when they are cleared away, mass movement is more likely
* people: work carried out by people, such as digging and drilling will disturb the ground and cause mass movement
48
What is soil creep?
The very slow movement of soil down a slope
49
What is evidence of soil creep?
* fences and trees bend downhill
* terracettes are formed
* walls collapse because of pressure building up behind them from soil moving downhill
50
What is regolith?
Loose earth materials such as rock, soil and mud
51
What are landslides?
The rapid movement of loose rock and soil down a slope
52
What are the causes of landslides?
* undercutting
* coastal erosion
* earthquakes
* heavy rainfall
53
What is a bog burst?
The fast movement of bog down a slope. The bog may be loosened by heavy rainfall or by work on mountaintop wind turbines when vegetation is removed
E.g the derrybrien bog burst
54
What is a lahar?
A mudflow caused by volcanic activity
55
What I an example of a lahar?
Nevado deal Ruiz's volcano erupted in 1985and hot ash and rocks melted the snow and ice. Floods of water picked up soil and rock from the valley floors to form a lahar.
•it destroyed the tower of Armero and killed 23000 people
56
What is the watershed?
The line diving the river basin of one river from the water basin of another river
57
What's the source?
Where the river begins
58
What are tributaries?
Smaller rivers that join a larger river
59
What is the confluence?
The place where a tributary joins the main river
60
What is the river basin?
The area drained by the river and its tributaries
61
What is the estuary?
The tidal mouth of a river
62
What is a delta?
Land that forms at the mouth of rivers
63
What are distributaries?
Small rivers that break off from the main river as it enters the sea
64
What is the course of a river?
The path of the river from its source to its mouth
65
What is the rivers load?
The material transported by the river
66
What is hydraulic action?
This is erosion carried out by the force of the flowing water in the river
67
What is abrasion?
The process of the river using its load to erode the bed and banks of the river
68
What is attrition?
The rivers load is worn down when the pieces collide so that the stones are smoothed and made smaller
69
What is solution?
Soluble rocks are dissolved in the river
70
What are the 4 ways a river can erode?
* hydraulic action
* abrasion
* attrition
* solution
71
What is the work of the river?
* erosion
* transportation
* depositio
72
What are the 4 ways a river transports its load?
* solution
* suspension
* saltation
* traction
73
How does a river transport its load by solution?
Rock minerals are dissolved in the water and carried away
74
How does a river transport its load by suspension?
Light material, such as silt, is transported in the water
75
How does a river transport its load by saltation?
Small stones are bounced along the bed of the river
76
How does a river transport its load by traction?
Larger rocks are rolled along the riverbed
77
When does a river deposit its load?
When a river slows down it loses its energy so it deposits some of its material or load.
-happens when a river enters a lake, or on a flat plain or when the river enters the sea
78
What are the 3 stages of a river?
* youthful stage
* mature stage
* old-age stage
79
What is vertical erosion/down cutting?
The water wears away the bed of the river, common is the youthful stage of a river
80
What is a a v-shaped valley and what causes it?
A v-shaped alley has steep sides and a narrow valley floor
- forms when the river wears down the valley floor (vertical erosion) while weathering wears back the slopes of the valley
- gravity causes regolith on the valley sides to move down
81
What are interlocking Spurs and how are they created?
Interlocking Spurs form when the sides of the valley jut into eachother, they are created when the youthful river avoids the harder rock on the sides of the river and flows around it
82
What are features of a youthful river?
- V-shaped valley with interlocking Spurs
| - waterfalls
83
How are waterfalls formed?
1. A band of hard rock lies next to softer rock
2. The river erodes the softer rock faster than the hard rock, creating the waterfall
3. A plunge pool develops at the base of the waterfall. The river undercuts the harder rock,creating an overhang
4. The rock overhead collapses
5. The waterfall retreats up stream
E.g Powerscourt Waterfall
84
What are landforms of a mature stage?
–floodplain
| -meanders
85
What is a floodplain?
A flat area along the river course that is flooded by the river, as the river floods, it lays down alluvium on the valley floor
86
What is alluvium?
A mixture of clay, silt, gravel and other material
87
What are meanders?
Meanders are bends in the river in its mature and old-age stages
88
How are meanders formed?
1. Water flows faster on the outer bend, the river erodes the bank of the river here by undercutting the bank and causing it to collapse
2. The water flows slower on the inner bend. The river deposits some of its load here
89
What are landforms of the old-age stage?
- ox-bow lakes
- levees
- delta
90
What is an ox-bow lake?
A curved body of water formed when a meander in a river is cut off, leaving the river to straighten its course
E.g River Moy, Co. Mayo
91
How is an of-bow lake formed?
1. The river forms a meander
2. The river keeps eroding on the outer bend and depositing on the inner bend as the meander grows more prominent
3. During a flood, the river breaks through to straighten its course
4. The meander is cut off from the river to form an ox-bow lake
92
What is a levee?
A raised bank of earth running along the sides of a river
93
How is a levee formed?
1. The river floods the floodplain
2. The river deposits silt on the floodplain as it slows down
3.
94
How does a delta form?
The river slows down as it enters the sea and it deposits its load. The delta forms when the sea currents are not strong enough to remove the silt
95
What are the causes of flooding?
* heavy rainfall
* poorly constructed bridges, weirs and failure to dredge the riverbed can all force the extra water out onto the land
* house construction on floodplain a
96
Effects of flooding
* death: 400 killed in Mississippi floods in 2011
* loss of farmland
* homes and businesses are destroyed by flooding e.g Yangtze floods
* river traffic transporting crops, goods and people is disrupted
* food prices increase because crops are destroyed by floods
* taxpayers have to fund much of the repairs
97
What is a dam?
A barrier built to hold back the flow of the river. Can produce electricity and can act as reservoirs to store water
98
Advantages of dams?
* hydroelectricity is produced for homes and industry (renewables energy)
* water is stored for houses and industry as lake behind the dam can act as a reservoir
* water can be used for irrigating farmland especially in drier climates
* dams are used for flood control, water is temporarily stored and released when water levels subside
* lakes behind the dams can be used for recreation
99
What are the disadvantages of dams?
* good farmland is flooded when the lake behind the dam is being created
* people in the valley are moved elsewhere e.g millions were displaced when the Three Georges Dam on the Yangtze River was built
* a danger is posed to those who live downstream of the dam in case it overflows
